Business Combinations [Abstract] Acquisitions Business Combination Disclosure [Text Block] Statement of Financial Position [Abstract] ASSETS: Assets [Abstract] Cash and due from banks Cash and Due from Banks Securities: Marketable Securities [Abstract] Available for sale, at fair value Available-for-sale Securities Held to maturity, at amortized cost (fair value of $2,863,909, and $1,357,997 at December 31, 2017 and 2016, respectively) Held-to-maturity Securities 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 Loans and Leases Receivable, Allowance 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 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 Deposits FHLB borrowings Long-term Federal Home Loan Bank Advances Other borrowings (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 18.) 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, 2017) Preferred Stock, Value, Issued Common stock (par value $0.01 per share; 310,000,000 and 190,000,000 shares authorized at 2017 and 2016, respectively; 229,872,925 and 141,043,149 shares issued at 2017 and 2016, respectively; 224,782,694 and 135,257,570, outstanding at 2017 and 2016, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Treasury stock, at cost (5,090,231 shares and 5,785,579 shares at December 31, 2017 and 2016, respectively) Treasury Stock, Value Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss, net of tax (benefit) of ($17,083) at December 31, 2017 and ($17,390) at December 31, 2016 Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Debt Instruments [Abstract] Borrowings, Senior Notes and Subordinated Notes Debt Disclosure [Text Block] Derivative Instruments and Hedges, Assets [Abstract] Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Summary of Company's stock option activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [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] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Quarterly Financial Information Disclosure [Abstract] Interest and dividend income Interest and Dividend Income, Operating Interest expense Interest Expense Net interest income Interest Income (Expense), Net Provisions for loan losses Provision for Loan and Lease Losses Non-interest income Noninterest Income Non-interest expense Noninterest Expense Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Preferred stock dividend Preferred Stock Dividends and Other Adjustments Net income available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Basic (USD per share) Earnings Per Share, Basic Diluted (USD per share) Earnings Per Share, Diluted Estimated deferred tax adjustment related to reduction in federal income tax rate Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Other restructuring charges Restructuring Charges Charge of asset write-downs, systems integration, severance and retention Restructuring Costs and Asset Impairment Charges 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 Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Stock options Employee Stock Option [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Fair value of options granted determined using weighted-average assumptions as grant date Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected stock price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Expected term in years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term 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 gain (loss) on AFS securities Accumulated Net Investment Gain (Loss) Attributable to 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 (loss) income AOCI 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] Balance Other comprehensive income before reclassification OCI, before Reclassifications, Net of Tax, Attributable to Parent Amounts reclassified from AOCI Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Total other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Balance Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of reporting units Number of Reporting Units Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [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] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Acquired intangible assets, weighted average useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] $6.71 to $9.00 Range One [Member] Range One [Member] $9.28 to $11.36 Range Two [Member] Range Two [Member] $11.36 to $13.18 Range Three [Member] Range Three [Member] $13.23 to $15.01 Range Four [Member] Range Four [Member] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Range of exercise price, lower range limit (USD per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit Range of exercise price, upper range limit (USD per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract] Outstanding, Number of stock options (in shares) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Outstanding, Weighted-average exercise price (USD per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price Outstanding, Weighted-average life (in years) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term Exercisable, Number of stock options (in shares) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options Exercisable, Weighted-average exercise price (USD per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land and land improvements Land and Land Improvements [Member] Buildings Building [Member] Leasehold improvements Leasehold Improvements [Member] Furniture, fixtures and equipment Furniture, Fixtures and Equipment [Member] Furniture, Fixtures and Equipment [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Total premises and equipment, gross Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total premises and equipment, net Depreciation and amortization of premises and equipment Depreciation, Depletion and Amortization Fair Value Disclosures [Abstract] 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 Inputs, Assets, Quantitative Information [Table Text Block] Carrying amounts and estimated fair value of financial assets and liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Cash pledged as collateral for swaps Derivative, Collateral, Right to Reclaim Cash Premises and equipment, useful life Property, Plant and Equipment, Useful Life Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Investment Type [Axis] Investment Type [Axis] Investment Type Categorization [Domain] Investments [Domain] Agency-backed Agency Securities [Member] CMO/Other MBS Collateralized Mortgage Obligations [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] Other Other Investment Securities [Member] Other investment securities. Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Residential MBS Residential Mortgage Backed Securities [Member] Other securities Securities Investment [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Available for Sale Available-for-sale Securities [Abstract] Amortized cost Available-for-sale Securities, Amortized Cost Basis Gross unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Held to Maturity Held-to-maturity Securities [Abstract] Amortized cost Gross unrealized gains Held-to-maturity Securities, Accumulated Unrecognized Holding Gain Gross unrealized losses Held-to-maturity Securities, Accumulated Unrecognized Holding Loss Fair value Held-to-maturity Securities, Fair Value 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] NSBC NewStar Business Credit LLC [Member] NewStar Business Credit LLC [Member] HVB Merger Hudson Valley Holding Corp [Member] Hudson Valley Holding Corp [Member] Damian Damian Services Corporation [Member] Damian Services Corporation [Member] Customer lists Customer Lists [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] 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. Building Improvements and Equipment Building Improvements And Equipment [Member] Building Improvements And Equipment [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] GE Capital GE Capital [Member] GE Capital [Member] FCC, LLC FCC, LLC [Member] FCC, LLC [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] 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 Acquired goodwill Goodwill, Acquired During Period Acquired intangible assets Finite-lived Intangible Assets Acquired Portfolio loan acquired, unpaid principal balance Loans And Leases Receivable, Unpaid Principal Balance Loans And Leases Receivable, Unpaid Principal Balance Portfolio loans purchased Payments to Acquire Loans Receivable Discount rate on acquired portfolio loan Loans and Leases Receivable, Purchase Discount Rate Loans And Leases Receivable, Purchase Discount Rate Discount amount on acquired loan receivable Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Percentage of outstanding common stock acquired Business Acquisition, Percentage of Voting Interests Acquired Loans receivable acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets Premium paid for loans receivable acquired as a percent of gross loans acquired Business Combination, Premium Paid For Loans Receivable, Percent Of Gross Loans Business Combination, Premium Paid For Loans Receivable, Percent Of Gross Loans Premium paid for loans receivable acquired Business Combination, Premium Paid For Loans Receivable, Amount Business Combination, Premium Paid For Loans Receivable, Amount Liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Intangible asset acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Estimated useful life Finite-Lived Intangible Asset, Useful Life Restructuring charges Common stock issued as consideration, shares Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Consideration paid Business Combination, Consideration Transferred Loans Useful life Merger-related expense Business Combination, Acquisition Related Costs Cash consideration Payments to Acquire Businesses, Gross Outstanding finance loans acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Outstanding factoring receivables balance acquired Factored Receivables, Acquired Factored Receivables, Acquired Factoring receivables, purchase price Financing Receivable, Significant Purchases Premium for factoring receivables acquired Premium Paid For Factored Receivables Acquired Premium Paid For Factored Receivables Acquired Closing share price (in dollars per share) Business Acquisition, Share Price Net assets acquired, book value Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Charge of asset write-downs, systems integration, severance and retention Asset Impairment, Severance, And Retention Charges Asset Impairment, Severance, And Retention Charges Receivables [Abstract] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] 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] Loss Unlikely to be Collected Financing Receivable [Member] 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] Consumer Consumer Portfolio Segment [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Gross loans by segment Financing Receivable, Net Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [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] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Federal agencies US Government Corporations and Agencies Securities [Member] Corporate bonds State and municipal 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] Summary of Assets and Liabilities measured at estimated fair value on a recurring basis Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] Investment securities available for sale: Investment Securities Available For Sale [Abstract] Investment securities available for sale. Residential MBS: Mortgage Backed Securities Residential [Abstract] Mortgage backed securities residential. Mortgage-backed securities-residential Mortgage-backed Securities Available-for-sale, Fair Value Disclosure Other securities: Investment Securities [Abstract] Investment securities. Total investment securities available for sale Investments, Fair Value Disclosure Securities available for sale Swaps Derivative Asset Total assets Assets, Fair Value Disclosure Swaps Derivative Liability Total liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Schedule of Quarterly Financial Information Quarterly Financial Information [Table Text Block] 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] Amortized cost, One year or less Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Amortized