0001465885 2018-01-01 2018-12-31 0001465885 2018-06-30 0001465885 2019-03-05 0001465885 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember 2018-12-31 0001465885 wmc:NonAgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 wmc:OtherSecuritiesMember 2017-12-31 0001465885 wmc:NonAgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 srt:AffiliatedEntityMember 2017-12-31 0001465885 srt:AffiliatedEntityMember 2018-12-31 0001465885 srt:AffiliatedEntityMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 srt:AffiliatedEntityMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 2017-01-01 2017-12-31 0001465885 2016-01-01 2016-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2016-01-01 2016-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2016-12-31 0001465885 us-gaap:CommonStockMember 2015-12-31 0001465885 us-gaap:TreasuryStockMember 2018-12-31 0001465885 us-gaap:CommonStockMember 2018-01-01 2018-12-31 0001465885 us-gaap:TreasuryStockMember 2017-12-31 0001465885 us-gaap:RetainedEarningsMember 2017-01-01 2017-12-31 0001465885 us-gaap:TreasuryStockMember 2017-01-01 2017-12-31 0001465885 us-gaap:RetainedEarningsMember 2015-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2017-01-01 2017-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2018-01-01 2018-12-31 0001465885 us-gaap:CommonStockMember 2018-12-31 0001465885 2015-12-31 0001465885 us-gaap:RetainedEarningsMember 2017-12-31 0001465885 us-gaap:CommonStockMember 2016-12-31 0001465885 us-gaap:CommonStockMember 2017-01-01 2017-12-31 0001465885 us-gaap:TreasuryStockMember 2018-01-01 2018-12-31 0001465885 us-gaap:RetainedEarningsMember 2018-01-01 2018-12-31 0001465885 us-gaap:CommonStockMember 2017-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2015-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2017-12-31 0001465885 us-gaap:RetainedEarningsMember 2016-01-01 2016-12-31 0001465885 us-gaap:RetainedEarningsMember 2016-12-31 0001465885 2016-12-31 0001465885 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0001465885 us-gaap:RetainedEarningsMember 2018-12-31 0001465885 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember 2017-12-31 0001465885 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:NonAgencyMortgageBackedSecuritiesMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:OtherSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:AgencyMortgageBackedSecuritiesMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:AgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:OtherSecuritiesMember 2018-01-01 2018-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedDebtMember us-gaap:FairValueMeasurementsRecurringMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:NonAgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedDebtMember 2018-01-01 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:OtherSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedDebtMember us-gaap:FairValueMeasurementsRecurringMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialLoanMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedDebtMember us-gaap:FairValueMeasurementsRecurringMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:AgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:NonAgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel1Member 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:MortgageBackedSecuritiesHaving20YearsMaturityPeriodMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:NonAgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:SecuritizedCommercialLoanMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:MortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:MortgageBackedSecuritiesHaving40YearsMaturityPeriodMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedCommercialLoanMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:MortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:MortgageBackedSecuritiesHaving40YearsMaturityPeriodMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:MortgageBackedSecuritiesHaving20YearsMaturityPeriodMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:NonAgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:MortgageBackedSecuritiesHaving30YearsMaturityPeriodMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:OtherSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:OtherSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member us-gaap:MortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:MortgageBackedSecuritiesHaving30YearsMaturityPeriodMember 2017-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember wmc:MeasurementInputBasisSpreadMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember wmc:MeasurementInputBasisSpreadMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:CommercialLoanMember wmc:MeasurementInputBasisSpreadMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputExpectedTermMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:WeightedAverageMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:ResidentialPortfolioSegmentMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 srt:MinimumMember us-gaap:FairValueInputsLevel3Member wmc:ResidentialBridgeLoansMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:NonAgencyMortgageBackedSecuritiesMember 2017-01-01 2017-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:DerivativeFinancialInstrumentsLiabilitiesMember us-gaap:FairValueMeasurementsRecurringMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:AgencyMortgageBackedSecuritiesMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:OtherSecuritiesMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedDebtMember us-gaap:FairValueMeasurementsRecurringMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:DerivativeFinancialInstrumentsLiabilitiesMember us-gaap:FairValueMeasurementsRecurringMember 2017-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:OtherSecuritiesMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:SecuritizedCommercialLoanMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:AgencyMortgageBackedSecuritiesMember 2017-01-01 2017-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:NonAgencyMortgageBackedSecuritiesMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:OtherSecuritiesMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedDebtMember us-gaap:FairValueMeasurementsRecurringMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:DerivativeFinancialInstrumentsLiabilitiesMember us-gaap:FairValueMeasurementsRecurringMember 2017-01-01 2017-12-31 0001465885 us-gaap:AssetsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:NonAgencyMortgageBackedSecuritiesMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialPortfolioSegmentMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:ResidentialBridgeLoansMember 2016-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember wmc:AgencyMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:NonAgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyMortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:CommercialLoanMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:OtherSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel1Member 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:OtherSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:AgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:NonAgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel3Member wmc:NonAgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 us-gaap:FairValueInputsLevel2Member wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:OtherSecuritiesMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:OtherSecuritiesMember 2016-01-01 2016-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2016-01-01 2016-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2016-01-01 2016-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2016-01-01 2016-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0001465885 wmc:OtherSecuritiesMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2016-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2015-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesAndCommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2016-01-01 2016-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2018-01-01 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember 2018-01-01 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember 2017-01-01 2017-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity10To20YearsMember 2018-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2016-01-01 2016-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember 2016-01-01 2016-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:AgencyCommercialMortgageBackedSecuritiesInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity20To30YearsMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 wmc:AgencyMortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturityOver30YearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:AgencyRMBSInterestOnlyStripsMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember wmc:InvestmentsContractualMaturityLessThanOrEqualToTenYearsMember 2017-12-31 0001465885 us-gaap:MortgageBackedSecuritiesMember wmc:InvestmentsContractualMaturity10To20YearsMember 2017-12-31 0001465885 wmc:MortgageBackedSecuritiesHaving20YearsMaturityPeriodMember 2017-12-31 0001465885 wmc:SubtotalCommercialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 wmc:SubtotalNonAgencyResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-12-31 0001465885 wmc:AgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2016-01-01 