Receivables [Abstract] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Real Estate [Domain] Real Estate [Domain] Multi-family Multifamily [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial loans portfolio segment Commercial Portfolio Segment [Member] Residential mortgage portfolio segment Residential Portfolio Segment [Member] Industry Sector [Axis] Industry Sector [Axis] Industry Sector [Domain] Industry Sector [Domain] Commercial and industrial Commercial and Industrial Sector [Member] Real estate Real Estate Sector [Member] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Domain] Class of Financing Receivable, Type [Domain] Payroll finance Payroll Finance [Member] Payroll Finance [Member] Traditional C&I Commercial And Industrial [Member] A loan, whether secured or unsecured, to a company for purposes such as seasonal working capital needs, inventory financing, equipment purchases and acquisitions. Asset-based lending Asset-Based Lending [Member] Asset-Based Lending [Member] Equipment financing Equipment Financing Receivables [Member] A loan related to equipment finance receivable. Commercial real estate Commercial Real Estate [Member] ADC Acquisition, Development And Construction [Member] Acquisition Development And Construction [Member] Residential mortgage Residential Mortgage [Member] Consumer Consumer Loan [Member] Warehouse lending Warehouse Lending [Member] Warehouse lending [Member] Factored receivables Factored Receivables [Member] A loan related to factored receivables. Public sector finance Public Sector Finance [Member] Public Sector Finance [Member] Multi-family Real Estate Loan [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Number Financing Receivable, Modifications, Number of Contracts Recorded investment, Pre-modification Financing Receivable, Modifications, Pre-Modification Recorded Investment Recorded investment, Post-modification Financing Receivable, Modifications, Post-Modification Recorded Investment Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Originated Loan Originated Loan [Member] Originated Loan [Member] Acquired Loan Acquired Loan [Member] Acquired Loan [Member] Consumer portfolio segment Consumer Portfolio Segment [Member] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] 30-59 days past due Financing Receivables, 30 to 59 Days Past Due [Member] 60-89 days past due Financing Receivables, 60 to 89 Days Past Due [Member] 90 days past due Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Nonperforming loans Nonperforming Financial Instruments [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Non-Performing loans: Non Performing Loans [Abstract] Non performing loans. Current loans Financing Receivable, Recorded Investment, Current Past due loans Financing Receivable, Recorded Investment, Past Due Non accrual loans Financing Receivable, Recorded Investment, Nonaccrual Status Total portfolio loans Loans and Leases Receivable, Gross Current loans Trouble Debt restructuring current loans Trouble Debt restructuring current loans Past due TDRs Financing Receivable, Modifications, Recorded Investment Non-Accrual TDRs Non Accrual Loans Under Troubled debt restructurings Non accrual loans. Non-performing loans: Non Performing Assets [Abstract] Non performing assets: Loans 90 days past due and still accruing Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Total non-performing loans Non Performing Loans Total Total non performing loans. Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Woodforest National Bank Woodforest National Bank [Member] Woodforest National Bank [Member] Advantage Funding Advantage Funding Management Co., Inc. [Member] Advantage Funding Management Co., Inc. [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Consideration paid Payments to Acquire Businesses, Gross Outstanding loans and leases held by acquiree at acquisition date Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets Premium paid for loans receivable, percentage of gross loans Business Combination, Premium Paid For Loans Receivable, Percent Of Gross Loans Business Combination, Premium Paid For Loans Receivable, Percent Of Gross Loans Unpaid principal balance of loans acquired Loans And Leases Receivable, Unpaid Principal Balance Loans And Leases Receivable, Unpaid Principal Balance Restructuring and integration costs Business Combination, Integration Related Costs Percentage of interest acquired Business Acquisition, Percentage of Voting Interests Acquired Loan premium Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Loan Premium Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Loan Premium Investments, Debt and Equity Securities [Abstract] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Agency-backed Agency Securities [Member] CMOs/Other MBS Collateralized Mortgage Obligations [Member] Total residential MBS Residential Mortgage Backed Securities [Member] Federal agencies US Government Agencies Debt Securities [Member] Corporate Corporate Debt Securities [Member] State and municipal US States and Political Subdivisions Debt Securities [Member] Total other securities Securities Investment [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Fair value, less than 12 months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Unrealized losses, less than 12 months, accumulated loss Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Fair value, 12 months or longer Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Unrealized losses, 12 months or longer Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair value, total Debt Securities, Available-for-sale, Unrealized Loss Position Unrealized losses, total Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Other Income and Expenses [Abstract] Schedule of Other Non-interest Expense Other non- interest expense [Table Text Block] Other non- interest expense [Table Text Block] Stockholders' Equity Note [Abstract] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Sterling National Bank Subsidiaries [Member] Sterling Bancorp Parent Company [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Regulatory Capital Requirements [Abstract] Regulatory Capital Requirements [Abstract] Common equity tier 1 to RWA: Tier One Common Equity [Abstract] Tier One Common Equity [Abstract] Tier 1 common equity, actual, capital amount Common Equity Tier One Capital Tier 1 common equity, actual, ratio Common Equity Tier One Capital Ratio Tier 1 common equity required for minimum capital adequacy, phase-in schedule, capital amount Tier One Common Capital Required For Capital Adequacy, Phase-In Schedule Tier One Common Capital Required for Capital Adequacy, Phase-In Schedule Tier 1 common equity required for minimum capital adequacy, phase-in