cost, One to five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Amortized cost, Five to ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Amortized cost, Greater than ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Amortized cost, Total securities with a stated maturity date Available-for-sale Debt Securities, Amortized Cost Basis Amortized cost, Available for sale securities Fair value, One year or less Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Fair value, One to five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Fair value, Five to ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Fair value, Greater than ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Fair value, Total securities with a stated maturity date Available-for-sale Securities, Debt Securities Fair value, Available for sale securities Amortized cost, One year or less Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount Amortized cost, One to five years Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount Amortized cost, Five to ten years Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount Amortized cost, Greater than ten years Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount Amortized cost, Total securities with a stated maturity date Held to Maturity Debt Maturities Net Carrying Amount Held to Maturity Debt Maturities Net Carrying Amount Amortized cost, Held to maturity securities Fair value, One year or less Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value Fair value, One to five years Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value Fair value, Five to ten years Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value Fair value, Greater than ten years Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value Fair value, Total securities with a stated maturity date Held to maturity Debt Maturities Fair value Held to maturity Debt Maturities Fair value Schedule of off-balance-sheet financial instruments Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block] Statement of Comprehensive Income [Abstract] Net income Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Change in unrealized holding gains (losses) on securities available for sale Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Change in net unrealized gain 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 Reclassification adjustment for net realized losses (gains) included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Change in funded status of defined benefit plans and acceleration of future amortization of accumulated other comprehensive (gain) loss on defined benefit pension plan Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Total other comprehensive income (loss) items Other Comprehensive Income (Loss), before Tax Related income tax (expense) benefit Other Comprehensive Income (Loss), Tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Portfolio Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] 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] 2014 Stock Incentive Plan 2014 Stock Incentive Plan [Member] [Member] 2014 Stock Incentive Plan [Member] [Member] 2012 Stock Plan 2012 Stock Plan [Member] 2012 Stock Plan [Member] 2015 Plan 2015 Omnibus Equity And Incentive Plan [Member] 2015 Omnibus Equity And Incentive Plan [Member] Non-vested stock awards/performance units Non-vested Stock Awards and Performance Units [Member] Non-vested Stock Awards and Performance Units [Member] Stock Compensation Grants associated with legacy Sterling Merger Stock Compensation Grants associated with legacy Sterling Merger [Member] Stock Compensation Grants associated with legacy Sterling Merger [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 Stock Incentive Plan (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Approval Of Incentive Plan, Additions Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Available For Grant, Approval Of Incentive Plan, Additions 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 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 (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 (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Number of shares granted for each share received Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Number of Shares Received for each Share Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Number of Shares Received for each Share Granted Postemployment Benefits [Abstract] 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] Changes in projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Beginning of year balance Defined Benefit Plan, Benefit Obligation Obligations assumed in acquisitions Defined Benefit Plan, Benefit Obligation, Business Combination Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Actuarial loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid End of year balance Changes in fair value of plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Beginning of year balance Defined Benefit Plan, Fair Value of Plan Assets Fair value of pension plan assets at October 2, 2017 Defined Benefit Plan, Plan Assets, Business Combination Actual gain on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Plan termination / Partial settlement Defined Benefit Plan, Plan Assets, Payment for Settlement End of year balance Reversion asset / Funded status at end of year Defined Benefit Plan, Funded (Unfunded) Status of Plan 2018 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value, Measurements, Nonrecurring Fair Value, Measurements, Nonrecurring [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Appraisal Market Approach Valuation Technique [Member] Third-party Third-Party Technique [Member] Third-Party Technique [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] Commercial and industrial CRE Commercial Real Estate [Member] Residential mortgage Residential Mortgage [Member] Mortgage servicing rights Mortgage Servicing Rights [Member] Mortgage Servicing Rights [Member] Weighted Average Weighted Average [Member] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Loans, net Loans Receivable, Fair Value Disclosure Mortgage servicing rights Servicing Asset at Fair