2016-12-31 0001465885 wmc:NonAgencyRMBSInterestOnlyStripsAccountedForAsDerivativesMember wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:ResidualInterestsInAssetBackedSecuritiesAsOtherSecuritiesMember 2017-12-31 0001465885 wmc:AgencyInterestOnlyStripsAccountedForAsDerivativesMember wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-01-01 2017-12-31 0001465885 wmc:ResidualInterestsInAssetBackedSecuritiesAsOtherSecuritiesMember 2018-12-31 0001465885 wmc:SubtotalNonAgencyResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 wmc:SubtotalCommercialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:AgencyResidentialMortgageBackedSecuritiesMember 2017-12-31 0001465885 wmc:AgencyResidentialMortgageBackedSecuritiesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:SubtotalNonAgencyResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2017-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:SubtotalCommercialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2018-01-01 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFiveMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2018-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 stpr:MA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 stpr:MA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 stpr:MA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:GA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 stpr:MA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:GA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 stpr:GA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 stpr:GA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember us-gaap:ResidentialPortfolioSegmentMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateOneMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2017-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2017-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2017-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:TX wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 stpr:NJ wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 stpr:FL wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:TX wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-12-31 0001465885 stpr:NJ wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 stpr:NY wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 stpr:CA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 wmc:OtherStatesMember wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 stpr:WA wmc:FinancingReceivablesTotalMember us-gaap:GeographicConcentrationRiskMember wmc:ResidentialBridgeLoansMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoansAtFairValueMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoansAtAmortizedCostMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoansAtAmortizedCostMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoansAtFairValueMember 2017-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTenMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateNineMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTenMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoanCurrentCouponRateNineMember 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentWithNoFicoScoreMember 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialPortfolioSegmentWithNoFicoScoreMember 2017-12-31 0001465885 wmc:ConsolidatedResidentialWholeLoanTrustsMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 us-gaap:EstimateOfFairValueFairValueDisclosureMember wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-01-01 2018-12-31 0001465885 wmc:NonQualifyingAdjustableRateMortgageMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember wmc:RNRTrustMember 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember wmc:RCRTrustMember 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentWithNoFicoScoreMember 2018-01-01 2018-12-31 0001465885 wmc:ConsolidatedResidentialWholeLoanTrustsMember us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 wmc:InvestorFixedRateMortgageMember us-gaap:ResidentialPortfolioSegmentMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialPortfolioSegmentWithNoFicoScoreMember 2017-01-01 2017-12-31 0001465885 wmc:ConsolidatedBridgeLoanTrustMember wmc:ResidentialBridgeLoansMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-01-01 2018-12-31 0001465885 wmc:ConsolidatedBridgeLoanTrustMember us-gaap:ResidentialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-01-01 2018-12-31 0001465885 us-gaap:ResidentialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2017-12-31 0001465885 wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateTenMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateTenMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateNineMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateSevenMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateEightMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateNineMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialBridgeLoanCurrentCouponRateSixMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialBridgeLoanCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateThreeMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2017-01-01 2017-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFiveMember 2018-01-01 2018-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateTwoMember 2018-01-01 2018-12-31 0001465885 srt:MinimumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateOneMember 2017-01-01 2017-12-31 0001465885 srt:MaximumMember wmc:ResidentialPortfolioSegmentCurrentCouponRateFourMember 2017-01-01 2017-12-31 0001465885 wmc:SecuritizedCommercialLoanMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:SBCLoan3Member 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:CommercialMezzanineLoanMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-06-01 2018-06-30 0001465885 wmc:TrustCertificateMember wmc:SecuritizedCommercialLoanMember wmc:RETLTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-03-01 2018-03-31 0001465885 wmc:RSBCTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-03-01 2018-03-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-03-31 0001465885 wmc:RETLTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 wmc:CmscTrustMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember 2018-06-30 0001465885 wmc:CmscTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:CommercialMezzanineLoanMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-03-01 2018-03-31 0001465885 us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-03-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember wmc:LondonInterbankOfferedRateLIBORCapMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:CmscTrustMember 2015-11-01 2015-11-30 0001465885 wmc:SecuritizedCommercialLoanMember 2018-03-31 0001465885 wmc:CmscTrustMember 2018-12-31 0001465885 wmc:RETLTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-11-30 0001465885 wmc:SecuritizedCommercialLoanMember wmc:CmscTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-01-01 2018-12-31 0001465885 wmc:RETLTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember wmc:LondonInterbankOfferedRateLIBORFloorMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-07-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-09-30 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RSBCTrustMember 2018-09-30 0001465885 wmc:SecuritizedCommercialLoanMember wmc:RETLTrustMember 2018-03-01 2018-03-31 0001465885 wmc:RSBCTrustMember wmc:LondonInterbankOfferedRateLIBORFloorMember 2018-03-01 2018-03-31 0001465885 wmc:RSBCTrustMember 2017-12-31 0001465885 wmc:CommercialMezzanineLoanMember 2017-12-31 0001465885 wmc:RSBCTrustMember 2018-12-31 0001465885 wmc:RETLTrustMember 2017-12-31 0001465885 wmc:CmscTrustMember 2017-12-31 0001465885 wmc:CommercialMezzanineLoanMember 2018-12-31 0001465885 us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassHRRMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassCMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassGMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassDMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassBMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassXCPMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassFMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassEMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassGMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassAMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassFMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassAMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassEMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassXEXTMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassDMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassBMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassCMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassHRRMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassXEXTMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CommercialMortgagePassThroughCertificateClassXCPMember us-gaap:SecuredDebtMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:CreditSuisseSecuritiesUSALLCMember 2018-12-31 0001465885 wmc:RbcBarbadosTradingBankCorporationMember 2018-12-31 0001465885 wmc:CreditSuisseSecuritiesUSALLCMember 2018-01-01 2018-12-31 0001465885 wmc:RbcBarbadosTradingBankCorporationMember 2018-01-01 2018-12-31 0001465885 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:WholeLoansAndSecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:OtherSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 