Sterling Bancorp (STL) 10-K 1 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 26, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Registrant Name	STERLING BANCORP
Entity Central Index Key	1,070,154
Document Period End Date	Dec. 31, 2017
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		224,724,542
Entity Public Float			$ 3,154,053,755
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ASSETS:
Cash and due from banks	$ 479,906	$ 293,646
Securities:
Available for sale, at fair value	3,612,072	1,727,417
Held to maturity, at amortized cost (fair value of $2,863,909, and $1,357,997 at December 31, 2017 and 2016, respectively)	2,862,489	1,391,421
Total securities	6,474,561	3,118,838
Loans held for sale	5,246	41,889
Portfolio loans	20,008,983	9,527,230
Allowance for loan losses	(77,907)	(63,622)
Portfolio loans, net	19,931,076	9,463,608
Federal Home Loan Bank (“FHLB”) and Federal Reserve Bank stock, at cost	284,112	135,098
Accrued interest receivable	94,098	43,319
Premises and equipment, net	321,722	57,318
Goodwill	1,579,891	696,600
Core deposit and other intangible assets	153,191	66,353
Bank owned life insurance	651,638	199,889
Other real estate owned	27,095	13,619
Other assets	357,005	48,270
Total assets	30,359,541	14,178,447
LIABILITIES:
Deposits	20,538,204	10,068,259
FHLB borrowings	4,510,123	1,791,000
Other borrowings (repurchase agreements)	30,162	16,642
Senior notes	278,209	76,469
Subordinated notes	172,716	172,501
Mortgage escrow funds	122,641	13,572
Other liabilities	467,308	184,821
Total liabilities	26,119,363	12,323,264
Commitments and Contingent liabilities (See Note 18.)	0	0
STOCKHOLDERS’ EQUITY:
Preferred stock (par value $0.01 per share; 10,000,000 shares authorized; 135,000 shares issued and outstanding at December 31, 2017)	139,220	0
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)	2,299	1,411
Additional paid-in capital	3,780,908	1,597,287
Treasury stock, at cost (5,090,231 shares and 5,785,579 shares at December 31, 2017 and 2016, respectively)	(58,039)	(66,188)
Retained earnings	401,956	349,308
Accumulated other comprehensive loss, net of tax (benefit) of ($17,083) at December 31, 2017 and ($17,390) at December 31, 2016	(26,166)	(26,635)
Total stockholders’ equity	4,240,178	1,855,183
Total liabilities and stockholders’ equity	$ 30,359,541	$ 14,178,447

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Securities held to maturity	$ 2,863,909	$ 1,357,997
Preferred stock, par value (USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	135,000	0
Preferred stock, shares outstanding	135,000	0
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	310,000,000	190,000,000
Common stock, shares issued	229,872,925	141,043,149
Common stock, shares outstanding	224,782,694	135,257,570
Treasury stock, shares	5,090,231	5,785,579
Accumulated other comprehensive income, tax expense (benefit)	$ (17,083)	$ (17,390)

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest and dividend income:
Loans, including fees	$ 570,761,000	$ 390,847,000	$ 292,496,000
Taxable securities	65,278,000	42,540,000	39,369,000
Non-taxable securities	37,245,000	23,669,000	12,076,000
Other earning assets	9,165,000	4,495,000	4,200,000
Total interest and dividend income	682,449,000	461,551,000	348,141,000
Interest expense:
Deposits	56,110,000	33,189,000	17,478,000
Borrowings	50,196,000	24,093,000	19,447,000
Total interest expense	106,306,000	57,282,000	36,925,000
Net interest income	576,143,000	404,269,000	311,216,000
Provisions for loan losses	26,000,000	20,000,000	15,700,000
Net interest income after provision for loan losses	550,143,000	384,269,000	295,516,000
Non-interest income:
Accounts receivable management / factoring commissions and other related fees	17,803,000	17,695,000	17,088,000
Deposit fees and service charges	17,128,000	15,166,000	15,871,000
Loan commissions and fees	11,637,000	9,524,000	4,869,000
Bank owned life insurance	7,816,000	5,832,000	5,235,000
Investment management fees	2,928,000	3,710,000	2,397,000
Mortgage banking income	524,000	6,173,000	11,405,000
Net (loss) gain on sale of securities	(344,000)	7,522,000	4,837,000
Other	6,710,000	5,365,000	1,049,000
Total non-interest income	64,202,000	70,987,000	62,751,000
Non-interest expense:
Compensation and employee benefits	149,948,000	125,916,000	104,939,000
Stock-based compensation plans	8,111,000	6,518,000	4,581,000
Occupancy and office operations	43,649,000	34,486,000	32,915,000
Amortization of intangible assets	13,008,000	12,416,000	10,043,000
FDIC insurance and regulatory assessments	11,969,000	8,240,000	7,380,000
Other real estate owned, net	3,423,000	2,051,000	274,000
Merger-related expense	39,232,000	265,000	17,079,000
Charge of asset write-downs, systems integration, severance and retention	105,110,000	4,485,000	29,046,000
Defined benefit plan termination charge	0	0	13,384,000
Loss on extinguishment of borrowings	0	9,729,000	0
Other	58,925,000	43,796,000	40,677,000
Total non-interest expense	433,375,000	247,902,000	260,318,000
Income before income taxes	180,970,000	207,354,000	97,949,000
Income tax expense	87,939,000	67,382,000	31,835,000
Net income	93,031,000	139,972,000	66,114,000
Preferred stock dividend		0	0
Net income available to common stockholders	$ 91,029,000	$ 139,972,000	$ 66,114,000
Weighted average common shares:
Basic (in shares)	157,513,639	130,607,994	109,907,645
Diluted (in shares)	158,124,270	131,234,462	110,329,353
Earnings per common share:
Basic (USD per share)	$ 0.58	$ 1.07	$ 0.60
Diluted (USD per share)	$ 0.58	$ 1.07	$ 0.60

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 93,031	$ 139,972	$ 66,114
Other comprehensive income (loss):
Change in unrealized holding gains (losses) on securities available for sale	173	(17,723)	(9,591)
Change in net unrealized gain on securities transferred to held to maturity	969	1,473	1,412
Reclassification adjustment for net realized losses (gains) included in net income	344	(7,522)	(4,837)
Change in funded status of defined benefit plans and acceleration of future amortization of accumulated other comprehensive (gain) loss on defined benefit pension plan	(711)	390	9,758
Total other comprehensive income (loss) items	775	(23,382)	(3,258)
Related income tax (expense) benefit	(306)	8,871	1,385
Other comprehensive income (loss)	469	(14,511)	(1,873)
Total comprehensive income	$ 93,500	$ 125,461	$ 64,241

Consolidated Statement of Chang

Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred stock	Common stock	Common stock	Common stockCommon stock	Preferred stock	Preferred stockPreferred stock	Additional paid-in capital	Additional paid-in capitalCommon stock	Treasury stock	Retained earnings	Accumulated other comprehensive (loss) income
Balance at Dec. 31, 2014	$ 975,200			$ 912				$ 858,489		$ (82,908)	$ 208,958	$ (10,251)
Balance, shares at Dec. 31, 2014				83,927,572
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	66,114										66,114
Other comprehensive income	(1,873)											(1,873)
Common stock issued in Merger transaction	563,613			$ 386				563,227
Common stock issued in Merger transaction, shares				38,525,154
Stock option & other stock transactions, net	5,162							940		3,502	720
Stock option & other stock transactions, net, shares				322,132
Restricted stock awards, net	2,182							(1,034)		3,216
Restricted stock awards, net, shares				332,068
Common equity issued, net of costs of issuance	85,059			$ 69				84,990
Common equity issued, net of costs of issuance, shares				6,900,000
Cash dividends declared, common	(30,384)										(30,384)
Balance at Dec. 31, 2015	1,665,073			$ 1,367				1,506,612		(76,190)	245,408	(12,124)
Balance, shares at Dec. 31, 2015				130,006,926
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	139,972										139,972
Other comprehensive income	(14,511)											(14,511)
Stock option & other stock transactions, net	5,182							486		5,894	(1,198)
Stock option & other stock transactions, net, shares				499,659
Restricted stock awards, net	4,923							(762)		4,108	1,577
Restricted stock awards, net, shares				380,985
Common equity issued, net of costs of issuance	90,995			$ 44				90,951
Common equity issued, net of costs of issuance, shares				4,370,000
Cash dividends declared, common	(36,451)										(36,451)
Balance at Dec. 31, 2016	1,855,183			$ 1,411				1,597,287		(66,188)	349,308	(26,635)
Balance, shares at Dec. 31, 2016				135,257,570
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	93,031										93,031
Other comprehensive income	469											469
Common stock issued in Merger transaction		$ 139,412	$ 2,189,687		$ 888		$ 139,412		$ 2,188,799
Common stock issued in Merger transaction, shares					88,829,776	135,000
Stock option & other stock transactions, net	2,727							149		3,328	(750)
Stock option & other stock transactions, net, shares				244,252
Restricted stock awards, net	5,898							(5,327)		4,821	6,404
Restricted stock awards, net, shares				451,096
Cash dividends declared, common	(44,035)										(44,035)
Cash dividends paid, preferred	(2,194)					$ (192)					(2,002)
Balance at Dec. 31, 2017	$ 4,240,178			$ 2,299		$ 139,220		$ 3,780,908		$ (58,039)	$ 401,956	$ (26,166)
Balance, shares at Dec. 31, 2017				224,782,694

Consolidated Statement of Chan7

Consolidated Statement of Changes in Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Common stock, cash dividends paid (USD per share)	$ 0.28	$ 0.28	$ 0.28
Preferred stock, cash dividends paid (USD per share)	$ 16.25
Preferred stock
Common stock issued in Merger transaction, shares	135,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 93,031	$ 139,972	$ 66,114
Adjustments to reconcile net income to net cash provided by operating activities:
Provisions for loan losses	26,000	20,000	15,700
Charge of asset write-downs, systems integration, severance and retention	105,110	4,485	40,350
Charge for termination of defined benefit pension plans	0	0	13,384
Loss on extinguishment of borrowings	0	9,729	0
Loss (gain) and write-downs on other real estate owned	1,715	294	(1,066)
Loss on sale of premises and equipment	0	0	116
Depreciation and amortization of premises and equipment	11,670	8,375	7,476
Amortization of intangibles	13,008	12,416	10,043
Net gains on loans held for sale	(954)	(7,591)	(11,405)
Net losses (gains) on sales of securities	344	(7,522)	(4,837)
Net (gain) on sale of trust division	0	(2,255)	0
Net (accretion) on loans	(44,242)	(18,093)	(10,555)
Net amortization of premiums on securities	24,061	16,024	5,916
Amortization of premium on certificates of deposit	(1,722)	0	0
Net accretion of discount, (amortization of premium) on borrowings	144	1,053	(81)
Restricted stock expense	7,961	6,114	3,671
Stock option compensation expense	149	404	909
Originations of loans held for sale	(6,224)	(447,950)	(599,853)
Proceeds from sales of loans held for sale	44,318	447,762	623,747
Increase in cash surrender value of BOLI	(7,816)	(5,832)	(5,235)
Deferred income tax expense (benefit)	81,383	(890)	339
Other adjustments (principally net changes in other assets and other liabilities)	(105,331)	22,404	(62,977)
Net cash provided by operating activities	242,605	198,899	91,756
Cash flows from investing activities:
Available for sale	(1,585,174)	(976,383)	(1,113,952)
Held to maturity	(1,556,670)	(751,206)	(193,282)
Proceeds from maturities, calls and other principal payments on securities:
Available for sale	276,872	286,371	135,978
Held to maturity	70,847	73,925	45,340
Proceeds from sales of securities available for sale	2,516,308	858,531	893,610
Loan originations, net	(1,054,704)	(1,298,341)	(1,266,519)
Portfolio loans purchased	(226,831)	(163,320)	0
Proceeds from sale of loans held for investment	33,740	121,028	44,020
Proceeds from sales of other real estate owned	8,881	6,205	3,566
Purchase of FHLB and FRB stock, net	(149,014)	(18,340)	(35,491)
Purchase of low income housing tax credit	(14,284)	0	0
Redemption of and benefits received on bank owned life insurance	3,585	2,231	3,700
Purchases of premises and equipment	(8,259)	(4,155)	(8,047)
Cash received from (paid for) acquisitions	275,409	(346,690)	854,318
Net cash (used in) investing activities	(1,409,294)	(2,210,144)	(636,759)
Cash flows from financing activities:
Net increase in transaction, savings and money market deposits	1,309,621	1,509,054	186,431
Net increase (decrease) in time deposits	117,985	(20,802)	20,505
Net (decrease) increase in short-term FHLB borrowings	(189,000)	331,000	127,000
Advances of term FHLB borrowings	3,978,415	1,050,000	605,000
Repayments of term FHLB borrowings	(2,659,464)	(999,896)	(325,243)
Net increase (decrease) in other borrowings	13,520	76	(18,646)
Repayment of Senior Notes	0	(23,793)	0
Repayment of debt assumed in acquisition	(1,143,279)	0	(4,485)
Issuance of Bank Subordinated Notes	0	171,813	0
Net (decrease) increase in mortgage escrow funds	(31,198)	(206)	4,995
Proceeds from stock option exercises	2,578	3,588	2,764
Proceeds from issuance of common equity	0	90,995	85,059
Cash dividends paid - common stock	(44,035)	(36,451)	(30,384)
Cash dividends paid - preferred stock	(2,194)	0	0
Net cash provided by financing activities	1,352,949	2,075,378	652,996
Net increase in cash and cash equivalents	186,260	64,133	107,993
Cash and cash equivalents at beginning of period	293,646	229,513	121,520
Cash and cash equivalents at end of period	479,906	293,646	229,513
Supplemental cash flow information:
Interest payments	114,391	57,971	37,198
Income tax payments	69,675	64,904	39,315
Real estate acquired in settlement of loans	7,967	4,780	11,025
Securities purchased pending settlement	0	24,720
Loans transfered from held for investment to held for sale	33,740	121,028	44,020
Non-cash assets acquired:
Securities available for sale	243,017	0	710,230
Securities held to maturity	2,858,776	0	3,611
Loans held for sale	497	0	0
Total loans, net	9,209,398	320,447	1,814,826
FRB stock	0	0	5,830
Accrued interest receivable	34,094	1,443	7,392
Goodwill	883,291	25,698	281,773
Core deposit and other intangibles	99,938	1,500	42,789
Bank owned life insurance	447,518	0	44,231
Premises and equipment, net	267,815	176	17,063
Other real estate owned	16,105	0	222
Other assets	335,612	2,265	25,871
Total non-cash assets acquired	14,396,061	351,529	2,953,838
Liabilities assumed:
Deposits	9,044,061	0	3,160,746
Escrow deposits	140,267	0	4,616
FHLB and other borrowings	1,589,464	0	0
Other borrowings	1,143,279	0	25,366
Subordinated debentures	201,520	0	0
Other liabilities	223,780	4,839	50,181
Total liabilities assumed	12,342,371	4,839	3,240,909
Preferred stock assumed	139,412	0	0
Net non-cash asset (liabilities) acquired (assumed)	1,914,278	346,690	(287,071)
Cash and cash equivalents acquired in acquisitions	275,409	4,762	879,240
Total consideration paid	$ 2,189,687	$ 351,452	$ 592,169