schedule, ratio Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Tier 1 common equity required for minimum capital adequacy, fully phased-in, capital amount Tier One Common Capital Required For Capital Adequacy, Fully Phased-In Tier One Common Capital Required For Capital Adequacy, Fully Phased-In Tier 1 common equity required for minimum capital adequacy, phase-in schedule, ratio Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Tier 1 common equity required to be well capitalized, capital amount Common Equity Tier One Capital Required to be Well-Capitalized Tier 1 common equity required to be well capitalized, ratio Tier One Common Capital Required To Be Well Capitalized To Risk Weighted Assets Tier One Common Capital Required To Be Well Capitalized To Risk Weighted Assets Tier 1 capital to RWA: Tier One Risk Based Capital [Abstract] Tier 1 risk-based capital, actual, capital amount Tier One Risk Based Capital Tier 1 risk-based capital, ratio Tier One Risk Based Capital to Risk Weighted Assets Tier 1 risk-based capital required for minimum capital adequacy, phase-in schedule, capital amount Tier One Risk Based Capital Required For Capital Adequacy, Phase-In Schedule Tier One Risk Based Capital Required For Capital Adequacy, Phase-In Schedule Tier 1 risk-based capital required for minimum capital adequacy, phase-in schedule, ratio Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, capital amount Tier One Risk Based Capital Required For Capital Adequacy, Fully Phased-In Tier One Risk Based Capital Required For Capital Adequacy, Fully Phased-In Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, ratio Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Tier 1 risk-based capital required to be well capitalized, capital amount Tier One Risk Based Capital Required to be Well Capitalized Tier 1 risk-based capital required to be well capitalized, ratio Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Total capital to RWA: Capital [Abstract] Total risk-based capital, actual, capital amount Capital Total risk-based capital, ratio Capital to Risk Weighted Assets Total risk-based capital required for minimum capital adequacy, phase-in schedule, capital amount Capital Required For Capital Adequacy, Phase-In Schedule Capital Required For Capital Adequacy, Phase-In Schedule Total risk-based capital required for minimum capital adequacy, phase-in schedule, ratio Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Capital Required For Capital Adequacy To Risk Weighted Assets, Phase-In Schedule Total risk-based capital required for minimum capital adequacy, fully phased-in, capital amount Capital Required For Capital Adequacy, Fully Phased-In Capital Required For Capital Adequacy, Fully Phased-In Total risk-based capital required for minimum capital adequacy, fully phased-in, ratio Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Capital Required For Capital Adequacy To Risk Weighted Assets, Fully Phased-In Total risk-based capital required to be well capitalized, capital amount Capital Required to be Well Capitalized Total risk-based capital required to be well capitalized, ratio Capital Required to be Well Capitalized to Risk Weighted Assets Tier 1 leverage ratio: Tier One Leverage Capital [Abstract] Tier 1 (core) capital, actual, capital amount Tier One Leverage Capital Tier 1 (core) capital, ratio Tier One Leverage Capital to Average Assets Tier 1 (core) capital required for minimum capital adequacy, phase-in schedule, capital amount Tier One Leverage Capital Required For Capital Adequacy, Phase-In Schedule Tier One Leverage Capital Required For Capital Adequacy, Phase-In Schedule Tier 1 (core) capital required for minimum capital adequacy, phase-in schedule, ratio Tier One Leverage Capital Required For Capital Adequacy To Average Assets, Phase-In Schedule Tier One Leverage Capital Required For Capital Adequacy To Average Assets, Phase-In Schedule Tier 1 (core) capital required for minimum capital adequacy, fully phased-in, capital amount Tier One Leverage Capital Required For Capital Adequacy, Fully Phased-In Tier One Leverage Capital Required For Capital Adequacy, Fully Phased-In Tier 1 (core) capital required for minimum capital adequacy, fully phased-in, ratio Tier One Leverage Capital Required For Capital Adequacy To Average Assets, Fully Phased-In Tier One Leverage Capital Required For Capital Adequacy To Average Assets, Fully Phased-In Tier 1 (core) capital required to be well capitalized, capital amount Tier One Leverage Capital Required to be Well Capitalized Tier 1 (core) capital required to be well capitalized, ratio Tier One Leverage Capital Required to be Well Capitalized to Average Assets Financial Instruments [Domain] CMOs/Other MBS Other Other Investment Securities [Member] Other investment securities. Available for Sale Debt Securities, Available-for-sale [Abstract] Amortized cost Debt Securities, Available-for-sale, Amortized Cost Gross unrealized gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Available for sale, at fair value Debt Securities, Available-for-sale Held to Maturity Debt Securities, Held-to-maturity [Abstract] Amortized cost Debt Securities, Held-to-maturity Gross unrecognized gains Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain Gross unrecognized losses Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss Securities held to maturity, fair value Debt Securities, Held-to-maturity, Fair Value Debt Instruments [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Adjustment Scenario, Adjustment [Member] Astoria Financial Corporation Astoria Financial Corporation [Member] Astoria Financial Corporation [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 3.50% Senior Notes Senior Notes, 3.50% [Member] Senior Notes, 3.50% [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] FHLB Borrowings Federal Home Loan Bank Advances [Member] Senior Notes Senior Notes [Member] Subordinated notes Subordinated Debt [Member] Line of Credit Line of Credit [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Three-month LIBOR Three-Month London Interbank Offered Rate [Member] Three-Month London Interbank Offered Rate [Member] One-month LIBOR London Interbank Offered Rate (LIBOR) [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Bank pledged mortgages Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value Unused borrowing capacity Debt Instrument, Unused Borrowing Capacity, Amount Increased borrowing capacity by pledging securities Market Value Of Mortgage Not Required To Be Pledged Market value of mortgage not required to be pledged. Repurchase agreements maturity Repurchase Agreements, Maturity Period Repurchase Agreements, Maturity Period Principal amount Debt Instrument, Face Amount Interest