Value, Amount Comparability adjustments Fair Value Inputs, Comparability Adjustments Current conditions/selling cost adjustments Fair Value Inputs, Discount for Lack of Marketability Discount rates Fair Value Inputs, Discount Rate Prepayment speed Fair Value, Prepayment Speed Fair Value, Prepayment Speed Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] PRIAC Pooled Separate Accounts PRIAC Pooled Separate Accounts [Member] PRIAC Pooled Separate Accounts [Member] Sterling Bancorp common stock Sterling Bancorp Common Stock [Member] Sterling Bancorp Common Stock [Member] PRIAC Guaranteed Deposit Account PRIAC Guaranteed Deposit Account [Member] PRIAC Guaranteed Deposit Account [Member] Cash and cash equivalents Cash and Cash Equivalents [Member] Large-cap equity Large-Cap Equity [Member] Large-Cap Equity [Member] Fixed income Fixed Income Securities [Member] International equity International Equity Securities [Member] International Equity Securities [Member] Small-cap equity Small-Cap Equity Securities [Member] Small-Cap Equity Securities [Member] Mid-cap equity Mid-Cap Equity Securities [Member] Mid-Cap Equity Securities [Member] Fair value of plan assets Plan asset allocations Defined Benefit Plan, Actual Plan Asset Allocations 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 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 Financial Instruments Owned and Pledged as Collateral [Table] Financial Instruments Owned and Pledged as Collateral [Table] Financial Instruments Owned and Pledged as Collateral by Type [Axis] Financial Instruments Owned and Pledged as Collateral by Type [Axis] Financial Instruments Owned and Pledged as Collateral, Type [Domain] Financial Instruments Owned and Pledged as Collateral, Type [Domain] Federal Home Loan Bank Borrowings Federal Home Loan Bank Borrowings [Member] Municipal Deposits Municipal Deposits [Member] Municipal deposits. Interest Rate Swap Interest Rate Swap [Member] Financial Instruments Owned and Pledged as Collateral [Line Items] Financial Instruments Owned and Pledged as Collateral [Line Items] Available-for-sale securities pledged as collateral Available-for-sale Securities Pledged as Collateral Held-to-maturity securities pledged as collateral Held-to-maturity Securities Pledged as Collateral Total securities pledged Total Pledged Securities Total Pledged Securities Accumulated Other Comprehensive (Loss) Income Comprehensive Income (Loss) Note [Text Block] Accounting Changes and Error Corrections [Abstract] Recently Issued Accounting Standards New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Net interest income Business Acquisition, Pro Forma Interest Income (Expense), Net Business Acquisition, Pro Forma Interest Income (Expense), Net Non-interest income Business Acquisition, Pro Forma Noninterest Income Business Acquisition, Pro Forma Noninterest Income Non-interest expense Business Acquisition, Pro Forma Noninterest Expense Business Acquisition, Pro Forma Noninterest Expense Net income Business Acquisition, Pro Forma Net Income (Loss) Pro forma earnings per share from continuing operations: Earnings Per Share, Pro Forma [Abstract] Basic (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Diluted (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Deposits [Abstract] Deposits Deposit Liabilities Disclosures [Text Block] 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 year Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Acquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Disposals 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 from Nonaccretable Difference Balance at end of year Purchased credit impaired loans 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. Savings Savings [Member] Savings [Member] Reciprocal CDARs Reciprocal CDAR's [Member] Reciprocal CDAR's. CDARs one way CDAR's One Way [Member] CDAR's 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 Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2018 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2019 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2020 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Thereafter Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter 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] Subsidiaries [Member] Subsidiaries [Member] Sterling Bancorp Parent Company [Member] Sterling National Bank Sterling National Bank [Member] Sterling National Bank [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 ratio, 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 ratio, 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 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, Actual, 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 ratio, 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, Actual, 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 ratio, 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 ratio, 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 leverage ratio, Actual, Capital amount Tier One Leverage Capital Tier 1 (core) capital, Actual, 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 ratio, 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 ratio, 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 Legacy Sterling 2013 Employment Inducement Award Plan Legacy Sterling 2013 Employment Inducement Award Plan [Member] Legacy Sterling 2013 Employment Inducement Award Plan [Member] Prior Plan Prior Share-Based Compensation Plan [Member] Prior Share-Based Compensation Plan [Member] Fully Vested legacy Sterling options Fully Vested legacy Sterling options [Member] Fully Vested legacy Sterling options [Member] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Sterling Bancorp (Legacy) Sterling Bancorp (Legacy) [Member] Sterling Bancorp (Legacy) [Member] 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) Number of shares granted for each share received (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Grants in Period, Number of Shares Received for each Share Granted Share-based Compensation Arrangement by Share-based Payment Award, Grants in Period, Number of Shares Received for each Share Granted 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 