Basis of Financial Statement Pr

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statement Presentation and Summary of Significant Accounting Policies	Basis of Financial Statement Presentation and Summary of Significant Accounting Policies Nature of Business Sterling Bancorp (“Sterling” or the “Company”) is a bank holding company and financial holding company under the Bank Holding Company Act of 1956 . Sterling is a Delaware corporation that owns all of the outstanding shares of Sterling National Bank (the “Bank”). Sterling is listed on the New York Stock Exchange under the symbol STL. The Bank, an independent, full-service national bank founded in 1888 , is headquartered in Montebello, New York and is the principal subsidiary of Sterling. The Bank accounts for substantially all of Sterling’s consolidated assets and results of operations. The Bank operates through commercial banking teams and financial centers which serve the greater New York metropolitan region. The Bank targets the following geographic markets: (i) the New York Metro Market, which includes Manhattan, the boroughs and Long Island; and (ii) the New York Suburban Market, which consists of Rockland, Orange, Sullivan, Ulster, Putnam and Westchester counties in New York and Bergen County in New Jersey. The Bank also operates its commercial finance businesses, which include asset-based lending, payroll financing, factoring, warehouse lending, equipment financing, public sector financing, which target markets across the U.S. The Bank’s principal business is accepting deposits and, together with funds generated from operations and borrowings, investing in various types of loans and securities. The Bank’s deposits are insured up to applicable limits by the Deposit Insurance Fund of the Federal Deposit Insurance Corporation (“FDIC”). The Office of the Comptroller of the Currency (“OCC”) and the Federal Reserve Board are the primary regulators for the Bank and the Company, respectively. Nature of Operations and Principles of Consolidation The consolidated financial statements include the accounts of Sterling, the Bank and the Bank’s wholly-owned subsidiaries. The Bank’s subsidiaries included at December 31, 2017 : (i) Sterling National Funding Corp, a company that originates loans to municipalities and governmental entities and acquires securities issued by state and local governments; (ii) Sterling REIT, Inc., a real estate investment trust that holds a portion of the Company’s real estate loans; (iii) Provest Services Corp. II, which has engaged a third-party provider to sell mutual funds and annuities to the Bank’s customers; (iv) AF Agency, Inc, which provides various annuity and wealth management products and through contractual agreements with various third parties and makes insurance products available, primarily to customers of the Bank; (v) several limited liability companies which hold other real estate owned; and (vi) several other companies that have no significant operations or assets. Intercompany transactions and balances are eliminated in consolidation. Merger with Astoria Financial Corporation On October 2, 2017 , Astoria Financial Corporation (“Astoria”) merged with and into Sterling (the “Astoria Merger”). In connection with the merger, Astoria Bank, the principal subsidiary of Astoria, also merged with and into the Bank. Merger with Hudson Valley Holding Corp. On June 30, 2015 , Hudson Valley Holding Corp. (“HVHC”) merged with and into Sterling (the “HVB Merger”). In connection with the merger, Hudson Valley Bank, the principal subsidiary of HVHC, also merged with and into the Bank. Merger with Sterling Bancorp On October 31, 2013 , Provident New York Bancorp (“Legacy Provident”) merged with Sterling Bancorp (“Legacy Sterling”). In connection with the merger, the following corporate actions occurred: • Legacy Sterling merged with and into Legacy Provident. Legacy Provident was the accounting acquirer and the surviving entity. • Legacy Provident changed its legal entity name to Sterling Bancorp and became a bank holding company and a financial holding company as defined by the Bank Holding Company Act of 1956, as amended. • Provident Bank converted to a national bank charter. • Sterling National Bank merged into Provident Bank. • Provident Bank changed its legal entity name to Sterling National Bank. We refer to the transactions detailed above collectively as the “Provident Merger.” Use of Estimates To prepare financial statements in conformity with U.S. generally accepted accounting principles management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided and actual results could differ. An estimate that is particularly susceptible to significant near-term change is the allowance for loan losses, which is discussed below. Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation. Reclassifications had no affect on prior period net income or stockholders’ equity. Cash Flows For purposes of reporting cash flows, cash equivalents include cash and deposits with other financial institutions with an original maturity of 90 days or less. Net cash flows are reported for customer loan and deposit transactions, interest bearing deposits in other financial institutions, and federal funds purchased and repurchase agreements. Restrictions on Cash The Bank was required to have $118,113 and $99,594 of cash on hand or on deposit with the Federal Reserve Bank to meet regulatory reserve and clearing requirements at December 31, 2017 and 2016 , respectively. Securities Securities include U.S. government agency and government sponsored agencies securities, state and municipal and corporate bonds, and mortgage-backed securities, including collateralized mortgage obligations and trust preferred securities. The Company classifies its securities among two categories: held to maturity and available for sale. The Company determines the appropriate classification of the Company’s securities at the time of purchase. Held to maturity securities are limited to debt securities for which there is the intent and the ability to hold to maturity. These securities are reported at amortized cost. The Company does not engage in trading activities. All other debt and marketable equity securities are classified as available for sale. Available for sale securities are reported at fair value, with unrealized gains and losses (net of the related deferred income tax effect) excluded from earnings and reported in a separate component of stockholders’ equity (accumulated other comprehensive income or loss). Available for sale securities include securities that the Company intends to hold for an indefinite period of time, such as securities to be used as part of the Company’s asset/liability management strategy or securities that may be sold to fund loan growth, in response to changes in interest rates and prepayment risks, the need to increase capital, or similar factors. Premiums on debt securities are amortized in interest income on a level yield basis over the earlier of the call date or maturity. Discounts on debt securities are accreted in interest income on a level yield basis over the period to maturity. Amortization of premiums and accretion of discounts on mortgage-backed securities are based on the estimated cash flows of the mortgage-backed securities, periodically adjusted for changes in estimated lives, on a level yield basis. The cost of securities sold is determined using the specific identification method. Securities are evaluated for other-than-temporary-impairment (“OTTI”) at least quarterly, and more frequently when economic and market conditions warrant such an evaluation. For securities in an unrealized loss position, the Company considers the extent and duration of the unrealized loss, and the financial condition of the issuer. The Company also assesses whether it intends to sell, or is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either criteria regarding intent to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. If (i) the Company does not expect to recover the entire amortized cost basis of the security; (ii) the Company does not intend to sell the security; (iii) and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the OTTI is separated into (a) the amount representing the credit loss and (b) the amount related to all other factors. The amount of OTTI related to credit loss is recognized in earnings while the amount related to other factors is recognized in other comprehensive income, net of applicable taxes. The cost basis of individual equity securities is written down to estimated fair value through a charge to earnings when declines in value below cost are considered to be other than temporary. As of December 31, 2017 , the Company did not intend to sell, nor is it more likely than not that it would be required to sell, any of its debt securities with unrealized losses prior to recovery of its amortized cost basis less any current period credit loss. (See Note 3. “Securities”). Loans Held For Sale Residential mortgage loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by outstanding commitments from investors. Mortgage loans held for sale are generally sold with servicing rights released. Commercial loans originated and intended for sale, generally represent loan syndications are carried at amortized cost which approximates fair value, as these loans are variable-rate loans that reprice frequently with no significant change in credit risk since origination. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings. Portfolio Loans Loans where Sterling has the intent and ability to hold for the foreseeable future or until maturity or payoff (other than loans held for sale) are reported at the principal balance outstanding, net of acquisition related purchase accounting adjustments, deferred loan fees and costs from loan originations and the allowance for loan losses. Interest income on loans is accrued on the unpaid principal balance. The Company defers nonrefundable loan origination and commitment fees, and certain direct loan origination costs, and amortizes the net amount as an adjustment of the yield over the estimated life of the loan using the level-yield method without anticipating prepayments. If a loan is prepaid or sold, the net deferred amount is recognized in the income statement at that time. Interest and fees on loans include prepayment fees and late charges collected. A loan is placed on non-accrual status upon the earlier of: (i) when Sterling determines that the borrower may likely be unable to meet contractual principal or interest obligations; or (ii) when payments are 90 days or more past due based on the contractual terms of the loan, unless the loan is well secured and in the process of collection. Accrual of interest ceases and, in general, uncollected past due interest is reversed and charged against current interest income. Interest payments received on non-accrual loans, including impaired loans, are generally applied to reduce the principal balance outstanding and not recognized as income unless warranted based on the borrower’s financial condition and payment record. (See Note 4. “Portfolio Loans”). Acquired Loans, Including Purchased Credit Impaired Loans Loans the Company acquired in acquisitions are initially recorded at fair value with no carryover of the related allowance for loan losses. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows initially expected to be collected on the loans and discounting those cash flows at an appropriate market rate of interest. Acquired loans are included with portfolio loans in the consolidated balance sheets. Loans for which there is both evidence of deterioration of credit quality since origination and probability, at acquisition, that all contractually required payments would not be collected represent purchase credit impaired loans (“PCI loans”). For PCI loans, the Company initially determines which loans will be treated under the cost recovery method (similar to a non-accrual loan) from loans that will be subject to accretion. The Company recognizes the accretable yield, which is defined as the excess of all cash flows expected at acquisition over the initial fair value of the loan, as interest income on a level-yield basis over the expected remaining life of the loan. The excess of the loan’s contractually required payments over the cash flows expected to be collected is the nonaccretable difference. The nonaccretable difference is not recognized as an adjustment of yield, a loss accrual, or a valuation allowance. Going forward, the Company continues to evaluate whether the timing and the amount of cash to be collected are reasonably expected. Subsequent significant increases in cash flows the Company expects to collect will first reduce any previously recognized valuation allowance and then be reflected prospectively as an increase to the level yield. Subsequent decreases in expected cash flows may result in the loan being considered impaired. Interest income is not recognized to the extent that the net investment in the loan would increase to an amount greater than the estimated payoff amount. For PCI loans, the expected cash flows reflect anticipated prepayments, determined on a loan by loan basis according to the anticipated collection plan of these loans. The expected prepayments used to determine the accretable yield are consistent between the cash flows expected to be collected and projections of contractual cash flows so as to not affect the nonaccretable difference. Changes in prepayment assumptions may change the amount of interest income and principal expected to be collected. For loans for which there was no clear evidence of deterioration of credit quality since origination nor evidence that all contractually required payments would not be collected, the Company accretes interest income based on the contractually required cash flows. Loans that do not meet the PCI loan criteria are collectively evaluated for an allowance for loan loss. Allowance for Loan Losses The allowance for loan losses is a valuation allowance, established through a provision for loan losses charged to expense, which represents management’s best estimate of probable incurred credit losses inherent in the loan portfolio. The level of the allowance for loan losses reflects management’s continuing evaluation of loan loss experience, specific credit risks, current loan portfolio quality, industry and loan type concentrations, economic and regulatory conditions and unidentified losses inherent in the loan portfolios. The allowance for loan losses is a critical accounting estimate and requires substantial judgment of management. The allowance for loan losses consists of specific and general components. The specific component relates to loans that are individually classified as impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loans in which the borrower is experiencing financial difficulties and for which the terms have been modified resulting in a concession are considered troubled debt restructurings (“TDRs”) and classified as impaired. Factors considered by the Company in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. The Company determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into account all circumstances surrounding the loan and the borrower, including the length of the delay, reasons for the delay, prior payment history and the amount of the shortfall in relation to the total amount owed. The Company’s policy is to evaluate loans over $750 individually for impairment. If a loan is impaired, and there is a shortfall of the present value of the estimated future cash flows using the existing interest rate of the loan or as determined by the fair value of collateral if repayment is expected solely from the collateral, the Company’s practice is to charge-off the identified impairment. As a result, at December 31, 2017 and 2016, there was no portion of the allowance for loan losses allocated to impaired loans. The general component of the allowance for loan losses covers loans that are collectively evaluated for impairment. Large groups of smaller balance homogeneous loans, such as consumer loans, which includes home equity lines of credit, and residential mortgage loans are generally collectively evaluated for impairment and they are not included in the separately identified impairment disclosures. The general allowance for loan losses component also includes loans that are not individually identified for impairment evaluation, such as commercial loans below the individual evaluation threshold as well as those loans that are individually evaluated but not considered impaired including loans rated special mention. The general component of the allowance is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over the most recent three years, two years for consumer loans. The actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: • levels of, and trends in, delinquencies and non-accruals; • trends in volume and terms of loans; • effects of any changes in lending policies and procedures; • experience, ability, and depth of lending management and staff; • national and local economic trends and conditions; • concentrations of credit by such factors as location, industry, inter-relationships, and borrowers; and • for commercial loans, trends in risk ratings. We apply the methodology described above to each portfolio segment. These segments include: traditional commercial and industrial, asset-based lending, payroll finance, warehouse lending, factored receivables, equipment financing, and public sector finance (collectively the C&I portfolio,) certain consumer loans, loans collateralized by real estate including commercial real estate (“CRE”), multi-family, and acquisition, development and construction (“ADC”) loans, residential mortgage, and certain consumer loans including home equity lines of credit. C&I lending presents a risk because repayment depends on the successful operation of the business, which is subject to a wide range of risks and uncertainties. In addition, the ability to successfully liquidate collateral, if any, is subject to a variety of risks because the Company must gain control of assets used in the borrower’s business before foreclosing, which it cannot be assured of doing, and the value in a foreclosure sale or other means of liquidation is uncertain. In addition, CRE and multi-family loans subject the Company to the risks that the property securing the loan may not generate sufficient cash flow to service the debt or the borrower may use the cash flow for other purposes. In addition, if necessary, the foreclosure process may be slow and properties may deteriorate in the process. The market values are also subject to a wide variety of factors, including general economic conditions, industry specific factors, environmental factors, interest rates and the availability and terms of credit. ADC lending is considered higher risk and exposes the Company to greater credit risk than permanent mortgage financing. The repayment of ADC loans depends upon the sale of the property to third parties or the availability of permanent financing upon completion of all improvements. The Company has deemphasized originations of land acquisition and land development loans; however, it does originate construction loans to select clients principally within our immediate footprint. When the Company evaluates residential mortgage loans and consumer - home equity loans it weighs both the credit capacity of the borrower and the collateral value of the home. If unemployment or underemployment increase, the credit capacity of underlying borrowers will decrease, which increases the risk of such loan. Similarly, as the Company obtains a mortgage on the property, if home prices decline, it is exposed to risk in both its first mortgage and equity lending programs due to declines in the value of its collateral. The Company is also exposed to risk because the time to foreclose is significant and has become longer under current market conditions. For smaller balance C&I loans we charge-off the full amount of the loan when it becomes 90 days or more past due, or earlier in the case of bankruptcy, after giving effect to any cash or marketable securities pledged as collateral for the loan. For other classes of C&I loans, commercial real estate, multi-family, acquisition development and construction loans, the Company evaluates available financial information from the borrower as well as collateral pledged, evaluates whether the borrower can continue to service the debt and their near term prospects. When we conclude the collateral and or debt service capacity of the borrower are insufficient to repay our debt, we charge-off the amount that is deemed uncollectible. For unsecured consumer loans, charge-offs are recognized once the loan is 90 days to 120 days or more past due or the borrower files for bankruptcy protection. For secured consumer loans and residential mortgage loans we monitor the value of the collateral and the borrowers ability to service our debt and record a charge-off when we become aware of the loss from and within the time frames specified by regulatory guidance. Subsequent recoveries, if any, are credited to the allowance for loan losses. Troubled Debt Restructuring TDR is a formally renegotiated loan in which the Bank, for economic or legal reasons related to a borrower’s financial difficulties, grants a concession to the borrower that would not have been granted to the borrower otherwise. At the time of restructuring, we evaluate whether a TDR loan should remain on accrual based on the accrual status immediately prior to modification and whether, as a result of the TDR, we recorded a partial charge-off. A TDR on accrual prior to modification may remain on accrual status provided we believe, based on our credit analysis, that collection of principal and interest in accordance with the modified terms is reasonably certain. If the restructuring results in a partial charge-off, the loan is generally classified as non-accrual. Restructured loans can convert from non-accrual to accrual status when said loans have demonstrated performance, generally evidenced by six months of consistent payment performance in accordance with the restructured terms, or by the presence of other significant items. (See Note 4. “Portfolio Loans”). Federal Reserve Bank of New York and Federal Home Loan Bank Stock As a member of the Federal Reserve Bank of New York (“FRB”) and the Federal Home Loan Bank of New York (“FHLB”), the Bank is required to hold a certain amount of FRB and FHLB common stock. This stock is a non-marketable equity security and is reported at cost. Premises and Equipment Land is reported at cost, while premises and equipment are reported at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, which range from three years for equipment and 40 years for premises. Leasehold improvements are amortized on a straight-line basis over the terms of the respective leases, including renewal options, or the estimated useful lives of the improvements, whichever is shorter. Routine holding costs are charged to expense as incurred, while significant improvements are capitalized. The Company recognizes an impairment charge to its premises and equipment, generally in connection with a decision to consolidate or close a financial center. Impairment is based on the excess of the carrying amount of assets over the fair value of the assets. Fair value is determined by third-party valuations or appraisals and evaluations prepared by management. (See Note 6. “Premises and Equipment, Net”). Goodwill, Trade Names and Other Intangible Assets Goodwill resulting from business combinations represents the excess of the purchase price over the fair value of the net assets of businesses acquired. Goodwill and trade names (which are included with core deposits and other intangible assets in the consolidated balance sheets) acquired in a purchase business combination that have an indefinite useful life are not amortized, but are tested for impairment at least annually. Goodwill and trade names are the only intangible assets with an indefinite life on the Company’s balance sheet. The Company accounts for goodwill, trade names and other intangible assets in accordance with GAAP, which, in general, requires that goodwill and trade names not be amortized, but rather that they be tested for impairment at least annually at the reporting unit level. The Company operates as one reporting unit. Goodwill is tested for impairment in the fourth quarter of each year, or on an interim basis if an conditions warrant that could more likely than not reduce the fair value of the reporting unit below its carrying value. Core deposit intangibles recorded in acquisitions are amortized to expense using an accelerated method over their estimated lives of eight to ten years . Non-compete agreements are amortized on a straight line basis over their estimated life. Impairment losses on intangible assets and other long-term assets are charged to expense, if and when they occur, with the assets recorded at fair value. (See Note 7. “Goodwill and Other Intangible Assets”). Bank Owned Life Insurance (BOLI) The Company owns life insurance policies (purchased and acquired) on certain officers and key executives. Bank owned life insurance (“BOLI”) is recorded at its cash surrender value (or the amount that can be realized). In the Astoria Merger we acquired BOLI with a carrying value of $441,751 at December 31, 2017 , which included a claims stabilization reserve of $32,624 . Repayment of the claims stabilization reserve (funds transferred from the cash surrender value to provide for future death benefit payments) is guaranteed by the insurance carrier provided that certain conditions are met at the date of contract surrender. The Company satisfied these conditions at December 31, 2017 . Other Real Estate Owned Real estate properties acquired through loan foreclosures are recorded initially at estimated fair value, less expected sales costs, with any resulting write-down charged to the allowance for loan losses. Other real estate owned (“OREO”) also includes the fair value of the Bank’s financial centers that are held for sale. Any write-down associated with the transfer of a financial center from premises and equipment to OREO is included as a charge to other non-interest expense in the consolidated income statements. The carrying amount of an OREO asset is reduced by a charge to OREO, net expense to reflect any subsequent declines in estimated fair value. Fair value estimates are based on recent appraisals and other available information. Routine holding costs are charged to expense as incurred, while significant improvements are capitalized. Gains and losses on sales of OREO properties are recognized upon disposition. Other Borrowings - Securities Repurchase Agreements In securities repurchase agreements, the Company transfers securities to a counterparty under an agreement to repurchase the identical securities at a fixed price on a future date. These agreements are accounted for as secured financing transactions since the Company maintains effective control over the transferred securities and the transfer meets other specified criteria. Accordingly, the transaction proceeds are recorded as borrowings and the underlying securities continue to be carried in the Company’s investment securities portfolio. Disclosure of the pledged securities is made in the consolidated balance sheets if the counterparty has the right by contract to sell or re-pledge such collateral. (See Note 9. “Borrowings, Senior Notes and Subordinated Notes”). Income Taxes Income tax expense includes U.S. federal corporate income taxes and income taxes due to states and other jurisdictions in which the Company operates. In addition, for the year ended December 31, 2017, income tax expense included the impact of the enactment of the Tax Cuts and Jobs Act of 2017 (the “Tax Act”) which reduced the U.S. federal corporate income tax rate from 35% to 21% and resulted in a charge to reduce the carrying value of the Company’s net deferred income tax assets, which are included in the consolidated balance sheets as part of other assets. Net deferred taxes are recognized for the estimated future tax effects attributable to “temporary differences” between the financial statement carrying amounts and the tax bases of existing assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax laws or rates is recognized in income tax expense in the period that includes the enactment date of the change. A deferred tax liability is recognized for all temporary differences that will result in future taxable income. A deferred tax asset is recognized for all temporary differences that will result in future tax deductions, subject to reduction of the asset by a valuation allowance in certain circumstances. This valuation allowance is recognized if, based on an analysis of available evidence, we determine that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The valuation allowance is subject to ongoing adjustment based on changes in circumstances that affect management’s judgment about the realizability of the deferred tax asset. Adjustments to increase or decrease the valuation allowance are charged or credited, respectively, to income tax expense. The Company recognizes interest and/or penalties related to income tax matters in other non-interest expense. The Company evaluates uncertain tax positions in a two step process. The first step is recognition, which requires a determination of whether it is more likely than not that a tax position will be sustained upon examination. The second step is measurement. Under the measurement step, a tax position that meets the more likely than not recognition threshold is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. Tax positions that previously failed to meet the more likely than not recognition threshold should be recognized in the first subsequent financial reporting period in which that threshold is met. A previously recognized tax position that no longer meets the more likely than not recognition threshold should be derecognized in the first subsequent financial reporting period in which the threshold is no longer met. The Company did not have any such position as of December 31, 2017 . (See Note 11. “Income Taxes”). Derivatives Derivatives are recognized as assets and liabilities in the consolidated balance sheets and measured at fair value. For exchange-traded contracts, fair value is based on quoted market prices. For non-exchange traded contracts, fair value is based on dealer quotes, pricing models, discounted cash flow methodologies, or similar techniques for which the determination of fair value may require management judgment or estimation relating to future rates and credit activities. For asset/liability management purposes, the Bank uses interest rate swap agreements to modify interest

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions	Acquisitions Astoria Merger On October 2, 2017 , the Company completed the Astoria Merger. Under the terms of the Astoria Merger agreement, Astoria shareholders received 0.875 shares of the Company’s common stock for each share of Astoria common stock, which resulted in the issuance of 88,829,776 of the Company’s common shares. Based on the Company’s closing stock price per share of $24.65 on September 29, 2017, the aggregate consideration was $2,189,687 , which included cash in lieu of fractional shares. Consistent with the Company’s strategy, the primary reason for the Astoria Merger was the expansion of the Company’s geographic footprint in the Greater New York metropolitan region including Long Island. The assets acquired and liabilities assumed have been accounted for under the acquisition method of accounting. The assets and liabilities, both tangible and intangible were recorded at their fair values as of October 2, 2017 based on management’s best estimate using the information available as of the Astoria Merger date. The application of the acquisition method of accounting resulted in the recognition of goodwill of $883,291 and a core deposit intangible of $99,938 . Accounting guidance provides that an acquirer must recognize adjustments to provisional amounts that are identified during the measurement period, which runs through October 2, 2018, in the reporting period in which the adjustment amounts are determined. The acquirer must record in the financial statements, the effect of earnings on changes in depreciation, amortization or other income effects, if any as a result of the changes to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. The Company is preparing final tax returns related to Astoria’s business and operations through October 1, 2017 and believes certain adjustments to income tax balances and goodill may result upon completion of these returns. As recorded by Astoria Fair value adjustments As recorded at acquisition Cash and cash equivalents $ 275,409 $ — $ 275,409 Investment securities 3,144,111 (42,318 ) (a) 3,101,793 Loans held for sale 497 — 497 Loans 9,546,307 (336,909 ) (b) 9,209,398 Allowance for loan losses (79,293 ) 79,293 (c) — Bank owned life insurance 447,518 — 447,518 Premises and equipment 90,678 177,137 (d) 267,815 Accrued interest receivable 34,094 — 34,094 Goodwill 185,151 (185,151 ) (e) — Core deposit and other intangibles — 99,938 (f) 99,938 Other real estate owned 17,705 (1,600 ) (g) 16,105 Other assets 288,075 47,537 (h) 335,612 Total assets acquired 13,950,252 (162,073 ) 13,788,179 Deposits (9,029,303 ) (14,758 ) (i) (9,044,061 ) FHLB borrowings (1,550,000 ) (39,464 ) (j) (1,589,464 ) Repurchase agreements (1,100,000 ) (43,279 ) (k) (1,143,279 ) Senior notes (198,044 ) (3,476 ) (l) (201,520 ) Other liabilities (354,725 ) (9,322 ) (m) (364,047 ) Total liabilities assumed (12,232,072 ) (110,299 ) (12,342,371 ) Preferred stock assumed (129,796 ) (9,616 ) (n) (139,412 ) Total liabilities and preferred stock assumed $ (12,361,868 ) $ (119,915 ) (12,481,783 ) Net assets acquired 1,306,396 Purchase price 2,189,687 Goodwill recorded in the Merger $ 883,291 Explanation of certain fair value related adjustments: (a) Represents the fair value adjustment on investment securities held to maturity. (b) Represents the fair value adjustment to the net book value of loans, which includes an interest rate mark and credit mark adjustment. (c) Represents the elimination of Astoria’s allowance for loan losses. (d) Represents the fair value adjustment to reflect the fair value of land and buildings, which will be amortized on a straight-line basis over the estimated useful lives of the individual assets. (e) Represents the elimination of Astoria’s goodwill. (f) Represents intangible assets recorded to reflect the fair value of core deposits. The core deposit asset was recorded as an identifiable intangible asset and will be amortized on an accelerated basis over the estimated average life of the deposit base. (g) Represents an adjustment to reduce the carrying value of other real estate owned to fair value. (h) Represents an adjustment to net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangible assets recorded. (i) Represents the fair value adjustment on time deposits, which will be accreted as a reduction of interest expense over the remaining term of the time deposits. (j) Represents the fair value adjustment on FHLB borrowings, which was equal to the price paid to terminate Astoria’s long-term FHLB borrowings. (k) Represents the fair value adjustment on repurchase agreements, which was equal to the price paid to various counterparties to terminate these agreements. (l) Represents the fair value adjustment on senior notes, as determined by quoted market prices, which will be accreted as a reduction of interest expense through maturity of the notes. (m) Represents the fair value adjustment to other liabilities assumed in the merger including actuarially determined liabilities of Astoria. (n) Represents the fair value adjustment on preferred stock, as determined by quoted market prices, which will be accreted as a reduction in the preferred stock dividends over the five-year call period ending on October 15, 2022. The fair values for loans acquired from Astoria were estimated using cash flow projections based on the remaining maturity and repricing terms. Cash flows were adjusted by estimating future credit losses and the rate of prepayments. Projected monthly cash flows were then discounted to present value using a risk-adjusted market rate for similar loans. For collateral dependent loans with deteriorated credit quality, fair value was estimated by analyzing the value of the underlying collateral, assuming the fair values of the loans were derived from the eventual sale of the collateral. These values were discounted using market derived rates of return, with consideration given to the period of time and costs associated with the foreclosure and disposition of the collateral. There was no carryover of Astoria’s allowance for loan losses associated with the loans that were acquired, as the loans were initially recorded at fair value on the date of the Astoria Merger. Acquired loan portfolio data in the Astoria Merger is presented below: Fair value of acquired loans at acquisition date Gross contractual amounts receivable at acquisition date Best estimate at acquisition date of contractual cash flows not expected to be collected Acquired loans with evidence of deterioration since origination $ 167,614 $ 221,550 $ 44,545 Acquired loans with no evidence of deterioration since origination 9,041,784 11,509,782 NA The core deposit intangible asset recognized is being amortized over its estimated useful life of approximately 10 years utilizing the sum-of-the-years digits method. Goodwill is not amortized for book purposes; however, it is reviewed at least annually for impairment and is not deductible for tax purposes. The fair value of land, buildings and equipment was estimated using appraisals. Buildings are amortized over their estimated useful lives of approximately 30 years . Improvements and equipment are amortized or depreciated over their estimated useful lives ranging from one to five years . The fair value of retail demand and interest bearing deposit accounts was assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. The fair value of time deposits was estimated by discounting the contractual future cash flows using market rates offered for time deposits of similar remaining maturities. Direct acquisition and other charges incurred in connection with the Astoria Merger were expensed as incurred and totaled $39,232 for 2017 . These expenses were recorded in merger-related expense on the consolidated income statements. Results of operations for 2017 included a charge for asset write-downs, systems integration, severance and retention which totaled $105,110 and was recorded in other non-interest expense in the consolidated statements of operations. The following table presents selected unaudited pro forma financial information reflecting the Astoria Merger assuming it was completed as of January 1, 2016. The unaudited pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the financial results of the combined companies had the Astoria Merger actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full year period. Pro forma basic and diluted EPS were calculated using the Company’s actual weighted average shares outstanding for the periods presented, plus the incremental shares issued, assuming the Astoria Merger occurred at the beginning of the periods presented. The unaudited pro forma information is based on the actual financial statements of the Company for the periods presented, and on the actual financial statements of Astoria for 2017 and in 2016 until the date of the Astoria Merger, at which time Astoria’s results of operations were included in the Company’s financial statements. The unaudited pro forma information for 2017 and 2016 set forth below reflects adjustments related to (a) purchase accounting fair value adjustments; (b) amortization of core deposit and other intangibles; and (c) adjustments to interest income and expense due to amortization of premiums and accretion of discounts. Direct merger-related expenses and charges incurred in calendar 2017 and costs incurred to write-down assets, accrue for systems integration, retention and severance compensation are assumed to have occurred prior to January 1, 2016. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated potential cost savings for periods that include data as of October 2, 2017 or earlier. Pro forma information For the year ended December 31, 2017 2016 Net interest income $ 939,036 $ 818,906 Non-interest income 98,726 121,949 Non-interest expense 516,333 544,821 Net income available to common stockholders 316,657 242,398 Pro forma earnings per common share from continuing operations: Basic $ 1.41 $ 1.11 Diluted 1.41 1.11 Restaurant Franchise Financing Loan Portfolio On September 9, 2016 , the Bank acquired a restaurant franchise financing loan portfolio from GE Capital with an unpaid principal balance of $169,760 . Total cash paid for the portfolio was $163,282 , which included a discount to the balance of gross loans receivable of 4.00% , or $6,790 , plus accrued interest receivable. As the acquired assets did not constitute a business, the transaction was accounted for as an asset purchase. These loans are classified as traditional C&I loans. Acquisition of NewStar Business Credit LLC (“NSBC”) On March 31, 2016 , the Bank acquired 100% of the outstanding equity interests of NSBC (the “NSBC Acquisition”). NSBC was a provider of asset-based lending solutions to middle market commercial clients. NSBC’s loans had a fair value of $320,447 on the acquisition date and consisted of 100% floating-rate assets. The Bank paid a premium on the balance of gross loans receivable acquired of 5.90% , or $18,906 . The Bank assumed $4,839 of liabilities, which consisted mainly of cash collateral on loans outstanding. The Bank recognized a customer list intangible asset of $1,500 that is being amortized over its 24 -month estimated life and $25,698 of goodwill. The Bank recorded a $1,500 restructuring charge consisting mainly of retention and severance compensation, IT contract terminations and professional fees. HVB Merger On June 30, 2015 , the Company completed the HVB Merger. Under the terms of the HVB Merger agreement, HVHC shareholders received 1.92 shares of the Company’s common stock for each share of HVHC common stock, which resulted in the issuance of 38,525,154 shares of the Company’s common stock. Based on the Company’s closing stock price of $14.63 per share on June 29, 2015 , the aggregate consideration paid to HVHC shareholders was $566,307 , which, in accordance with the HVB Merger agreement, also included the in-the-money cash value of outstanding HVHC stock options, the fair value of outstanding HVHC restricted stock awards and cash in lieu of fractional shares. Consistent with the Company’s strategy, the primary reason for the HVB Merger was the expansion of the Company’s geographic footprint in the greater New York metropolitan region and beyond. The assets acquired and liabilities assumed were accounted for under the acquisition method of accounting. The assets and liabilities, both tangible and intangible, were recorded at their fair values as of June 30, 2015 based on management’s best estimate using the information available as of the HVB Merger date. The table below summarizes the amounts recognized as of the HVB Merger date for each major class of assets acquired and liabilities assumed, the estimated fair value adjustments and the amounts recorded in the Company’s financial statements at fair value at the HVB Merger date: Acquired from HVHC Fair value adjustments As recorded by the Company Cash and cash equivalents $ 878,988 $ — $ 878,988 Investment securities 713,625 217 (a) 713,842 Loans 1,816,767 (24,248 ) (b) 1,792,519 Federal Reserve Bank stock 5,830 — 5,830 Bank owned life insurance 44,231 — 44,231 Premises and equipment 11,918 4,925 (c) 16,843 Accrued interest receivable 7,392 — 7,392 Core deposits and other intangibles — 33,839 (d) 33,839 Other real estate owned 222 — 222 Other assets 32,639 (7,931 ) (e) 24,708 Deposits (3,160,746 ) — (3,160,746 ) Other borrowings (25,366 ) — (25,366 ) Other liabilities (37,292 ) 1,540 (f) (35,752 ) Total identifiable net assets acquired $ 288,208 $ 8,342 296,550 Purchase price 566,307 Goodwill recorded in the HVB Merger $ 269,757 Explanation of certain fair value related adjustments: (a) Represents the fair value adjustment on investment securities held to maturity. (b) Represents the elimination of HVHC ’ s allowance for loan losses and an adjustment of the net book value of loans to estimated fair value, which includes an interest rate mark and credit mark adjustment. (c) Represents an adjustment to reflect the fair value of HVHC owned real estate, as determined by independent appraisals, which will be amortized on a straight-line basis over the estimated useful lives of the individual assets. (d) Represents intangible assets recorded to reflect the fair value of core deposits. The core deposit asset was recorded as an identifiable intangible asset and will be amortized on an accelerated basis over the estimated average life of the deposit base. (e) Represents an adjustment in net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangibles recorded. (f) Represents the elimination of HVHC’s deferred rent liability. The fair values for loans acquired from HVHC were estimated using cash flow projections based on the remaining maturity and repricing terms. Cash flows were adjusted by estimating future credit losses and the rate of prepayments. Projected monthly cash flows were then discounted to present value using a risk-adjusted market rate for similar loans. For collateral dependent loans with deteriorated credit quality, fair value was estimated by analyzing the value of the underlying collateral, assuming the fair values of the loans were derived from the eventual sale of the collateral. These values were discounted using market derived rates of return, with consideration given to the period of time and costs associated with the foreclosure and disposition of the collateral. There was no carryover of HVHC’s allowance for loan losses associated with the loans that were acquired, as the loans were initially recorded at fair value on the date of the HVB Merger. Acquired loan portfolio data in the HVB Merger is presented below: Fair value of acquired loans at acquisition date Gross contractual amounts receivable at acquisition date Best estimate at acquisition date of contractual cash flows not expected to be collected Acquired loans with evidence of deterioration since origination $ 96,973 $ 122,104 $ 12,604 Acquired loans with no evidence of deterioration since origination 1,695,546 1,974,740 NA The core deposit intangible asset recognized is being amortized over its estimated useful life of approximately 10 years utilizing the sum-of-the-years digits method. Goodwill is not amortized for book purposes; however, it is reviewed at least annually for impairment and is not deductible for tax purposes. The fair value of land, buildings and equipment was estimated using appraisals. Buildings are amortized over their estimated useful lives of approximately 30 years . Improvements and equipment are amortized or depreciated over their estimated useful lives ranging from one to five years . The fair value of retail demand and interest bearing deposit accounts was assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. The fair value of time deposits was estimated by discounting the contractual future cash flows using market rates offered for time deposits of similar remaining maturities. Management concluded the carrying value was an appropriate estimate of fair value for these deposits. Direct acquisition and other charges incurred in connection with the HVB Merger were expensed as incurred and totaled $14,381 for calendar 2015. These expenses were recorded in Merger-related expense on the consolidated income statements. Results of operations for calendar 2015 included a charge for asset write-downs, systems integration, severance and retention compensation, which totaled $28,055 and was recorded in other non-interest expense in the consolidated income statements. The results of operations were not impacted by the HVB Merger for the other periods presented on the consolidated income statements. The following table presents selected unaudited pro forma financial information reflecting the HVB Merger assuming it was completed as of January 1, 2015. The unaudited pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the financial results of the combined companies had the HVB Merger actually been completed at the beginning of the period presented, nor does it indicate future results for any other interim or full year period. Pro forma basic and diluted EPS were calculated using the Company’s actual weighted average shares outstanding for the periods presented, plus the incremental shares issued, assuming the HVB Merger occurred at the beginning of the period presented. The unaudited pro forma information is based on the actual financial statements of the Company for the periods presented, and on the actual financial statements of HVHC for 2015 until the date of the HVB Merger, at which time HVHC’s results of operations were included in the Company’s financial statements. The unaudited pro forma information for calendar 2015 set forth below reflects adjustments related to (a) purchase accounting fair value adjustments; (b) amortization of core deposit and other intangibles; and (c) adjustments to interest income and expense due to amortization of premiums and accretion of discounts. Direct merger-related expenses and charges incurred in calendar 2015 and costs incurred to write-down assets and accrue for systems integration, retention and severance compensation are assumed to have occurred prior to January 1, 2015. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated potential cost savings for periods that include data as of June 30, 2015 or earlier. Pro forma information For the year ended December 31, 2015 Net interest income $ 360,271 Non-interest income 66,686 Non-interest expense 261,453 Net income 100,086 Pro forma earnings per share from continuing operations: Basic $ 0.78 Diluted 0.78 Damian Acquisition On February 27, 2015 , the Bank acquired 100% of the outstanding common stock of Damian Services Corporation (“Damian”) for total consideration of $24,670 in cash (the “Damian Acquisition”). Damian was a payroll services provider located in Chicago, Illinois. In connection with the acquisition, the Bank acquired $22,307 of outstanding payroll finance loans and assumed $14,560 of liabilities. The Bank recognized a customer list intangible asset of $8,950 that is being amortized over its 16 year estimated life, and $11,930 of goodwill. The Bank also recognized a $1,500 restructuring charge, consisting mainly of retention and severance compensation and asset write-downs related to the consolidation of Damian’s operations, and approximately $300 of legal fees. FCC Acquisition On May 7, 2015 , the Bank acquired a factoring portfolio from FCC, LLC, a subsidiary of First Capital Holdings, Inc., with an outstanding factoring receivables balance of approximately $44,500 (the “FCC Acquisition”). The total consideration was $45,500 and included a premium of $1,000 in addition to the outstanding receivables balance. As the acquired assets did not constitute a business, the transaction was accounted for as an asset purchase.

