Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Astoria Financial Corporation Astoria Financial Corporation [Member] Astoria Financial Corporation [Member] 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] Business Acquisition [Line Items] Business Acquisition [Line Items] Fair value of acquired loans at acquisition date Business Combination, Acquired Receivable, Fair Value Gross contractual amounts receivable at acquisition date Business Combination, Acquired Receivables, Gross Contractual Amount Best estimate at acquisition date of contractual cash flows not expected to be collected Business Combination, Acquired Receivables, Estimated Uncollectible Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Investments in Affordable Housing Projects [Abstract] Gross investment in LIHTC Amortization Method Qualified Affordable Housing Project Investments, Gross Amortization Method Qualified Affordable Housing Project Investments, Gross Accumulated amortization Amortization Method Qualified Affordable Housing Project Investments, Accumulated Amortization Amortization Method Qualified Affordable Housing Project Investments, Accumulated Amortization Net investment in LIHTC Amortization Method Qualified Affordable Housing Project Investments Unfunded commitments for LIHTC investments Qualified Affordable Housing Project Investments, Commitment Derivative Instruments and Hedges, Assets [Abstract] Cash pledged as collateral for swaps Derivative, Collateral, Right to Reclaim Cash Organization, Consolidation and Presentation of Financial Statements [Abstract] Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Consumer loans, including home equity Consumer Portfolio Segment [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] 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 Loss history period to determine allowance for loan and lease losses Loss History Period To Determine Allowance For Loan And Lease Losses Loss History Period To Determine Allowance For Loan And Lease Losses Duration period past due for charge off Allowance for Credit Losses, Duration Past Due Until Chargeoff Allowance for Credit Losses, Duration Past Due Until Chargeoff Receivables [Abstract] Portfolio Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Quarterly Financial Information Disclosure [Abstract] Quarterly Results of Operations (Unaudited) Quarterly Financial Information [Text Block] Investments, Debt and Equity Securities [Abstract] Available for sale Debt Securities, Available-for-sale [Abstract] Proceeds from sales of securities available for sale 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 Held to maturity Debt Securities, Held-to-maturity [Abstract] Proceeds from sales of securities held to maturity Proceeds from Sale of Held-to-maturity Securities Gross realized loss Debt Securities, Held-to-maturity, Sold, Realized Gain (Loss) Income tax (benefit) on realized loss Tax expense held to maturity security gains Tax expense held to maturity security gains Fair Value Disclosures [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Recurring [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. Mortgage servicing rights Servicing Asset at Fair Value, Amount Assets taken in foreclosure, defaulted loans and facilities held for sale Other Real Estate, Foreclosed Assets, and Repossessed Assets 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 Condensed Financial Information Disclosure [Abstract] Schedule of Condensed Financial Statements [Table] Condensed Financial Statements [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Sterling Bancorp Parent Company [Member] Investment in Subsidiaries by Name [Axis] Investment in Subsidiaries by Name [Axis] Investment in Subsidiaries by Name [Axis] Investment in Subsidiaries by Name [Domain] Investment in Subsidiaries by Name [Domain] [Domain] for Investment in Subsidiaries by Name [Axis] Sterling National Bank Sterling National Bank [Member] Sterling National Bank [Member] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Equity in excess distributed (undistributed) earnings of the Bank Income (Loss) from Equity Method Investments (Gain) on extinguishment of 3.50% Senior Notes Gain (Loss) on Extinguishment of Debt Other adjustments, net Other Operating Activities, Cash Flow Statement Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Investment in the Bank Payments to Acquire Interest in Subsidiaries and Affiliates Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from issuance of Subordinated Notes - Company Proceeds from Issuance of Subordinated Long-term Debt Early redemption of 3.50% Senior Notes Repayments of Senior Debt Maturity of 5.50% Senior Notes Repayments of Subordinated Debt Cash dividends paid on common stock Payments of Ordinary Dividends, Common Stock Cash dividend paid on preferred stock Payments of Ordinary Dividends, Preferred Stock and Preference Stock Stock-based compensation transactions Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Repurchase of treasury stock Payments for Repurchase of Common Stock Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease) increase in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Agency-backed Agency Securities [Member] Other MBS Collateralized Mortgage Obligations [Member] Total residential MBS Residential Mortgage Backed Securities [Member] Corporate bonds Corporate Debt Securities [Member] State and municipal US States and Political Subdivisions Debt Securities [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 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] Amortized cost Debt Securities, Held-to-maturity Fair value Debt Securities, Held-to-maturity, Fair Value Schedule of Fair Value, Off-balance Sheet Risks [Table] Schedule of Fair Value, Off-balance Sheet Risks [Table] Types of Financial Instruments [Domain] Letters of credit Letter of Credit [Member] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] Lending-related instruments Fair Value Disclosure, Off-balance Sheet Risks, Amount, Asset Assets secured by cash as collateral Fair Value Disclosure, Off-balance Sheet Risks, Asset Amount Secured by Cash as Collateral Fair Value Disclosure, Off-balance Sheet Risks, Asset Amount Secured by Cash as Collateral Assets secured by other collateral Fair Value Disclosure, Off-balance Sheet Risks, Asset Amount Secured by Other Collateral Fair Value Disclosure, Off-balance Sheet Risks, Asset Amount Secured by Other Collateral Fair Value Measurements Fair Value Disclosures [Text Block] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Originated loans Originated Loan [Member] Originated Loan [Member] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Special Mention Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Unlikely to be Collected Financing Receivable Unlikely to be Collected Financing Receivable [Member] Consumer Consumer Loan [Member] Warehouse lending Warehouse Lending [Member] Warehouse lending [Member] Public sector finance Public Sector Finance [Member] Public Sector Finance [Member] Maximum loan balance for credit risk to be evaluated on a homogeneous basis Maximum Loan Balance for Credit Risk to be Evaluated on a Homogeneous Basis Maximum Loan Balance for Credit Risk to be Evaluated on a Homogeneous Basis 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 PCI loans Financing Receivable, after Allowance for Credit Loss Other Income and Expenses [Abstract] Commitment to fund low income housing tax credit investments Operating lease liability Operating Lease, Liability Payroll finance and factoring liabilities Payroll Finance And Factoring Liabilities Payroll Finance And Factoring Liabilities Swaps, liabilities Derivative Liability Other liability balances Other Liabilities, Other Other Liabilities, Other Total other liabilities Other Liabilities Equity [Abstract] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Income Tax Disclosure [Abstract] Current income tax expense: Current Federal, State and Local, Tax Expense (Benefit) [Abstract] Federal Current Federal Tax Expense (Benefit) State and local Current State and Local Tax Expense (Benefit) Total current income tax expense Current Income Tax Expense (Benefit) Deferred income tax expense: Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State and local Deferred State and Local Income Tax Expense (Benefit) Total deferred income tax expense Deferred Income Tax Expense (Benefit) Total income tax expense Income Tax Expense (Benefit) Deferred tax assets: Deferred Tax Assets, Net [Abstract] Allowance for loan losses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Lease liability Deferred Tax Assets, Operating Lease Liability Deferred Tax Assets, Operating Lease Liability Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Other accrued compensation and benefits Deferred Tax Assets, Purchase Accounting Adjustments Deferred Tax Assets, Purchase Accounting Adjustments Deferred rent Deferred tax assets deferred rent Deferred tax assets deferred rent Intangible asset amortization Deferred Tax Assets, Goodwill and Intangible Assets Other comprehensive loss (securities) Deferred Tax Assets, Other Comprehensive Loss Pension and post retirement expense Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions Deferred loan fees and costs Deferred Loan Fee and Cost Deferred Loan Fee and Cost Accrued expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals Net operating loss carryfowards Deferred Tax Assets, Operating Loss Carryforwards, State and Local Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross Deferred tax liabilities: Deferred Tax Liabilities, Net [Abstract] Right of use asset (leases) Deferred Tax Liability, Leases, Right-Of-Use Asset Deferred Tax Liability, Leases, Right-Of-Use Asset Acquisition fair value adjustments Deferred Tax Liabilities, Purchase Accounting, Fair Value Adjustments Deferred Tax Liabilities, Purchase Accounting, Fair Value Adjustments Depreciation of premises and equipment and tax leases Deferred Tax Liabilities, Property, Plant and Equipment Other comprehensive income (securities) Other Comprehensive Income (securities) Other Comprehensive Income (securities) Deferred capital gains Capital Mortgage servicing rights Deferred Tax Liabilities, Mortgage Servicing Rights Other comprehensive gain (defined benefit plans) Deferred tax liability prepaid pension cost Deferred tax liability prepaid pension cost Deferred loan fees and costs Deferred Tax Liabilities, Deferred Loans Fees And Costs Deferred Tax Liabilities, Deferred Loans Fees And Costs Intangible asset amortization Deferred Tax Liabilities, Acquisitions Deferred Tax Liabilities, Acquisitions Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax liability Deferred Tax Liabilities, Net Net deferred tax asset Deferred Tax Assets, Net Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-maturity [Table] Other MBS Federal agencies US Government Agencies Debt Securities [Member] Other Other Investment Securities [Member] Other investment securities. Total other securities Debt Securities, Excluding Residential Mortgage Backed Securities [Member] Debt Securities, Excluding Residential Mortgage Backed Securities [Member] 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 Unrealized 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 Unrealized 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 Unrealized losses, total Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss Earnings Per Share [Abstract] Computation of basic and diluted earnings per share: Earnings Per Share, Basic and Diluted [Abstract] Net income available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Weighted average common shares outstanding for computation of basic EPS (in shares) Weighted Average Number of Shares Outstanding, Basic Common-equivalent shares due to the dilutive effect of stock options (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average common shares for computation of diluted EPS (in shares) Weighted Average Number of Shares Outstanding, Diluted Basic - earnings per common share (in dollars per share) Earnings Per Share, Basic Diluted - earnings per common share (in dollars per share) Earnings Per Share, Diluted Weighted average common shares that could be exercised that were anti-dilutive for the period (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Preferred stock Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Common stock, cash dividends paid (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Preferred stock, cash dividends paid (in dollars per share) Preferred Stock, Dividends, Per Share, Cash Paid Stock issued in merger transaction (in shares) Stock Issued During Period, Shares, Acquisitions Schedule of off-balance-sheet financial instruments Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block] Postemployment Benefits [Abstract] Pension and Other Post Retirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Summary of securities available for sale Debt Securities, Available-for-sale [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 Schedule of Unrealized Loss on Investments [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] Stockholders' Equity Note [Abstract] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Leases [Abstract] Operating lease expense Operating Lease, Cost Sub-lease income Sublease Income Net lease expense Lease, Cost Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [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] Fair Value, Net Asset (Liability) [Abstract] Fair Value, Net Asset (Liability) [Abstract] Investment securities available for sale: Investment Securities Available For Sale [Abstract] Investment securities available for sale. Available for sale, at fair value Debt Securities, Available-for-sale Swaps Derivative Asset Total assets Assets, Fair Value Disclosure Total liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure 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 Schedule of Direct Financing Lease and Sales-type Lease Sales-type and Direct Financing Leases, Lease Receivable, Maturity [Table Text Block] Schedule of Operating Lease Receivable Maturities Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Schedule of Lease Cost Lease, Cost [Table Text Block] Schedule of Operating Lease Liability Maturities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Litigation Commitments and Contingencies Disclosure [Text Block] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension benefits Pension Plan [Member] Other post retirement benefits Other Postretirement Benefits Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Thereafter Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Efftective tax rate reconciliation: Effective Income Tax Rate Reconciliation, Percent [Abstract] Tax at federal statutory rate of 21% for 2019 and 2018 and 35% for 2017 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 Non-deductible acquisition related costs Income Tax Reconciliation, Nondeductible Expense, Acquisition Costs Income Tax Reconciliation, Nondeductible Expense, Acquisition Costs 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 Payment Arrangement, Amount FDIC insurance premium limitation Effective Income Tax Rate Reconciliation, FDIC Insurance Premium Limitation Effective Income Tax Rate Reconciliation, FDIC Insurance Premium Limitation Deferred tax adjustment related to reduction in federal income tax rate Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Schedule of Other Non-interest Expense Other non- interest expense [Table Text Block] Other non- interest expense [Table Text Block] Schedule of Other Assets Schedule of Other Assets [Table Text Block] Schedule of Other Liabilities Other Liabilities [Table Text Block] Operating Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] 2020 Lessor, Operating Lease, Payments to be Received, Next Twelve Months 2021 Lessor, Operating Lease, Payments to be Received, Two Years 2022 Lessor, Operating Lease, Payments to be Received, Three Years 2023 Lessor, Operating Lease, Payments to be Received, Four Years 2024 Lessor, Operating Lease, Payments to be Received, Five Years Thereafter Lessor, Operating Lease, Payments to be Received, Thereafter Total lease payments Lessor, Operating Lease, Payments to be Received Sales-type Finance Lease, Liability, Payment, Due, Rolling Maturity [Abstract] 2020 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Next Twelve Months 2021 