rate Debt Instrument, Interest Rate, Stated Percentage Principal amount of debt assumed in merger Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Percentage recorded for estimated fair value of debt assumed Fair Value, Debt Assumed, Percentage Recorded For Estimated Fair Value Fair Value, Debt Assumed, Percentage Recorded For Estimated Fair Value Fair value of debt Debt Instrument, Fair Value Disclosure Weighted average interest rate on debt Long-term Debt, Weighted Average Interest Rate, at Point in Time Senior Notes amount repurchased Debt Instrument, Repurchased Face Amount Gain recognized on debt repurchased Debt Instrument, Repurchased Face Amount, Gain Recognized Debt Instrument, Repurchased Face Amount, Gain Recognized Private placement discount rate Private placement discount rate Private placement discount rate Debt issuance costs Debt Issuance Costs, Gross Issue premium Debt Instrument, Issue Premium, Percentage Debt Instrument, Issue Premium, Percentage Unamortized discount Debt Instrument, Unamortized Discount Effective yield Debt Instrument, Interest Rate, Effective Percentage Basis spread on LIBOR rates Debt Instrument, Basis Spread on Variable Rate Revolving line of credit amount Line of Credit Facility, Maximum Borrowing Capacity Revolving line of credit balance Long-term Line of Credit Required balance Line of Credit Facility, Required Balance Line of Credit Facility, Required Balance Duration of minimum outstanding balance Line of Credit, Required Duration For Minimum Outstanding Balance Line of Credit, Required Duration For Minimum Outstanding Balance Available for Sale Amortized cost Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Available-for-sale, one year or less, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Available-for-sale, one to five years, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Available-for-sale, five to ten years, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Available-for-sale, greater than ten years, amortized cost Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Available-for-sale, with a stated maturity date, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Available-for-sale, without single maturity date, amortized cost Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Fair value Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] Available-for-sale, one year or less, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Available-for-sale, one to five years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Available-for-sale, five to ten years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Available-for-sale, greater than ten years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Available-for-sale, with a stated maturity date, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Available-for-sale, without single maturity date, fair value Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Securities available for sale Amortized cost Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract] Held-to-maturity, one year or less, amortized cost Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Held-to-maturity, one to five years, amortized cost Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Held-to-maturity, five to ten years, amortized cost Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Held-to-maturity, greater than ten years, amortized cost Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost Held-to-maturity, with a stated maturity date, amortized cost Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost Held-to-maturity, without single maturity date, amortized cost Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Amortized Cost Fair value Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract] Held-to-maturity, one year or less, fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Held-to-maturity, one to five years, fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Held-to-maturity, five to ten years, fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Held-to-maturity, greater than ten years, fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Held-to-maturity, with a stated maturity date, fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value Held-to-maturity, without single maturity date, fair value Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value Held-to-maturity, fair value Non- accrual Retirement Benefits [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] February 2016 February 2016 [Member] February 2016 [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Recognition and Retention Plan Recognition and Retention Plan [Member] Recognition and Retention Plan [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Performance Shares Performance Shares [Member] Non-vested stock awards/performance units Non-vested Stock Awards and Performance Units [Member] Non-vested Stock Awards and Performance Units [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant [Roll Forward] Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Granted (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Granted In Period Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Granted In Period Stock awards vested (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Vested In Period Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Vested In Period Exercised (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Exercised In Period Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Exercised In Period Forfeited (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Forfeitures in Period Share-Based Compensation Arrangement By Share-Based Payment Award, Forfeitures in Period Canceled/expired (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Cancellations in Period Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Cancellations in Period Ending balance (in shares) Non-vested stock awards/stock units outstanding - Number of shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Stock awards vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Canceled/expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Expirations Ending balance (in shares) Non-vested stock awards/stock units outstanding - Weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Beginning balance (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Stock awards vested (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Canceled/expired (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expirations, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expirations, Weighted Average Grant Date Fair Value Ending balance (USD per share) Stock options outstanding - Number of shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Stock awards vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Canceled/expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Ending balance (in shares) Exercisable at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Stock options outstanding - Weighted average exercise price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Beginning balance (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Stock awards vested (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value Exercised (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeited (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Canceled/expired (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Ending balance (USD per share) Exercisable at end of period (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Performance measurement period Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Measurement Period Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Measurement Period Vesting percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Stock-based compensation expense Allocated Share-based Compensation Expense Deposits [Abstract] Municipal deposits Municipal Deposits Municipal deposits. New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2017-12 Accounting Standards Update 2017-12 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Book value of held to maturity securities transfered to available-for-sale Fair value of held to maturity securities transfered to available-for-sale Document and Entity Information [Abstract] Document and entity information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Smaller Reporting Company Entity Small Business Emerging Growth Company Entity Emerging Growth Company Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Derivative Instruments and Hedges, Assets [Abstract] Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Summary of derivatives Schedule of Derivative Instruments [Table Text Block] Non-interest bearing demand Demand Deposit Accounts Interest bearing demand Deposits, Negotiable Order of Withdrawal (NOW) Savings Deposits, Savings Deposits Money market Deposits, Money Market Deposits Certificates of deposit Time Deposits Total deposits Deposits Statement of Financial Position [Abstract] ASSETS: Assets [Abstract] Cash and due from banks Cash and Due from Banks Securities: Marketable Securities [Abstract] Held to maturity, at amortized cost (fair value of $2,079,057 and $2,740,522 at March 31, 2019 and December 31, 2018, respectively) Total securities Investments Loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Portfolio loans Allowance for loan losses Loans and Leases Receivable, Allowance Portfolio loans, net Loans and Leases Receivable, Net Amount Federal Home Loan Bank (“FHLB”) and Federal Reserve Bank (“FRB”) stock, at cost Federal Home Loan Bank Stock Accrued interest receivable Interest Receivable Premises and equipment, net Property, Plant and Equipment, Net Goodwill Goodwill Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Bank owned life insurance Bank Owned Life Insurance Other real estate owned Other Real Estate, Foreclosed Assets, and Repossessed Assets Other assets Other Assets Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] LIABILITIES: Liabilities [Abstract] Deposits FHLB borrowings Long-term Federal Home Loan Bank Advances Repurchase agreements Securities Sold under Agreements to Repurchase Senior Notes Senior Notes Subordinated Notes Subordinated Debt Mortgage escrow funds Advance Payments by Borrowers for Taxes and Insurance Other liabilities Other Liabilities Total liabilities Liabilities Commitments and Contingent liabilities (See Note 17. “Commitments and Contingencies”) Commitments and Contingencies STOCKHOLDERS’ EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock (par value $0.01 per share; 10,000,000 shares authorized; 135,000 shares issued and outstanding at March 31, 2019 and December 31, 2018) Preferred Stock, Value, Issued Common stock (par value $0.01 per share; 310,000,000 shares authorized at March 31, 2019 and December 31, 2018; 229,872,925 shares issued at March 31, 2019 and December 31, 2018; 209,560,824 and 216,227,852 shares outstanding at March 31, 2019 and December 31, 2018, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Treasury stock, at cost (20,312,101 shares at March 31, 2019 and 13,645,073 shares at December 31, 2018) Treasury Stock, Value Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss, net of tax benefit of $(2,763) at March 31, 2019 and $(25,429) at December 31, 2018 Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Allowance for Loan Losses Financing Receivables [Text Block] 2015 Plan 2015 Omnibus Equity And Incentive Plan [Member] 2015 Omnibus Equity And Incentive Plan [Member] Stock options Employee Stock Option [Member] Number of active stock-based compensation plans Number Of Active Stock-Based Compensation Plans Number Of Active Stock-Based Compensation Plans Number of shares authorized (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares remaining that are authorized and available for future grant (in shares) Vesting period for awards Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Term of contract Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Intrinsic value of options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Grant of share options (in shares) Weighted-average period total unrecognized compensation cost related to non-vested shares granted Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Credit Loss Status [Axis] Credit Loss Status [Axis] Credit Loss Status [Domain] Credit Loss Status [Domain] PCI Loans Financial Asset Acquired with Credit Deterioration [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Loans acquired transferred to originated Loans And Leases Receivable, Gross, Reclassified From Acquired To Originated Loans And Leases Receivable, Gross, Reclassified From Acquired To Originated Loans acquired transferred to originated, allowance Loans And Leases Receivable, Allowance, Transfered From Acquired To Origniated Loans And Leases Receivable, Allowance, Transfered From Acquired To Origniated Net deferred loan origination costs Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Discounts on acquired loans Business Combination, Provisional Information, Initial Accounting Incomplete, Loans Business Combination, Provisional Information, Initial Accounting Incomplete, Loans Loans formally in process of foreclosure Mortgage Loans in Process of Foreclosure, Amount Maximum loan balance for credit risk to be evaluated on a homogeneous basis Minimum Loan Balance for Credit Risk to be Evaluated on a Homogeneous Basis Minimum Loan Balance for Credit Risk to be Evaluated on a Homogeneous