Securities

Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Securities	Securities A summary of amortized cost and estimated fair value of our securities is presented below: December 31, 2017 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 2,171,044 $ 1,570 $ (21,965 ) $ 2,150,649 $ 355,013 $ 978 $ (2,504 ) $ 353,487 CMO/Other MBS 656,514 31 (7,142 ) 649,403 33,496 26 (760 ) 32,762 Total residential MBS 2,827,558 1,601 (29,107 ) 2,800,052 388,509 1,004 (3,264 ) 386,249 Other securities: Federal agencies 409,322 — (9,326 ) 399,996 58,640 949 — 59,589 Corporate bonds 147,781 1,421 (976 ) 148,226 56,663 1,255 (103 ) 57,815 State and municipal 264,310 1,380 (1,892 ) 263,798 2,342,927 12,396 (10,900 ) 2,344,423 Other — — — — 15,750 83 — 15,833 Total other securities 821,413 2,801 (12,194 ) 812,020 2,473,980 14,683 (11,003 ) 2,477,660 Total securities $ 3,648,971 $ 4,402 $ (41,301 ) $ 3,612,072 $ 2,862,489 $ 15,687 $ (14,267 ) $ 2,863,909 December 31, 2016 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 1,213,733 $ 569 $ (20,821 ) $ 1,193,481 $ 277,539 $ 1,353 $ (3,625 ) $ 275,267 CMO/Other MBS 57,563 44 (926 ) 56,681 40,594 74 (572 ) 40,096 Total residential MBS 1,271,296 613 (21,747 ) 1,250,162 318,133 1,427 (4,197 ) 315,363 Other securities: Federal agencies 204,770 2 (10,793 ) 193,979 58,200 1,392 — 59,592 Corporate 43,464 150 (1,108 ) 42,506 35,048 431 (11 ) 35,468 State and municipal 245,304 739 (5,273 ) 240,770 974,290 3,571 (36,232 ) 941,629 Other — — — — 5,750 195 — 5,945 Total other securities 493,538 891 (17,174 ) 477,255 1,073,288 5,589 (36,243 ) 1,042,634 Total securities $ 1,764,834 $ 1,504 $ (38,921 ) $ 1,727,417 $ 1,391,421 $ 7,016 $ (40,440 ) $ 1,357,997 The amortized cost and estimated fair value of securities at December 31, 2017 are presented below by contractual maturity. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Residential mortgage-backed securities are shown separately since they are not due at a single maturity date. December 31, 2017 Available for sale Held to maturity Amortized cost Fair value Amortized cost Fair value Other securities remaining period to contractual maturity: One year or less $ 11,994 $ 12,003 $ 89,155 $ 88,949 One to five years 146,471 145,499 83,615 84,742 Five to ten years 526,968 520,904 387,647 390,749 Greater than ten years 135,980 133,614 1,913,563 1,913,220 Total other securities 821,413 812,020 2,473,980 2,477,660 Residential MBS 2,827,558 2,800,052 388,509 386,249 Total securities $ 3,648,971 $ 3,612,072 $ 2,862,489 $ 2,863,909 Sales of securities for the periods indicated below were as follows: Year ended December 31, 2017 2016 2015 Available for sale: Proceeds from sales $ 2,516,308 $ 858,531 $ 893,610 Gross realized gains 8 10,665 6,018 Gross realized losses (352 ) (3,143 ) (1,181 ) Income tax (benefit) expense on realized net (losses) gains (91 ) 2,445 1,572 At December 31, 2017 and 2016 , there were no holdings of securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of stockholders’ equity. The following table summarizes securities available for sale with unrealized losses, segregated by the length of time in a continuous unrealized loss position: Continuous unrealized loss position Less than 12 months 12 months or longer Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses Available for sale December 31, 2017 Residential MBS: Agency-backed $ 1,349,217 $ (10,550 ) $ 486,948 $ (11,415 ) $ 1,836,165 $ (21,965 ) CMO/Other MBS 605,200 (6,064 ) 36,107 (1,078 ) 641,307 (7,142 ) Total residential MBS 1,954,417 (16,614 ) 523,055 (12,493 ) 2,477,472 (29,107 ) Other securities: Federal agencies 243,476 (1,955 ) 156,520 (7,371 ) 399,996 (9,326 ) Corporate 65,056 (397 ) 15,268 (579 ) 80,324 (976 ) State and municipal 97,307 (757 ) 56,324 (1,135 ) 153,631 (1,892 ) Total other securities 405,839 (3,109 ) 228,112 (9,085 ) 633,951 (12,194 ) Total $ 2,360,256 $ (19,723 ) $ 751,167 $ (21,578 ) $ 3,111,423 $ (41,301 ) December 31, 2016 Residential MBS: Agency-backed $ 1,101,641 $ (20,816 ) $ 686 $ (5 ) $ 1,102,327 $ (20,821 ) CMO/Other MBS 38,841 (506 ) 15,239 (420 ) 54,080 (926 ) Total residential MBS 1,140,482 (21,322 ) 15,925 (425 ) 1,156,407 (21,747 ) Other securities: Federal agencies 185,504 (10,793 ) 4 — 185,508 (10,793 ) Corporate 10,399 (137 ) 14,942 (971 ) 25,341 (1,108 ) State and municipal 173,062 (5,196 ) 3,733 (77 ) 176,795 (5,273 ) Total other securities 368,965 (16,126 ) 18,679 (1,048 ) 387,644 (17,174 ) Total $ 1,509,447 $ (37,448 ) $ 34,604 $ (1,473 ) $ 1,544,051 $ (38,921 ) The following table summarizes securities held to maturity with unrealized losses, segregated by the length of time in a continuous unrealized loss position: Continuous unrealized loss position Less than 12 months 12 months or longer Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses Held to maturity December 31, 2017 Residential MBS: Agency-backed $ 136,679 $ (572 ) $ 74,303 $ (1,932 ) $ 210,982 $ (2,504 ) CMO/Other MBS 10,314 (129 ) 20,160 (631 ) 30,474 (760 ) Total residential MBS 146,993 (701 ) 94,463 (2,563 ) 241,456 (3,264 ) Other securities: Corporate 16,560 (103 ) — — 16,560 (103 ) State and municipal 860,536 (5,310 ) 393,200 (5,590 ) 1,253,736 (10,900 ) Total other securities 877,096 (5,413 ) 393,200 (5,590 ) 1,270,296 (11,003 ) Total $ 1,024,089 $ (6,114 ) $ 487,663 $ (8,153 ) $ 1,511,752 $ (14,267 ) December 31, 2016 Residential MBS: Agency-backed $ 185,116 $ (3,623 ) $ 213 $ (2 ) $ 185,329 $ (3,625 ) CMO/Other MBS 34,786 (572 ) — — 34,786 (572 ) Total residential MBS 219,902 (4,195 ) 213 (2 ) 220,115 (4,197 ) Other securities: Corporate — — 5,037 (11 ) 5,037 (11 ) State and municipal 758,690 (36,169 ) 2,816 (63 ) 761,506 (36,232 ) Total other securities 758,690 (36,169 ) 7,853 (74 ) 766,543 (36,243 ) Total $ 978,592 $ (40,364 ) $ 8,066 $ (76 ) $ 986,658 $ (40,440 ) At December 31, 2017 , a total of 321 available for sale securities were in a continuous unrealized loss position for less than 12 months and 155 securities were in an unrealized loss position for 12 months or longer. Declines in the fair value of held to maturity and available for sale securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of the impairment related to other factors is recognized in other comprehensive income. In estimating OTTI losses, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than cost; (ii) the financial condition and near-term prospects of the issuer; and (iii) the intent and ability of the Company to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in cost. Management has the ability and intent to hold the securities classified as held to maturity in the table above until they mature, at which time the Company will receive full value for the securities. Furthermore, as of December 31, 2017 , management did not have the intent to sell any of the securities classified as available for sale in the table above and believes that it is more likely than not that the Company will not have to sell any such securities before a recovery of cost. Any unrealized losses are largely due to increases in market interest rates over the yields available at the time the underlying securities were purchased. The fair value is expected to recover as the securities approach their maturity date or repricing date or if market yields for such investments decline. Management does not believe any of the securities are impaired due to reasons related to credit quality. As of December 31, 2017 , management believes the impairments detailed in the table above are temporary. Securities pledged for borrowings at FHLB and other institutions, and securities pledged for municipal deposits and other purposes were as follows: December 31, 2017 2016 Available for sale securities pledged for borrowings, at fair value $ 10,225 $ 67,599 Available for sale securities pledged for municipal deposits, at fair value 323,341 398,961 Available for sale securities pledged for customer back-to-back swaps, at fair value — 126 Held to maturity securities pledged for borrowings, at amortized cost 35,047 55,343 Held to maturity securities pledged for municipal deposits, at amortized cost 1,182,674 958,246 Total securities pledged $ 1,551,287 $ 1,480,275

Portfolio Loans

Portfolio Loans	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Portfolio Loans	Portfolio Loans The composition of the Company’s loan portfolio, excluding loans held for sale, was the following: December 31, 2017 2016 Commercial: C&I: Traditional C&I $ 1,979,448 $ 1,404,774 Asset-based lending 797,570 741,942 Payroll finance 268,609 255,549 Warehouse lending 723,335 616,946 Factored receivables 220,551 214,242 Equipment financing 679,541 589,315 Public sector finance 637,767 349,182 Total C&I 5,306,821 4,171,950 Commercial mortgage: CRE 4,138,864 3,162,942 Multi-family 4,859,555 981,076 ADC 282,792 230,086 Total commercial mortgage 9,281,211 4,374,104 Total commercial 14,588,032 8,546,054 Residential mortgage 5,054,732 697,108 Consumer 366,219 284,068 Total portfolio loans 20,008,983 9,527,230 Allowance for loan losses (77,907 ) (63,622 ) Total portfolio loans, net $ 19,931,076 $ 9,463,608 Total portfolio loans include net deferred loan origination fees of $4,813 at December 31, 2017 and $1,788 at December 31, 2016 . At December 31, 2017 , the Company pledged loans totaling $9,123,601 to the FHLB as collateral for certain borrowing arrangements. See Note 9. “Borrowings, Senior Notes and Subordinated Notes”. The following tables set forth the amounts and status of the Company’s loans and TDRs at December 31, 2017 and 2016 : December 31, 2017 Current 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 1,940,387 $ 1,232 $ 187 $ — $ 37,642 $ 1,979,448 Asset-based lending 797,570 — — — — 797,570 Payroll finance 268,609 — — — — 268,609 Warehouse lending 723,335 — — — — 723,335 Factored receivables 220,551 — — — — 220,551 Equipment financing 667,083 1,143 3,216 — 8,099 679,541 Public sector finance 637,767 — — — — 637,767 CRE 4,104,173 8,403 4,131 437 21,720 4,138,864 Multi-family 4,853,677 595 834 — 4,449 4,859,555 ADC 278,587 — — — 4,205 282,792 Residential mortgage 4,925,996 22,416 6,038 324 99,958 5,054,732 Consumer 350,502 4,364 974 95 10,284 366,219 Total loans $ 19,768,237 $ 38,153 $ 15,380 $ 856 $ 186,357 $ 20,008,983 Total TDRs included above $ 13,175 $ 389 $ — $ — $ 29,325 $ 42,889 Non-performing loans: Loans 90+ days past due and still accruing $ 856 Non-accrual loans 186,357 Total non-performing loans $ 187,213 December 31, 2016 Current 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 1,376,181 $ 835 $ 817 $ 555 $ 26,386 $ 1,404,774 Asset-based lending 741,942 — — — — 741,942 Payroll finance 254,715 — 14 621 199 255,549 Warehouse lending 616,946 — — — — 616,946 Factored receivables 213,624 — — — 618 214,242 Equipment financing 583,835 2,142 1,092 — 2,246 589,315 Public sector finance 349,182 — — — — 349,182 CRE 3,140,561 967 — 406 21,008 3,162,942 Multi-family 981,005 — — — 71 981,076 ADC 224,817 — — — 5,269 230,086 Residential mortgage 675,750 5,509 951 108 14,790 697,108 Consumer 274,719 2,423 350 — 6,576 284,068 Total loans $ 9,433,277 $ 11,876 $ 3,224 $ 1,690 $ 77,163 $ 9,527,230 Total TDRs included above $ 11,032 $ 253 $ — $ — $ 1,989 $ 13,274 Non-performing loans: Loans 90+ days past due and still accruing $ 1,690 Non-accrual loans 77,163 Total non-performing loans $ 78,853 The Company had no asset-based lending, warehouse lending or public sector finacne non-accrual loans at December 31, 2017 and 2016. The following table provides additional analysis of the Company’s non-accrual loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Recorded investment non-accrual loans Recorded investment PCI non-accrual loans Recorded investment total non-accrual loans Unpaid principal balance non-accrual loans Recorded investment non-accrual loans Recorded investment PCI non-accrual loans Recorded investment total non-accrual loans Unpaid principal balance non-accrual loans Traditional C&I $ 33,631 $ 4,011 $ 37,642 $ 37,853 $ 22,338 $ 4,048 $ 26,386 $ 26,386 Payroll finance — — — — 199 — 199 199 Factored receivables — — — — 618 — 618 618 Equipment financing 8,099 — 8,099 8,099 2,246 — 2,246 2,246 CRE 18,762 2,958 21,720 25,739 15,063 5,945 21,008 25,619 Multi-family 4,449 — 4,449 4,705 71 — 71 71 ADC 4,205 — 4,205 4,205 5,269 — 5,269 5,398 Residential mortgage 99,644 314 99,958 113,002 13,399 1,391 14,790 18,190 Consumer 9,575 709 10,284 12,096 5,719 857 6,576 7,865 Total loans $ 178,365 $ 7,992 $ 186,357 $ 205,699 $ 64,922 $ 12,241 $ 77,163 $ 86,592 When the ultimate collectibility of the total principal of an impaired loan is in doubt and the loan is on non-accrual status, all payments are applied to principal, under the cost recovery method. When the ultimate collectibility of the total principal of an impaired loan is not in doubt and the loan is on non-accrual status, contractual interest is credited to interest income when received, under the cash basis method. At December 31, 2017 and 2016 , the recorded investment of residential mortgage loans that were formally in process of foreclosure was $76,712 and $9,263 , respectively, which are included in non-accrual residential mortgage loans above. The increase from December 31, 2016 was due to loans acquired in the Astoria Merger. The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at December 31, 2017 : Loans evaluated by segment Allowance evaluated by segment Individually evaluated for impairment Collectively evaluated for impairment Purchased credit impaired loans Total loans Individually evaluated for impairment Collectively evaluated for impairment Total allowance for loan losses Traditional C&I $ 35,921 $ 1,933,155 $ 10,372 $ 1,979,448 $ — $ 19,072 $ 19,072 Asset-based lending — 797,570 — 797,570 — 6,625 6,625 Payroll finance — 268,609 — 268,609 — 1,565 1,565 Warehouse lending — 723,335 — 723,335 — 3,705 3,705 Factored receivables — 220,551 — 220,551 — 1,395 1,395 Equipment financing 5,341 674,200 — 679,541 — 4,862 4,862 Public sector finance — 637,767 — 637,767 — 1,797 1,797 CRE 9,663 4,090,143 39,058 4,138,864 — 24,945 24,945 Multi-family 1,597 4,842,898 15,060 4,859,555 — 3,261 3,261 ADC 5,208 277,322 262 282,792 — 1,680 1,680 Residential mortgage — 4,903,218 151,514 5,054,732 — 5,819 5,819 Consumer 3,132 352,741 10,346 366,219 — 3,181 3,181 Total loans $ 60,862 $ 19,721,509 $ 226,612 $ 20,008,983 $ — $ 77,907 $ 77,907 The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at December 31, 2016 : Loans evaluated by segment Allowance evaluated by segment Individually evaluated for impairment Collectively evaluated for impairment Purchased credit impaired loans Total loans Individually evaluated for impairment Collectively evaluated for impairment Total allowance for loan losses Traditional C&I $ 25,221 $ 1,365,466 $ 14,087 $ 1,404,774 $ — $ 12,864 $ 12,864 Asset-based lending — 724,247 17,695 741,942 — 3,316 3,316 Payroll finance 570 254,979 — 255,549 — 951 951 Warehouse lending — 616,946 — 616,946 — 1,563 1,563 Factored receivables — 214,242 — 214,242 — 1,669 1,669 Equipment financing 1,413 587,902 — 589,315 — 5,039 5,039 Public sector finance — 349,182 — 349,182 — 1,062 1,062 CRE 14,853 3,104,057 44,032 3,162,942 — 20,466 20,466 Multi-family — 976,710 4,366 981,076 — 4,991 4,991 ADC 9,025 216,094 4,967 230,086 — 1,931 1,931 Residential mortgage 2,545 692,396 2,167 697,108 — 5,864 5,864 Consumer 1,764 280,710 1,594 284,068 — 3,906 3,906 Total loans $ 55,391 $ 9,382,931 $ 88,908 $ 9,527,230 $ — $ 63,622 $ 63,622 The Company acquired PCI loans in the Astoria Merger, the NSBC Acquisition, the HVB Merger and the Provident Merger. The carrying value of these loans is presented in the tables above. At December 31, 2017 and 2016 the net recorded amount of PCI loans was $226,612 and $88,908 , respectively. The increase from December 31, 2016 was due to PCI loans acquired in the Astoria Merger. The following table presents the changes in the balance of the accretable yield discount for PCI loans for 2017 , 2016 , and 2015 : Year ended December 31, 2017 2016 2015 Balance at beginning of year $ 11,117 $ 11,211 $ 724 Acquisition 46,111 2,200 12,527 Accretion (7,468 ) (4,937 ) (2,229 ) Disposals (2,000 ) — (50 ) Reclassification (to) from non-accretable difference (2,178 ) 2,643 239 Balance at end of year $ 45,582 $ 11,117 $ 11,211 Income is not recognized on PCI loans unless the Company can reasonably estimate the cash flows that are expected to be collected over the life of the loan. The following table presents the carrying value of the Company’s PCI loans segregated by those PCI loans subject to accretion, and those PCI loans under the cost recovery method at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 PCI loans subject to accretion PCI loans under cost recovery method (non-accrual) Total PCI loans PCI loans subject to accretion PCI loans under cost recovery method (non-accrual) Total PCI loans Traditional C&I $ 6,361 $ 4,011 $ 10,372 $ 10,039 $ 4,048 $ 14,087 Asset-based lending — — — 17,695 — 17,695 CRE 36,100 2,958 39,058 38,087 5,945 44,032 Multi-family 15,060 — 15,060 4,366 — 4,366 ADC 262 — 262 4,967 — 4,967 Residential 151,200 314 151,514 776 1,391 2,167 Consumer 9,637 709 10,346 737 857 1,594 Total $ 218,620 $ 7,992 $ 226,612 $ 76,667 $ 12,241 $ 88,908 The following table presents loans individually evaluated for impairment by segment of loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Unpaid principal balance Recorded investment Unpaid principal balance Recorded investment Loans with no related allowance recorded: Traditional C&I $ 36,408 $ 35,921 $ 25,221 $ 25,221 Payroll finance — — 570 570 Equipment financing 5,341 5,341 1,413 1,413 CRE 10,128 9,663 16,365 14,853 Multi-family 1,597 1,597 — — ADC 5,474 5,208 9,025 9,025 Residential — — 2,545 2,545 Consumer 3,132 3,132 1,764 1,764 Total $ 62,080 $ 60,862 $ 56,903 $ 55,391 The following tables present the average recorded investment and interest income recognized related to loans individually evaluated for impairment by segment for 2017 , 2016 and 2015 : For the year ended December 31, 2017 December 31, 2016 December 31, 2015 YTD average recorded investment Interest income recognized YTD average recorded investment Interest income recognized YTD average recorded investment Interest income recognized With no related allowance recorded: Traditional C&I $ 26,413 $ 460 $ 25,508 $ 22 $ 2,718 $ — Payroll finance — — 71 — — — Equipment Financing 4,004 — 1,275 — 757 — CRE 11,808 374 13,625 133 12,155 102 Multi-family 399 65 — — 1,078 — ADC 5,687 206 6,132 31 8,819 234 Residential mortgage 1,068 — 768 — 515 — Consumer 1,977 — 1,530 — — — Total $ 51,356 $ 1,105 $ 48,909 $ 186 $ 26,042 $ 336 There was no cash-basis interest income recognized from impaired loans during the years ended December 31, 2017 and 2016 . There were no impaired loans with a related allowance recorded at December 31, 2017 , 2016 and 2015 . Troubled Debt Restructuring The following tables set forth the amounts and past due status of the Company’s TDRs at December 31, 2017 and December 31, 2016 : December 31, 2017 Current loans 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 565 $ — $ — $ — $ 21,083 $ 21,648 Equipment financing 898 — — — 826 1,724 CRE 2,921 — — — 115 3,036 ADC 1,495 — — — 4,205 5,700 Residential mortgage 5,154 336 — — 2,810 8,300 Consumer 2,142 53 — — 286 2,481 Total $ 13,175 $ 389 $ — $ — $ 29,325 $ 42,889 December 31, 2016 Current loans 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 572 $ — $ — $ — $ 128 $ 700 Equipment financing — — — — 29 29 CRE 2,443 253 — — — 2,696 ADC 5,962 — — — 458 6,420 Residential mortgage 2,055 — — — 1,374 3,429 Total $ 11,032 $ 253 $ — $ — $ 1,989 $ 13,274 There were no asset-based lending, payroll finance, warehouse lending, factored receivables, public sector finance, or multifamily loans that were TDRs for either period presented above. At December 31, 2016 there were also no consumer loans that were TDRs. The Company had no outstanding commitments to lend additional amounts to customers with TDR loans as of December 31, 2017 and 2016 , respectively. The following table identifies TDRs that occurred during 2017 and 2016: December 31, 2017 December 31, 2016 Recorded investment Recorded investment Number Pre- modification Post- modification Number Pre- modification Post- modification Traditional C&I 1 $ 23,188 $ 23,188 — $ — $ — Equipment financing 3 3,558 3,337 — — — Commercial real estate 2 1,724 1,724 — — — ADC 1 797 797 — — — Residential mortgage 4 1,140 1,033 1 469 347 Total TDRs 11 $ 30,407 $ 30,079 1 $ 469 $ 347 There were no asset-based lending, payroll finance, warehouse lending, factored receivables, public sector finance, multi-family or consumer loans modified as TDRS during 2017 and 2016. The amount of TDRs charged-off against the allowance for loan losses was $ 585 in 2017 , $286 in 2016 , and $74 in 2015