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Two Years 2022 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Three Years 2023 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Four Years 2024 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Five Years Thereafter Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Thereafter Total lease payments Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received Unearned income Sales-type and Direct Financing Leases, Lease Receivable, Undiscounted Excess Amount Net lease receivables Sales-type and Direct Financing Leases, Lease Receivable 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] Payroll finance Payroll Finance [Member] Payroll Finance [Member] Factored receivables Factored Receivables [Member] A loan related to factored receivables. Equipment financing Equipment Financing Receivables [Member] A loan related to equipment finance receivable. CRE Commercial Real Estate Portfolio Segment [Member] Multi-family Multi-family financing [Member] Multi-family financing [Member] ADC Acquisition, Development And Construction [Member] Acquisition Development And Construction [Member] Residential mortgage Residential Portfolio Segment [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 balance Loans and Leases Receivable, Allowance Charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Net charge-offs Allowance For Doubtful Accounts Receivable, Charge-Offs (Recoveries), Net Allowance For Doubtful Accounts Receivable, Charge-Offs (Recoveries), Net Provision Provision for Loan, Lease, and Other Losses Ending balance Annualized net charge-offs to average loans outstanding Net Charge Offs To Average Gross Loans Annualized Net charge offs to average gross loans annualized. Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Debt Instruments [Abstract] Borrowings, Senior Notes and Subordinated Notes Debt Disclosure [Text Block] Deposits [Abstract] Less than one year Time Deposit Maturities, Next Twelve Months One to two years Time Deposit Maturities, Year Two Two to three years Time Deposit Maturities, Year Three Three to four years Time Deposit Maturities, Year Four Four to five years Time Deposit Maturities, Year Five Total certificates of deposit Certificates Of Deposit Certificates of deposit. Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other assets Other Assets [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] Pension plans excluding astoria Pension Plans Excluding Astoria [Member] Pension Plans Excluding Astoria [Member] Employee savings plan Employee Savings Plan [Member] Employee Savings Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Gain on termination of pension plan Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Pension reversion asset Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position Employer contributions to fund pension plan Defined Benefit Plan, Plan Assets, Contributions by Employer Maximum contribution by employee, percent Defined Contribution Plan, Maximum Contribution by Employee, Percent Defined Contribution Plan, Maximum Contribution by Employee, Percent Maximum annual contribution per employee, percent Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Savings plan expense Defined Contribution Plan, Cost Loan origination commitments Loan Origination Commitments [Member] Undrawn lines of credit Unused lines of Credit [Member] Leases Lessor, Direct Financing Leases [Text Block] Leases Lessor, Sales-type Leases [Text Block] Leases Lessee, Operating Leases [Text Block] Other Commitments [Table] Other Commitments [Table] Other Commitments [Axis] Other Commitments [Axis] Other Commitments [Domain] Other Commitments [Domain] Low Income Housing Tax Credit Expected Payments Low Income Housing Tax Credit Expected Payments [Member] Low Income Housing Tax Credit Expected Payments [Member] Other Commitments [Line Items] Other Commitments [Line Items] 2020 Other Commitment, Due in Next Twelve Months 2021 Other Commitment, Due in Second Year 2022 Other Commitment, Due in Third Year 2023 Other Commitment, Due in Fourth Year 2024 Other Commitment, Due in Fifth Year 2025 and thereafter Other Commitment, Due after Fifth Year Total unfunded commitments for LIHTC investments Other Commitment Municipal deposits Municipal Deposits Municipal deposits. Cash in excess of FDIC insurance limits Cash, Uninsured Amount Summary of major classification of deposits Schedule Of Major Classification Of Deposits [Table Text Block] Major classification of deposits. Schedule of Maturities of Deposits Schedule of Maturities of Deposits [Table Text Block] Schedule of Maturities of Deposits [Table Text Block] List of Company's Brokered deposits Schedule of List of Brokered Deposits [Table Text Block] Schedule of list of brokered deposits. Common stock Common Stock [Member] Additional paid-in capital Additional Paid-in Capital [Member] Treasury stock Treasury Stock [Member] Retained earnings Retained Earnings [Member] Accumulated other comprehensive (loss) income AOCI Attributable to Parent [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Shares, Issued Beginning balance Stockholders' Equity Attributable to Parent Net income Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Common stock issued in Astoria Merger transaction (in shares) Common stock issued in Astoria Merger transaction Stock Issued During Period, Value, Acquisitions Preferred stock issued in Astoria Merger transaction, 135,000 shares Stock Issued During Period, Value, New