us-gaap:CommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:OtherSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:WholeLoansAndSecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:OtherSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 us-gaap:CommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:WholeLoansAndSecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:WholeLoansAndSecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:OtherSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 wmc:ResidentialBridgeLoansMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-01-01 2018-12-31 0001465885 wmc:ResidentialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-01-01 2017-12-31 0001465885 us-gaap:MaturityUpTo30DaysMember 2018-12-31 0001465885 us-gaap:MaturityUpTo30DaysMember 2017-12-31 0001465885 wmc:Maturity30To59DaysMember 2018-12-31 0001465885 wmc:Maturity60To89DaysMember 2018-12-31 0001465885 us-gaap:MaturityOvernightMember 2018-12-31 0001465885 wmc:Maturity60To89DaysMember 2017-12-31 0001465885 wmc:Maturity90To119DaysMember 2018-12-31 0001465885 us-gaap:MaturityOvernightMember 2017-12-31 0001465885 wmc:MaturityOver119DaysMember 2018-12-31 0001465885 wmc:Maturity30To59DaysMember 2017-12-31 0001465885 wmc:Maturity90To119DaysMember 2017-12-31 0001465885 wmc:MaturityOver119DaysMember 2017-12-31 0001465885 wmc:ThreePointSeventyFivePercentConvertibleSeniorUnsecuredNotesMember us-gaap:ConvertibleDebtMember 2017-10-01 2017-10-31 0001465885 wmc:ThreePointSeventyFivePercentConvertibleSeniorUnsecuredNotesMember us-gaap:ConvertibleDebtMember 2017-10-31 0001465885 wmc:SecuritizedDebtMember wmc:SecuritizedCommercialLoanMember wmc:CmscTrustMember 2018-12-31 0001465885 wmc:SecuritizedCommercialLoanMember wmc:CmscTrustMember 2018-01-01 2018-12-31 0001465885 wmc:CmscTrustMember 2018-01-01 2018-09-30 0001465885 us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 srt:AffiliatedEntityMember wmc:RETLTrustMember 2018-12-31 0001465885 wmc:ThirdPartyMember wmc:RETLTrustMember 2018-12-31 0001465885 us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 us-gaap:CashMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 us-gaap:CashMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2018-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByUsGovernmentSponsoredEnterprisesMember us-gaap:VariableInterestEntityPrimaryBeneficiaryMember 2017-12-31 0001465885 wmc:CommercialMortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2018-12-31 0001465885 us-gaap:NondesignatedMember 2017-12-31 0001465885 us-gaap:CreditDefaultSwapMember us-gaap:NondesignatedMember 2017-12-31 0001465885 us-gaap:CreditDefaultSwapMember us-gaap:NondesignatedMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2018-12-31 0001465885 us-gaap:StockOptionMember us-gaap:NondesignatedMember 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2017-12-31 0001465885 us-gaap:NondesignatedMember 2018-12-31 0001465885 us-gaap:FutureMember us-gaap:NondesignatedMember 2018-12-31 0001465885 us-gaap:FutureMember us-gaap:NondesignatedMember 2017-12-31 0001465885 wmc:ToBeAnnouncedPurchaseContractsMember us-gaap:NondesignatedMember 2017-12-31 0001465885 us-gaap:OptionMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:CurrencySwapMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:ForeignExchangeForwardMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:OptionMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 us-gaap:ForeignExchangeForwardMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:FutureMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwaptionMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:TotalReturnSwapMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:FutureMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:FutureMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 us-gaap:CreditDefaultSwapMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwaptionMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:CreditDefaultSwapMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:OptionMember us-gaap:NondesignatedMember 2016-01-01 2016-12-31 0001465885 us-gaap:TotalReturnSwapMember us-gaap:NondesignatedMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:FixedIncomeInterestRateMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:OneYearOrLessMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:OneYearOrLessMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanOneYearAndLessThanThreeYearsMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:OneYearOrLessMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanThreeYearsAndLessThanFiveYearsMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanOneYearAndLessThanThreeYearsMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanThreeYearsAndLessThanFiveYearsMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanThreeYearsAndLessThanFiveYearsMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanOneYearAndLessThanThreeYearsMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanThreeYearsAndLessThanFiveYearsMember 