Allowance for Loan Losses

Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses Activity in the allowance for loan losses for 2017 and 2016 , and 2015 is summarized below: For the year ended December 31, 2017 Beginning Charge-offs Recoveries Net Provision Ending balance Traditional C&I $ 12,864 $ (5,489 ) $ 1,142 $ (4,347 ) $ 10,555 $ 19,072 Asset-based lending 3,316 — 5 5 3,304 6,625 Payroll finance 951 (188 ) 6 (182 ) 796 1,565 Warehouse lending 1,563 — — — 2,142 3,705 Factored receivables 1,669 (982 ) 23 (959 ) 685 1,395 Equipment financing 5,039 (3,165 ) 387 (2,778 ) 2,601 4,862 Public sector finance 1,062 — — — 735 1,797 CRE 20,466 (2,379 ) 163 (2,216 ) 6,695 24,945 Multi-family 4,991 — — — (1,730 ) 3,261 ADC 1,931 (27 ) 269 242 (493 ) 1,680 Residential mortgage 5,864 (860 ) 161 (699 ) 654 5,819 Consumer 3,906 (1,095 ) 314 (781 ) 56 3,181 Total allowance for loan losses $ 63,622 $ (14,185 ) $ 2,470 $ (11,715 ) $ 26,000 $ 77,907 Annualized net charge-offs to average loans outstanding 0.10 % For the year ended December 31, 2016 Beginning balance Charge-offs Recoveries Net charge-offs Provision Ending balance Traditional C&I $ 9,953 $ (1,707 ) $ 999 $ (708 ) $ 3,619 $ 12,864 Asset-based lending 2,762 — 62 62 492 3,316 Payroll finance 1,936 (28 ) 32 4 (989 ) 951 Warehouse lending 589 — — — 974 1,563 Factored receivables 1,457 (1,200 ) 61 (1,139 ) 1,351 1,669 Equipment financing 4,925 (1,982 ) 560 (1,422 ) 1,536 5,039 Public sector finance 547 — — — 515 1,062 CRE 11,461 (959 ) 353 (606 ) 9,611 20,466 Multi-family 5,141 (417 ) 2 (415 ) 265 4,991 ADC 2,009 — 104 104 (182 ) 1,931 Residential mortgage 5,007 (1,045 ) 30 (1,015 ) 1,872 5,864 Consumer 4,358 (1,615 ) 227 (1,388 ) 936 3,906 Total allowance for loan losses $ 50,145 $ (8,953 ) $ 2,430 $ (6,523 ) $ 20,000 $ 63,622 Annualized net charge-offs to average loans outstanding 0.08 % For the year ended December 31, 2015 Beginning balance Charge-offs Recoveries Net charge-offs Provision Ending balance Traditional C&I $ 6,966 $ (1,575 ) $ 1,720 $ 145 $ 2,842 $ 9,953 Asset-based lending 4,061 — — — (1,299 ) 2,762 Payroll finance 1,506 (406 ) 35 (371 ) 801 1,936 Warehouse lending 608 — — — (19 ) 589 Factored receivables 1,205 (291 ) 60 (231 ) 483 1,457 Equipment financing 2,569 (3,423 ) 825 (2,598 ) 4,954 4,925 Public sector finance — — — — 547 547 CRE 7,721 (1,695 ) 148 (1,547 ) 5,287 11,461 Multi-family 4,511 (17 ) 9 (8 ) 638 5,141 ADC 2,987 — 52 52 (1,030 ) 2,009 Residential mortgage 5,843 (1,251 ) 92 (1,159 ) 323 5,007 Consumer 4,397 (2,360 ) 148 (2,212 ) 2,173 4,358 Total allowance for loan losses $ 42,374 $ (11,018 ) $ 3,089 $ (7,929 ) $ 15,700 $ 50,145 Annualized net charge-offs to average loans outstanding 0.13 % Credit Quality Indicators As part of the on-going monitoring of the credit quality of the Company’s loan portfolio, management tracks certain credit quality indicators including trends related to (i) the weighted-average risk grade of commercial loans; (ii) the level of classified commercial loans; (iii) the delinquency status of residential mortgage loans and consumer loans; (iv) net charge-offs; (v) non-performing loans (see details above); and (vi) the general economic conditions in the greater New York metropolitan region. The Bank analyzes loans individually by classifying the loans as to credit risk, except residential mortgage loans and consumer loans, which are evaluated on a homogeneous pool basis unless the loan balance is greater than $500 . This analysis is performed at least quarterly on all criticized/classified loans. The Bank uses the following definitions of risk ratings: 1 and 2 - These grades include loans that are secured by cash, marketable securities or cash surrender value of life insurance policies. 3 - This grade includes loans to borrowers with strong earnings and cash flow and that have the ability to service debt. The borrower’s assets and liabilities are generally well matched and are above average quality. The borrower has ready access to multiple sources of funding including alternatives such as term loans, private equity placements or trade credit. 4 - This grade includes loans to borrowers with above average cash flow, adequate earnings and debt service coverage ratios. The borrower generates discretionary cash flow, assets and liabilities are reasonably matched, and the borrower has access to other sources of debt funding or additional trade credit at market rates. 5 - This grade includes loans to borrowers with adequate earnings and cash flow and reasonable debt service coverage ratios. Overall leverage is acceptable and there is average reliance upon trade credit. Management has a reasonable amount of experience and depth, and owners are willing to invest available outside capital as necessary. 6 - This grade includes loans to borrowers where there is evidence of some strain, earnings are inconsistent and volatile, and the borrowers’ outlook is uncertain. Generally such borrowers have higher leverage than those with a better risk rating. These borrowers typically have limited access to alternative sources of bank debt and may be dependent upon debt funding for working capital support. 7 - Special Mention (OCC definition) - Other Assets Especially Mentioned (OAEM) are loans that have potential weaknesses which may, if not reversed or corrected, weaken the asset or inadequately protect the Bank’s credit position at some future date. Such assets constitute an undue and unwarranted credit risk but not to the point of justifying a classification of “Substandard.” The credit risk may be relatively minor yet constitute an unwarranted risk in light of the circumstances surrounding a specific asset. 8 - Substandard (OCC definition) - These loans are inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Assets so classified must have a well-defined weakness that jeopardizes the liquidation of the debt. They are characterized by the distinct possibility that the Bank will sustain some losses if the deficiencies are not corrected. Loss potential, while existing in the aggregate amount of substandard assets, does not have to exist in individual assets classified as substandard. 9 - Doubtful (OCC definition) - These loans have all the weakness inherent in one classified as “Substandard” with the added characteristics that the weakness makes collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. The possibility of loss is extremely high, but because of certain important and reasonably specific pending factors which may work to the advantage and strengthening of the asset, its classification as an estimated loss is deferred until its more exact status may be determined. Pending factors include proposed merger, acquisition, or liquidating procedures, capital injections, perfecting liens or additional collateral and refinancing plans. 10 - Loss (OCC definition) - These loans are charged-off because they are determined to be uncollectible and unbankable assets. This classification does not reflect that the asset has no absolute recovery or salvage value, but rather it is not practical or desirable to defer writing-off this asset even though partial recovery may be effected in the future. Losses should be taken in the period in which they are determined to be uncollectible. Loans that are risk-rated 1 through 6 as defined above are considered to be pass-rated loans. As of December 31, 2017 and 2016 the risk category of gross loans by segment was as follows: December 31, 2017 December 31, 2016 Special mention Substandard Doubtful Special mention Substandard Doubtful Traditional C&I $ 7,453 $ 53,915 $ 746 $ 12,125 $ 28,977 $ 442 Asset-based lending 30,958 3,835 — 35,373 — — Payroll finance 15,542 352 — — 820 — Factored receivables 187 — — 185 433 — Equipment financing 4,093 9,299 — 2,128 3,397 — CRE 40,438 34,529 — 39,190 29,463 — Multi-family 26,602 14,266 — 7,072 658 — ADC 4,204 4,639 — 6,899 8,870 — Residential mortgage 6,038 101,149 — 951 15,796 — Consumer 1,043 10,507 18 646 6,738 — Total $ 136,558 $ 232,491 $ 764 $ 104,569 $ 95,152 $ 442 There were no warehouse lending or public sector finance loans rated special mention, substandard or doubtful for the periods presented. There were no loans rated loss at December 31, 2017 and 2016 .

Premises and Equipment, Net

Premises and Equipment, Net	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Premises and Equipment, Net	Premises and Equipment, Net Premises and equipment are summarized as follows: December 31, 2017 2016 Land and land improvements $ 160,376 $ 11,679 Buildings 127,959 29,785 Leasehold improvements 40,442 33,070 Furniture, fixtures and equipment 81,424 63,877 Total premises and equipment, gross 410,201 138,411 Accumulated depreciation and amortization (88,479 ) (81,093 ) Total premises and equipment, net $ 321,722 $ 57,318 Depreciation and amortization of premises and equipment totaled $11,670 , $8,375 and $7,476 for the year ended 2017 , 2016 , and 2015 , respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill and other intangible assets are presented in the tables below. The increase in goodwill and certain other intangible assets in 2017 was related to the Astoria Merger. (See Note 2. “Acquisitions”). Goodwill The change in goodwill for the periods presented was as follows: For the year ended December 31, 2017 2016 Beginning of period balance $ 696,600 $ 670,699 Acquired goodwill 883,291 25,901 End of period balance $ 1,579,891 $ 696,600 Other intangible assets The balance of other intangible assets for the periods presented was as follows: Gross intangible assets Accumulated amortization Net intangible assets December 31, 2017 Core deposits $ 157,959 $ (31,414 ) $ 126,545 Customer lists 10,450 (4,596 ) 5,854 Non-compete agreements 11,808 (11,516 ) 292 Trade name 20,500 — 20,500 Fair value of below market leases 725 (725 ) — $ 201,442 $ (48,251 ) $ 153,191 December 31, 2016 Core deposits $ 58,021 $ (20,566 ) $ 37,455 Customer lists 10,450 (2,767 ) 7,683 Non-compete agreements 11,808 (11,183 ) 625 Trade name 20,500 — 20,500 Fair value of below market leases 725 (635 ) 90 $ 101,504 $ (35,151 ) $ 66,353 Other intangible assets, except the trade name intangible asset, are amortized on a straight-line or accelerated bases over their estimated useful lives, which range from one to 10 years. Other intangible asset amortization expense totaled $13,008 in 2017 ; $12,416 in 2016 ; and $10,043 in 2015 . The amortization of the fair value of below market leases was included in rent expense for all periods. The estimated aggregate future amortization expense for other intangible assets remaining as of December 31, 2017 was as follows: Amortization expense 2018 $ 23,646 2019 19,181 2020 16,800 2021 15,104 2022 13,703 Thereafter 44,257 Total $ 132,691

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Deposits	Deposits Deposit balances at December 31, 2017 and 2016 are summarized as follows: December 31, 2017 2016 Non-interest bearing demand $ 4,080,742 $ 3,239,332 Interest bearing demand 3,882,064 2,220,456 Savings 2,758,642 747,031 Money market 7,377,118 3,277,686 Certificates of deposit 2,439,638 583,754 Total deposits $ 20,538,204 $ 10,068,259 Municipal deposits totaled $1,585,076 and $1,270,921 at December 31, 2017 and December 31, 2016 , respectively. See Note 3. “Securities” for the amount of securities that were pledged as collateral for municipal deposits and other purposes. Certificates of deposit had remaining periods to contractual maturity as follows: December 31, 2017 2016 Remaining period to contractual maturity: Less than one year $ 1,270,605 $ 480,162 One to two years 525,846 47,768 Two to three years 362,233 42,492 Three to four years 160,432 7,210 Four to five years 120,522 6,122 Total certificates of deposit $ 2,439,638 $ 583,754 Certificate of deposit accounts that exceed the FDIC Insurance limit of $250 or more totaled $371,671 and $132,406 at December 31, 2017 and 2016 , respectively. Listed below are the Company’s brokered deposits: December 31, 2017 2016 Interest bearing demand $ 23,820 $ 426,437 Money market 773,804 5,560 Savings — 246,572 Reciprocal CDARs 1 102,259 153,060 CDARs one way 204,331 — Total brokered deposits $ 1,104,214 $ 831,629 1 Certificate of deposit account registry service

Borrowings, Senior Notes and Su

Borrowings, Senior Notes and Subordinated Notes	12 Months Ended
	Dec. 31, 2017
Debt Instruments [Abstract]
Borrowings, Senior Notes and Subordinated Notes	Borrowings, Senior Notes and Subordinated Notes The Company’s borrowings and weighted average interest rates are summarized as follows: December 31, 2017 2016 Amount Rate Amount Rate By type of borrowing: FHLB advances and overnight $ 4,510,123 1.69 % $ 1,791,000 1.01 % Repurchase agreements 30,162 0.64 16,642 0.75 5.50% Senior Notes 76,805 5.98 76,469 5.98 3.50% Senior Notes 201,404 3.19 — — Subordinated Notes 172,716 5.45 172,501 5.45 Total borrowings $ 4,991,210 1.96 $ 2,056,612 1.56 By remaining period to maturity: Less than one year $ 2,989,093 1.69 % $ 1,397,642 0.87 % One to two years 775,714 1.79 311,469 2.53 Two to three years 802,650 2.34 75,000 1.50 Three to four years 251,037 2.04 50,000 1.38 Four to five years — — 50,000 1.68 Greater than five years 172,716 5.45 172,501 5.45 Total borrowings $ 4,991,210 1.96 $ 2,056,612 1.56 FHLB advances and overnight. As a member of the FHLB, the Bank may borrow up to the amount of eligible mortgages and securities that have been pledged as collateral under a blanket security agreement. As of December 31, 2017 and 2016 , the Bank had pledged residential mortgage and CRE loans with eligible collateral values of $9,123,601 and $2,349,604 , respectively. The Bank had also pledged securities to secure borrowings, which are disclosed in Note 3. “Securities.” As of December 31, 2017 , the Bank may increase its borrowing capacity by pledging unencumbered securities and mortgage loans that are not required to be pledged for other purposes with an estimated collateral value of $4,622,150 . Repurchase agreements. Securities sold under repurchase agreements are utilized to facilitate the needs of our clients and are secured short-term borrowings that mature in one to 30 days . Repurchase agreements are stated at the amount of cash received in connection with these transactions. The Bank monitors collateral levels on a continuous basis. The Bank may be required to provide additional collateral based on the fair value of the underlying securities. Securities pledged as collateral are maintained with our safekeeping agents. 5.50% Senior Notes. The Company issued $100,000 principal amount of 5.50% fixed rate senior notes (the “ 5.50% Senior Notes”) through a private placement at a discount of 1.75% . The cost of issuance was $303 , and at December 31, 2017 and 2016 the unamortized discount was $195 and $531 , respectively, which will be accreted to interest expense over the life of the 5.50% Senior Notes, resulting in an effective yield of 5.98% . Interest is due semi-annually in arrears on January 2 and July 2 until maturity on July 2, 2018 . During the third quarter of 2016, the Company reacquired $23,000 of the Senior Notes and incurred a loss on extinguishment of debt associated with this redemption of $1,013 , which was included in non-interest expense in the consolidated income statements. The 5.50% Senior Notes are unsecured obligations of the Company and rank equally with all other unsecured unsubordinated indebtedness, and will be effectively subordinated to any secured indebtedness to the extent of the value of the collateral securing such indebtedness, and structurally subordinated to the existing and future indebtedness of the Company’s subsidiaries. The 5.50% Senior Notes were issued under an indenture between the Company and U.S. Bank National Association, as trustee (the “U.S. Bank Indenture”). The U.S. Bank Indenture includes provisions that, among other things, restrict the Company’s ability to dispose of or issue shares of voting stock of a principal subsidiary bank (as defined in the U.S. Bank Indenture) or transfer the entirety of, or a substantial amount of, the Company’s assets or merge or consolidate with or into other entities, without satisfying certain conditions. Such conditions were satisfied in the Astoria Merger. The 5.50% Senior Notes are not registered under the Securities Act of 1933, as amended, and may not be offered or sold in the U.S. absent registration or an applicable exemption from registration requirements. 3.50% Senior Notes. On October 2, 2017 , in connection with the Astoria Merger, the Company assumed $ 200,000 principal amount of 3.50% fixed rate senior notes that mature on June 8, 2020 (the “ 3.50% Senior Notes”). The 3.50% Senior Notes were issued by Astoria on June 8, 2017 through a public offering. The Company recorded 3.50% Senior Notes at estimated fair value of 100.76 on the acquisition date, which was based on quoted market value. The fair value adjustment of $ 1,520 is being amortized over the remaining maturity using a level-yield methodology which results in an effective cost of 3.19% . The 3.50% Senior Notes were issued under an indenture assumed by the Company and Wilmington Trust National Association, as trustee (the “Wilmington Indenture”). The Wilmington Indenture includes provisions that among other things, restrict the Company’s ability to dispose of or issue shares of voting stock of a material subsidiary (as defined in the Wilmington Indenture) or transfer the entirety of, or a substantial amount of, the Company’s assets or merge or consolidate with or into other entities, without satisfying certain conditions. Such conditions were satisfied in the Astoria Merger. Subordinated Notes. On March 29, 2016 , the Bank issued $110,000 aggregate principal amount of 5.25% fixed-to-floating rate subordinated notes (the “Subordinated Notes”) through a private placement at a discount of 1.25% . The cost of issuance was $500 . On September 2, 2016 , the Bank reopened the Subordinated Notes offering and issued an additional $65,000 principal amount of Subordinated Notes. The Subordinated Notes issued September 2, 2016 are fully fungible with, rank equally in right of payment with, and form a single series with the Subordinated Notes issued March 29, 2016 . Such notes were issued to the purchasers at a premium of 0.50% and an underwriters discount of 1.25% . The cost of issuance was $275 . At December 31, 2017 , the net unamortized discount of all Subordinated Notes was $2,284 , which will be accreted to interest expense over the life of the Subordinated Notes, resulting in an effective yield of 5.45% . Interest is due semi-annually in arrears on April 1 and October 1 of each year, until April 1, 2021 . From and including April 1, 2021 , the Subordinated Notes will bear interest at a floating rate per annum equal to three-month LIBOR plus 3.937% , payable quarterly on January 1 , April 1 , July 1 and October 1 of each year, beginning on July 1, 2021 , through maturity on April 1, 2026 or earlier redemption. The Subordinated Notes are also redeemable by the Bank, in whole or in part, on April 1, 2021 and each interest payment date thereafter. The Subordinated Notes are redeemable in whole at any time upon the occurrence of certain specified events. The Subordinated Notes are unsecured, subordinated obligations of the Bank and are subordinated in right of payment to all of the Bank’s existing and future senior indebtedness, including claims of depositors and general creditors. The Subordinated Notes qualify as Tier 2 capital for regulatory purposes. See Note 16. “Stockholders’ Equity”, for additional information. Revolving line of credit. On September 5, 2017 , the Company amended and renewed its existing revolving line of credit agreement for a new 12-month term. The loan agreement is for a $35,000 revolving line of credit facility (the “Credit Facility”) with a financial institution that matures on September 4, 2018 . The balance was zero at December 31, 2017 and December 31, 2016 . The use of proceeds are for general corporate purposes. The line and accrued interest is payable at maturity, and is required to maintain a zero balance for at least 30 days during its term. The line bears interest at one-month LIBOR plus 1.25% . Under the terms of the Credit Facility, the Company and the Bank must maintain certain ratios related to capital, non-performing assets to capital, reserves to non-performing loans and debt service coverage. The Company and the Bank were in compliance with all requirements of the Credit Facility at December 31, 2017 .