Basis Balance of PCI loans treated under cost recovery method Impaired Financing Receivable, Unpaid Principal Balance Loans not individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Impaired loans with an allowance recorded Impaired Financing Receivable, with Related Allowance, Recorded Investment Impaired loans cash-basis interest income recognized Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method Loans not classified as TDRs Loans modified by TDR TDRs modified and subsequently defaulted Financing Receivable, Modifications, Subsequent Default, Number of Contracts Statement of Comprehensive Income [Abstract] Net income Net Income (Loss) Attributable to Parent Other comprehensive income (loss), before tax: Other Comprehensive Income (Loss), before Tax [Abstract] Change in unrealized holding gains (losses) on securities available for sale Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Unrealized loss on transfer of securities held to maturity to available for sale Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax Reclassification adjustment for net realized losses included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Accretion of net unrealized loss on securities transferred to held to maturity Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Securities Transferred To Held To Maturity Arising During Period, before Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Securities Transferred To Held To Maturity Arising During Period, before Tax Change in the actuarial loss of defined benefit plan and post-retirement benefit plans Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Total other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax Deferred tax (expense) benefit related to other comprehensive (loss) income Other Comprehensive Income (Loss), Tax Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Measurement Input, Prepayment Rate Measurement Input, Prepayment Rate [Member] Measurement Input, Discount Rate Measurement Input, Discount Rate [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Nonrecurring Fair Value, Measurements, Nonrecurring [Member] Weighted Average Weighted Average [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Portfolio loans, net Loans Receivable, Fair Value Disclosure Changes in fair value recognized on provisions on loans held by the Company Changes In Fair Value Recognized On Provisions On Loans Held By Company Changes in fair value recognized on provisions on loans held by company. Servicing assets and liabilities, measurement input Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate Mortgage servicing rights Servicing Asset at Fair Value, Amount Percentage appraisals discounted Other Real Estate, Appraisal, Discount Rate Other Real Estate, Appraisal, Discount Rate Assets taken in foreclosure, defaulted loans and facilities held for sale Changes in fair value recognized through income for foreclosed assets held by the Company Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss Included In Income Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss Included In Income Equity [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net unrealized holding (loss) gain on available for sale securities Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Net unrealized holding (loss) gain on retirement plans Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated other comprehensive (loss) AOCI Attributable to Parent [Member] Available-for-sale securities Available-for-sale Securities [Member] Held-to-maturity securities Held-to-maturity Securities [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other comprehensive income (loss), before tax Other comprehensive income (loss), tax benefit Other comprehensive income (loss), net of tax Total stockholders’ equity Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Basis of Financial Statement Presentation Basis of Presentation and Significant Accounting Policies [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 inputs Fair Value, Inputs, Level 1 [Member] Level 2 inputs Fair Value, Inputs, Level 2 [Member] Level 3 inputs Fair Value, Inputs, Level 3 [Member] Carrying amount Reported Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Loans held for sale Loans Held-for-sale, Fair Value Disclosure Accrued interest receivable on securities Accrued Interest Receivables, Securities, Fair Value Disclosure Accrued interest receivables fair value disclosure. Accrued interest receivable on loans Accrued Interest Receivables, Loans, Fair Value Disclosure Accrued Interest Receivables, Loans, Fair Value Disclosure FHLB stock and FRB stock Investment in Federal Home Loan Bank Stock, Fair Value Disclosure Swaps Derivative Asset Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Non-maturity deposits Non Maturity Deposits Fair Value Disclosure Non maturity deposits fair value disclosure. Certificates of deposit Certificates Of Deposit Fair Value Disclosure Certificates of deposit fair value disclosure. FHLB borrowings Federal Home Loan Bank Borrowings, Fair Value Disclosure Other borrowings Other Borrowings Senior Notes Subordinated Notes Mortgage escrow funds Mortgage Escrow Funds Fair Value Disclosure Mortgage escrow funds fair value disclosure. Accrued interest payable on deposits Accrued Interest Payable, Deposits Including Escrow, Fair Value Disclosure Accrued Interest Payable, Deposits Including Escrow, Fair Value Disclosure Accrued interest payable on borrowings Accrued Interest Payable, Borrowings, Fair Value Disclosure Accrued Interest Payable, Borrowings, Fair Value Disclosure Swaps Derivative Liability Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Balance at beginning of period Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Accretion of income Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Charge-offs Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans Reclassification (to) from non-accretable difference Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Other, adjustments Certain Loans Acquired In Transfer Not Accounted For As Debt Securities, Accretable Yield, Other Adjustments Certain Loans Acquired In Transfer Not Accounted For As Debt Securities, Accretable Yield, Other Adjustments Balance at end of period Loans evaluated for impairment by segment Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Loans evaluated by segment, Individually evaluated for impairment Loans evaluated by segment, Collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Loans evaluated by segment, Purchased credit impaired loans Financing Receivable, Net Allowance evaluated by segment, Individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Allowance evaluated by segment, Collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Total