Statement of Financial Position [Abstract] Total interest income Investment Income, Interest Total interest expense Interest Expense Net interest income Investment Income, Net Net realized gain (loss) on investments Realized Investment Gains (Losses) Net unrealized gain (loss) on investments Unrealized Gain (Loss) on Securities Net unrealized gain (loss) on FHLBC Advances UnrealizedGainLossonLong-TermFHLBCAdvances UnrealizedGainLossonLong-TermFHLBCAdvances Other income Other Income Net realized and unrealized gain (loss) on investments, FHLBC Advances and other income Noninterest Income, Other Operating Income Before Gains (Losses) and Interest from Derivatives Noninterest Income, Other Operating Income Before Gains (Losses) and Interest from Derivatives Interest rate hedge expense, net Interest rate hedge expense, net Interest rate hedge expense, net. Net realized and unrealized gain (loss) on derivative instruments Net Realized and Unrealized Gain (Loss) on Derivatives Net Realized and Unrealized Gain (Loss) on Derivatives Net gain (loss) on derivative instruments Net Gain (Loss) from Derivatives Net Gain (Loss) from Derivatives Total other income (loss) Noninterest Income (Expense) Noninterest Income (Expense) Total other income (loss) Gain (Loss) on Investments Total expenses Costs and Expenses Net income (loss) Net Income (Loss) Attributable to Parent Dividends on preferred stock Dividends, Preferred Stock Net income (loss) available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Net income (loss) per common share basic & diluted Earnings Per Share, Basic and Diluted Transfers and Servicing [Abstract] Schedule of Investments [Table] Schedule of Investments [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Repurchase Agreements [Member] Repurchase Agreements [Member] Derivative [Member] Derivative [Member] Forward Settling Trades [Member] Forward Settling Trades [Member] Forward Settling Trades [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Agency RMBS Residential Mortgage Backed Securities [Member] U.S. Treasuries US Treasury Securities [Member] Accrued Interest on Pledged Securities [Member] Accrued Interest on Pledged Securities [Member] Accrued Interest on Pledged Securities [Member] Cash [Member] Cash [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Pledged Assets Separately Reported, Pledged as Collateral to Counterparties, at Fair Value Pledged Assets Separately Reported, Pledged as Collateral to Counterparties, at Fair Value Pledged Assets Separately Reported, Pledged as Collateral to Counterparties, at Fair Value Pledged Assets Separately Reported, Pledged as Collateral from Counterparties, at Fair Value Pledged Assets Separately Reported, Pledged as Collateral from Counterparties, at Fair Value Pledged Assets Separately Reported, Pledged as Collateral from Counterparties, at Fair Value Assets_repledged_to_counterparties Assets_repledged_to_counterparties Assets_repledged_to_counterparties Derivative [Table] Derivative [Table] Residential Mortgage Backed Securities and US Treasury Securities Residential Mortgage Backed Securities and US Treasury Securities [Member] Residential Mortgage Backed Securities and US Treasury Securities [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Interest Rate Cap [Member] Interest Rate Cap [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Derivative [Line Items] Derivative [Line Items] Haircuts on Securities, Percent Haircuts on Securities, Percent Haircuts on Securities, Percent Interest Rate Swap and Cap Agreement Counterparty, Excluding Centrally Cleared Swaps, Amount at Risk, Percent of Stockholders' Equity (less than) Interest Rate Swap and Cap Agreement Counterparty, Excluding Centrally Cleared Swaps, Amount at Risk, Percent of Stockholders' Equity Interest Rate Swap and Cap Agreement Counterparty, Excluding Centrally Cleared Swaps, Amount at Risk, Percent of Stockholders' Equity Repurchase Agreement Counterparty, Amount at Risk, Percent of Stockholders' Equity Repurchase Agreement Counterparty, Amount at Risk, Percent of Stockholders' Equity Repurchase Agreement Counterparty, Amount at Risk, Percent of Stockholders' Equity Collateral pledged to company Collateral pledged to counterparties Derivative, Fair Value, Net [Abstract] Fair Value, Less than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Unrealized loss, Less than 12 Months Unrealized loss on investments, owned less than 12 months Unrealized loss on investments, owned less than 12 months Fair value, Greater than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Unrealized loss, Greater than 12 months Unrealized loss on investments, owned more than 12 months Unrealized loss on investments, owned more than 12 months Fair value, Total Fair value of investments in unrealized loss position Fair value of investments in unrealized loss position Unrealized loss, Total Available for sale securities, continuous unrealized loss Available for sale securities, continuous unrealized loss Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series A Preferred Stock Series A Preferred Stock [Member] Series B Preferred Stock Series B Preferred Stock [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance Stockholders' Equity Attributable to Parent Net income (loss) Issuance of common stock Stock Issued During Period, Value, New Issues Amortization of share-based compensation Stock Issued During Period, Value, Share-based Compensation, Gross Return of capital distributions Partners' Capital Account, Return of Capital Repurchase and cancellation of common stock Stock Repurchased During Period, Value Common dividends Dividends, Common Stock, Cash Ending Balance Pledged Assets Pledged Assets [Text Block] Pledged Assets [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Earnings Per Share [Abstract] Earnings Per Share [Text Block] Earnings Per Share [Text Block] Assets Pledged to Counterparties Assets Pledged to Counterparties [Table Text Block] Assets Pledged to Counterparties [Table Text Block] Assets Pledged from Counterparties Assets Pledged from Counterparties [Table Text Block] Assets Pledged from Counterparties [Table Text Block] Schedule of Derivative Instruments Schedule of Derivative Instruments [Table Text Block] DerivativeAssetSubjectToMasterNettingArrangement DerivativeAssetSubjectToMasterNettingArrangement DerivativeAssetSubjectToMasterNettingArrangement InstrumentsAvailableToOffsetDerivativeLiability InstrumentsAvailableToOffsetDerivativeLiability InstrumentsAvailableToOffsetDerivativeLiability Fair Value of Securities Received as Collateral that Have Been Resold or Repledged Fair Value of Securities Received as Collateral that Have Been Resold or Repledged Derivative Asset, Fair Value, Amount Offset Against Collateral Derivative Asset, Fair Value, Amount Offset Against Collateral Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Interest rate hedge expense, net Gain (Loss) on Sale of Derivatives Gain (Loss) on Sale of Derivatives Net gain (loss) on derivative instruments Income_on_derivatives Income_on_derivatives Investments, Debt and Equity Securities [Abstract] Fair Value Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity [Abstract] Less than one year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Greater than one year through five years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Greater than five years through ten years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Greater than ten years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value Total Available-for-sale Securities, Debt Maturities, Single Maturity Date Amortized Cost Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Rolling Maturity [Abstract] Less than one year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis Greater than one year through five years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Greater than five years through ten years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis Greater than ten years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis Total Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis TBA Derivatives [Member] TBA Derivatives [Member] TBA Derivatives [Member] Interest Rate Swaps and Caps [Member] Interest Rate Contract [Member] Weighted Average [Member] Weighted Average [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Notional amount Derivative, Notional Amount Trading Securities Pledged as Collateral Trading Securities Pledged as Collateral Derivative, Collateral, Obligation to Return Cash Derivative, Collateral, Obligation to Return Cash Securities Received as Collateral Securities Received as Collateral SwapandCapNotional SwapandCapNotional SwapandCapNotional SwapandCapNotionalasPercentageofRepoBorrowings SwapandCapNotionalasPercentageofRepoBorrowings SwapandCapNotionalasPercentageofRepoBorrowings Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Derivative Assets [Member] Derivative Assets [Member] Derivative Assets [Member] Derivative Liabilities [Member] Derivative Liabilities [Member] Derivative Liabilities [Member] Position [Axis] Position [Axis] Position [Domain] Position [Domain] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative, Notional Amount Derivative Asset, Notional Amount Derivative Asset, Notional Amount Derivative Asset, Fair Value, Gross Asset Derivative Asset, Fair Value, Gross Asset Derivative Liability, Notional Amount Derivative Liability, Notional Amount Derivative Liability, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Liability Stockholders' Equity Note [Abstract] Schedule of Capitalization, Equity [Table] Schedule of Capitalization, Equity [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] July 2014 Repurchase Plan [Member] July 2014 Repurchase Plan [Member] July 2014 Repurchase Plan [Member] Equity Placement Program [Member] Equity Placement Program [Member] Equity Placement Program [Member] Dividend Reinvestment And Direct Stock Purchase Plan [Member] Dividend Reinvestment And Direct Stock Purchase Plan [Member] Dividend Reinvestment And Direct Stock Purchase Plan [Member] Schedule of Capitalization, Equity [Line Items] Schedule of Capitalization, Equity [Line Items] Common stock, shares authorized Common Stock, Shares Authorized Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares issued Common Stock, Shares, Issued Series A Cumulative Redeemable