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedges, Assets [Abstract]
Derivatives	Derivatives The Company utilizes interest rate swap agreements as part of its asset liability management strategy to help manage its interest rate risk position. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each swap transaction, the Company agrees to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on a similar notional amount at a fixed interest rate. At the same time, the Company agrees to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows the Company to provide a fixed rate borrowing to a customer and effectively convert the loan to a variable rate loan. Because the Company acts as an intermediary for its customers, changes in the fair value of the underlying derivative contracts largely offset each other and do not materially impact results of operations. The Company has entered into interest rate swap contracts that are both over-the-counter, or OTC, and those that are exchanged on futures markets such as the Chicago Mercantile Exchange, or the CME. At December 31, 2017 and December 31, 2016, the OTC derivatives are included in the financial statements at the gross fair value amount of the asset (included in other assets) and liability (included in other liabilities), which represents the change in the fair value of the contract since inception. Effective for 2017 , the CME amended its rulebook to legally characterize variation margin payments (a payment made based on changes in the fair value of the interest rate swap contracts) as a settlement, referred to as settled-to-market, or STM. As a result of this change, at December 31, 2017 the Company paid cash as STM in the amount of $3,523 for the net fair value of its CME interest rate swap contracts with another financial institution. The variation margin payment changes daily, positively or negatively, based on a change in the fair value of the underlying interest rate swap contracts. The Company does not typically require its commercial customers to post cash or securities as collateral on its program of back-to-back swaps. However, certain language is written into the International Swaps and Derivatives Association agreement and loan documents where, in default situations, the Company is allowed to access collateral supporting the loan relationship to recover any losses suffered on the derivative asset or liability. Summary information as of December 31, 2017 and 2016 regarding these derivatives is presented below: Notional amount Average maturity (in years) Weighted average fixed rate Weighted average variable rate Fair value December 31, 2017 Included in other assets: Third-party interest rate swap $ 314,754 $ 1,155 Customer interest rate swap 306,529 3,302 Total $ 621,283 5.79 4.28 % 1 m Libor + 1.94% $ 4,457 Included in other liabilities: Third-party interest rate swap $ (306,529 ) $ (4,718 ) Customer interest rate swap (314,754 ) (3,262 ) $ (621,283 ) 5.79 4.28 % 1 m Libor + 1.94% $ (7,980 ) December 31, 2016 Third-party interest rate swap $ 296,282 5.63 3.94 1 m Libor + 2.29% $ 2,088 Customer interest rate swap (296,282 ) 5.63 3.94 1 m Libor + 2.29% (2,088 ) The Company enters into various commitments to sell real estate loans into the secondary market. Such commitments are considered to be derivative financial instruments; however, the fair value of these commitments is not material.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense for the periods indicated consisted of the following: For the year ended December 31, 2017 2016 2015 Current tax expense: Federal $ 4,375 $ 55,418 $ 25,634 State and local 2,181 12,854 5,862 Total current tax expense 6,556 68,272 31,496 Deferred tax expense (benefit): Federal 71,536 (1,069 ) (1,406 ) State and local 9,847 179 1,745 Total deferred tax expense (benefit) 81,383 (890 ) 339 Total income tax expense $ 87,939 $ 67,382 $ 31,835 Actual income tax expense differs from the tax computed based on pre-tax income and the applicable statutory Federal tax rate for the following reasons: For the year ended December 31, 2017 2016 2015 Tax at federal statutory rate of 35% $ 63,341 $ 72,574 $ 34,282 State and local income taxes, net of federal tax benefit 7,818 8,472 4,945 Tax-exempt interest, net of disallowed interest (18,948 ) (11,094 ) (5,218 ) BOLI income (2,665 ) (1,933 ) (1,853 ) Non-deductible acquisition related costs 2,965 — 700 Low income housing tax credits (1,872 ) (469 ) (215 ) Equity-based stock compensation benefit (1,528 ) — — Estimated deferred tax adjustment related to reduction in federal income tax rate 40,285 — — Other, net (1,457 ) (168 ) (806 ) Actual income tax expense $ 87,939 $ 67,382 $ 31,835 Effective income tax rate 48.6 % 32.5 % 32.5 % The following table presents the Company’s deferred tax position at December 31, 2017 and 2016 : December 31, 2017 2016 Deferred tax assets: Allowance for loan losses $ 20,468 $ 25,039 Deferred compensation 315 656 Other accrued compensation and benefits 22,321 9,920 Accrued post retirement expense 7,885 2,060 Deferred rent 3,445 3,268 Intangible assets 1,612 3,108 Other comprehensive loss (securities) 11,422 16,911 Other comprehensive loss (defined benefit plans) 447 479 Pension expense 11,691 — Accrued expenses 4,923 252 State NOL carryforward 15,400 — AMT credit carryforward 4,070 — Other 3,237 3,719 Total deferred tax assets 107,236 65,412 Deferred tax liabilities: Mortgage servicing rights 2,722 403 Prepaid pension costs — 3,798 Acquisition fair value adjustments — 18,948 Depreciation of premises and equipment 1,026 809 Deferred loan fees and costs 5,001 — Other 1,154 906 Total deferred tax liabilities 9,903 24,864 Net deferred tax asset $ 97,333 $ 40,548 On December 22, 2017, the Tax Act was enacted, which included a reduction of the U.S. federal corporate income tax rate from 35% to 21% effective January 1, 2018. As a result, the Company was required to remeasure, through income tax expense, the Company’s deferred tax assets and liabilities using the enacted rate at which the deferred items are expected to be recovered or settled. The remeasurement of our net deferred tax asset resulted in additional income tax expense of $40,285 in 2017. Also on December 22, 2017, the SEC released Staff Accounting Bulletin No. 118 (“SAB 118”) to address any uncertainty or diversity of views in practice in accounting for the income tax effects of the Tax Act in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete this accounting in the reporting period ended December 31, 2017. SAB 118 allows for a measurement period not to extend beyond one year from the enactment of the Tax Act to complete the necessary accounting. The Company recorded provisional adjustments but has not completed its accounting for income tax effects for certain elements of the Tax Act, including purchase accounting adjustments recorded in connection with the Astoria Merger. Moreover, the Company has made no adjustments to deferred tax assets representing future deductions for accrued compensation that may be subject to new limitations under Internal Revenue Code 162(m) which, generally, limits the annual deduction for certain compensation paid to certain employees to $1,000. There is uncertainty in applying the newly-enacted rules to existing contracts, and the Company is seeking further clarifications in order to complete its analysis. Based on the Company’s consideration of historical and anticipated future pre-tax income, and the reversal period for the items resulting in the deferred tax assets and liabilities, a valuation allowance for deferred tax assets was not considered necessary at either December 31, 2017 or 2016 . Retained earnings at December 31, 2017 and 2016 included approximately $9,313 for which no provision for federal income taxes has been made. This amount represents the tax bad debt reserve at December 31, 1987 , which is the end of the Bank ’ s base year for purposes of calculating the bad debt deduction for tax purposes. If this portion of retained earnings is used in the future for any purposes other than to absorb bad debts, the amount used will be added to future taxable income. The unrecorded deferred tax liability on the above amount at both December 31, 2017 and 2016 , was approximately $3,260 . The Company acquired state and local net operating loss (“NOL”) carryforwards in the Astoria Merger. The Company has an available New York State NOL carryforward of $164,786 , which expires in 2024. The Company has an available New York City NOL carryforward of $66,612 , which expires in various years from 2024 through 2037. At December 31, 2017 and 2016 , the Company had no unrecognized tax benefits or accrued interest and penalties recorded. The Company does not expect the total amount of unrecognized tax benefits to significantly increase within the next twelve months. The Company records interest and penalties as a component of other non-interest expense. The Company and its subsidiaries are subject to U.S. federal income tax, as well as income tax of the state of New York and various other states. The Company is generally no longer subject to examination by federal, state and local taxing authorities for tax fiscal years prior to September 30, 2014.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company has active stock-based compensation plans, as described below. The Company’s stockholders approved the 2015 Omnibus Equity and Incentive Plan (the “ 2015 Plan ”) on May 28, 2015 . The 2015 Plan permits the grant of stock options, stock appreciation rights, restricted stock (both time-based and performance-based), restricted stock units, deferred stock and other stock-based awards. The total number of shares that may be awarded under the 2015 Plan is 2,800,000 shares plus the remaining shares available for grant under the 2014 Stock Incentive Plan (the “ 2014 Plan ”). At December 31, 2017 , there were 3,101,327 shares available for future grant under the 2015 Plan . Under the 2015 Plan , one share is deducted from the 2015 Plan for every share that is awarded and delivered under the 2015 Plan . Restricted stock awards are granted with a fair value equal to the market price of the Company’s common stock at the date of grant. Stock option awards are granted with a strike price that is equal to the market price of the Company’s stock at the date of grant. The awards generally vest in equal installments annually on the anniversary date and have total vesting periods ranging from 1 to 5 years and stock options have 10 year contractual terms. In connection with the Provident Merger, the Company granted 104,152 options at an exercise price of $14.25 per share under which the Company assumed all outstanding fully-vested Legacy Sterling stock options. All options were exercised or expired on March 15, 2017 . The Company also granted 95,991 shares under the Legacy Sterling Bancorp 2013 Employment Inducement Award Plan to certain executive officers of Legacy Sterling. In addition, the Company issued 255,973 shares of restricted stock from shares available under a prior plan to certain executives of Legacy Sterling. The weighted average grant date fair value under both of these plans was $11.72 per share and the restricted stock awards vested in October 2016. The following table summarizes the activity in the Company’s active stock-based compensation plans for the periods presented: Non-vested stock awards/stock units outstanding Stock options outstanding Shares available for grant Number of shares Weighted average grant date fair value Number of shares Weighted average exercise price Balance at December 31, 2014 1,999,022 643,887 $ 11.79 2,040,299 $ 11.10 2015 Plan 2,800,000 — — — — Granted (1) (732,023 ) 447,807 14.02 24,566 14.22 Stock awards vested — (330,384 ) 11.23 — — Exercised — — — (406,422 ) 11.58 Forfeited 192,970 (34,510 ) 12.92 (71,871 ) 12.90 Canceled/expired (134.304 ) — — — — Balance at December 31, 2015 4,125,665 726,800 $ 13.36 1,586,572 $ 10.95 Granted (515,869 ) 515,869 14.60 — — Stock awards vested — (261,989 ) 13.09 — — Exercised — — — (503,893 ) 10.47 Forfeited 130,758 (48,457 ) 13.88 (78,560 ) 13.41 Canceled/expired (100,716 ) — — — — Balance at December 31, 2016 3,639,838 932,223 $ 14.09 1,004,119 $ 11.00 Granted (610,075 ) 610,075 24.13 — — Stock awards vested — (228,661 ) 16.23 — — Exercised — — — (244,252 ) 10.52 Forfeited 76,877 (74,877 ) 18.92 (2,000 ) 13.18 Canceled/expired (5,313 ) — — — — Balance at December 31, 2017 3,101,327 1,238,760 $ 20.00 757,867 $ 11.15 Exercisable at December 31, 2017 754,678 $ 11.13 (1) Reflects certain non-vested stock awards that counted as either 3.5 shares or 3.6 shares (depending on under which stock plan the awards were granted) for each share award granted. Other information regarding options outstanding at December 31, 2017 follows: Outstanding Exercisable Weighted average Weighted average Number of stock options Exercise price Life (in years) Number of stock options exercise price Range of exercise prices: $6.71 to $9.00 198,278 $ 8.34 4.43 198,278 $ 8.34 9.28 to 11.36 220,862 10.86 5.07 220,862 10.86 11.36 to 13.18 91,050 12.02 4.85 91,050 12.02 13.23 to 15.01 247,677 13.33 6.85 244,488 13.31 757,867 11.15 5.46 754,678 11.13 The total intrinsic value of outstanding in-the-money stock options and outstanding in-the-money exercisable stock options was $10,196 and $10,165 , respectively, at December 31, 2017 . Proceeds from stock option exercises were $2,578 ; $3,588 ; and $2,764 for 2017 , 2016 , and 2015 respectively. The Company uses an option pricing model to estimate the grant date fair value of stock options granted. There were no stock options granted in 2017 and 2016 . The weighted average estimated value per option granted was $2.14 for 2015 . The fair value of options granted was determined using the following weighted-average assumptions as of the grant date: For the year ended December 31, 2015 Risk-free interest rate 1.8 % Expected stock price volatility 21.2 Dividend yield (1) 3.1 Expected term in years 5.76 (1) Represents the approximate annualized cash dividend rate paid with respect to a share of common stock at or near the grant date. Stock-based compensation expense is recognized ratably over the requisite service period for all awards. Stock-based compensation expense associated with stock options and non-vested stock awards and the related income tax benefit was as follows: For the year ended December 31, 2017 2016 2015 Stock options $ 149 $ 404 $ 909 Non-vested stock awards/performance units 7,961 6,114 3,671 Total $ 8,110 $ 6,518 $ 4,580 Income tax benefit $ 2,149 $ 2,118 $ 1,417 Unrecognized stock-based compensation expense at December 31, 2017 was as follows: December 31, 2017 Stock options $ 2 Non-vested stock awards/performance units 13,540 Total $ 13,542 The weighted average period over which unrecognized stock options is expected to be recognized is 0.75 years . The weighted average period over which unrecognized non-vested awards/performance units is expected to be recognized is 1.55 years .

Pension and Other Post Retireme

Pension and Other Post Retirement Benefits	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Pension and Other Post Retirement Benefits	Pension and Other Post Retirement Benefits (a) Existing Pension Plans and Other Post Retirement Benefits On October 2, 2017 , in connection with the Astoria Merger, the Company assumed all of the assets and liabilities of the Astoria Bank Pension Plan the Astoria Excess and Supplemental Benefit Plans, Astoria Directors’ Retirement Plan, the Greater New York Savings Bank Directors’ Retirement Plan (the “Greater Plan”) and the Long Island Bancorp Directors’ Retirement Plan (the “LIB Plan”). The Company also assumed other post retirement benefits plans including the Astoria Bank Retiree Health Care Plan, and the Astoria Bank BOLI plan. The following is a summary of changes in the projected benefit obligation and fair value of pension plans and other post retirement benefits plan assets. Pension benefits Other post retirement benefits December 31, December 31, 2017 2016 2017 2016 Changes in projected benefit obligation: Beginning of year balance $ — $ — $ 12,125 $ 11,733 Benefit obligation assumed in Astoria Merger 259,152 — 21,325 — Service cost — — 22 — Interest cost 2,189 — 557 417 Actuarial loss 3,561 — 984 64 Benefits and distributions paid (11,319 ) — (236 ) (89 ) End of year balance 253,583 — 34,777 12,125 Changes in fair value of plan assets: Beginning of year balance — — — — Fair value of pension plan assets at October 2, 2017 194,010 — — — Actual gain on plan assets 6,234 — — — Employer contributions 9,470 — 236 89 Benefits and distributions paid (11,319 ) — (236 ) (89 ) End of year balance 198,395 — — — Funded status at end of year $ (55,188 ) $ — $ (34,777 ) $ (12,125 ) The underfunded pension benefits and other post retirement benefits at December 31, 2017 and 2016 are included in other liabilities in our consolidated balance sheets. The Company did not make a contribution to the Astoria Bank Pension Plan in 2017 . Management anticipates it will make a contribution in 2018 of approximately $30,000 . No pension plan assets are expected to be returned to the Company. The following is a summary of the pre-tax components of accumulated other comprehensive loss related to pension plans and other post retirement benefits. We do not expect that any net actuarial (gain) loss and prior service cost will be recognized as components of net periodic cost in 2018 . Pension benefits Other post retirement benefits December 31, December 31, 2017 2016 2017 2016 Net actuarial loss $ 613 $ — $ 101 $ — Total accumulated other comprehensive loss $ 613 $ — $ 101 $ — The following is a summary of the discount rates used to determine the benefit obligations at the dates indicated. December 31, 2017 2016 Pension benefit plans: Astoria Bank Pension Plan 3.44 % N/A Astoria Excess and Supplemental Benefit Plans 3.14 N/A Astoria Directors’ Retirement Plan 2.82 N/A Greater Directors’ Retirement Plan 2.96 N/A LIB Directors’ Retirement Plan N/A N/A Other post retirement benefit plans: Sterling Other Post retirement medical, dental and vision plans 2.80% to 3.62% 2.78% to 4.00% Astoria Bank Retiree Health Care Plan 3.42 N/A The components of net periodic pension expense were as follows: Pension benefits Other post retirement benefits For the Year Ended December 31, For the Year Ended December 31, 2017 2016 2015 2017 2016 2015 Service cost $ — $ — $ — $ 22 $ — $ 6 Interest cost 2,189 — 1,766 557 417 373 Expected return on plan assets (3,287 ) — (2,187 ) — — — Amortization of unrecognized actuarial loss — — 272 19 — — Amortization of transition obligation — — — 2 — — Amortization of prior service cost — — — 14 64 161 Plan termination / Partial settlement charge — — 13,384 — — — Net periodic pension (benefit) expense $ (1,098 ) $ — $ 13,235 $ 614 $ 481 $ 540 Net periodic pension (benefit) expense is included in compensation and benefits in the consolidated income statements; however, the termination and settlement charge for the defined benefit pension plan was presented as a separate line item due to its significance. The following is a summary of the assumptions used to determine the net periodic (benefit) cost for the years ended December 31, 2017 and 2016 . Discount rate Expected return on plan assets 2017 2016 2017 2016 Pension benefit plans: Astoria Bank Pension Plan 3.61 % N/A 7.00 % N/A Astoria Excess and Supplemental Benefit Plans 3.21 N/A N/A N/A Astoria Directors’ Retirement Plan 2.78 N/A N/A N/A Greater Directors’ Retirement Plan 2.96 N/A N/A N/A LIB Directors’ Retirement Plan N/A N/A N/A N/A Other post retirement benefit plans: Sterling Other Post retirement medical, dental and vision plans 2.78% to 4.15% 2.78% to 4.00% N/A N/A Astoria Bank Retiree Health Care Plan 3.58 N/A N/A N/A (b) Former Pension Plan On October 15, 2015, the Company terminated the Sterling National Bank Defined Benefit Pension Plan (the “Plan”) and satisfied all obligations owed to Plan participants, through the purchase of annuities from a third-party insurance carrier and lump sum distributions, as elected by Plan participants in an aggregate amount of $58,171 . In connection with the Plan termination, the Company incurred a settlement charge of $13,384 , which was comprised of the change in fair value of Plan assets of $4,068 , the recognition of the remaining balance of accumulated other comprehensive loss through earnings of $7,936 , and a charge representing the difference between the Company’s effective tax rate and its marginal tax rate of $1,380 . The balance of the pension reversion asset is $6,648 (which is recorded in other assets in the consolidated balance sheets) at December 31, 2017 . This asset will be held in custody by the Company’s 401(k) plan custodian and is expected to be charged to earnings over the next three to four years as it is distributed to employees under qualified compensation and benefit programs. (c) Other Existing Post Retirement Benefit Plans The Company provides other post retirement benefit plans, which are unfunded. Included in the tables below is information regarding Supplemental Executive Retirement Plans (“SERP”) to certain former directors and officers of the Company, life insurance benefits to certain directors and officers of the Company and former Legacy Sterling officers and directors. In connection with the HVB Merger, the Company assumed SERP liabilities of $16,059 . The Company terminated the HVHC SERP as of the acquisition date. Plan participants received a lump-sum cash payment in July 2015 and all plan obligations were satisfied. On October 2, 2017 , as part of the Astoria Merger, the Company assumed the Astoria Bank Retiree Health Care Plan. The following table presents the assumed health care cost trend rates at the dates indicated. December 31, 2017 2016 Health care cost trend rate assumed for the next year: Pre-age 65 7.00 % N/A Post-age 65 6.75 N/A Rate to which the cost trend rate is assumed to decline (the “ultimate trend rate”) 4.75 N/A Year that ultimate trend rate is reached 2026 N/A Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plan. The following table presents the effects on a one-percentage point change in assumed health care cost trend rates. One percentage point increase One percentage point decrease Effect on total service and interest cost components $ 25 $ (20 ) Effect on the post retirement benefit obligation 2,300 (1,896 ) Estimated future total benefits expected to be paid are the following for the years ending December 31 : Pension benefits Other post retirement benefits 2018 $ 12,568 $ 1,270 2019 12,560 1,400 2020 12,801 1,483 2021 14,162 1,566 2022 13,241 1,562 Thereafter 67,102 16,669 The Astoria Bank Pension Plan’s assets are measured at estimated fair value on a recurring basis. The Astoria Bank Pension Plan groups its assets at fair value in three levels, based on the markets in which the assets are traded and the reliability of the assumptions used to determine fair value. These levels are described in Note 19. “Fair Value Measurements.” Other than the Astoria Bank Pension Plan’s investment in Sterling Bancorp common stock, the assets are managed by Prudential Retirement Insurance and Annuity Company (“PRIAC”). The following tables set forth the carrying values of the Astoria Bank Pension Plan’s assets measured at estimated fair value on a recurring basis and the level within the fair value for the fair value measurements. Carrying value at December 31, 2017 Total Level 1 Level 2 Level 3 PRIAC Pooled Separate Accounts (1) $ 165,315 $ 165,315 $ — $ — Sterling Bancorp common stock 20,553 20,553 — — PRIAC Guaranteed Deposit Account 12,464 — — 12,464 Cash and cash equivalents 63 63 — — Total $ 198,395 $ 185,931 $ — $ 12,464 (1) Investment allocation consists of 42% large-cap equity 33% fixed income, 11% international equity, 8% small-cap equity and 6% mid-cap equity. The following table sets forth a summary of changes in the estimated fair value of the Astoria Bank Pension Plan’s Level 3 assets for the period indicated. For the period from October 2, 2017 to December 31, 2017 Fair value at October 2, 2017 $ 11,888 Total net loss, realized and unrealized, included in net assets (1) (47 ) Purchases 3,375 Sales (2,752 ) Fair value at December 31, 2017 $ 12,464 (1) Includes unrealized gain related to assets held at December 31, 2017 of $153 for the period October 2, 2017 to December 31, 2017 . The following table presents information about significant unobservable inputs related to the Astoria Bank Pension Plan’s investment in Level 3 assets at the date indicated. PRIAC guaranteed deposit account range at December 31, 2017 Significant unobservable inputs: Composite market value factor 1.012 - 1.020 Gross guaranteed crediting rate (1) 2.55 % - 3.59% (1) Gross guaranteed crediting rates must be greater than or equal to contractual minimum crediting rate. The overall strategy of the Astoria Bank Pension Plan investment policy is to have a diverse investment portfolio that reasonably spans established risk/return levels, preserves liquidity and provides long-term investment returns equal to or greater than the actuarial assumptions. The strategy allows for a moderate risk approach in order to achieve greater long-term asset growth. The asset mix within the various insurance company pooled separate accounts and trust company trust funds can vary but should not be more than 80% in equity securities, 50% in debt securities and 25% in liquidity funds. Within equity securities, the mix is further clarified to have ranges not to exceed 10% in any one company, 30% in any one industry, 50% in funds that mirror the S&P 500, 50% in large-cap equity securities, 20% in mid-cap equity securities, 20% in small-cap equity securities and 10% in international equities. In addition, up to 15% of total plan assets may be held in Sterling Bancorp common stock. However, the Astoria Bank Pension Plan will not acquire Sterling Bancorp common stock to the extent that, immediately after the acquisition, such common stock would represent more than 10% of total plan assets. The following is a description of valuation methodologies used for the Astoria Bank Pension Plan's assets measured at estimated fair value on a recurring basis. PRIAC Pooled Separate Accounts The fair value of the Astoria Bank Pension Plan’s investments in the PRIAC Pooled Separate Accounts is based on the fair value of the underlying securities included in the pooled separate accounts which consist of equity securities and bonds. Investments in these accounts are represented by units and a per unit value. The unit values are calculated by PRIAC and fair value is reported at unit value which is priced daily. For the underlying equity securities, PRIAC obtains closing market prices for those securities traded on a national exchange. For bonds, PRIAC obtains prices from a third party pricing service using inputs such as benchmark yields, reported trades, broker/dealer quotes and issuer spreads. Prices are reviewed by PRIAC and are challenged if PRIAC believes the price is not reflective of fair value. There are no restrictions as to the redemption of these pooled separate accounts nor does the Astoria Bank Pension Plan have any contractual obligations to further invest in any of the individual pooled separate accounts. These investments are classified as Level 1. Sterling Bancorp common stock The fair value of the Astoria Bank Pension Plan’s investment in Sterling Bancorp common stock is obtained from a quoted market price in an active market and, as such, this investment is classified as Level 1. PRIAC Guaranteed Deposit Account The fair value of the Astoria Bank Pension Plan’s investment in the PRIAC Guaranteed Deposit Account is calculated by PRIAC and approximates the fair value of the underlying investments by discounting expected future investment cash flows from both investment income and repayment of principal for each investment purchased directly for the general account. The discount rates assumed in the calculation reflect both the current level of market rates and spreads appropriate to the quality, average life and type of investment being valued. PRIAC calculates a contract-specific composite market value factor, which is determined by summing the product of each investment year's market value factor as of the plan year end by the particular contracts balance within the investment year and dividing the result by the contracts total investment year balance. This contract-specific market value factor is then multiplied by the contract value, which represents deposits made to the contract, plus earnings at the guaranteed crediting rates, less withdrawals and fees, to arrive at the estimated fair value. This investment is classified as Level 3. Cash and cash equivalents The fair value of the Astoria Bank Pension Plan’s cash and cash equivalents represents the amount available on demand and, as such, are classified as Level 1. (d) Employee Savings Plan The Company also sponsors a defined contribution plan established under Section 401(k) of the IRS Code. Eligible employees may elect to contribute up to 50.0% of their compensation to the plan. In 2015, the Company made matching contributions equal to 50.0% of a participant’s contributions up to a maximum matching contribution of 3.0% of eligible compensation. The plan also provides for a discretionary profit sharing component, in addition to the matching contributions. Beginning January 1, 2016, the Company implemented a profit sharing contribution equal to 3.0% of eligible compensation of all employees, to be funded by the pension reversion asset described above. The contribution is made to all eligible employees regardless of their 401(k) elective deferral percentage. Voluntary matching and profit sharing contributions are invested in accordance with the participant’s direction in one or a number of investment options. Savings plan expense was $3,827 for 2017 , $3,210 for 2016 ; $1,769 for 2015 . Prior to 2016, there was no profit sharing component contributed by the Company.