Grant of share options (in shares) Exercise price (USD per share) Options outstanding (in shares) Grants in period, other than options (in shares) Weighted average grant date fair value (USD per share) Intrinsic value of options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Intrinsic value of options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Proceeds from stock option exercises Proceeds from Stock Options Exercised Weighted average fair value of options granted (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value 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 Summary of securities available for sale Available-for-sale Securities [Table Text Block] Summary of securities held-to-maturity Held-to-maturity Securities [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 Sale of Securities [Table Text Block] Sale of Securities [Table Text Block] Securities available for sale with unrealized losses, by length of time in continuous unrealized loss position Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Securities held to maturity with unrealized losses, by length of time in continuous unrealized loss position Held To Maturity Securities Continuous Unrealized Loss Position [Table Text Block] Held to maturity securities continuous unrealized loss position. 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] Premises and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Non-compete agreements Noncompete Agreements [Member] Trade name Trade Names [Member] Fair value of below market leases Off-Market Favorable Lease [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross intangible assets Finite-Lived Intangible Assets, Gross Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Net intangible assets Amortization of intangible assets Amortization of Intangible Assets 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 Notes 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 Note, 5.50% Senior Note, 5.50% [Member] Senior Note, 5.50% [Member] Senior Notes, 3.50% Senior Notes, 3.50% [Member] Senior Notes, 3.50% [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Fair value adjustments Scenario, Adjustment [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] 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 Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value Increased borrowing capacity by pledging securities Market Value Of Mortgage Not Required To Be Pledged Market value of mortgage not required to be pledged. Interest rate Debt Instrument, Interest Rate, Stated Percentage Debt, fair value Debt Instrument, Fair Value Disclosure Gain (loss) on extinguishment of borrowings Gain (Loss) on Extinguishment of Debt Debt assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Repurchase agreements maturity Repurchase Agreements, Maturity Period Repurchase Agreements, Maturity Period Long-term debt Long-term Debt Fixed interest rate Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate Private placement discount rate Private placement discount rate Private placement discount rate Debt issuance costs Debt Issuance Costs, Gross Unamortized discount Debt Instrument, Unamortized Discount Effective yield, rate Long-term Debt, Weighted Average Interest Rate, at Point in Time Amount of debt redeemed Extinguishment of Debt, Amount Principal amount Debt Instrument, Face Amount Issue premium Debt Instrument, Issue Premium, Percentage Debt Instrument, Issue Premium, Percentage 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 Employee Savings Plan Employee Savings Plan [Member] Employee Savings Plan [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets Other Assets [Member] Other Liabilities Other Liabilities [Member] Equity securities Equity Securities [Member] Debt securities Debt Securities [Member] Liquidity funds Any one company Any One Company [Member] Any One Company [Member] Any one industry Any One Industry [Member] Any One Industry [Member] Funds that mirror S&P 500 Funds That Mirror Standard And Poor's 500 [Member] Funds That Mirror Standard And Poor's 500 [Member] Limited Sterling Bancorp Common Stock, Due to Merger Limited Sterling Bancorp Common Stock, Due to Merger [Member] Limited Sterling Bancorp Common Stock, Due to Merger [Member] Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Anticipated future contribution, next fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Lump sum distributions as elected by Plan participants Plan termination / Partial settlement charge Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Change in fair value of Plan assets Defined Benefit Plan, Plan Assets, Period Increase (Decrease) Remaining balance of accumulated other comprehensive loss through earnings recognized Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Settlements, Before Tax Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Settlements, Before Tax Difference between effective tax rate and marginal tax rate Effective Income Tax Rate Reconciliation, Settlements of Pension and Other Postretirement Defined Benefit Plans Effective Income Tax Rate Reconciliation, Settlements of Pension and Other Postretirement Defined Benefit Plans Remaining reversion asset Defined Benefit Plan, Reversion Asset, Due To Settlement Defined Benefit Plan, Reversion Asset, Due To Settlement Remaining reversion asset, recognition period Defined Benefit Plan, Reversion Asset, Recognition Period Defined Benefit Plan, Reversion Asset, Recognition Period Assumed SERP liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Postretirement Defined Benefit Plan, Liabilities Assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Postretirement Defined Benefit Plan, Liabilities Assumed Maximum contribution by employee, percent Defined Contribution Plan, Maximum Contribution by Employee, Percent Defined Contribution Plan, Maximum Contribution by Employee, Percent Maximum contribution by employer, percent of employee contribution Defined Contribution Plan, Maximum Contribution by Employer, Percent of Employee Contribution Defined Contribution Plan, Maximum Contribution by Employer, Percent of Employee Contribution Maximum annual contribution per