Preferred Stock, shares authorized Preferred Stock, Shares Authorized Series A Cumulative Redeemable Preferred Stock, par value Preferred Stock, Par or Stated Value Per Share Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Series A Cumulative Redeemable Preferred Stock, dividend rate Preferred Stock, Dividend Rate, Percentage Series A Cumulative Redeemable Preferred Stock, liquidation preference per share Preferred Stock, Liquidation Preference Per Share Series B Cumulative Redeemable Preferred Stock, Value Issued us-gaap_PreferredStockValue_SeriesB us-gaap_PreferredStockValue_SeriesB Series B Cumulative Redeemable Preferred Stock, shares issued us-gaap_PreferredStockSharesIssued_SeriesB us-gaap_PreferredStockSharesIssued_SeriesB Preferred Stock B, Dividend Rate, Percentage us-gaap_PreferredStockDividendRatePercentage_SeriesB us-gaap_PreferredStockDividendRatePercentage_SeriesB Shares issued under DSPP (in shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan Value of shares issued under DSPP Stock Issued During Period, Value, Dividend Reinvestment Plan Shares available for issuance during period shares dividend reinvestment plan Stock Available For Issuance During Period Shares Dividend Reinvestment Plan Stock available for issuance during period shares dividend reinvestment plan Number Of Common Stock Available To Sell Under Sales Agreement Number Of Common Stock Available To Sell Under Sales Agreement Number of common stock available to sell under sales agreement Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Shares Treasury Stock Acquired, Average Cost Per Share Treasury Stock Acquired, Average Cost Per Share Proceeds from (Repurchase of) Equity Proceeds from (Repurchase of) Equity Remaining authorized share repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Schedule of Interest Rate Derivatives Schedule of Interest Rate Derivatives [Table Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Federal Tax Cost and the Tax Basis Components [Abstract] Federal Tax Cost and the Tax Basis Components [Abstract] Summary of Operating Loss Carryforwards [Table Text Block] Summary of Operating Loss Carryforwards [Table Text Block] Summary of Tax Credit Carryforwards [Table Text Block] Summary of Tax Credit Carryforwards [Table Text Block] Short-term Debt [Abstract] Repurchase Agreements and Short-Term FHLBC Advances Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block] Weighted average coupon on Agency RMBS Weighted average coupon on Agency RMBS Weighted average coupon on Agency RMBS Weighted average coupon interest rate on U.S. Treasuries weighted average coupon interest rate on U.S. Treasury Securities weighted average coupon interest rate on U.S. Treasury Securities Agency RMBS Maturity Years Agency RMBS Maturity Years Agency RMBS Maturity Years Agency RMBS Maturity Date Min Agency RMBS Maturity Date Min Agency RMBS Maturity Date Min Agency RMBS Maturity Date Max Agency RMBS Maturity Date Max Agency RMBS Maturity Date Max Agency RMBS Contractual Maturity Agency RMBS Contractual Maturity Agency RMBS Contractual Maturity U.S. Treasury Securities Maturity Date Max U.S. Treasury Securities Maturity Date Max U.S. Treasury Securities Maturity Date Max Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Amortization of share-based compensation Share-based Compensation Amortization of premiums and discounts on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Amortization of premiums on interest rate cap contracts and swaptions Amortization Net realized (gain) loss on investments Gain (Loss) on Investments, Excluding Other than Temporary Impairments Net unrealized (gain) loss on investments Unrealized Gain (Loss) on Investments Unrealized Gain (Loss) on Derivatives and Commodity Contracts Unrealized Gain (Loss) on Derivatives and Commodity Contracts Net unrealized (gain) loss on FHLBC Advances Change in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Other assets Increase (Decrease) in Other Operating Assets Accrued interest payable Increase (Decrease) in Interest Payable, Net Accrued expenses and other liabilities Increase (Decrease) in Other Accrued Liabilities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchase of available-for-sale investment securities Payments to Acquire Available-for-sale Securities Purchase of other investments Payments to Acquire Other Investments Premium paid on interest rate cap Premium paid on interest rate cap Premium paid on interest rate cap Proceeds from sale of available-for-sale investment securities Proceeds from Sale of Available-for-sale Securities Proceeds from sale of other investments Proceeds from Sale and Maturity of Other Investments Proceeds from termination of interest rate cap contracts Proceeds from Derivative Instrument, Financing Activities Proceeds from paydowns of available-for-sale investment securities Proceeds from Maturities, Repayments and Calls of Trading Securities Held-for-investment Change in assets and liabilities: Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Receivable for securities sold and principal repayments Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Receivable for cash pledged as collateral Increase (Decrease) in Cash Collateral for Borrowed Securities Payable for securities purchased Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Payable for cash received as collateral Increase (Decrease) Cash Collateral from Counterparties Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from repurchase agreements Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase Repayments of repurchase agreements Repayments of Other Short-term Debt Proceeds from FHLBC Advances Proceeds from Federal Home Loan Bank Advances Repayments of FHLBC Advances Payments for Federal Home Loan Bank Advances Net proceeds from issuance of common shares Proceeds from Issuance of Common Stock Net payments for repurchase of common shares Payments for Repurchase of Common Stock Dividends paid Payments of Dividends Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents - Beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents - End of period Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Interest paid (excluding interest paid on interest rate hedges) Interest Paid Net interest paid on interest rate hedges InterestPaidNetInterestRateDerivative InterestPaidNetInterestRateDerivative Income taxes paid Income Taxes Paid Supplemental disclosures of non-cash flow information: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Dividends declared, not paid Dividends Payable Risks and Uncertainties [Abstract] Concentration Risk Disclosure [Text Block] Concentration Risk Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] U.S. Treasuries US Treasury and Government [Member] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Up to 30 days Maturity Less than 30 Days [Member] 30-90 days Maturity 30 to 90 Days [Member] Greater than 90 days Maturity Greater than 90 Days [Member] Maturity Overnight [Member] Maturity Overnight [Member] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Collateral for repurchase agreements and short-term FHLBC advances Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Available-for-sale investments, at cost Available-for-sale Securities Purchased During Period, Amortized Cost Basis Available-for-sale Securities Purchased During Period, Amortized Cost Basis Proceeds from sale of available-for-sale investments Net realized gain (loss) on sale of available-for-sale investments Available-for-sale Securities, Gross Realized Gain (Loss) Gross gain on sale of available-for-sale investments Available-for-sale Securities, Gross Realized Gains Gross (loss) on sale of available-for-sale investments Available-for-sale Securities, Gross Realized Losses Schedule Of Company's Borrowings Schedule of Short-term Debt [Table Text Block] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block] Income Tax Disclosure [Abstract] Other Tax Carryforward [Table] Tax Credit Carryforward [Table] Tax Period [Axis] Tax Period [Axis] Tax Period [Domain] Tax Period [Domain] Tax Year 2018 [Member] Tax Year 2018 [Member] Tax Year 2018 [Member] Tax Year 2021 [Member] Tax Year 2021 [Member] Tax Year 2021 [Member] cys_TaxYear2022Member [Domain] cys_TaxYear2022Member [Domain] cys_TaxYear2022Member [Domain] Other Tax Carryforward [Line Items] Tax Credit Carryforward [Line Items] Operating loss carryforwards Operating Loss Carryforwards Percentage of REIT taxable income that must be distributed to stockholders Percentage Of Reit Taxable Income That Must Be Distributed To Stockholders Percentage Of REIT Taxable Income That Must Be Distributed To Stockholders. Dividends declared per common share Common Stock, Dividends, Per Share, Declared Preferred stock, dividends declared (in dollars per share) Preferred Stock, Dividends Per Share, Declared Distribution to common shareholders as ordinary income (in dollars per share) Real Estate Investment Trust, Distribution to Common Shareholders as Ordinary Income Real Estate Investment Trust, Distribution to Common Shareholders as Ordinary Income Distribution to shareholders as return of capital (in dollars per share) Real Estate Investment Trust, Distribution to Shareholders as Return of Capital Real Estate Investment Trust, Distribution to Shareholders as Return of Capital Cost of investments Tax Basis of Investments, Cost for Income Tax Purposes Gross appreciation Tax Basis of Investments, Gross, Unrealized Appreciation Gross depreciation Tax Basis of Investments, Gross, Unrealized Depreciation Net unrealized appreciation (depreciation) Tax Basis of Investments, Unrealized Appreciation (Depreciation), Net Undistributed ordinary income Undistributed Taxable Income Undistributed Taxable Income Non-recurring charge related to prior period tax liability Tax Adjustments, Settlements, and Unusual Provisions Transaction Type [Axis] Transaction Type [Axis] Transaction [Domain] Transaction [Domain] January Two Thousand Sixteen Terminated [Member] January Two Thousand Sixteen Terminated [Member] January Two Thousand Sixteen Terminated [Member] Short [Member] Short [Member] Long [Member] Long [Member] Transaction And Trade Date [Axis] Transaction And Trade Date [Axis] Transaction And Trade Date [Axis] Transaction And Trade Date [Domain] Transaction And Trade Date [Domain] Transaction And Trade Date [Domain] Interest