Other Non-Interest Expense

Other Non-Interest Expense	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Other Non-interest Expense	Other Non-interest Expense Other non-interest expense items are presented in the following table. Significant components of the aggregate of total net interest income and total non-interest income are presented separately. For the year ended December 31, 2017 2016 2015 Other non-interest expense: Advertising and promotion $ 3,682 $ 2,948 $ 2,522 Professional fees 9,982 10,276 8,308 Data and check processing 19,387 8,866 8,825 Insurance & surety bond premium 3,317 3,150 3,186 Other 22,557 18,556 17,836 Total other non-interest expense $ 58,925 $ 43,796 $ 40,677

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The following is a summary of the calculation of earnings per common share (“EPS”): For the year ended December 31, 2017 2016 2015 Net income available to common stockholders $ 91,029 $ 139,972 $ 66,114 Weighted average common shares outstanding for computation of basic EPS 157,513,639 130,607,994 109,907,645 Common-equivalent shares due to the dilutive effect of stock options (1) 610,631 626,468 421,708 Weighted average common shares for computation of diluted EPS 158,124,270 131,234,462 110,329,353 Earnings per common share: Basic $ 0.58 $ 1.07 $ 0.60 Diluted 0.58 1.07 0.60 Weighted average common shares that could be exercised that were anti-dilutive for the period (2) — — 2,394 (1) Represents incremental shares computed using the treasury stock method. (2) Anti-dilutive shares are not included in determining diluted earnings per share.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity (a) Regulatory Capital Requirements Banks and bank holding companies are subject to various regulatory capital requirements administered by the federal banking agencies. Capital adequacy guidelines, and, additionally for banks, prompt corrective action regulations, involve quantitative measures of assets, liabilities, and certain off-balance sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgments by regulators about components, risk-weighting, and other factors. The Basel III Capital Rules became effective for the Company and the Bank on January 1, 2015 (subject to a phase-in period for certain provisions). Quantitative measures established by the Basel III Capital Rules to ensure capital adequacy require the maintenance of minimum amounts and ratios (set forth in the table below) of Common Equity Tier 1 capital (as defined in the regulations), Tier 1 capital (as defined in the regulations) and Total capital (as defined in the regulations) to risk-weighted assets (as defined, “RWA”), and of Tier 1 capital to adjusted quarterly average assets (as defined) (the “Tier 1 leverage ratio”). The Company’s and the Bank’s Common Equity Tier 1 capital consists of common stock and related paid-in capital, net of treasury stock, and retained earnings. In connection with the adoption of the Basel III Capital Rules, we elected to opt-out of the requirement to include most components of accumulated other comprehensive income in Common Equity Tier 1 capital. Common Equity Tier 1 capital for both the Company and the Bank is reduced by goodwill and other intangible assets, net of associated deferred tax liabilities and subject to transition provisions. Tier 1 capital includes Common Equity Tier 1 capital and additional Tier 1 capital, including preferred stock. Total capital includes Tier 1 capital and Tier 2 capital. Tier 2 capital (as defined in the regulations) for both the Bank and the Company includes a permissible portion of the allowance for loan losses and $172,716 and $142,174 of the Subordinated Notes, respectively. During the final five years of the term of the Subordinated Notes the permissible portion eligible for inclusion in Tier 2 capital decreases by 20% annually. The Common Equity Tier 1, Tier 1 and Total capital ratios are calculated by dividing the respective capital amounts by RWA. RWA is calculated based on regulatory requirements and includes total assets, excluding goodwill and other intangible assets, allocated by risk weight category, and certain off-balance-sheet items, among other items. The Tier 1 leverage ratio is calculated by dividing Tier 1 capital by adjusted quarterly average total assets, which exclude goodwill and other intangible assets, among other things. When fully phased-in on January 1, 2019, the Basel III Capital Rules will require the Company and the Bank to maintain: (i) a minimum ratio of Common Equity Tier 1 capital to RWA of at least 4.5%, plus a 2.5% “capital conservation buffer” (which is added to the 4.5% Common Equity Tier 1 capital ratio as that buffer is phased in, effectively resulting in a minimum ratio of Common Equity Tier 1 capital to RWA of at least 7.0% upon full implementation); (ii) a minimum ratio of Tier 1 capital to RWA of at least 6.0%, plus the capital conservation buffer (which is added to the 6.0% Tier 1 capital ratio as that buffer is phased in, effectively resulting in a minimum Tier 1 capital ratio of 8.5% upon full implementation); (iii) a minimum ratio of Total capital to RWA of at least 8.0%, plus the capital conservation buffer (which is added to the 8.0% total capital ratio as that buffer is phased in, effectively resulting in a minimum total capital ratio of 10.5% upon full implementation); and (iv) a minimum Tier 1 leverage ratio of 4.0%. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and is being phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reaches 2.5% on January 1, 2019). The Basel III Capital Rules also provide for a “countercyclical capital buffer” that is applicable to only certain covered institutions and does not have any current applicability to the Company or the Bank. The aforementioned capital conservation buffer is designed to absorb losses during periods of economic stress. Banking institutions with a ratio of Common Equity Tier 1 capital to RWA above the minimum but below the conservation buffer (or below the combined capital conservation buffer and countercyclical capital buffer, when the latter is applied) will face constraints on dividends, equity repurchases and compensation based on the amount of the shortfall. The following table presents actual and required capital ratios as of December 31, 2017 and December 31, 2016 for the Company and the Bank under the Basel III Capital Rules. The minimum required capital amounts presented include the minimum required capital levels as of December 31, 2017 based on the phase-in provisions of the Basel III Capital Rules and the minimum required capital levels as of January 1, 2019 when the Basel III Capital Rules have been fully phased-in. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended, to reflect the changes under the Basel III Capital Rules. Actual Minimum capital required - Basel III phase-in schedule Minimum capital required - Basel III fully phased-in Required to be considered well capitalized Capital amount Ratio Capital amount Ratio Capital amount Ratio Capital amount Ratio December 31, 2017 Common equity tier 1 to RWA: Sterling National Bank $ 2,770,381 13.95 % $ 1,142,247 5.75 % $ 1,390,561 7.00 % $ 1,291,236 6.50 % Sterling Bancorp 2,458,449 12.37 1,143,045 5.75 1,391,534 7.00 N/A N/A Tier 1 capital to RWA: Sterling National Bank 2,770,381 13.95 1,440,224 7.25 1,688,539 8.50 1,589,213 8.00 Sterling Bancorp 2,597,669 13.07 1,441,231 7.25 1,689,719 8.50 N/A N/A Total capital to RWA: Sterling National Bank 3,021,658 15.21 1,837,527 9.25 2,085,842 10.50 1,986,516 10.00 Sterling Bancorp 2,818,404 14.18 1,838,812 9.25 2,087,300 10.50 N/A N/A Tier 1 leverage ratio: Sterling National Bank 2,770,381 10.10 1,097,449 4.00 1,097,449 4.00 1,371,811 5.00 Sterling Bancorp 2,597,669 9.39 1,106,977 4.00 1,106,977 4.00 N/A N/A Actual Minimum capital required - Basel III phase-in schedule Minimum capital required - Basel III fully phased-in Required to be considered well capitalized Capital amount Ratio Capital amount Ratio Capital amount Ratio Capital amount Ratio December 31, 2016 Common equity tier 1 to RWA: Sterling National Bank $ 1,176,497 10.87 % $ 554,663 5.125 % $ 757,588 7.00 % $ 703,475 6.50 % Sterling Bancorp 1,160,739 10.73 554,474 5.125 757,330 7.00 N/A N/A Tier 1 capital to RWA: Sterling National Bank 1,176,497 10.87 717,003 6.625 919,928 8.50 865,815 8.00 Sterling Bancorp 1,160,739 10.73 716,759 6.625 919,615 8.50 N/A N/A Total capital to RWA: Sterling National Bank 1,413,165 13.06 933,457 8.625 1,136,382 10.50 1,082,269 10.00 Sterling Bancorp 1,377,547 12.73 933,139 8.625 1,135,995 10.50 N/A N/A Tier 1 leverage ratio: Sterling National Bank 1,176,497 9.08 518,308 4.00 518,308 4.00 647,885 5.00 Sterling Bancorp 1,160,739 8.95 518,733 4.00 518,733 4.00 N/A N/A Management believes that as of December 31, 2017 , the Bank was “well-capitalized”. At December 31, 2017 , and December 31, 2016 , the most recent regulatory notifications categorized the Bank as well capitalized under the regulatory framework for prompt corrective action. There are no conditions or events since that notification that management believes have changed the Bank’s category. A reconciliation of the Company’s and the Bank’s stockholders’ equity to their respective regulatory capital at December 31, 2017 and 2016 is as follows: The Company The Bank December 31, December 31, 2017 2016 2017 2016 Total U.S. GAAP stockholders’ equity $ 4,240,178 $ 1,855,183 $ 4,373,108 $ 1,843,476 Disallowed goodwill and other intangible assets (1,668,680 ) (721,079 ) (1,628,898 ) (693,614 ) Net unrealized loss on available for sale securities 22,324 22,637 22,324 22,637 Net accumulated other comprehensive income components 3,847 3,998 3,847 3,998 Tier 1 risk-based capital 2,597,669 1,160,739 2,770,381 1,176,497 Tier 2 capital 142,174 152,641 172,716 172,501 Allowance for loan losses and off-balance sheet commitments 78,561 64,167 78,561 64,167 Total risk-based capital $ 2,818,404 $ 1,377,547 $ 3,021,658 $ 1,413,165 (b) Dividend Restrictions The Company is mainly dependent upon dividends from the Bank to provide funds for the payment of dividends to stockholders and to provide for other cash requirements. Banking regulations may limit the amount of dividends that may be paid. Approval by regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of the Bank to fall below specified minimum levels. Approval is also required if dividends declared exceed the net profits for that year combined with the retained net profits for the preceding two years. Under the foregoing dividend restrictions, and while maintaining its “well-capitalized” status, at December 31, 2017 , the Bank had capacity to pay aggregate dividends of up to $190,117 to the Company without prior regulatory approval. (c) Preferred Stock On October 2, 2017 , in connection with the Astoria Merger, the Company registered and issued 135,000 shares equal to $135,000 of 6.50% Non-Cumulative Perpetual Preferred Stock, Series A, par value $0.01 with a liquidation preference of $1,000 per share in exchange for each share of Astoria’s 6.50% Non-Cumulative Perpetual Preferred Stock, Series C, par value $1.00 per share, issued and outstanding immediately prior to the the Astoria Merger (the “Company Preferred Stock”). In addition, the Company registered and issued 5,400,000 depositary shares, with each depositary share representing 1/40th interest in the Company Preferred Stock, (the “Depositary Shares”). Holders of the Depositary Shares will be entitled to all proportional rights and preferences of the Company Preferred Stock (including dividends, voting, redemption and liquidation rights). Under the terms of the Company Preferred Stock, the ability of the Company to pay dividends on, make distributions with respect to or repurchase, redeem or otherwise acquire shares of its common stock or any preferred stock ranking on parity with or junior to the Company Preferred Stock will be subject to restrictions in the event that the Company does not declare and either pay or set aside a sum sufficient for payment of dividends on the Company Preferred Stock for the immediately preceding dividend period. Dividends are payable January 15, April 15, July 15 and October 15 of each year. The Preferred Stock is redeemable in whole or in part from time to time, on October 15, 2022 or any dividend payment date thereafter. (d) Stock Repurchase Plan On February 27, 2018 the Company’s Board of Directors authorized a new common stock repurchase plan to plan to replace the plan that existed at December 31, 2017 in which 776,713 common shares were available to be purchased. Under the new repurchase plan the Company may purchase up to 10,000,000 common shares, which represents 4.4% of shares outstanding common shares at December 31, 2017. Repurchases may be made at management’s discretion through open market purchases and block trades in accordance with SEC and regulatory requirements. Any common shares purchased will be held as Treasury stock and made available for general corporate purposes. There were no shares repurchased during 2017 and 2016 , or 2015 . (e) Liquidation Rights Upon completion of the second-step conversion in January 2004 , the Bank established a special “liquidation account” in accordance with OCC regulations. The account was established for the benefit of Eligible Account Holders and Supplemental Eligible Account Holders (as defined in the plan of conversion) in an amount equal to the greater of (i) the Mutual Holding Company’s ownership interest in the retained earnings of the Bank as of the date of its latest balance sheet contained in the prospectus; or (ii) the retained earnings of the Bank at the time that the Bank reorganized into the Mutual Holding Company in 1999. Each Eligible Account Holder and Supplemental Eligible Account Holder that continues to maintain his or her deposit account at the Bank would be entitled, in the event of a complete liquidation of the Bank, to a pro rata interest in the liquidation account prior to any payment to the stockholders of the Holding Company (as defined in the plan of conversion). The liquidation account is reduced annually on September 30 to the extent that Eligible Account Holders and Supplemental Eligible Account Holders have reduced their qualifying deposits as of each anniversary date. At December 31, 2017 , the liquidation account had a balance of $13,300 . Subsequent increases in deposits do not restore such account holder’s interest in the liquidation account. The Bank may not pay cash dividends or make other capital distributions if the effect thereof would be to reduce its stockholder’s equity below the amount of the liquidation account.

Off-Balance-Sheet Financial Ins

Off-Balance-Sheet Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Off-Balance-Sheet Financial Instruments	Off-Balance-Sheet Financial Instruments In the normal course of business, the Company enters into various transactions, which, in accordance with GAAP, are not included in its consolidated balance sheets. The Company enters into these transactions to meet the financing needs of its customers. These transactions include commitments to extend credit and standby letters of credit, which involve, to varying degrees, elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. The Company minimizes its exposure to loss under these commitments by subjecting them to credit approval and monitoring procedures. The Company enters into contractual commitments to extend credit, normally with fixed expiration dates or termination clauses, at specified rates and for specific purposes. Substantially all of the Company’s commitments to extend credit are contingent upon customers maintaining specific credit standards at the time of loan funding. Standby letters of credit are written conditional commitments issued by the Company to guarantee the performance of a customer to a third-party. In the event the customer does not perform in accordance with the terms of the agreement with the third-party, the Company would be required to fund the commitment. The maximum potential amount of future payments the Company could be required to make is represented by the contractual amount of the commitment. If the commitment were funded, the Company would be entitled to seek recovery from the customer. Based on the Company’s credit risk exposure assessment of standby letter of credit arrangements, the arrangements contain security and debt covenants similar to those contained in loan agreements. As of December 31, 2017 , the Company had $166,824 in outstanding letters of credit, of which $46,455 were secured by cash collateral and $33,538 were secured by other collateral. The carrying value of these obligations are not considered material. The contractual or notional amounts of these instruments, which reflect the extent of the Company’s involvement in particular classes of off-balance sheet financial instruments, are summarized as follows: December 31, 2017 2016 Loan origination commitments $ 510,135 $ 245,319 Unused lines of credit 1,195,656 968,288 Letters of credit 166,824 114,582