allowance for loan losses Financing Receivable, Allowance for Credit Losses Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Funding Status [Axis] Retirement Plan Funding Status [Axis] Retirement Plan Funding Status [Domain] Retirement Plan Funding Status [Domain] Overfunded Plan Overfunded Plan [Member] Underfunded Plan Underfunded Plan [Member] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Retirement Plan Name [Domain] Retirement Plan Name [Domain] Astoria Bank Pension Plan Astoria Bank Pension Plan [Member] Astoria Bank Pension Plan [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other liabilities Other Liabilities [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Employer contributions to fund pension and other post retirement benefits Defined Benefit Plan, Plan Assets, Contributions by Employer Funded (unfunded) amount Defined Benefit Plan, Funded (Unfunded) Status of Plan Schedule of Classification of Deposits [Table] Schedule of Classification of Deposits [Table] Schedule of classification of deposits. Brokered Deposits [Axis] Brokered Deposits [Axis] Brokered deposits. Brokered Deposits [Domain] Brokered Deposits [Domain] Brokered Deposits [Domain] Interest bearing demand Interest-bearing Deposits [Member] Money market Money Market Deposits [Member] Money market deposits. CDARS and ICS one way CDARs And ICS One Way [Member] CDARs And ICS One Way Schedule of Classification of Deposits [Line Items] Schedule of Classification of Deposits [Line Items] Schedule of classification of deposits. List of Company's Brokered deposits List of Company's Brokered Deposits [Abstract] List of company's brokered deposits. Brokered deposits Noninterest-bearing Domestic Deposit, Brokered Estimated fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Impaired loans measured at estimated fair value on nonrecurring basis Fair Value Measurements, Nonrecurring [Table Text Block] Carrying amounts and estimated fair value of financial assets and liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Commercial real estate Commercial Real Estate Portfolio Segment [Member] Multi-family Multi-family financing [Member] Multi-family financing [Member] Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method Allowance for Loan and Lease Losses [Roll Forward] Beginning allowance for loan losses Charge-offs Financing Receivable, Allowance for Credit Losses, Write-downs Recoveries Financing Receivable, Allowance for Credit Losses, Recovery Net charge-offs Allowance For Doubtful Accounts Receivable, Charge-Offs (Recoveries), Net Allowance For Doubtful Accounts Receivable, Charge-Offs (Recoveries), Net Provision / (credit) Provision for Loan, Lease, and Other Losses Ending allowance for Loan Losses Annualized net charge-offs to average loans outstanding: Net Charge Offs To Average Gross Loans Annualized Net charge offs to average gross loans annualized. Summary of securities available for sale Debt Securities, Available-for-sale [Table Text Block] Schedule of held for sale securities transferred to available-for-sale Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Summary of securities held-to-maturity Debt Securities, Held-to-maturity [Table Text Block] Summary of amortized cost and fair value of investment securities available for sale by remaining period to contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Sale of securities Schedule of Realized Gain (Loss) [Table Text Block] Securities available for sale with unrealized losses, by length of time in continuous unrealized loss position Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block] Securities pledged for borrowings at FHLB and other institutions, and securities pledged for municipal deposits and other purposes Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Acquisitions Business Combination Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of off-balance-sheet financial instruments Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recently Issued Accounting Standards, Adopted and Not Yet Adopted New Accounting Pronouncements, Policy [Policy Text Block] Fair Value Measurement, Policy Fair Value Measurement, Policy [Policy Text Block] Collateral [Axis] Collateral [Axis] Collateral [Domain] Collateral [Domain] Collateral Pledged Collateral Pledged [Member] Types of Financial Instruments [Domain] Traditional C&I Multi-family Real Estate Commercial Mortgage CBL [Member] Real estate commercial mortgage CBL. Total impaired loans measured at fair value Cash Paid as STM Derivative, Collateral, Right to Reclaim Cash Non-Interest Income and Other Non-Interest Expense Other non-interest expense [Text Block] Other non-interest expense [Text Block] Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-maturity [Table] Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Fair value, less than 12 months Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value Unrecognized losses, less than 12 months Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Fair value, 12 months or longer Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Unrecognized losses, 12 months or longer Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair value, total Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value Unrecognized losses, total Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss Schedule of Credit Derivatives [Table] Schedule of Credit Derivatives [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Credit Derivatives Contract Type [Domain] Derivative Contract [Domain] Interest rate swap Interest Rate Swap [Member] Third-party interest rate swap Third Party Interest Rate Swap [Member] Third party interest rate swap. Customer interest rate swap Customer Interest Rate Swap [Member] Customer interest rate swap. Other assets Other Assets [Member] Credit Derivatives [Line Items] Credit Derivatives [Line Items] Summary of derivatives Summary of Credit Derivatives [Abstract] Derivative assets, notional amount Derivative Asset, Notional Amount Derivative liabilities, notional amount Derivative Liability, Notional Amount Average maturity (in years) Derivative, Average Remaining Maturity Weighted average fixed rate Derivative, Average Fixed Interest Rate Basis spread Derivative, Basis Spread on Variable Rate Derivative assets, fair value Portfolio Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Summary of major classification of deposits Schedule Of Major Classification Of Deposits [Table Text Block] Major classification of deposits. List of Company's Brokered deposits Schedule of List of Brokered Deposits [Table Text Block] Schedule of list of brokered deposits. Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Leases [Abstract] Weighted average remaining lease term (years) Operating Lease, Weighted Average Remaining Lease Term Weighted average remaining discount rate Operating Lease, Weighted Average Discount Rate, Percent Pension and Other Post-Retirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Deposits Deposit Liabilities Disclosures [Text Block] Schedule of goodwill and intangible assets Schedule of Intangible Assets and Goodwill [Table Text Block] Future amortization expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Loans individually evaluated for impairment by segment of loans Loans Individually Evaluated For Impairment By Segment Of Loans [Abstract] Loans individually evaluated for impairment by segment of loans. With no related allowance recorded: Impaired Financing Receivable, Unpaid Principal Balance [Abstract] Unpaid principal balance with no related allowance recorded Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Recorded investment with no related allowance recorded Impaired Financing Receivable, with No Related Allowance, Recorded Investment Schedule of net pension (benefit) expense and post-retirement expense Schedule of Net Benefit Costs [Table Text Block] Remainder of 2019 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Operating Lease liabilities Operating Lease, Liability Operating lease remaining lease term Operating Lease, Remaining Lease Term Operating Lease, Remaining Lease Term Operating lease renewal term Lessee, Operating Lease, Renewal Term Operating lease option to terminate term Lessee, Operating Lease, Option To Terminate Term Lessee, Operating Lease, Option To Terminate Term Operating leases rent expense, before Topic 842 adoption Operating Leases, Rent Expense, Net Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Class of Stock [Line Items] Class of Stock [Line Items] Tier 2 capital Tier Two Risk Based Capital Aggregate dividend capacity without prior regulatory approval Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval Shares authorized for repurchase program (in shares) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Stock repurchased during period (in shares) Treasury Stock, Shares, Acquired Additional number of shares authorized to be repurchased Stock Repurchase Program, Additional Number Of Shares Authorized To Be Repurchased Stock Repurchase Program, Additional Number Of Shares Authorized To Be Repurchased Number of available for sale securities which were in continuous unrealized loss position for less than 12 months Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Number Of Securities Available for sale securities continuous unrealized loss position less than twelve months number of securities. Number of available for sale securities which were in continuous unrealized loss position for 12 months or more Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Number Of Securities Available for sale securities continuous unrealized loss position twelve months or longer number of securities. Number of held to maturity securities which were in continuous unrealized loss position for less than 12 months Held To Maturity Securities Continuous Loss Position Less Than Twelve Months Number Of Securities Held To Maturity Securities Continuous Loss Position Less Than Twelve Months Number Of Securities Number of held to maturity securities which were in continuous unrealized loss position for 12 months or more Held To Maturity Securities Continuous Loss Position More Than Twelve Months Number Of Securities Held To Maturity Securities Continuous Loss Position More Than Twelve Months Number Of Securities Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Book value of available-for-sale securities transfered from held to maturity Fair value of available-for-sale securities transfered from held to maturity Securities sold to raise liquidity Debt Securities, Held-to-maturity, Sold, Amount Schedule of Lease Cost Lease, Cost [Table Text Block] Schedule of Operating Lease Liability Maturities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Summary of Lease Weighted-Average Terms and Discount Rates Lease, Weighted-Average Terms And Discount Rates [Table Text Block] Lease, Weighted-Average Terms And Discount Rates [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Components of loan portfolio, excluding loans held for sale Loans and Leases Receivable, Net Amount [Abstract] Total portfolio loans Preferred stock, par value (USD per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Common stock, par value (USD per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock, shares (in shares) Treasury Stock, Shares Accumulated other comprehensive loss, tax benefit AOCI Tax, Attributable to Parent Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common stock Common Stock [Member] Preferred stock Preferred Stock [Member] Additional paid-in capital Additional Paid-in Capital [Member] Treasury stock Treasury Stock [Member] Retained earnings Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance (in shares) Shares, Issued Balance, beginning Net income Other comprehensive income Stock options & other stock transactions, net (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease) Stock option & other stock transactions, net Adjustments to Additional Paid in Capital, Share-based Compensation and Exercise of Stock Options Restricted stock awards, net (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock awards, net Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Cash dividends declared, common Dividends, Common Stock, Cash Cash dividends declared, preferred Dividends, Preferred Stock, Cash Purchase of treasury stock (in shares) Purchase of treasury stock Treasury Stock, Value, Acquired, Cost Method Reclassification of the stranded income tax effects from the enactment of the Tax Cuts and Jobs Act from accumulated other comprehensive (loss) Tax Cuts And Jobs Act Of 2017 Reclassification From Aoci To Retained Earnings Tax Effect Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act. Balance (in shares) Balance, ending Borrowings Debt Disclosure [Text Block] Internal Credit Assessment [Axis] Special mention Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Loss Unlikely to be Collected Financing Receivable [Member] Gross loans by segment Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Summary of Assets and Liabilities measured at estimated fair value on a recurring basis Fair Value, Net Asset (Liability) [Abstract] Investment securities available for sale: Investment Securities Available For Sale [Abstract] Investment securities available for sale. Financial assets: Financial Assets [Abstract] Financial Assets [Abstract] Total assets Assets, Fair Value Disclosure Financial liabilities: Financial