2017-01-01 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:FixedIncomeInterestRateMember wmc:GreaterThanOneYearAndLessThanThreeYearsMember 2017-01-01 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:LongMember 2018-01-01 2018-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:ShortMember 2018-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:LongMember 2018-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:LongMember 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:ShortMember 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:ShortMember 2018-01-01 2018-12-31 0001465885 wmc:UsTreasuryFuturesMember us-gaap:LongMember 2018-12-31 0001465885 wmc:UsTreasuryFuturesMember us-gaap:ShortMember 2017-12-31 0001465885 us-gaap:StockOptionMember us-gaap:LongMember 2018-12-31 0001465885 us-gaap:StockOptionMember us-gaap:ShortMember 2018-12-31 0001465885 wmc:UsTreasuryFuturesMember us-gaap:LongMember 2017-12-31 0001465885 wmc:ForwardStartingInterestRateSwapMember 2017-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:VariableIncomeInterestRateMember 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:VariableIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:VariableIncomeInterestRateMember 2018-01-01 2018-12-31 0001465885 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember us-gaap:VariableIncomeInterestRateMember wmc:GreaterThanFiveYearsMember 2018-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:LongMember 2017-01-01 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:ShortMember 2017-01-01 2017-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:LongMember 2016-12-31 0001465885 wmc:ToBeAnnouncedSecuritiesMember us-gaap:NondesignatedMember us-gaap:ShortMember 2016-12-31 0001465885 wmc:ForwardStartingInterestRateSwapMember 2017-01-01 2017-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2018-12-31 0001465885 wmc:DerivativeInstrumentsExcludingInterestOnlyStripsAccountedForAsDerivativesAndLinkedTransactionsMember 2018-12-31 0001465885 wmc:AgencyAndNonAgencyInterestOnlyStripsAccountedForAsDerivativesMember 2017-12-31 0001465885 wmc:DerivativeInstrumentsExcludingInterestOnlyStripsAccountedForAsDerivativesAndLinkedTransactionsMember 2017-12-31 0001465885 wmc:WesternAssetManagementCompanyMember 2016-01-01 2016-12-31 0001465885 wmc:WesternAssetManagementCompanyMember 2018-01-01 2018-12-31 0001465885 wmc:WesternAssetManagementCompanyMember 2017-12-31 0001465885 wmc:WesternAssetManagementCompanyMember 2017-01-01 2017-12-31 0001465885 wmc:SecondaryOfferingMember 2018-09-01 2018-09-30 0001465885 wmc:WesternAssetManagementCompanyMember 2018-12-31 0001465885 srt:MinimumMember wmc:WesternAssetManagementCompanyMember 2018-01-01 2018-12-31 0001465885 us-gaap:RestrictedStockMember wmc:June2019Member 2017-12-31 0001465885 us-gaap:RestrictedStockMember wmc:March2018Member 2018-12-31 0001465885 us-gaap:RestrictedStockMember wmc:March2018Member 2017-12-31 0001465885 us-gaap:RestrictedStockMember 2017-12-31 0001465885 us-gaap:RestrictedStockMember wmc:June2018Member 2018-12-31 0001465885 us-gaap:RestrictedStockMember 2018-12-31 0001465885 us-gaap:RestrictedStockMember wmc:June2019Member 2018-12-31 0001465885 us-gaap:RestrictedStockMember wmc:June2018Member 2017-12-31 0001465885 us-gaap:RestrictedStockMember 2018-01-01 2018-12-31 0001465885 us-gaap:RestrictedStockMember 2016-12-31 0001465885 us-gaap:RestrictedStockMember 2017-01-01 2017-12-31 0001465885 us-gaap:RestrictedStockMember us-gaap:DirectorMember 2018-06-07 2018-06-07 0001465885 us-gaap:RestrictedStockMember us-gaap:DirectorMember 2017-06-01 2017-06-01 0001465885 us-gaap:RestrictedStockMember wmc:DirectorDeferredFeePlanMember 2018-01-01 2018-12-31 0001465885 us-gaap:RestrictedStockMember wmc:DirectorDeferredFeePlanMember 2017-01-01 2017-12-31 0001465885 wmc:EquityAwardsMember 2017-12-31 0001465885 wmc:LiabilityAwardsMember 2018-12-31 0001465885 us-gaap:RestrictedStockMember us-gaap:DirectorMember 2015-06-04 2015-06-04 0001465885 us-gaap:RestrictedStockMember 2012-05-15 2016-06-30 0001465885 us-gaap:RestrictedStockMember 2016-01-01 2016-12-31 0001465885 wmc:LiabilityAwardsMember 2017-12-31 0001465885 wmc:EquityAwardsMember 2018-12-31 0001465885 2017-09-21 2017-09-21 0001465885 2017-12-21 2017-12-21 0001465885 2018-03-22 2018-03-22 0001465885 2018-06-21 2018-06-21 0001465885 2016-09-22 2016-09-22 0001465885 2017-03-23 2017-03-23 0001465885 2017-06-30 2017-06-30 0001465885 2018-12-19 2018-12-19 0001465885 2016-03-24 2016-03-24 