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Certain premises and equipment are leased under operating leases with terms expiring through 2033. The Company has the option to renew certain of these leases for additional terms. Future minimum rental payments due under non-cancellable operating leases with initial or remaining terms of more than one year at December 31, 2017 were as follows: 2018 $ 20,691 2019 18,867 2020 17,666 2021 14,966 2022 11,096 2023 and thereafter 31,682 $ 114,968 Occupancy and office operations expense includes net rent expense of $10,647 , $10,430 and $9,566 , respectively, for 2017 , 2016 and 2015 . Litigation The Company and the Bank are involved in a number of judicial proceedings concerning matters arising from conducting their business activities. These include routine legal proceedings arising in the ordinary course of business. These proceedings also include actions brought against the Company and the Bank with respect to corporate matters and transactions in which the Company and the Bank were involved. In addition, the Company and the Bank may be requested to provide information or otherwise cooperate with government authorities in the conduct of investigations of other persons or industry groups. There can be no assurance as to the ultimate outcome of a legal proceeding; however, the Company and the Bank have generally denied, or believe they have meritorious defenses and will deny, liability in all significant litigation pending against them and intend to defend vigorously each case, other than matters determined appropriate to be settled. The Company accrues a liability for legal claims when payments associated with the claims become probable and the costs can be reasonably estimated. The actual costs of resolving legal claims may be substantially higher or lower than the amounts accrued for those claims.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is the exchange price that would be received for an asset or paid to transfer a liability (exit price) in an orderly transaction occurring in the principal or most advantageous market for such asset or liability in an orderly transaction between market participants on the measurement date. In estimating fair value, we use valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. GAAP establishes a fair value hierarchy comprised of three levels of inputs that may be used to measure fair values. Level 1 Inputs – Unadjusted quoted prices in active markets for identical assets and liabilities that the reporting entity has the ability to access at the measurement date. Level 2 Inputs – Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risk, etc.) or inputs that are derived principally from, or corroborated by, market data by correlation or other means. Level 3 Inputs – Unobservable inputs for determining the fair value of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. In general, fair value is based on quoted market prices, when available. If quoted market prices in active markets are not available, fair value is based on internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and the Company’s creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. The Company’s valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes the Company’s valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincide with the Company’s monthly and/or quarterly valuation process. Investment Securities Available for Sale The majority of the Company’s available for sale investment securities are reported at fair value utilizing Level 2 inputs as quoted market prices are generally not available. For these securities, the Company obtains fair value measurements from an independent pricing service. The fair value measurements are calculated based on market prices of similar securities and consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the securities’ terms and conditions, among other things. The Company reviews the prices supplied by the independent pricing service, as well as their underlying pricing methodologies, for reasonableness and to ensure such prices are aligned with traditional pricing matrices. In general, the Company does not purchase investment securities that have a complicated structure. The Company’s entire portfolio consists of traditional investments, nearly all of which are mortgage pass-through securities, state and municipal general obligation or revenue bonds, U.S. agency bullet and callable securities and corporate bonds. Pricing for such instruments is fairly generic and is generally easily obtained. From time to time, the Company validates, on a sample basis, prices supplied by the independent pricing service by comparison to prices obtained from third-party sources or derived using internal models. At December 31, 2017 , we do not believe any of our securities are OTTI; however, we review all of our securities on at least a quarterly basis to assess whether impairments, if any, are OTTI. Derivatives The fair values of derivatives are based on valuation models using current observable market data (including interest rates and fees), the remaining terms of the agreements and the credit worthiness of the counterparty as of the measurement date, which are considered Level 2 inputs. Our derivatives are traded in an over-the-counter market where quoted market prices are not always available. The Company’s derivatives at December 31, 2017 , consist of interest rate swaps. (See Note 10. “Derivatives.”) A summary of assets and liabilities at December 31, 2017 measured at estimated fair value on a recurring basis is as follows: December 31, 2017 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets: Investment securities available for sale: Residential MBS: Agency-backed $ 2,150,649 $ — $ 2,150,649 $ — CMO/Other MBS 649,403 — 649,403 — Total residential MBS 2,800,052 — 2,800,052 — Federal agencies 399,996 — 399,996 — Corporate bonds 148,226 — 148,226 — State and municipal 263,798 — 263,798 — Total other securities 812,020 — 812,020 — Total investment securities available for sale 3,612,072 — 3,612,072 — Swaps 4,457 — 4,457 — Total assets $ 3,616,529 $ — $ 3,616,529 $ — Liabilities: Swaps $ 7,980 $ — $ 7,980 $ — Total liabilities $ 7,980 $ — $ 7,980 $ — A summary of assets and liabilities at December 31, 2016 measured at estimated fair value on a recurring basis is as follows: December 31, 2016 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets: Investment securities available for sale: Residential MBS: Agency-backed $ 1,193,481 $ — $ 1,193,481 $ — CMO/Other MBS 56,681 — 56,681 — Total residential MBS 1,250,162 — 1,250,162 — Federal agencies 193,979 — 193,979 — Corporate bonds 42,506 — 42,506 — State and municipal 240,770 — 240,770 — Total investment securities available for sale 477,255 — 477,255 — Total available for sale securities 1,727,417 — 1,727,417 — Interest rate caps and swaps 2,088 — 2,088 — Total assets $ 1,729,505 $ — $ 1,729,505 $ — Liabilities: Swaps $ 2,088 $ — $ 2,088 $ — Total liabilities $ 2,088 $ — $ 2,088 $ — The following categories of financial assets are not measured at fair value on a recurring basis, but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Loans Held for Sale and Impaired Loans The estimated fair value of commercial loans originated and intended for sale approximates carrying value as these loans are variable-rate loans that reprice frequently with no significant change in credit risk since origination. Residential loans held for sale are carried at the lower of cost or fair value, which is evaluated on a pool-level basis. Fair value is determined using quoted prices for similar assets, adjusted for specific attributes of that loan or other observable market data, such as outstanding commitments from third party investors. The Company may record adjustments to the carrying value of loans based on fair value measurements, generally as partial charge-offs of the uncollectible portions of these loans. These adjustments also include certain impairment amounts for collateral dependent loans calculated in accordance with GAAP. Impairment amounts are generally based on the fair value of the underlying collateral supporting the loan and, as a result, the carrying value of the loan less the calculated impairment amount applicable to that loan does not necessarily represent the fair value of the loan. Real estate collateral is valued using independent appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable by market participants. However, due to the substantial judgment applied and limited volume of activity as compared to other assets, fair value is based on Level 3 inputs. Estimates of fair value used for collateral supporting commercial loans not collateralized by real estate generally are based on assumptions not observable in the market place and are also based on Level 3 inputs. Impaired loans are evaluated on at least a quarterly basis for additional impairment and their carrying values are adjusted as needed. Loans subject to non-recurring fair value measurements were $60,862 and $55,391 at December 31, 2017 , and 2016 , respectively. Changes in fair value recognized as a charge-off on loans held by the Company were $280 for 2017 , $513 for 2016 , and $0 for 2015 . When valuing impaired loans that are collateral dependent, the Company charges-off the difference between the recorded investment in the loan and the appraised value, which is generally less than 12 months old. A discount for estimated costs to dispose of the asset is used when evaluating the impaired loans. A summary of impaired loans at December 31, 2017 measured at estimated fair value on a non-recurring basis is the following: December 31, 2017 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Commercial & industrial $ 114 $ — $ — $ 114 CRE 782 — — 782 Total impaired loans measured at fair value $ 896 $ — $ — $ 896 A summary of impaired loans at December 31, 2016 measured at estimated fair value on a non-recurring basis is the following: December 31, 2016 Fair value Level 1 inputs Level 2 inputs Level 3 inputs CRE $ 6,786 $ — $ — $ 6,786 Total impaired loans measured at fair value $ 6,786 $ — $ — $ 6,786 Mortgage Servicing Rights When mortgage loans are sold with servicing retained, servicing rights are initially recorded at fair value with the effect recorded in net gain on sales of loans in the consolidated statements of operations. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or, alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The Company utilizes the amortization method to subsequently measure the carrying value of its servicing rights. In accordance with GAAP , the Company must record impairment charges on a non-recurring basis when the carrying value exceeds the estimated fair value. To estimate the fair value of servicing rights, the Company utilizes a third-party, which, on a quarterly basis, considers the market prices for similar assets and the present value of expected future cash flows associated with the servicing rights. Assumptions utilized include estimates of the cost of servicing, loan default rates, an appropriate discount rate and prepayment speeds. The determination of fair value of servicing rights relies upon Level 3 inputs. The fair value of mortgage servicing rights at December 31, 2017 and 2016 were $10,363 and $1,024 , respectively. Assets Taken in Foreclosure of Defaulted Loans Assets taken in foreclosure of defaulted loans are initially recorded at fair value less costs to sell when acquired, which establishes a new cost basis. These assets are subsequently accounted for at the lower of cost or fair value, less costs to sell, and are primarily comprised of commercial and residential real estate property and, upon initial recognition, are re-measured and reported at fair value through a charge-off to the allowance for loan losses based on the fair value of the foreclosed asset. The fair value is generally determined using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the market place. Adjustments are routinely made in the appraisal process by the independent appraisers to adjust for differences between comparable sales and income data available. The fair value is derived using Level 3 inputs. Appraisals are reviewed by our credit department, our external loan review consultant and verified by officers in our credit administration area. Assets taken in foreclosure of defaulted loans and facilities held for sale subject to non-recurring fair value measurement were $27,095 and $13,619 at December 31, 2017 and 2016 , respectively. There were write-downs of $2,273 in 2017 , $582 in 2016 ; $0 in 2015 related to changes in fair value recognized through income for those foreclosed assets held by the Company. Significant Unobservable Inputs to Level 3 Measurements The following table presents quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets at December 31, 2017 : Non-recurring fair value measurements Fair value Valuation technique Unobservable input / assumptions Discount rate/prepayment speeds(1) (weighted average) Impaired loans: C&I $ 114 Appraisal Adjustments by management to reflect current conditions/selling costs 10.0% -19.0% (14.4%) CRE 782 Appraisal Adjustments for comparable properties 22.0% Assets taken in foreclosure: Residential mortgage 17,537 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% CRE 7,271 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% ADC 2,287 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% Mortgage servicing rights 10,363 Third-party Discount rates 9.5% - 20.0% (9.9%) Third-party Prepayment speeds 9.79 - 16.76 (10.30) (1) For loans collateralized by real estate and real estate assets taken in foreclosure the discount rate represents the discount factors applied to the appraisal to determine fair value, which includes a general discount to the appraised value, and estimated costs to carry and costs of sale. The amounts used for mortgage servicing rights are discounts applied by a third-party valuation provider, which the Company believes are appropriate. The following table presents quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets at December 31, 2016 : Non-recurring fair value measurements Fair value Valuation technique Unobservable input / assumptions Discount rate/prepayment speeds(1) (weighted average) Impaired loans: CRE $ 6,786 Appraisal Adjustments for comparable properties 22.0% Assets taken in foreclosure: Residential mortgage 4,929 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% CRE (2) 3,919 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% ADC 3,737 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% Mortgage servicing rights 1,024 Third-party Discount rates 8.5% - 11.5% (9.7%) Third-party Prepayment speeds 100 - 555 (174) (1) See (1) above. (2) Excludes $1,034 of commercial buildings that are former financial centers held for sale. These assets were not taken in foreclosure and their fair value is determined by appraisal, and our internal assessment of the market for this type of real estate in these locations. Fair Values of Financial Instruments GAAP requires disclosure of fair value information for those financial instruments for which it is practicable to estimate fair value, whether or not such financial instruments are recognized in the consolidated financial statements for interim and annual periods. Quoted market prices are used to estimate fair values when those prices are available, although active markets do not exist for many types of financial instruments. Fair values for these instruments must be estimated by management using techniques such as discounted cash flow analysis and comparison to similar instruments. These estimates are highly subjective and require judgments regarding significant matters, such as the amount and timing of future cash flows and the selection of discount rates that appropriately reflect market and credit risks. Changes in these judgments often have a material effect on the fair value estimates. Since these estimates are made as of a specific point in time, they are susceptible to material near-term changes. Fair values disclosed in accordance with GAAP do not reflect any premium or discount that could result from the sale of a large volume of a particular financial instrument, nor do they reflect possible tax ramifications or estimated transaction costs. The following is a summary of the carrying amounts and estimated fair value of financial assets and liabilities (none of which were held for trading purposes) as of December 31, 2017 : December 31, 2017 Carrying amount Level 1 inputs Level 2 inputs Level 3 inputs Financial assets: Cash and due from banks $ 479,906 $ 479,906 $ — $ — Securities available for sale 3,612,072 — 3,612,072 — Securities held to maturity 2,862,489 — 2,863,909 — Loans, net 19,931,076 — — 19,903,231 Loans held for sale 5,246 — 5,246 — Accrued interest receivable on securities 34,652 — 34,652 — Accrued interest receivable on loans 59,446 — — 59,446 FHLB stock and FRB stock 284,112 — — — Swaps 4,457 — 4,457 — Financial liabilities: Non-maturity deposits (18,098,566 ) (18,098,566 ) — — Certificates of deposit (2,439,638 ) — (2,412,495 ) — FHLB borrowings (4,510,123 ) — (4,496,184 ) — Other borrowings (30,162 ) — (30,160 ) — Senior Notes (278,209 ) — (278,968 ) — Subordinated Notes (172,716 ) — (179,619 ) — Mortgage escrow funds (122,641 ) — (117,050 ) — Accrued interest payable on deposits (1,103 ) — (1,103 ) — Accrued interest payable on borrowings (9,649 ) — (9,649 ) — Swaps (7,980 ) — (7,980 ) — The following is a summary of the carrying amounts and estimated fair value of financial assets and liabilities (none of which were held for trading purposes) as of December 31, 2016 : December 31, 2016 Carrying amount Level 1 inputs Level 2 inputs Level 3 inputs Financial assets: Cash and due from banks $ 293,646 $ 293,646 $ — $ — Securities available for sale 1,727,417 — 1,727,417 — Securities held to maturity 1,391,421 — 1,357,997 — Loans, net 9,463,608 — — 9,461,469 Loans held for sale 41,889 — 41,889 — Accrued interest receivable on securities 16,495 — 16,495 — Accrued interest receivable on loans 26,824 — — 26,824 FHLB stock and FRB stock 135,098 — — — Swaps 2,088 — 2,088 — Financial liabilities: Non-maturity deposits (9,484,505 ) (9,484,505 ) — — Certificates of deposit (583,754 ) — (582,811 ) — FHLB borrowings (1,791,000 ) — (1,788,676 ) — Other borrowings (16,642 ) — (16,642 ) — Senior Notes (76,469 ) — (79,283 ) — Mortgage escrow funds (13,572 ) — (13,572 ) — Accrued interest payable on deposits (663 ) — (663 ) — Accrued interest payable on borrowings (3,621 ) — (3,621 ) — Swaps (2,088 ) — (2,088 ) — The following paragraphs summarize the principal methods and assumptions used by the Company to estimate the fair value of certain the Company’s financial instruments noted above: Loans The estimated fair value approximates carrying value for variable-rate loans that reprice frequently and with no significant change in credit risk. The fair value of fixed-rate loans and variable-rate loans which reprice on an infrequent basis is estimated by discounting future cash flows using the current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. An overall valuation adjustment is made for specific credit risks, as well as general portfolio credit risk. Impaired loans are valued at the lower of cost or fair value, as described above. The methods utilized to estimate the fair value of loans do not necessarily result in the fair value representing an exit price. Accrued Interest Receivable/Payable The carrying amounts of accrued interest approximate fair value and are classified in the fair value hierarchy in the same level as with the asset/liability they are associated with. FHLB of New York Stock and FRB Stock Due to restrictions placed on transferability, it is not practical to determine the fair value of these securities. Deposits and Mortgage Escrow Funds The fair values disclosed for non-maturity deposits ( e.g., interest and non-interest checking, savings, and money market accounts) are by definition, equal to the amount payable on demand at the reporting date ( i.e., their carrying amount) resulting in a Level 1 classification. The carrying amounts of certificates of deposit and mortgage escrow funds are segregated by account type and original term, and fair values are estimated by using a discounted cash flows calculation that applies interest rates currently being offered on certificates to a schedule of aggregated expected monthly maturities on time deposits, resulting in a Level 2 classification. These fair values do not include the value of core deposit relationships that comprise a significant portion of the Company’s deposits. We believe that the Company’s core deposit relationships provide a relatively stable, low-cost funding source that has a substantial value separate from the deposit balances. FHLB Borrowings, Other borrowings, Senior Notes and Subordinated Notes The carrying amounts of FHLB short-term borrowings, and borrowings under repurchase agreements, generally maturing within ninety days, approximate their fair values, resulting in a Level 2 classification. The fair value of long-term FHLB borrowings, Senior Notes, and Subordinated Notes are estimated using discounted cash flow analyzes based on current borrowing rates for similar types of borrowing arrangements, resulting in a Level 2 classification. Other Financial Instruments Other financial assets and liabilities listed in the table above have estimated fair values that approximate the respective carrying amounts because the instruments are payable on demand or have short-term maturities and present relatively low credit risk and interest rate risk. The fair values of the Company’s off-balance-sheet financial instruments described in Note 17. “Off-Balance Sheet Financial Instruments” were estimated based on current market terms (including interest rates and fees), considering the remaining terms of the agreements and the credit worthiness of the counterparties. At December 31, 2017 and 2016 , the estimated fair value of these instruments approximated the related carrying amounts, which were not material. Accrued interest receivable/payable The carrying amounts of accrued interest approximate fair value and are classified in accordance with the related instrument.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive Loss Components of accumulated other comprehensive income (loss) (“AOCI”) were as follows as of the dates shown below: December 31, 2017 2016 Net unrealized holding loss on available for sale securities $ (36,899 ) $ (37,417 ) Related income tax benefit 14,575 14,780 Available for sale securities AOCI, net of tax (22,324 ) (22,637 ) Net unrealized holding loss on securities transferred to held to maturity (4,426 ) (5,395 ) Related income tax benefit 1,748 2,131 Securities transferred to held to maturity AOCI, net of tax (2,678 ) (3,264 ) Net unrealized holding loss on retirement plans (1,924 ) (1,213 ) Related income tax benefit 760 479 Retirement plan AOCI, net of tax (1,164 ) (734 ) Accumulated other comprehensive loss $ (26,166 ) $ (26,635 ) The following table presents the changes in each component of AOCI for 2017 and 2016 , and 2015 : Net unrealized holding gain (loss) on AFS securities Net unrealized holding gain (loss) on securities transferred to held to maturity Net unrealized holding gain (loss) on retirement plans Total Year ended December 31, 2017 Balance at beginning of the period $ (22,637 ) $ (3,264 ) $ (734 ) $ (26,635 ) Other comprehensive income before reclassification 64 — — 64 Amounts reclassified from AOCI 249 586 (430 ) 405 Total other comprehensive income (loss) 313 586 (430 ) 469 Balance at end of period $ (22,324 ) $ (2,678 ) $ (1,164 ) $ (26,166 ) Year ended December 31, 2016 Balance at beginning of the period $ (6,999 ) $ (4,155 ) $ (970 ) $ (12,124 ) Other comprehensive (loss) before reclassification (11,087 ) — — (11,087 ) Amounts reclassified from AOCI (4,551 ) 891 236 (3,424 ) Total other comprehensive (loss) income (15,638 ) 891 236 (14,511 ) Balance at end of period $ (22,637 ) $ (3,264 ) $ (734 ) $ (26,635 ) Year ended December 31, 2015 Balance at beginning of the period $ 1,297 $ (4,967 ) $ (6,581 ) $ (10,251 ) Other comprehensive (loss) gain before reclassification (5,515 ) — 435 (5,080 ) Amounts reclassified from AOCI (2,781 ) 812 5,176 3,207 Total other comprehensive (loss) income (8,296 ) 812 5,611 (1,873 ) Balance at end of period $ (6,999 ) $ (4,155 ) $ (970 ) $ (12,124 ) Location in statement of operations where reclassification from AOCI is included Net gain (loss) on sale of securities Interest income on securities Compensation and benefits expense

Condensed Parent Company Financ

Condensed Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Parent Company Financial Statements	Condensed Parent Company Financial Statements Set forth below is the condensed balance sheets of the Company: December 31, 2017 2016 Assets: Cash $ 88,174 $ 48,765 Investment in the Bank 4,373,108 1,843,476 Goodwill 27,910 20,023 Trade name 20,500 20,500 Other assets 16,842 3,258 Total assets $ 4,526,534 $ 1,936,022 Liabilities: Senior Notes $ 278,209 $ 76,469 Other liabilities 8,147 4,370 Total liabilities 286,356 80,839 Stockholders’ equity 4,240,178 1,855,183 Total liabilities & stockholders’ equity $ 4,526,534 $ 1,936,022 The table below presents the condensed income statement: For the year ended December 31, 2017 2016 2015 Interest income $ 29 $ 14 $ 15 Dividends from the Bank 30,000 60,000 42,500 Dividends from non-bank subsidiaries — 5,026 500 Net gain on sale of trust division — 2,255 — Interest expense (6,186 ) (5,398 ) (5,894 ) Non-interest expense (9,225 ) (12,989 ) (7,031 ) Income tax benefit 7,258 3,700 4,154 Income before equity in undistributed earnings of subsidiaries 21,876 52,608 34,244 Equity in undistributed (excess distributed) earnings of: The Bank 71,155 87,364 32,230 Non-bank subsidiaries — — (360 ) Net income 93,031 139,972 66,114 Preferred stock dividends 2,002 — — Net income available to common shareholders $ 91,029 $ 139,972 $ 66,114 The table below presents the condensed statements of cash flows: For the year ended December 31, 2017 2016 2015 Cash flows from operating activities: Net income $ 93,031 $ 139,972 $ 66,114 Adjustments to reconcile net income to net cash provided by operating activities: Equity in (undistributed) excess distributed earnings of: The Bank (71,155 ) (87,364 ) (32,230 ) Non-bank subsidiaries — — 360 Loss on extinguishment of borrowings — 1,013 — Other adjustments, net 61,184 6,273 (3,123 ) Net cash provided by operating activities 83,060 59,894 31,121 Cash flows from investing activities: Sales of securities — 3 — Investment in subsidiaries — (65,000 ) (84,500 ) Net cash used for investing activities — (64,997 ) (84,500 ) Cash flows from financing activities: Equity capital raise — 90,995 85,059 Redemption of Senior Notes — (23,793 ) — Cash dividends paid (46,229 ) (36,451 ) (30,384 ) Stock-based compensation transactions 2,578 3,588 4,472 Net cash (used for) provided by financing activities (43,651 ) 34,339 59,147 Net increase in cash 39,409 29,236 5,768 Cash at beginning of the period 48,765 19,529 13,761 Cash at end of the period $ 88,174 $ 48,765 $ 19,529

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	Quarterly Results of Operations (Unaudited) The following is a condensed summary of quarterly results of operations for 2017 and 2016 : For the year ended December 31, 2017 Reporting period First quarter Second quarter Third quarter Fourth quarter For the quarter ended March 31 June 30 September 30 December 31 Interest and dividend income $ 126,000 $ 134,263 $ 145,692 $ 276,495 Interest expense 17,210 21,005 25,619 42,471 Net interest income 108,790 113,258 120,073 234,024 Provision for loan losses 4,500 4,500 5,000 12,000 Non-interest income 12,836 13,618 13,988 23,762 Non-interest expense 60,350 59,657 62,617 250,746 Income (loss) before income tax 56,776 62,719 66,444 (4,960 ) Income tax expense 17,709 20,319 21,592 28,319 Net income (loss) 39,067 42,400 44,852 (33,279 ) Preferred stock dividend — — — 2,002 Net income (loss) available to common stockholders $ 39,067 $ 42,400 $ 44,852 $ (35,281 ) Earnings per common share: Basic $ 0.29 $ 0.31 $ 0.33 $ (0.16 ) Diluted 0.29 0.31 0.33 (0.16 ) For the year ended December 31, 2016 Reporting period First quarter Second quarter Third quarter Fourth quarter For the quarter ended March 31 June 30 September 30 December 31 Interest and dividend income $ 106,006 $ 114,309 $ 118,161 $ 123,075 Interest expense 12,495 13,929 15,031 15,827 Net interest income 93,511 100,380 103,130 107,248 Provision for loan losses 4,000 5,000 5,500 5,500 Non-interest income 15,449 20,442 19,039 16,057 Non-interest expense 68,934 59,640 62,256 57,072 Income before income tax 36,026 56,182 54,413 60,733 Income tax expense 12,242 18,412 16,991 19,737 Net income 23,784 37,770 37,422 40,996 Preferred stock dividend — — — — Net income available to common stockholders $ 23,784 $ 37,770 $ 37,422 $ 40,996 Earnings per common share: Basic $ 0.18 $ 0.29 $ 0.29 $ 0.31 Diluted 0.18 0.29 0.29 0.31 The Company incurred a net loss in the fourth quarter ended December 31, 2017 due mainly to merger-related expense, asset write-downs and other charges associated with the Astoria Merger and an adjustment to write-down deferred taxes to their estimated fair value due to the Tax Act in the amount of $40,285 . The Company recognized charges of $30,230 , which mainly included charges for change-in-control payments, employee benefit plan terminations, financial and legal advisory fees and merger-related marketing expenses. Other restructuring charges of $104,506 mainly included charges for information technology services, contract terminations, impairments of leases and facilities and retention compensation.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 implements a common revenue standard that clarifies the principles for recognizing revenue. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. This standard is effective for the Company on January 1, 2018. THe company’s revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income, which is subject to ASU 2014-09. At this time the Company believes the adoption of this standard will not have a significant impact to its consolidated financial statements. ASU 2016-1, “No. 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-1, among other things: (i) requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and (vii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale. ASU 2016-1 will be effective for the Company on January 1, 2018 and is not expected to have a significant impact on its financial statements. ASU 2016-02, “Leases.” ASU 2016-02 amends existing lease accounting guidance, including the requirement to recognize most lease arrangements on the balance sheet. The adoption of this standard will result in the Company recognizing a right-of-use asset representing its rights to use the underlying asset for the lease term with an offsetting lease liability. ASU 2016-02 will be effective for for the company on January 1, 2019, with early adoption permitted and will require transition using a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The Company has not yet concluded whether it will adopt the standard prior to January 1, 2019; however, if the standard were effective at December 31, 2017, it would not have had an impact on any borrowings or covenants that are relevant to the Company and management estimates that the impact to the Bank’s and the Company’s regulatory capital ratios would be approximately five basis points. ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 amends current guidance on the impairment of financial instruments. ASU 2016-13 adds an impairment model known as the current expected credit loss (“CECL”) model that is based on expected losses rather than incurred losses. For the Company, the CECL model will apply mainly to held-to-maturity investment securities, loans and loan commitments. ASU 2016-13 will be effective for the Company for fiscal years beginning after December 15, 2019, and the Company is permitted to early adopt the new guidance for fiscal years beginning after December 15, 2018. ASU 2016-13 will significantly change the accounting for credit impairment. The new guidance will require the Company to modify current processes and systems for establishing the allowance for loan losses and OTTI to ensure they comply with the requirements of the new standard. As as result, the Company has engaged a nationally recognized accounting firm to advise and assist management in performing an implementation readiness assessment and adopt the standard. During the 2017, the Company performed the following: • in conjunction with its advisor, established a CECL program steering committee, identified significant work streams and created a CECL program project timeline; • evaluated several third-party models in order to determine the CECL modeling approach that will be used for the Company’s loan portfolios; • selected vendors that will assist in data analytics and modeling; and • evaluated data, gaps in data and mitigation strategies. The Company is unable to estimate the impact of adopting ASU 2016-13 at this time; however, it anticipates the allowance for loan losses will be greater under the CECL model compared to the current incurred loss model and that the composition of the loan and securities portfolio as well as the status of the economic environment, will be significant factors that impact the balance at date of adoption. ASU 2017-08, “Premium Amortization on Purchased Callable Debt Securities.” ASU 2017-08 shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. Today, entities generally amortize the premium over the contractual life of the security. The new guidance does not change the accounting for purchased callable debt securities held at a discount as discounts continue to be amortized to maturity. ASU No. 2017-08 is effective for interim and annual reporting periods beginning after December 15, 2018 and early adoption is permitted. The guidance includes a modified retrospective transition approach under which a cumulative-effect adjustment will be made to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. Management intends to adopt this standard effective January 1, 2018 and the impact of adoption is not expected to have a significant impact on the Company’s financial statements. ASU 2017-09, “Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting.” ASU 2017-09 clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under ASU 2017-09, an entity will not apply modification accounting to a share-based payment award if all of the following are the same immediately before and after the change: (i) the fair value of the award, (ii) the vesting conditions of the award and (iii) the classification of the award as an equity or liability instrument. ASU 2017-09 will be effective for the Company on January 1, 2018 and is not expected to have a significant impact on its financial statements. ASU 2017-12, “Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities.” ASU 2017-12 amends the hedge accounting recognition and presentation requirements in ASC 815 to improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities to better align the entity’s financial reporting for hedging relationships with those risk management activities and to reduce the complexity of and simplify the application of hedge accounting. ASU 2017-12 will be effective for the Company on January 1, 2019 and is not expected to have a significant impact on the Company’s financial statements. ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” ASU 2018-02 allows the Company to reclassify from accumulated other comprehensive income (loss) to retained earnings for the stranded tax effect resulting from the Tax Act. ASU 2018-02 is required to be adopted by the Company no later than January 1, 2019. The company expects to adopt ASU 2018-02 in the first quarter of 2018, which is not expected to have a significant impact on its financial statements. See Note 1. “Basis of Financial Statement Presentation and Summary of Significant Accounting Policies” for a discussion of the adoption of new accounting standards that affected the consolidated financial statements contained in this report.