Rate Swap and Cap, April 2017 [Member] Interest Rate Swap and Cap, April 2017 [Member] Interest Rate Swap and Cap, April 2017 [Member] Interest Rate Swap and Cap, May 2016 [Member] Interest Rate Swap and Cap, May 2016 [Member] Interest Rate Swap and Cap, May 2016 [Member] Interest Rate Swap and Cap, January 2016 [Member] Interest Rate Swap and Cap, January 2016 [Member] Interest Rate Swap and Cap, January 2016 [Member] Interest Rate Swap and Cap, May 2017 [Member] Interest Rate Swap and Cap, May 2017 [Member] Interest Rate Swap and Cap, May 2017 [Member] InterestRateSwapandCapsSeptember2016 [Member] InterestRateSwapandCapsSeptember2016 [Member] InterestRateSwapandCapsSeptember2016 [Member] Interest Rate Swap and Cap, June 2017 [Member] Interest Rate Swap and Cap, June 2017 [Member] Interest Rate Swap and Cap, June 2017 [Member] Interest Rate Swap and Cap, August 2017 [Member] Interest Rate Swap and Cap, August 2017 [Member] Interest Rate Swap and Cap, August 2017 [Member] Interest Rate Swap and Cap, September 2017 [Member] Interest Rate Swap and Cap, September 2017 [Member] Interest Rate Swap and Cap, September 2017 [Member] cys_InterestRateSwapandCapNovember2017 [Domain] cys_InterestRateSwapandCapNovember2017 [Domain] cys_InterestRateSwapandCapNovember2017 [Domain] cys_InterestRateSwapandCapDecember2017 [Domain] cys_InterestRateSwapandCapDecember2017 [Domain] cys_InterestRateSwapandCapDecember2017 [Domain] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Residential Mortgage Backed Securities and US Treasury Securities [Member] Investments in Interest Rate Swap and CAP Contracts Derivatives and Fair Value [Text Block] Repurchase Agreement Counterparty and FHLBC Advances, Amount at Risk, Percent of Stockholders' Equity Repurchase Agreement Counterparty and FHLBC Advances, Amount at Risk, Percent of Stockholders' Equity Repurchase Agreement Counterparty and FHLBC Advances, Amount at Risk, Percent of Stockholders' Equity Repurchase agreements Securities Sold under Agreements to Repurchase Interest accrued thereon Accrued Interest Payable Including Accrued Interest On Repurchase Agreement Accrued interest payable including accrued interest on repurchase agreement. Weighted average borrowing rate Short-term Debt, Weighted Average Interest Rate Weighted average remaining maturity (in days) Weighted Average Remaining Maturity (In Days) Weighted average remaining maturity (in days) Fair value of the collateral Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure FHLBC Advances, at fair value Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months Long-term FHLBC advances Long-term Federal Home Loan Bank Advances FHLBC stock Federal Home Loan Bank Stock Schedule of Quarterly Financial Information Quarterly Financial Information [Table Text Block] Unvested Share Based Compesation Employees Unvested Share Based Compesation Employees Unvested Share Based Compesation Employees Unvested Share Based Compensation Directors Unvested Share Based Compensation Directors Unvested Share Based Compensation Directors Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number StockIssuedDuringPeriodSharesShareBasedCompensationGrossEmployee StockIssuedDuringPeriodSharesShareBasedCompensationGrossEmployee StockIssuedDuringPeriodSharesShareBasedCompensationGrossEmployee StockIssuedDuringPeriodSharesShareBasedCompensationGrossDirector StockIssuedDuringPeriodSharesShareBasedCompensationGrossDirector StockIssuedDuringPeriodSharesShareBasedCompensationGrossDirector Stock Issued During Period, Shares, Share-based Compensation, Gross Stock Issued During Period, Shares, Share-based Compensation, Gross SharesPaidForTaxWithholdingForShareBasedCompensationEmployee SharesPaidForTaxWithholdingForShareBasedCompensationEmployee SharesPaidForTaxWithholdingForShareBasedCompensationEmployee SharesPaidForTaxWithholdingForShareBasedCompensationDirector SharesPaidForTaxWithholdingForShareBasedCompensationDirector SharesPaidForTaxWithholdingForShareBasedCompensationDirector Shares Paid for Tax Withholding for Share Based Compensation Shares Paid for Tax Withholding for Share Based Compensation ShareBasedCompensationAwardVestedEmployee ShareBasedCompensationAwardVestedEmployee ShareBasedCompensationAwardVestedEmployee ShareBasedCompensationAwardVestedDirector ShareBasedCompensationAwardVestedDirector ShareBasedCompensationAwardVestedDirector Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Quarterly Financial Information [Text Block] Quarterly Financial Information [Text Block] Assets: Assets [Abstract] Receivable for cash pledged as collateral Agency RMBS (including pledged assets of $9,287,317 and $10,233,165, respectively) Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value U.S. Treasury securities (including pledged assets of $1,046,934 and $44,469, respectively) Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value Receivable for securities sold and principal repayments Receivables from Brokers-Dealers and Clearing Organizations Receivable for cash pledged as collateral Derivative, Collateral, Right to Reclaim Cash Interest receivable Interest Receivable Derivative assets, at fair value Derivative Asset Other investments