0001465885 2018-09-17 2018-09-17 0001465885 2016-06-23 2016-06-23 0001465885 2016-12-22 2016-12-22 0001465885 us-gaap:CommonStockMember 2018-01-01 2018-12-31 0001465885 us-gaap:InvestorMember 2012-05-09 0001465885 us-gaap:CommonStockMember 2017-04-30 0001465885 2012-05-09 0001465885 wmc:SecondaryOfferingMember 2018-01-01 2018-09-30 0001465885 wmc:SecondaryOfferingMember 2018-09-30 0001465885 2016-02-25 0001465885 us-gaap:CommonStockMember 2017-01-01 2017-12-31 0001465885 2018-10-26 2018-10-26 0001465885 2017-04-26 2017-04-26 0001465885 us-gaap:SubsequentEventMember 2019-01-25 2019-01-25 0001465885 2018-04-26 2018-04-26 0001465885 2017-07-26 2017-07-26 0001465885 2016-10-25 2016-10-25 0001465885 2017-01-26 2017-01-26 0001465885 2018-07-26 2018-07-26 0001465885 2017-10-26 2017-10-26 0001465885 2016-07-26 2016-07-26 0001465885 2018-01-26 2018-01-26 0001465885 2016-04-26 2016-04-26 0001465885 wmc:TaxableREITSubsidiaryMember us-gaap:StateAndLocalJurisdictionMember 2017-12-31 0001465885 wmc:OperatingLossCarryforwardsMember 2018-12-31 0001465885 us-gaap:TaxYear2015Member 2017-01-01 2017-12-31 0001465885 wmc:TaxableREITSubsidiaryMember us-gaap:StateAndLocalJurisdictionMember 2018-12-31 0001465885 wmc:TaxableREITSubsidiaryMember 2018-12-31 0001465885 us-gaap:DomesticCountryMember 2018-12-31 0001465885 us-gaap:StateAndLocalJurisdictionMember 2018-12-31 0001465885 wmc:OperatingLossCarryforwardsMember 2017-12-31 0001465885 2018-01-01 2018-03-31 0001465885 2018-07-01 2018-09-30 0001465885 2018-04-01 2018-06-30 0001465885 2018-10-01 2018-12-31 0001465885 2017-01-01 2017-03-31 0001465885 2017-07-01 2017-09-30 0001465885 2017-10-01 2017-12-31 0001465885 2017-04-01 2017-06-30 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:MortgageLoansAt25000000Member 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member wmc:ResidentialWholeLoanAndResidentialBridgeLoanMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount25000000Member wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanBalance45185500Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount20000000Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount30000000Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount5744800Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount115500000Member us-gaap:CommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount25000000Member wmc:SecuritizedCommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanBalance45185500Member us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount1350000000Member wmc:SecuritizedCommercialLoanMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount30000000Member us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount20000000Member us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount115500000Member us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount1350000000Member wmc:SecuritizedCommercialLoanMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount5744800Member us-gaap:CommercialLoanMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount20000000Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount30000000Member 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount1350000000Member 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 wmc:OriginalLoanAmount25000000Member 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MaximumMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount115500000Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount115500000Member 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount20000000Member 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount30000000Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount1350000000Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanBalance45185500Member 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MinimumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MinimumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansUnder250000Member srt:MaximumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MinimumMember 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween250000And499999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember srt:MortgageLoansBetween500000And749999Member srt:MaximumMember wmc:ResidentialBridgeLoansMember 2018-01-01 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount5744800Member 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanAmount5744800Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 wmc:OriginalLoanAmount25000000Member 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1000000And1249999Member srt:MinimumMember 2018-12-31 0001465885 us-gaap:AdjustableRateResidentialMortgageMember srt:MortgageLoansBetween750000And999999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 