Issues Stock option & 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 APIC, Share-based Payment Arrangement, Recognition and Exercise 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 Purchase of treasury stock (in shares) Treasury Stock, Shares, Acquired Purchase of treasury stock Treasury Stock, Value, Acquired, Cost Method Cash dividends declared, common Dividends, Common Stock, Cash Cash dividends paid, preferred Dividends, Preferred Stock, Cash 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, Reclassification from AOCI to Retained Earnings, Tax Effect Ending balance (in shares) Ending balance 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 Financing Receivable, Past Due [Table Text Block] Schedule of additional analysis of non-accrual loans Financing Receivable, Nonaccrual [Table Text Block] Impaired financing receivables Impaired Financing Receivables [Table Text Block] Schedule of changes in the balance of accretable yield discount for PCI loans Certain Loans Acquired in Transfer Not Accounted For As Debt Securities, Accretable Yield Movement Schedule [Table Text Block] Certain Loans Acquired in Transfer Not Accounted For As Debt Securities, Accretable Yield Movement Schedule [Table Text Block] Troubled debt restructurings Financing Receivable, Troubled Debt Restructuring [Table Text Block] Summary of derivatives Schedule of Derivative Instruments [Table Text Block] Net actuarial gain Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Deferred tax (expense) Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, Tax Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, Tax Amount included in accumulated other comprehensive gain, net of tax Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Level 1 inputs 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] 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] Cash and due from banks Cash and Cash Equivalents, Fair Value Disclosure Securities held to maturity 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 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 Senior Notes Subordinated Notes Subordinated Debt 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 Health care cost trend rate assumed for the next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Rate to which the cost trend rate is assumed to decline (the “ultimate trend rate”) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that ultimate trend rate is reached Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate On percentage point increase, effect on total service and interest cost components Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components On percentage point increase, effect on the post retirement benefit obligation Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation On percentage point decrease, effect on total service and interest cost components Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components On percentage point decrease, effect on the post retirement benefit obligation Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation 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 Property, Plant and Equipment [Abstract] Premises and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Statement of Financial Position [Abstract] Sterling National Bank Subsidiaries [Member] Parent Parent [Member] 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 $2,053,191 and $2,740,522 at December 31, 2019 and December 31, 2018, respectively) Total securities Marketable Securities Loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Portfolio loans Loans and Leases Receivable, Gross Allowance for loan losses Portfolio loans, net Loans and Leases Receivable, Net Amount Federal Home Loan Bank (“FHLB”) and Federal Reserve Bank stock, at cost Federal Home Loan Bank Stock Accrued interest receivable Interest Receivable Premises and equipment, net Property, Plant and Equipment, Net Goodwill Goodwill Core deposit and other intangible assets Intangible Assets, Net (Excluding Goodwill) Bank owned life insurance Bank Owned Life Insurance Other real estate owned 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 Other borrowings (repurchase agreements) Securities Sold under Agreements to Repurchase Senior notes Mortgage escrow funds Advance Payments by Borrowers for Taxes and Insurance Other liabilities Total liabilities Liabilities Commitments and Contingent liabilities (See Notes 19 and 20.) 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 December 31, 2019 and December 31, 2018) Preferred Stock, Value, Issued Common stock (par value $0.01 per share; 310,000,000 shares authorized at December 31, 2019 and December 31, 2018; 229,872,925 shares issued at December 31, 2019 and December 31, 2018; 198,455,324 and 216,227,852 shares outstanding at December 31, 2019 and December 31, 2018, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Treasury stock, at cost (31,417,601 shares at December 31, 2019 and 13,645,073 shares at December 31, 2018) Treasury Stock, Value Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss), net of tax expense (benefit) of $15,361 at December 31, 2019 and $(25,429) at December 31, 2018 Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Financing lease income Lease Income Operating lease income Operating Lease, Lease Income Term of contract Lessee, Operating Lease, Term of Contract 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 lease, right-of-use asset Operating Lease, Right-of-Use