Liabilities [Abstract] Financial Liabilities [Abstract] Swaps Total liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Income Tax Disclosure [Abstract] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Remainder of 2019 Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating Lease, Liability, Payments, Due Year Five 2024 Lessee, Operating Lease, Liability, Payments, Due Year Six Lessee, Operating Lease, Liability, Payments, Due Year Six 2025 and thereafter Lessee, Operating Lease, Liability, Payments, Due After Year Six Lessee, Operating Lease, Liability, Payments, Due After Year Six Total lease payments Lessee, Operating Lease, Liability, Payments, Due Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities Allowance for loan losses activity Allowance for Credit Losses on Financing Receivables [Table Text Block] Financing receivable credit quality indicators Financing Receivable Credit Quality Indicators [Table Text Block] Efftective tax rate reconciliation: Effective Income Tax Rate Reconciliation, Percent [Abstract] Income before income tax expense Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Tax at federal statutory rate of 21% Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State and local income taxes, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Tax exempt interest, net of disallowed interest Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount BOLI income Income Tax Reconciliation, Bank Owned Life Insurance Income Income Tax Reconciliation, Bank Owned Life Insurance Income Low income housing tax credits and other benefits Effective Income Tax Rate Reconciliation, Tax Credit, Low Income Housing, Amount Effective Income Tax Rate Reconciliation, Tax Credit, Low Income Housing, Amount Low income housing investment amortization expense Effective Income Tax Rate Reconciliation, Tax Credit, Low Income Housing Amortization Expense, Amount Effective Income Tax Rate Reconciliation, Tax Credit, Low Income Housing Amortization Expense, Amount Equity-based stock compensation benefit Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount FDIC insurance premium limitation Effective Income Tax Rate Reconciliation, FDIC Insurance Premium Limitation Effective Income Tax Rate Reconciliation, FDIC Insurance Premium Limitation Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Actual income tax expense Income Tax Expense (Benefit) Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Net deferred tax asset Deferred Tax Assets, Net Valuation allowance Deferred Tax Assets, Valuation Allowance Unrecognized tax benefits Unrecognized Tax Benefits FHLB borrowings Repurchase agreements Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] Subordinated Notes Schedule of debt Long-term Debt, by Category, Current and Noncurrent [Abstract] By period to maturity: Long-term Debt, Rolling Maturity [Abstract] Total borrowings, amount Long-term Debt Total borrowings, rate Less than one year, amount Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months Less than one year, rate Long Term Debt Maturities Weighted Average Interest Rate In Next Rolling Twelve Months Long term debt maturities weighted average interest rate in next rolling twelve months. One to two years, amount Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two One to two years, rate Long Term Debt Maturities Weighted Average Interest Rate In Rolling Year Two Long term debt maturities weighted average interest rate in rolling year two. Two to three years, amount Long-term Debt, Maturities, Repayments of Principal in Rolling Year Three Two to three years, rate Long Term Debt Maturities Weighted Average Interest Rate In Rolling Year Three Long term debt maturities weighted average interest rate in rolling year three. Greater than five years, amount Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five Greater than five years, rate Long Term Debt Maturities Weighted Average Interest Rate In Rolling After Year Five Long term debt maturities weighted average interest rate in rolling after year five. Professional fees Professional Fees Advertising and promotion Marketing and Advertising Expense Telephone Communication Operational losses Operational Loss Operational Loss Insurance & surety bond premium Insurance and Surety Bond Premium Expense Insurance and Surety Bond Premium Expense Pension plan expense (benefit) Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Other Other Noninterest Expense, Miscellaneous Other Noninterest Expense, Miscellaneous Total other non-interest expense Other Noninterest Expense Operating lease expense Operating Lease, Cost Sub-lease income Sublease Income Net lease expense Lease, Cost Average recorded investment with no related allowance Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment Interest income recognized with no related allowance Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method Cash-basis interest income recognized with no related allowance Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method Fair Value Measurements Fair Value Disclosures [Text Block] Income Taxes Income Tax Disclosure [Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Cash dividends paid, common (usd per share) Common Stock, Dividends, Per Share, Cash Paid Cash dividends paid, preferred (usd per share) Preferred Stock, Dividends, Per Share, Cash Paid Summary of Company's stock option activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of stock-based compensation expense associated with stock options and non-vested stock awards Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Unrecognized stock-based compensation expense Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Core deposits Core Deposits [Member] Customer lists Customer Lists [Member] Non-compete agreements Noncompete Agreements [Member] Trade name Trade Names [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Other intangible assets Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Proceeds from sales Proceeds from Sale of Debt Securities, Available-for-sale Gross realized gains Debt Securities, Available-for-sale, Realized Gain Gross realized losses Debt Securities, Available-for-sale, Realized Loss Income tax benefit on realized net losses Tax Expense (Benefit) Of Securities Gains Tax expense (benefit) of securities gains Earnings Per Share [Abstract] Computation of basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Components of loan portfolio excluding loans held for sale Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of amounts and status of loans and TDRs Past Due Financing Receivables [Table Text Block] Schedule of additional analysis of non-accrual loans Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Impaired financing receivables