employee, percent Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Savings plan expense Defined Contribution Plan, Cost Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivables Acquired with Deteriorated Credit Quality [Axis] Receivables Acquired with Deteriorated Credit Quality [Axis] Receivables Acquired with Deteriorated Credit Quality [Domain] Receivables Acquired with Deteriorated Credit Quality [Domain] Receivables without deteriorated credit quality Receivables Without Deteriorated Credit Quality [Member] Receivables Without Deteriorated Credit Quality [Member] Receivables acquired with deteriorated credit quality Receivables Acquired with Deteriorated Credit Quality [Member] Factored receivables Consumer Consumer Loan [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Non accrual loans Financing Receivable, Recorded Investment, Nonaccrual Status Non-accrual loans, unpaid principal balance Financing Receivable, Recorded Investment, Nonaccrual Status, Unpaid Principal Balance Financing Receivable, Recorded Investment, Nonaccrual Status, Unpaid Principal Balance Loans formally in process of foreclosure Mortgage Loans in Process of Foreclosure, Amount Earnings Per Share [Abstract] Earnings Per Common Share Earnings Per Share [Text Block] Proceeds from sales Proceeds from Sale of Available-for-sale Securities Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Income tax (benefit) expense on realized net (losses) gains Tax Expense (Benefit) Of Securities Gains Tax expense (benefit) of securities gains Financial Instrument [Axis] Financial Instrument [Axis] Types of Financial Instruments [Domain] Financial Instruments [Domain] Portfolio loans, impaired, net Income Tax Disclosure [Abstract] 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] 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] 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 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 Accrued post retirement expense Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits Deferred rent Deferred tax assets deferred rent Deferred tax assets deferred rent Intangible assets Deferred Tax Assets, Goodwill and Intangible Assets Other comprehensive loss (securities) Deferred Tax Assets, Other Comprehensive Loss Other comprehensive loss (defined benefit plans) Deferred tax assets, other comprehensive loss- Defined benefit plans Deferred tax assets, other comprehensive loss- Defined benefit plans Pension expense Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions Accrued expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals State NOL carryforward Deferred Tax Assets, Operating Loss Carryforwards, State and Local AMT credit carryforward Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross Deferred tax liabilities: Deferred Tax Liabilities, Net [Abstract] Mortgage servicing rights Deferred Tax Liabilities, Mortgage Servicing Rights Prepaid pension costs Deferred tax liability prepaid pension cost Deferred tax liability prepaid pension cost 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 Deferred Tax Liabilities, Property, Plant and Equipment Deferred loan fees and costs Deferred Tax Liabilities, Deferred Loans Fees And Costs Deferred Tax Liabilities, Deferred Loans Fees And Costs Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax asset Deferred Tax Assets, Net Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] 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] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Current loans Trouble Debt restructuring current loans Trouble Debt restructuring current loans Troubled debt restructurings Financing Receivable, Modifications, Recorded Investment Non-accrual Non Accrual Loans Under Troubled debt restructurings Non accrual loans. 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. Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Stock-based compensation expense Allocated Share-based Compensation Expense Stock-based compensation expense, income tax benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Stock options Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options Non-vested stock awards/performance units Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Total Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Securities held to maturity Preferred stock, par value (USD per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value (USD per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Treasury stock, shares Treasury Stock, Shares Accumulated other comprehensive income, tax expense (benefit) AOCI Tax, Attributable to Parent Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2018 Operating Leases, Future Minimum Payments, Due in Two Years 2019 Operating Leases, Future Minimum Payments, Due in Three Years 2020 Operating Leases, Future Minimum Payments, Due in Four Years 2021 Operating Leases, Future Minimum Payments, Due in Five Years 2022 Operating Leases, Future Minimum Payments, Due in Six Years Operating Leases, Future Minimum Payments, Due in Six Years 2023 and thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total future minimum payments Operating Leases, Future Minimum Payments Due Rent expense Operating Leases, Rent Expense 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. Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] 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 Cash-basis interest income recognized Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method Schedule of future minimum lease payments due Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] 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 Fair value, Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Unrealized losses, Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Fair value, 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Unrealized losses, 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair value, Total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Unrealized losses, Total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Other Income and Expenses [Abstract] Advertising and promotion Marketing and Advertising Expense Professional fees Professional Fees