Other Investments Other assets Other Assets Total assets Assets Liabilities and stockholders' equity: Liabilities and Equity [Abstract] Liabilities: Liabilities [Abstract] FHLBC Advances, at fair value Payable for cash received as collateral Payables to Broker-Dealers and Clearing Organizations Accrued interest payable Payble for cash received as collateral Payble for cash received as collateral Dividends payable Interest Payable Derivative liabilities, at fair value Other Accounts Payable and Accrued Liabilities Accrued expenses and other liabilities Payable for securities purchased Interest Rate Derivative Liabilities, at Fair Value Total liabilities Liabilities Commitments and contingencies (Note 12) Commitments and Contingencies Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] 7.75% Series A Cumulative Redeemable Preferred Stock, (3,000 shares issued and outstanding, respectively, $75,000 in aggregate liquidation preference) Preferred Stock, Value, Issued 7.50% Series B Cumulative Redeemable Preferred Stock, (8,000 shares issued and outstanding, respectively, $200,000 in aggregate liquidation preference) Common Stock, $0.01 par value, 500,000 shares authorized (155,010 and 151,435 shares issued and outstanding, respectively) Common Stock, Value, Issued Additional paid in capital Additional Paid in Capital Retained earnings (accumulated deficit) Retained Earnings (Accumulated Deficit) Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Weighted average exercise price for stock options Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Net income (loss) available to common stockholders Common shares Dividends, Common Stock Unvested shares Dividends, Share-based Compensation Undistributed earnings (loss) Undistributed Earnings, Basic Common shares Weighted Average Number of Shares Outstanding, Basic Distributed earnings, basic Earnings Per Share, Basic, Distributed Undistributed earnings Earnings Per Share, Basic, Undistributed Basic earnings (loss) per common share Earnings Per Share, Basic Net effect of dilutive warrants (1) Weighted Average Number Diluted Shares Outstanding Adjustment Diluted weighted average shares outstanding Weighted Average Number of Shares Outstanding, Diluted Distributed earnings Earnings Per Share, Diluted, Distributed Undistributed earnings Earnings Per Share, Diluted, Undistributed Diluted earnings per common share Earnings Per Share, Diluted Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Series A Cumulative Redeemable Preferred Stock, liquidation preference per share Series B Cumulative Redeemable Preferred Stock, liquidation preference per share us-gaap_PreferredStockLiquidationPreference_SeriesB us-gaap_PreferredStockLiquidationPreference_SeriesB Income Statement [Abstract] Interest income: Investment Income, Net [Abstract] Agency RMBS Interest Income, Securities, Mortgage Backed Other Interest and Other Income Total interest income Interest expense: Interest Expense [Abstract] Repurchase agreements Interest Expense, Securities Sold under Agreements to Repurchase FHLBC Advances Interest Expense, Federal Home Loan Bank and Federal Reserve Bank Advances, Long-term Total interest expense Net interest income Interest Income (Expense), Net Other income (loss): Noninterest Income [Abstract] Expenses: Interest Rate Derivatives [Abstract] Compensation and benefits Labor and Related Expense General, administrative and other General and Administrative Expense Total expenses Net income (loss) Net income (loss) per common share basic & diluted Schedule Of Computation Of Basic And Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Accounting Policies [Abstract] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Net investment in real estate Real Estate Investments, Net Principal balance Investment Owned, Balance, Principal Amount Debt Instrument, Unamortized Premium Debt Instrument, Unamortized Premium Unamortized discount Available-for-sale, Unamortized Discount Available-for-sale, Unamortized Discount Gross unrealized gains Available-for-sale Securities, Continuous Unrealized Gain Position, Fair Value Available-for-sale Securities, Continuous Unrealized Gain Position, Fair Value Gross unrealized losses Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Fair value Available-for-sale Securities Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Fannie Mae Certificates Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Freddie Mac Certificates Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Ginnie Mae Certificates Government National Mortgage Association Certificates and Obligations (GNMA) [Member] Total Agency RMBS Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Total Investments [Member] Fixed Rate Fixed Rate Residential Mortgage [Member] ARMs Adjustable Rate Residential Mortgage [Member] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Loss Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Gross Unrealized Gain Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Fair Value Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value ShareBasedCompensationOfficersandEmployees ShareBasedCompensationOfficersandEmployees ShareBasedCompensationOfficersandEmployees