Asset Operating leases, rent expense Operating Leases, Rent Expense, Net Professional fees Professional Fees Residential mortgage loan servicing Marketing and Advertising Expense Communication Communication Residential mortgage loan servicing Residential Loan Servicing Residential Loan Servicing Insurance & surety bond premium Insurance and Surety Bond Premium Expense Insurance and Surety Bond Premium Expense Operational losses Operational Loss Operational Loss Other Other Noninterest Expense, Miscellaneous Other Noninterest Expense, Miscellaneous Total other non-interest expense Other Noninterest Expense Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Reconciliation of Stockholders' Equity to Bank Regulatory Capital Reconciliation of Stockholders' Equity to Bank Regulatory Capital [Table Text Block] Reconciliation of Stockholders' Equity to Bank Regulatory Capital [Table Text Block] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Buildings Building [Member] Improvements And Equipments Improvements And Equipments [Member] Improvements And Equipments [Member] 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] Number of shares received by acquiree for each share of acquiree's stock Business Acquisition, Number Of Shares Received by Acquiree For Each Share Of Acquiree's Stock Business Acquisition, Number Of Shares Received by Acquiree For Each Share Of Acquiree's Stock Common stock issued as consideration (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Closing share price (in dollars per share) Business Acquisition, Share Price Total consideration paid Business Combination, Consideration Transferred Acquired goodwill Goodwill, Acquired During Period Acquired intangible assets Finite-lived Intangible Assets Acquired Adjustment to provisional goodwill from Astoria Merger Goodwill, Purchase Accounting Adjustments Acquired intangible assets, weighted average useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Premises and equipment, useful life Property, Plant and Equipment, Useful Life Direct acquisition and other merger-related expense Business Combination, Acquisition Related Costs Charge for asset write-downs, systems integration, severance and retention Asset Impairment, Severance, And Retention Charges Asset Impairment, Severance, And Retention Charges Share-based Payment Arrangement [Abstract] 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] Amended and restated 2015 omnibus plan Amended And Restated 2015 Omnibus Plan [Member] Amended And Restated 2015 Omnibus Plan [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Non-vested stock awards/performance units Non-vested Stock Awards and Performance Units [Member] Non-vested Stock Awards and Performance Units [Member] Shares available for grant (in shares) 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 Amended 2015 omnibus equity and incentive plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized 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 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars 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 (in dollars 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 (in dollars 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 (in dollars 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 (in dollars 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 (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 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Stock awards vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Canceled/expired (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Ending balance (in dollars per share) Exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Vesting percentage of shares initially granted Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Stock-based compensation expense Share-based Payment Arrangement, Expense 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 Schedule of Recognized Identified Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Accounting Changes and Error Corrections [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Scenario, Forecast Forecast [Member] Accounting Standards Update 2016-13 Accounting Standards Update 2016-13 [Member] Allowance for credit losses Financing Receivable, Allowance for Credit Loss Loans Increase to allowance for credit losses, due to off-balance sheet, credit loss, liability Off-Balance Sheet, Credit Loss, Liability Percent of securities portfolio comprised of U.S. Government and Government Agency securities, minimum Percent Of Securities Portfolio, U.S. Government And Government Agency Securities, Minimum Percent Of Securities Portfolio, U.S. Government And Government Agency Securities, Minimum Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Future amortization expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] 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] Quantitative information of Level 3 assets Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Carrying amounts and estimated fair value of financial assets and liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Real Estate [Domain] Real Estate [Domain] Multi-family Multifamily [Member] Industry Sector [Axis] Industry Sector [Axis] Industry Sector [Domain] Industry Sector [Domain] Commercial & Industrial (C&I) Commercial and Industrial Sector [Member] Commercial mortgage Real Estate Sector [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial Commercial Portfolio