wmc:CommercialMezzanineLoanHeldInSecuritizationTrustMember wmc:OriginalLoanBalance45185500Member us-gaap:LondonInterbankOfferedRateLIBORMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MinimumMember 2018-01-01 2018-12-31 0001465885 wmc:VariableRateResidentialMortgageMember wmc:MortgageLoansBetween1250000And1499999Member srt:MaximumMember 2018-01-01 2018-12-31 0001465885 us-gaap:FixedRateResidentialMortgageMember wmc:MortgageLoansOver1500000Member srt:MinimumMember wmc:ResidentialBridgeLoansMember 2018-12-31 iso4217:USD xbrli:shares xbrli:shares iso4217:USD xbrli:pure wmc:score wmc:loan wmc:item wmc:entity wmc:director false --12-31 FY 2018 2018-12-31 10-K 0001465885 48116379 Yes false Accelerated Filer 417274538 Western Asset Mortgage Capital Corp false false No No 0 0 3252200000 1692200000 600000000 960000000 400000000 1500000000 125000000 0 480000000 3127800000 1423100000 200000000 1104700000 728400000 728400000 0 0 300400000 53714000 80550000 769748000 144321000 51080000 14199000 10061000 9114000 56631000 4703000 4660000 9244000 6645000 2899000 24581000 232270000 105868000 232270000 1520000 25001000 19728000 4016000 919000 10656000 25608000 18420000 42066000 63802000 105868000 2264000 55593000 48553000 125860000 56500000 2475278000 499999 250000 263675000 749999 500000 135510000 999999 750000 86322000 249999 0 66916000 1249999 1000000 28689000 1499999 1250000 7836000 1500000 41428000 1245781000 499999 499999 250000 250000 41359000 216989000 749999 749999 500000 500000 34361000 55582000 999999 750000 35760000 10829000 249999 249999 0 0 41658000 74360000 1249999 1249999 1000000 1000000 18045000 6193000 1499999 1499999 1250000 1250000 5420000 7684000 1500000 1500000 45652000 15487000 115500000 115500000 1350000000 988609000 20000000 20000000 24456000 30000000 30000000 5744800 5745000 45187500 45187000 216432000 1013065000 499999 250000 2163000 749999 500000 1086000 249999 0 941000 1249999 1000000 467000 1499999 1250000 1369000 25000000 686275000 119761000 19942000 12672000 26918000 21197000 10419000 175390000 21160000 14711000 93802000 43534000 1023524000 222257000 1023524000 3354000 53804000 86764000 2743000 8274000 10150000 88000 53911000 3169000 9766000 212491000 222257000 94000 14589000 22046000 496722000 490073000 93200000 0.1800 0.1000 0.0900 0.0600 0.1200 0.1100 0.0800 0.0700 0.0700 0.0400 0.0600 0.0500 0.1701 0.0901 0.0801 0.0501 0.1101 0.1001 0.0701 0.0601 0.0601 0.0301 0.0501 0.0401 0.045 0.180 0.097 0.089 0.059 0.114 0.108 0.076 0.067 0.086 0.063 0.039 0.052 0.045 0.065 0.045 0.060 0.045 0.060 0.045 0.060 0.045 0.059 0.040 0.058 0.048 0.059 0.048 0.072 0.180 0.038 0.063 0.061 0.130 0.039 0.063 0.180 0.073 0.084 0.180 0.038 0.000 0.063 0.100 0.050 0.073 0.063 0.108 0.056 0.090 0.100 0.100 0.080 0.075 0.0530 0.0950 0.0650 0.0450 0.0525 0.0425 0.063 0.040 0.061 0.055 0.058 0.054 0.065 0.065 0.057 0.054 0.0900 0.1800 0.1000 0.0900 0.1300 0.1200 0.1100 0.1400 0.0800 0.0700 0.0800 0.0700 0.0400 0.0600 0.0500 0.1701 0.0901 0.0801 0.1201 0.1101 0.1001 0.1301 0.0701 0.0601 0.0701 0.0601 0.0301 0.0501 0.0401 0.051 0.180 0.097 0.087 0.128 0.114 0.107 0.140 0.078 0.067 0.091 0.080 0.062 0.039 0.054 0.048 616 8 67 56 9 2 36 98 64 340 4 142 132 338 141 13 518 1 2769 765 236 105 394 26 6 21 122 623 57 97 43 12 256 460 18 6 4 6 20 8 881 1 1 1 1 1 1 1 13 1888 6 2 6 1 2 2782 11 143 180 11 28 43 1 95 8 520 1 37 66 1283 1395 274 579000 1800000 5127000 1362000 700000 803000 967000 1295000 5127000 0 0 1100000 3118000 188000 1000 189000 3858000 677000 31000 708000 99000 379000 548000 -21372000 7431000 -1701000 2977000 -5243000 -24836000 2070000 20000 -1043000 2219000 -1046000 -14000 -2191000 8276000 507000 1559000 525000 -13058000 -5374000 276000 -4045000 -1902000 -2000 170000 -513000 -898000 -2587000 -6816000 6366000 -646000 -6371000 -1073000 -5092000 768763000 833810000 2656000 2656000 1699000 1699000 981000 981000 265000 265000 373000 373000 10448000 8100000 8673000 1700000 981000 265000 191000 192000 767000 3886906000 354958000 25037000 379995000 4497395000 1348975000 1239175000 2588150000 728000 3323632000 362016000 3686376000 0 1740004000 2562861000 4302865000 6364000 24521000 13145000 1062000 5021000 12083000 382000 5012000 961000 1062000 12083000 1343000 2652000 33043000 30001000 407000 2645000 29594000 7000 390000 0 407000 29594000 7000 247144000 1813403000 1510975000 11480000 197925000 1499495000 11154000 55284000 38065000 11480000 17000000 1499495000 49219000 7175000 41708000 10000 22372000 878000 4571000 1702000 16913000 0 12161000 5473000 5449000 16923000 5473000 15309000 27395000 11899000 191000 2314000 15132000 9394000 16000 187000 161000 2505000 9394000 177000 386292000 3328334000 0 2831951000 14750000 669920000 292034000 2147281000 8738000 110091000 85520000 684670000 22900000 2147281000 94258000 13563000 13379000 184000