ShareBasedCompensationDirectors ShareBasedCompensationDirectors ShareBasedCompensationDirectors Restricted Stock or Unit Expense Restricted Stock or Unit Expense Basis Of Presentation Basis Of Presentation [Policy Text Block] Basis of presentation [Policy Text Block] Reclassification and Presentation Reclassification, Policy [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Investments in Securities Investment, Policy [Policy Text Block] Interest Income Revenue Recognition, Interest [Policy Text Block] Other Investments Cost Method Investments, Policy [Policy Text Block] Repurchase Agreements Repurchase Agreements, Collateral, Policy [Policy Text Block] Derivative Instruments Derivatives, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Leases Lease, Policy [Policy Text Block] Stock-based compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Earnings Per Share (EPS) Earnings Per Share, Policy [Policy Text Block] Recent Accounting Pronouncements Description of New Accounting Pronouncements Not yet Adopted [Text Block] Collateral [Axis] Collateral [Axis] Collateral [Domain] Collateral [Domain] Preferred Stock, Shares Authorized Investments in agency mortgage-backed securities, pledged assets Pledged Assets Separately Reported, Securities Pledged as Collateral, at Fair Value Series A Cumulative Redeemable Preferred Stock, shares issued Preferred Stock, Shares Issued Series A Cumulative Redeemable Preferred Stock, shares outstanding Series A Cumulative Redeemable Preferred Stock, aggregate liquidation value Preferred Stock, Liquidation Preference, Value Series A Cumulative Redeemable Preferred Stock, dividend rate Preferred Stock, Dividend Rate, Percent_Series B Preferred Stock, Dividend Rate, Percent_Series B Series B Cumulative Redeemable Preferred Stock, shares issued Series B Cumulative Redeemable Preferred Stock, shares outstanding us-gaap_PreferredStockSharesOutstanding_SeriesB us-gaap_PreferredStockSharesOutstanding_SeriesB Series B Cumulative Redeemable Preferred Stock, aggregate liquidation value Auction Market Preferred Securities, Stock Series, Liquidation Value Common stock, par value Common stock, shares outstanding Common Stock, Shares, Outstanding Schedule of Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits, by Title of Individual and by Type of Deferred Compensation [Table] Schedule of Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits, by Title of Individual and by Type of Deferred Compensation [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Restricted Stock Restricted Stock [Member] Deferred Bonus and Profit Sharing Plan by Title of Individual [Axis] Title of Individual [Axis] Title of Individual with Relationship to Entity [Domain] Relationship to Entity [Domain] Non-employee Directors [Member] Non-employee Directors [Member] Non-employee Directors [Member] Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period IncentiveCompensation IncentiveCompensation IncentiveCompensation Salaries, Wages and Officers' Compensation Salaries, Wages and Officers' Compensation Stock Issued During Period, Value, Restricted Stock Award, Gross Stock Issued During Period, Value, Restricted Stock Award, Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross3YearVest StockIssuedDuringPeriodValueRestrictedStockAwardGross3YearVest StockIssuedDuringPeriodValueRestrictedStockAwardGross3YearVest StockIssuedDuringPeriodValueRestrictedStockAwardGross5YearVest StockIssuedDuringPeriodValueRestrictedStockAwardGross5YearVest StockIssuedDuringPeriodValueRestrictedStockAwardGross5YearVest ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod3Year ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod3Year ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod3Year ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod5Year ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod5Year ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod5Year Residential Mortgage Backed Securities [Member] Derivative liabilities Derivative Liability Derivative Asset, Not Subject to Master Netting Arrangement Derivative Asset, Not Subject to Master Netting Arrangement DerivativeAssetSubjectToMasterNettingArrangement cys_DerivativeLiabilitySubjectToMasterNettingArrangement cys_DerivativeLiabilitySubjectToMasterNettingArrangement cys_DerivativeLiabilitySubjectToMasterNettingArrangement Derivative Liability, Not Subject to Master Netting Arrangement Derivative Liability, Not Subject to Master Netting Arrangement DerivativeLiabilitySubjectToMasterNettingArrangement cys_DerivativeLiabilitySubjectToMasterNettingArrangement RepurchaseagreementsandFederalHomeLoanBankAdvances RepurchaseagreementsandFederalHomeLoanBankAdvances RepurchaseagreementsandFederalHomeLoanBankAdvances Securities Sold under Agreements to Repurchase and FHLBC Advances, Not Offset, Policy Election Deduction Securities Sold under Agreements to Repurchase and FHLBC Advances, Not Offset, Policy Election Deduction Securities Sold under Agreements to Repurchase and FHLBC Advances, Not Offset, Policy Election Deduction Securities Sold under Agreements to Repurchase and FHLBC Advances, Right to Reclaim Securities and Cash Securities Sold under