Segment [Member] Receivables acquired with deteriorated credit quality Residential mortgage Residential Mortgage [Member] Factored receivables Real estate loan Real Estate Loan [Member] Transfered from acquired to originated 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 Purchase accounting adjustments to loans Business Combination, Provisional Information, Initial Accounting Incomplete, Loans Business Combination, Provisional Information, Initial Accounting Incomplete, Loans Pledged loans Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value Recorded investment of PCI non-accrual loans, transferred from acquired to originated Financing Receivable, Recorded Investment, Nonaccrual Status, Transferred From Acquired To Originated Financing Receivable, Recorded Investment, Nonaccrual Status, Transferred From Acquired To Originated Loans formally in process of foreclosure Mortgage Loans in Process of Foreclosure, Amount Cash-basis interest income recognized Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method Impaired loans with related allowance recorded Impaired Financing Receivable, with Related Allowance, Recorded Investment Number of contracts, troubled debt restructurings Financing Receivable, Modifications, Number of Contracts Recorded investment, pre-modification Financing Receivable, Troubled Debt Restructuring, Premodification Recorded investment, post-modification Financing Receivable, Troubled Debt Restructuring, Postmodification Troubled debt restructurings Financing Receivable, Troubled Debt Restructuring Charge-offs Charge Offs From Troubled Debt Restructurings Charge Offs From Troubled Debt Restructurings Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Fair Value, Measurements, Nonrecurring Fair Value, Nonrecurring [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Third-Party Technique Third-Party Technique [Member] Third-Party Technique [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Mainly value of taxi medallions Measurement Input, Value Of Taxi Medallions [Member] Measurement Input, Value Of Taxi Medallions [Member] Value of underlying collateral Value of Underlying Collateral [Member] Value of Underlying Collateral [Member] Adjustments for comparable properties Measurement Input, Comparability Adjustment [Member] Adjustments by management to reflect current conditions/selling costs Measurement Input, Cost to Sell [Member] Discount rates Measurement Input, Discount Rate [Member] Prepayment speeds Measurement Input, Prepayment Rate [Member] C&I CRE Commercial Real Estate [Member] Multi-family Consumer Consumer [Member] Consumer [Member] Mortgage servicing rights Mortgage Servicing Rights [Member] Mortgage Servicing Rights [Member] Loan Status [Axis] Loan Status [Axis] Loan Status [Axis] Loan Status [Domain] Loan Status [Domain] Loan Status [Domain] Impaired Impaired [Member] Impaired [Member] Taken in Foreclosure Taken in Foreclosure [Member] Taken in Foreclosure [Member] Weighted Average Weighted Average [Member] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Portfolio loans, impaired, net Impaired loans, measurement input Impaired Loans, Measurement Input Impaired Loans, Measurement Input Assets taken in foreclosure, measurement input Other Real Estate, Foreclosed Assets, And Repossessed Asset, Measurement Input Other Real Estate, Foreclosed Assets, And Repossessed Asset, Measurement Input Mortgage servicing rights, measurement input Servicing Asset, Measurement Input Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Stock options Share-based Payment Arrangement, Option [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Stock-based compensation expense, income tax benefit Share-based Payment Arrangement, Expense, Tax Benefit Proceeds from stock option exercises Proceeds from Stock Options Exercised Investments in Low Income Housing Tax Credits Affordable Housing Program [Text Block] 2020 Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months 2021 Lessee, Operating Lease, Liability, Payments, Due Year Two 2022 Lessee, Operating Lease, Liability, Payments, Due Year Three 2023 Lessee, Operating Lease, Liability, Payments, Due Year Four 2024 Lessee, Operating Lease, Liability, Payments, Due Year Five 2025 and thereafter Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five Total lease payments Lessee, Operating Lease, Liability, Payments, Due Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities 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 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 Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Notes Senior Notes [Member] Subordinated Debt Subordinated Debt [Member] Line of Credit Line of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Senior Notes, 3.50% Senior Notes, 3.50% [Member] Senior Notes, 3.50% [Member] Fair value adjustments Scenario, Adjustment [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (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 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 Debt assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Interest rate Debt Instrument, Interest Rate, Stated Percentage Percentage of acquisition date fair value recorded Fair Value, Debt Assumed, Percentage Recorded For Estimated Fair Value Fair Value, Debt Assumed, Percentage Recorded For Estimated Fair Value Debt, fair value adjustment Debt Instrument, Fair Value Disclosure Effective yield, rate Long-term Debt, Weighted Average Interest Rate, at Point in Time Amount of debt redeemed Extinguishment of Debt, Amount Gain on extinguishment of debt Principal amount Debt Instrument, Face Amount 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 rate 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 Loans and Leases Receivable Disclosure [Table] Loans and Leases Receivable Disclosure [Table] Loans and Leases Receivable Disclosure [Line Items] Loans and Leases Receivable Disclosure [Line Items] Loans transfered from held for investment to held for sale Transfer of Portfolio Loans and Leases to Held-for-sale Loan purchase accounting adjustments transferred from held for investment to held for sale Transfer Of Portfolio Loans Purchase Accounting Adjustments To Held-for-sale Transfer Of Portfolio Loans Purchase Accounting Adjustments To Held-for-sale Gain on sale of residential mortgage loans Gain (Loss) on Sale of Mortgage Loans Residential loans transferred from held for sale to portfolio Transfer of Loans Held-for-sale to Portfolio Loans Financing Receivable, Troubled Debt Restructuring [Table] Financing Receivable, Troubled Debt Restructuring [Table] Financial asset, other than financial asset acquired with credit deterioration Financial Asset, Other than Financial Asset Acquired with Credit Deterioration [Member] Consumer Financial Asset, Period Past Due [Axis] Financial Asset, Period Past Due [Axis] Financial Asset, Period Past Due [Domain] Financial Asset, Period Past Due [Domain] 30-59 days past due Financial Asset, 30 to 59 Days Past Due [Member] 60-89 days past due Financial Asset, 60 to 89 Days Past Due [Member] 90 days past due Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Financing Receivable, Troubled Debt Restructuring [Line Items] Financing Receivable, Troubled Debt Restructuring [Line Items] Current loans Trouble Debt restructuring current loans Trouble Debt restructuring current loans Non-accrual Non Accrual Loans Under Troubled debt restructurings Non accrual loans. Activity in Investments in Low Income Housing Tax Credits Activity in Affordable Housing Program Obligation [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Net unrealized holding gain (loss) on AFS securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Net unrealized holding gain (loss) on securities transferred to held to maturity Net Unrealized Holding Gain (Loss) On Securities Transferred To Held-to-maturity [Member] Net Unrealized Holding Gain (Loss) On Securities Transferred To Held-to-maturity [Member] Net unrealized holding gain (loss) on retirement plans Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Other comprehensive income before reclassification OCI, before Reclassifications, Net of Tax, Attributable to Parent Securities reclassified from held to maturity to available for sale Proceeds from Sale and Maturity of Held-to-maturity Securities Reclassification of the stranded income tax effects from the enactment of the Tax Cuts and Jobs Act of 2017 from accumulated other comprehensive loss Amounts reclassified from AOCI Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] With no related allowance recorded: Impaired Financing Receivable, Unpaid Principal Balance [Abstract] Unpaid principal balance Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Recorded investment Impaired Financing Receivable, with No Related Allowance, Recorded Investment Average recorded investment Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment Interest income recognized Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method Interest income Interest Income, Operating Dividends from the Bank Dividend Income, Investments in Subsidiaries Dividend Income, Investments in Subsidiaries Interest expense Interest Expense Non-interest expense Noninterest Expense Income tax benefit Income before equity in undistributed earnings of the Bank Income (Loss) from Continuing Operations, Before Equity in Undistributed Earnings of Subsidiaries Income (Loss) from Continuing Operations, Before Equity in Undistributed Earnings of Subsidiaries Equity in undistributed (excess distributed) earnings Net income Preferred stock dividends Preferred Stock Dividends and Other Adjustments Net income available to common stockholders Loans evaluated by segment Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Total portfolio loans Allowance evaluated by segment Loan Allowances Individually Evaluated For Impairment By Segment of Loans [Abstract] Loan Allowances Individually Evaluated For Impairment By Segment of Loans [Abstract] Individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Total allowance for loan losses Accumulated other comprehensive income (loss) Accumulated other comprehensive loss, before tax AOCI before Tax, Attributable to Parent Accumulated other comprehensive loss, related tax benefit AOCI Tax, Attributable to Parent Accumulated other comprehensive loss, net Accumulated other comprehensive income (loss) Schedule of Components of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Acquired loans Acquired Loan [Member] Acquired Loan [Member] Gross loans by segment Schedule of Credit Derivatives [Table] Schedule of Credit Derivatives [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] 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 Liabilities Other Liabilities [Member] One Month LIBOR One Month Libor [Member] One Month Libor [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 Derivative liabilities, fair value Cover page. Entities [Table] Entities [Table]