Agreements to Repurchase and FHLBC Advances, Right to Reclaim Securities and Cash Securities Sold under Agreements to Repurchase and FHLBC Advances, Right to Reclaim Securities and Cash Securities Sold under Agreements to Repurchase and FHLBC Advances, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Securities Sold under Agreements to Repurchase and FHLBC Advances, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Securities Sold under Agreements to Repurchase and FHLBC Advances, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Derivative Liability, Fair Value of Collateral Derivative Liability, Fair Value of Collateral Derivative Liability, Fair Value, Amount Offset Against Collateral Derivative Liability, Fair Value, Amount Offset Against Collateral Common Stock Transactions Schedule of Stockholders Equity [Table Text Block] Available-for-sale Securities Available-for-sale Securities [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Operating Leases, Rent Expense Operating Leases, Rent Expense 2017 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2018 Operating Leases, Future Minimum Payments, Due in Two Years 2019 Operating Leases, Future Minimum Payments, Due in Three Years 2020 Operating Leases, Future Minimum Payments, Due in Four Years 2021 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Operating Leases, Future Minimum Payments Due Operating Leases, Future Minimum Payments Due Lessee Leasing Arrangements, Operating Leases, Term of Contract Lessee Leasing Arrangements, Operating Leases, Term of Contract Indemnification claims Indemnification Claims Indemnification claims Investments In Securities Fair Value, Measurement Inputs, Disclosure [Text Block] Dividend Reinvestment and Direct Stock Purchase Plan [Table] Dividend Reinvestment and Direct Stock Purchase Plan [Table] Dividend Reinvestment and Direct Stock Purchase Plan [Table] Dividend Reinvestment and Direct Stock Purchase Plan [Line Items] Dividend Reinvestment and Direct Stock Purchase Plan [Line Items] [Line Items] for Dividend Reinvestment and Direct Stock Purchase Plan [Table] Direct Share Purchase Program Price per Share Direct Share Purchase Program Price per Share Direct Share Purchase Program Price per Share Shares Issued Equity Placement Program Shares Issued Equity Placement Program Shares Issued Equity Placement Program Equity Placement Program Price per Share Equity Placement Program Price per Share Equity Placement Program Price per Share Stock Available For Issuance During Period Shares Dividend Reinvestment Plan Proceeds from Stock Plans Proceeds from Stock Plans cys_NumberOfCommonStockAvailableToSellUnderSalesAgreement cys_NumberOfCommonStockAvailableToSellUnderSalesAgreement cys Number Of Common Stock Available To Sell Under Sales Agreement Stock Issued During Period, Value, Dividend Reinvestment Plan Stock Issued During Period, Shares, Dividend Reinvestment Plan Shares sold in public offerings or issued as restricted stock, Shares Stock Issued During Period, Shares, New Issues Shares Repurchased or Canceled (Shares) SharesCanceledShares SharesCanceledShares Stock Issued During Period, Shares, Period Increase (Decrease) Stock Issued During Period, Shares, Period Increase (Decrease) Shares sold in public offerings or issued as restricted stock, Amount Stock Issued During Period, Value, Other Shares Repurchased or Canceled (Value) SharesCanceledValue SharesCanceledValue Increase in net assets from capital transactions Increase (Decrease) in paid in capital from share transactions Increase (decrease) in paid in capital from share transactions Common stock, dividends declared (in dollars per share) Share-based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Significant Accounting Policies Significant Accounting Policies [Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Agency RMBS Mortgage-backed Securities Available-for-sale, Fair Value Disclosure U.S. Treasuries US Treasury fair value disclosure US Treasury fair value disclosure Other investments Other Assets, Fair Value Disclosure Total Assets, Fair Value Disclosure, Recurring FHLBC Advances Federal Home Loan Bank Borrowings, Fair Value Disclosure Liabilities, Fair Value Disclosure, Recurring Liabilities, Fair Value Disclosure, Recurring Document And Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Public Float Entity Public Float Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Other Investments Other Investments [Member] Real Estate Investments, Net Beginning balance Level 3 assets Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Cash payments recorded as a reduction of cost basis Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Change in net unrealized gain (loss) Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Gross purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances Gross sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Net gain (loss) on sales Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings Transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Ending balance Level 3 assets Unobservable input capitalization rate min unobservable input capitalization rate min unobservable input capitalization rate min