Basis of Financial Statement 32

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Principles of Consolidation	Nature of Operations and Principles of Consolidation The consolidated financial statements include the accounts of Sterling, the Bank and the Bank’s wholly-owned subsidiaries. The Bank’s subsidiaries included at December 31, 2017 : (i) Sterling National Funding Corp, a company that originates loans to municipalities and governmental entities and acquires securities issued by state and local governments; (ii) Sterling REIT, Inc., a real estate investment trust that holds a portion of the Company’s real estate loans; (iii) Provest Services Corp. II, which has engaged a third-party provider to sell mutual funds and annuities to the Bank’s customers; (iv) AF Agency, Inc, which provides various annuity and wealth management products and through contractual agreements with various third parties and makes insurance products available, primarily to customers of the Bank; (v) several limited liability companies which hold other real estate owned; and (vi) several other companies that have no significant operations or assets. Intercompany transactions and balances are eliminated in consolidation.
Mergers	Merger with Astoria Financial Corporation On October 2, 2017 , Astoria Financial Corporation (“Astoria”) merged with and into Sterling (the “Astoria Merger”). In connection with the merger, Astoria Bank, the principal subsidiary of Astoria, also merged with and into the Bank. Merger with Hudson Valley Holding Corp. On June 30, 2015 , Hudson Valley Holding Corp. (“HVHC”) merged with and into Sterling (the “HVB Merger”). In connection with the merger, Hudson Valley Bank, the principal subsidiary of HVHC, also merged with and into the Bank. Merger with Sterling Bancorp On October 31, 2013 , Provident New York Bancorp (“Legacy Provident”) merged with Sterling Bancorp (“Legacy Sterling”). In connection with the merger, the following corporate actions occurred: • Legacy Sterling merged with and into Legacy Provident. Legacy Provident was the accounting acquirer and the surviving entity. • Legacy Provident changed its legal entity name to Sterling Bancorp and became a bank holding company and a financial holding company as defined by the Bank Holding Company Act of 1956, as amended. • Provident Bank converted to a national bank charter. • Sterling National Bank merged into Provident Bank. • Provident Bank changed its legal entity name to Sterling National Bank. We refer to the transactions detailed above collectively as the “Provident Merger.”
Use of estimates	Use of Estimates To prepare financial statements in conformity with U.S. generally accepted accounting principles management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided and actual results could differ. An estimate that is particularly susceptible to significant near-term change is the allowance for loan losses, which is discussed below.
Reclassifications	Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation. Reclassifications had no affect on prior period net income or stockholders’ equity.
Cash Flows	Cash Flows For purposes of reporting cash flows, cash equivalents include cash and deposits with other financial institutions with an original maturity of 90 days or less. Net cash flows are reported for customer loan and deposit transactions, interest bearing deposits in other financial institutions, and federal funds purchased and repurchase agreements.
Restrictions on Cash	Restrictions on Cash The Bank was required to have $118,113 and $99,594 of cash on hand or on deposit with the Federal Reserve Bank to meet regulatory reserve and clearing requirements at December 31, 2017 and 2016 , respectively.
Securities	Securities Securities include U.S. government agency and government sponsored agencies securities, state and municipal and corporate bonds, and mortgage-backed securities, including collateralized mortgage obligations and trust preferred securities. The Company classifies its securities among two categories: held to maturity and available for sale. The Company determines the appropriate classification of the Company’s securities at the time of purchase. Held to maturity securities are limited to debt securities for which there is the intent and the ability to hold to maturity. These securities are reported at amortized cost. The Company does not engage in trading activities. All other debt and marketable equity securities are classified as available for sale. Available for sale securities are reported at fair value, with unrealized gains and losses (net of the related deferred income tax effect) excluded from earnings and reported in a separate component of stockholders’ equity (accumulated other comprehensive income or loss). Available for sale securities include securities that the Company intends to hold for an indefinite period of time, such as securities to be used as part of the Company’s asset/liability management strategy or securities that may be sold to fund loan growth, in response to changes in interest rates and prepayment risks, the need to increase capital, or similar factors. Premiums on debt securities are amortized in interest income on a level yield basis over the earlier of the call date or maturity. Discounts on debt securities are accreted in interest income on a level yield basis over the period to maturity. Amortization of premiums and accretion of discounts on mortgage-backed securities are based on the estimated cash flows of the mortgage-backed securities, periodically adjusted for changes in estimated lives, on a level yield basis. The cost of securities sold is determined using the specific identification method. Securities are evaluated for other-than-temporary-impairment (“OTTI”) at least quarterly, and more frequently when economic and market conditions warrant such an evaluation. For securities in an unrealized loss position, the Company considers the extent and duration of the unrealized loss, and the financial condition of the issuer. The Company also assesses whether it intends to sell, or is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either criteria regarding intent to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. If (i) the Company does not expect to recover the entire amortized cost basis of the security; (ii) the Company does not intend to sell the security; (iii) and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the OTTI is separated into (a) the amount representing the credit loss and (b) the amount related to all other factors. The amount of OTTI related to credit loss is recognized in earnings while the amount related to other factors is recognized in other comprehensive income, net of applicable taxes. The cost basis of individual equity securities is written down to estimated fair value through a charge to earnings when declines in value below cost are considered to be other than temporary. As of December 31, 2017 , the Company did not intend to sell, nor is it more likely than not that it would be required to sell, any of its debt securities with unrealized losses prior to recovery of its amortized cost basis less any current period credit loss. (See Note 3. “Securities”).
Loans Held For Sale	Loans Held For Sale Residential mortgage loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by outstanding commitments from investors. Mortgage loans held for sale are generally sold with servicing rights released. Commercial loans originated and intended for sale, generally represent loan syndications are carried at amortized cost which approximates fair value, as these loans are variable-rate loans that reprice frequently with no significant change in credit risk since origination. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings.
Portfolio Loans	Portfolio Loans Loans where Sterling has the intent and ability to hold for the foreseeable future or until maturity or payoff (other than loans held for sale) are reported at the principal balance outstanding, net of acquisition related purchase accounting adjustments, deferred loan fees and costs from loan originations and the allowance for loan losses. Interest income on loans is accrued on the unpaid principal balance. The Company defers nonrefundable loan origination and commitment fees, and certain direct loan origination costs, and amortizes the net amount as an adjustment of the yield over the estimated life of the loan using the level-yield method without anticipating prepayments. If a loan is prepaid or sold, the net deferred amount is recognized in the income statement at that time. Interest and fees on loans include prepayment fees and late charges collected. A loan is placed on non-accrual status upon the earlier of: (i) when Sterling determines that the borrower may likely be unable to meet contractual principal or interest obligations; or (ii) when payments are 90 days or more past due based on the contractual terms of the loan, unless the loan is well secured and in the process of collection. Accrual of interest ceases and, in general, uncollected past due interest is reversed and charged against current interest income. Interest payments received on non-accrual loans, including impaired loans, are generally applied to reduce the principal balance outstanding and not recognized as income unless warranted based on the borrower’s financial condition and payment record. (See Note 4. “Portfolio Loans”).
Acquired Loans, Including Purchased Credit Impaired Loans	Acquired Loans, Including Purchased Credit Impaired Loans Loans the Company acquired in acquisitions are initially recorded at fair value with no carryover of the related allowance for loan losses. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows initially expected to be collected on the loans and discounting those cash flows at an appropriate market rate of interest. Acquired loans are included with portfolio loans in the consolidated balance sheets. Loans for which there is both evidence of deterioration of credit quality since origination and probability, at acquisition, that all contractually required payments would not be collected represent purchase credit impaired loans (“PCI loans”). For PCI loans, the Company initially determines which loans will be treated under the cost recovery method (similar to a non-accrual loan) from loans that will be subject to accretion. The Company recognizes the accretable yield, which is defined as the excess of all cash flows expected at acquisition over the initial fair value of the loan, as interest income on a level-yield basis over the expected remaining life of the loan. The excess of the loan’s contractually required payments over the cash flows expected to be collected is the nonaccretable difference. The nonaccretable difference is not recognized as an adjustment of yield, a loss accrual, or a valuation allowance. Going forward, the Company continues to evaluate whether the timing and the amount of cash to be collected are reasonably expected. Subsequent significant increases in cash flows the Company expects to collect will first reduce any previously recognized valuation allowance and then be reflected prospectively as an increase to the level yield. Subsequent decreases in expected cash flows may result in the loan being considered impaired. Interest income is not recognized to the extent that the net investment in the loan would increase to an amount greater than the estimated payoff amount. For PCI loans, the expected cash flows reflect anticipated prepayments, determined on a loan by loan basis according to the anticipated collection plan of these loans. The expected prepayments used to determine the accretable yield are consistent between the cash flows expected to be collected and projections of contractual cash flows so as to not affect the nonaccretable difference. Changes in prepayment assumptions may change the amount of interest income and principal expected to be collected. For loans for which there was no clear evidence of deterioration of credit quality since origination nor evidence that all contractually required payments would not be collected, the Company accretes interest income based on the contractually required cash flows. Loans that do not meet the PCI loan criteria are collectively evaluated for an allowance for loan loss.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is a valuation allowance, established through a provision for loan losses charged to expense, which represents management’s best estimate of probable incurred credit losses inherent in the loan portfolio. The level of the allowance for loan losses reflects management’s continuing evaluation of loan loss experience, specific credit risks, current loan portfolio quality, industry and loan type concentrations, economic and regulatory conditions and unidentified losses inherent in the loan portfolios. The allowance for loan losses is a critical accounting estimate and requires substantial judgment of management. The allowance for loan losses consists of specific and general components. The specific component relates to loans that are individually classified as impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loans in which the borrower is experiencing financial difficulties and for which the terms have been modified resulting in a concession are considered troubled debt restructurings (“TDRs”) and classified as impaired. Factors considered by the Company in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. The Company determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into account all circumstances surrounding the loan and the borrower, including the length of the delay, reasons for the delay, prior payment history and the amount of the shortfall in relation to the total amount owed. The Company’s policy is to evaluate loans over $750 individually for impairment. If a loan is impaired, and there is a shortfall of the present value of the estimated future cash flows using the existing interest rate of the loan or as determined by the fair value of collateral if repayment is expected solely from the collateral, the Company’s practice is to charge-off the identified impairment. As a result, at December 31, 2017 and 2016, there was no portion of the allowance for loan losses allocated to impaired loans. The general component of the allowance for loan losses covers loans that are collectively evaluated for impairment. Large groups of smaller balance homogeneous loans, such as consumer loans, which includes home equity lines of credit, and residential mortgage loans are generally collectively evaluated for impairment and they are not included in the separately identified impairment disclosures. The general allowance for loan losses component also includes loans that are not individually identified for impairment evaluation, such as commercial loans below the individual evaluation threshold as well as those loans that are individually evaluated but not considered impaired including loans rated special mention. The general component of the allowance is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over the most recent three years, two years for consumer loans. The actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: • levels of, and trends in, delinquencies and non-accruals; • trends in volume and terms of loans; • effects of any changes in lending policies and procedures; • experience, ability, and depth of lending management and staff; • national and local economic trends and conditions; • concentrations of credit by such factors as location, industry, inter-relationships, and borrowers; and • for commercial loans, trends in risk ratings. We apply the methodology described above to each portfolio segment. These segments include: traditional commercial and industrial, asset-based lending, payroll finance, warehouse lending, factored receivables, equipment financing, and public sector finance (collectively the C&I portfolio,) certain consumer loans, loans collateralized by real estate including commercial real estate (“CRE”), multi-family, and acquisition, development and construction (“ADC”) loans, residential mortgage, and certain consumer loans including home equity lines of credit. C&I lending presents a risk because repayment depends on the successful operation of the business, which is subject to a wide range of risks and uncertainties. In addition, the ability to successfully liquidate collateral, if any, is subject to a variety of risks because the Company must gain control of assets used in the borrower’s business before foreclosing, which it cannot be assured of doing, and the value in a foreclosure sale or other means of liquidation is uncertain. In addition, CRE and multi-family loans subject the Company to the risks that the property securing the loan may not generate sufficient cash flow to service the debt or the borrower may use the cash flow for other purposes. In addition, if necessary, the foreclosure process may be slow and properties may deteriorate in the process. The market values are also subject to a wide variety of factors, including general economic conditions, industry specific factors, environmental factors, interest rates and the availability and terms of credit. ADC lending is considered higher risk and exposes the Company to greater credit risk than permanent mortgage financing. The repayment of ADC loans depends upon the sale of the property to third parties or the availability of permanent financing upon completion of all improvements. The Company has deemphasized originations of land acquisition and land development loans; however, it does originate construction loans to select clients principally within our immediate footprint. When the Company evaluates residential mortgage loans and consumer - home equity loans it weighs both the credit capacity of the borrower and the collateral value of the home. If unemployment or underemployment increase, the credit capacity of underlying borrowers will decrease, which increases the risk of such loan. Similarly, as the Company obtains a mortgage on the property, if home prices decline, it is exposed to risk in both its first mortgage and equity lending programs due to declines in the value of its collateral. The Company is also exposed to risk because the time to foreclose is significant and has become longer under current market conditions. For smaller balance C&I loans we charge-off the full amount of the loan when it becomes 90 days or more past due, or earlier in the case of bankruptcy, after giving effect to any cash or marketable securities pledged as collateral for the loan. For other classes of C&I loans, commercial real estate, multi-family, acquisition development and construction loans, the Company evaluates available financial information from the borrower as well as collateral pledged, evaluates whether the borrower can continue to service the debt and their near term prospects. When we conclude the collateral and or debt service capacity of the borrower are insufficient to repay our debt, we charge-off the amount that is deemed uncollectible. For unsecured consumer loans, charge-offs are recognized once the loan is 90 days to 120 days or more past due or the borrower files for bankruptcy protection. For secured consumer loans and residential mortgage loans we monitor the value of the collateral and the borrowers ability to service our debt and record a charge-off when we become aware of the loss from and within the time frames specified by regulatory guidance. Subsequent recoveries, if any, are credited to the allowance for loan losses.
Troubled Debt Restructuring	Troubled Debt Restructuring TDR is a formally renegotiated loan in which the Bank, for economic or legal reasons related to a borrower’s financial difficulties, grants a concession to the borrower that would not have been granted to the borrower otherwise. At the time of restructuring, we evaluate whether a TDR loan should remain on accrual based on the accrual status immediately prior to modification and whether, as a result of the TDR, we recorded a partial charge-off. A TDR on accrual prior to modification may remain on accrual status provided we believe, based on our credit analysis, that collection of principal and interest in accordance with the modified terms is reasonably certain. If the restructuring results in a partial charge-off, the loan is generally classified as non-accrual. Restructured loans can convert from non-accrual to accrual status when said loans have demonstrated performance, generally evidenced by six months of consistent payment performance in accordance with the restructured terms, or by the presence of other significant items. (See Note 4. “Portfolio Loans”).
Federal Reserve Bank of New York and Federal Home Loan Bank Stock	Federal Reserve Bank of New York and Federal Home Loan Bank Stock As a member of the Federal Reserve Bank of New York (“FRB”) and the Federal Home Loan Bank of New York (“FHLB”), the Bank is required to hold a certain amount of FRB and FHLB common stock. This stock is a non-marketable equity security and is reported at cost.
Premises and Equipment	Premises and Equipment Land is reported at cost, while premises and equipment are reported at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, which range from three years for equipment and 40 years for premises. Leasehold improvements are amortized on a straight-line basis over the terms of the respective leases, including renewal options, or the estimated useful lives of the improvements, whichever is shorter. Routine holding costs are charged to expense as incurred, while significant improvements are capitalized. The Company recognizes an impairment charge to its premises and equipment, generally in connection with a decision to consolidate or close a financial center. Impairment is based on the excess of the carrying amount of assets over the fair value of the assets. Fair value is determined by third-party valuations or appraisals and evaluations prepared by management. (See Note 6. “Premises and Equipment, Net”).
Goodwill, Trade Names and Other Intangible Assets	Goodwill, Trade Names and Other Intangible Assets Goodwill resulting from business combinations represents the excess of the purchase price over the fair value of the net assets of businesses acquired. Goodwill and trade names (which are included with core deposits and other intangible assets in the consolidated balance sheets) acquired in a purchase business combination that have an indefinite useful life are not amortized, but are tested for impairment at least annually. Goodwill and trade names are the only intangible assets with an indefinite life on the Company’s balance sheet. The Company accounts for goodwill, trade names and other intangible assets in accordance with GAAP, which, in general, requires that goodwill and trade names not be amortized, but rather that they be tested for impairment at least annually at the reporting unit level. The Company operates as one reporting unit. Goodwill is tested for impairment in the fourth quarter of each year, or on an interim basis if an conditions warrant that could more likely than not reduce the fair value of the reporting unit below its carrying value. Core deposit intangibles recorded in acquisitions are amortized to expense using an accelerated method over their estimated lives of eight to ten years . Non-compete agreements are amortized on a straight line basis over their estimated life. Impairment losses on intangible assets and other long-term assets are charged to expense, if and when they occur, with the assets recorded at fair value. (See Note 7. “Goodwill and Other Intangible Assets”).
Bank Owned Life Insurance (BOLI)	Bank Owned Life Insurance (BOLI) The Company owns life insurance policies (purchased and acquired) on certain officers and key executives. Bank owned life insurance (“BOLI”) is recorded at its cash surrender value (or the amount that can be realized).
Other Real Estate Owned	Other Real Estate Owned Real estate properties acquired through loan foreclosures are recorded initially at estimated fair value, less expected sales costs, with any resulting write-down charged to the allowance for loan losses. Other real estate owned (“OREO”) also includes the fair value of the Bank’s financial centers that are held for sale. Any write-down associated with the transfer of a financial center from premises and equipment to OREO is included as a charge to other non-interest expense in the consolidated income statements. The carrying amount of an OREO asset is reduced by a charge to OREO, net expense to reflect any subsequent declines in estimated fair value. Fair value estimates are based on recent appraisals and other available information. Routine holding costs are charged to expense as incurred, while significant improvements are capitalized. Gains and losses on sales of OREO properties are recognized upon disposition.
Other Borrowings - Securities Repurchase Agreements	Other Borrowings - Securities Repurchase Agreements In securities repurchase agreements, the Company transfers securities to a counterparty under an agreement to repurchase the identical securities at a fixed price on a future date. These agreements are accounted for as secured financing transactions since the Company maintains effective control over the transferred securities and the transfer meets other specified criteria. Accordingly, the transaction proceeds are recorded as borrowings and the underlying securities continue to be carried in the Company’s investment securities portfolio. Disclosure of the pledged securities is made in the consolidated balance sheets if the counterparty has the right by contract to sell or re-pledge such collateral. (See Note 9. “Borrowings, Senior Notes and Subordinated Notes”).
Income Taxes	Income Taxes Income tax expense includes U.S. federal corporate income taxes and income taxes due to states and other jurisdictions in which the Company operates. In addition, for the year ended December 31, 2017, income tax expense included the impact of the enactment of the Tax Cuts and Jobs Act of 2017 (the “Tax Act”) which reduced the U.S. federal corporate income tax rate from 35% to 21% and resulted in a charge to reduce the carrying value of the Company’s net deferred income tax assets, which are included in the consolidated balance sheets as part of other assets. Net deferred taxes are recognized for the estimated future tax effects attributable to “temporary differences” between the financial statement carrying amounts and the tax bases of existing assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax laws or rates is recognized in income tax expense in the period that includes the enactment date of the change. A deferred tax liability is recognized for all temporary differences that will result in future taxable income. A deferred tax asset is recognized for all temporary differences that will result in future tax deductions, subject to reduction of the asset by a valuation allowance in certain circumstances. This valuation allowance is recognized if, based on an analysis of available evidence, we determine that it is more likely than not that some portion, or all, of the deferred tax asset will not be realized. The valuation allowance is subject to ongoing adjustment based on changes in circumstances that affect management’s judgment about the realizability of the deferred tax asset. Adjustments to increase or decrease the valuation allowance are charged or credited, respectively, to income tax expense. The Company recognizes interest and/or penalties related to income tax matters in other non-interest expense. The Company evaluates uncertain tax positions in a two step process. The first step is recognition, which requires a determination of whether it is more likely than not that a tax position will be sustained upon examination. The second step is measurement. Under the measurement step, a tax position that meets the more likely than not recognition threshold is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. Tax positions that previously failed to meet the more likely than not recognition threshold should be recognized in the first subsequent financial reporting period in which that threshold is met. A previously recognized tax position that no longer meets the more likely than not recognition threshold should be derecognized in the first subsequent financial reporting period in which the threshold is no longer met. The Company did not have any such position as of December 31, 2017 . (See Note 11. “Income Taxes”).
Derivatives	Derivatives Derivatives are recognized as assets and liabilities in the consolidated balance sheets and measured at fair value. For exchange-traded contracts, fair value is based on quoted market prices. For non-exchange traded contracts, fair value is based on dealer quotes, pricing models, discounted cash flow methodologies, or similar techniques for which the determination of fair value may require management judgment or estimation relating to future rates and credit activities. For asset/liability management purposes, the Bank uses interest rate swap agreements to modify interest rate risk characteristics of certain portfolio loans as an accommodation to our borrowers. Interest rate swaps are contracts in which a series of interest rate flows are exchanged over a prescribed period. The notional amount on which the interest payments are based is not exchanged. These swap agreements are derivative instruments and these instruments effectively convert a portion of the Bank’s fixed-rate loans to variable rate loans. (See Note 10. “Derivatives”).
Fair Values of Financial Instruments	Fair Values of Financial Instruments Fair values of financial instruments are estimated using relevant market information and other assumptions, as more fully disclosed in Note 19. “Fair Value Measurements.” Fair value estimates involve uncertainties and matters of significant judgment regarding interest rates, credit risk, prepayments, and other factors, especially in the absence of broad markets for particular items. Changes in assumptions or in market conditions could significantly affect the estimates.
Retirement Plans	Retirement Plans In the Astoria Merger we assumed Astoria’s Bank pension plan, which covers Astoria employees and former Astoria employees meeting specified eligibility criteria. The Company intends to fund pension costs at an amount that will avoid the 2018 Pension Benefit Guarantee Corporation variable rate premium, which we estimate will be approximately $30,000 . In addition to this pension plan, we assumed other non-qualified and unfunded supplemental retirement plans. These plans were suspended for the accrual of additional benefits prior to the Company’ assumption. The Company also assumed the liability for a health care plan that provides for post-retirement medical and dental coverage to select individuals, which is an active plan in which select individuals continue to vest over the next twelve months. The net liabilities for all of these retirement plans is included in other liabilities in the consolidated balance sheets. (See Note 13. “Pension and Other Post Retirement Plans”).
Loss Contingencies	Loss Contingencies Loss contingencies, including claims and legal actions arising in the ordinary course of business, are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. The Company does not believe there are such matters that will have a material effect on the consolidated financial statements. (See Note 18. “Commitments and Contingencies”).
Loan Commitments and Related Financial Instruments	Loan Commitments and Related Financial Instruments Financial instruments include off-balance sheet credit instruments, such as commitments to make loans and commercial letters of credit, issued to meet customer financing needs. The face amount for these items represents the exposure to loss, before considering customer collateral or ability to repay. Such financial instruments are recorded when they are funded. (See Note 17. “Off-Balance Sheet Financial instruments”).
Stock-Based Compensation Plans	Stock-Based Compensation Plans Compensation expense for stock options and non-vested stock awards/stock units is based on the fair value of the award on the measurement date, which is the date of grant. The expense is recognized ratably over the service period of the award. The fair value of stock options is estimated using a Black-Scholes valuation model. The fair value of non-vested stock awards/stock units is generally the market price of the Company’s common stock on the date of grant. (See Note 12. “Stock-Based Compensation”).
Earnings Per Common Share	Earnings Per Common Share Basic earnings per common share (“EPS”) is computed by dividing net income available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted EPS is computed in a similar manner to basic EPS, except that the weighted average number of common shares is increased to include incremental shares (computed using the treasury stock method) that would have been outstanding if all potentially dilutive stock options were exercised and unvested restricted stock became vested during the periods. (See Note 15. “Earnings Per Common Share”).
Revenue Recognition	Revenue Recognition The Company recognizes revenue when all of the criteria below have been met: (i) persuasive evidence of an arrangement exists; (ii) delivery of our obligations to our client has occurred; (iii) the price is fixed or determinable: and (iv) collectability of the balance advanced is reasonably assured. Interest income and fees. Interest income and fees on loans and investment securities are recognized based on the contractual provisions of the underlying agreements and instruments. Loan origination fees and costs are generally deferred and amortized into interest income as yield adjustments over the contractual life and / or commitment period using the effective interest method. Payroll finance. The Company provides financing and full service where in addition to providing financing and back office support services, which includes preparation of payroll, payroll tax payments, billings and collections for clients in the temporary staffing industry. Non-interest income is recognized when billing to the Company’s customer occurs. The Company remits collections from the client’s customers to the Company’s clients for the amounts collected, net of payroll taxes withheld, the Company’s fees, subject to a hold back reserve to offset potential uncollectible balances from the client’s other customers. Factored Receivables. The Company provide accounts receivable management services. The purchase of a client’s accounts receivable is traditionally known as “factoring” and results in payment by the client of a factoring fee. The factoring fee included in non-interest income represents compensation to the Company for the bookkeeping and collection services provided. The factoring fee, which is non-refundable, is recognized at the time the receivable is assigned to the Company. Other revenue associated with factored receivables includes wire fees, technology fees, field examination fees and UCC fees. All such fees are recognized as income upon receipt, which is when the Company’s obligations are provided to the Company’s customers.
Segment Information	Segment Information Public companies are required to report certain financial information about significant revenue-producing segments of the business for which such information is available and utilized by the chief operating decision maker. Substantially all of the Company’s operations occur through the Bank and involve the delivery of loan and deposit products to customers. Management makes operating decisions and assesses performance based on an ongoing review of its banking operation, which constitutes the Company’s only operating segment for financial reporting purposes.
Recently Issued Accounting Standards	Recently Issued Accounting Standards ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 implements a common revenue standard that clarifies the principles for recognizing revenue. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. This standard is effective for the Company on January 1, 2018. THe company’s revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income, which is subject to ASU 2014-09. At this time the Company believes the adoption of this standard will not have a significant impact to its consolidated financial statements. ASU 2016-1, “No. 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-1, among other things: (i) requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and (vii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale. ASU 2016-1 will be effective for the Company on January 1, 2018 and is not expected to have a significant impact on its financial statements. ASU 2016-02, “Leases.” ASU 2016-02 amends existing lease accounting guidance, including the requirement to recognize most lease arrangements on the balance sheet. The adoption of this standard will result in the Company recognizing a right-of-use asset representing its rights to use the underlying asset for the lease term with an offsetting lease liability. ASU 2016-02 will be effective for for the company on January 1, 2019, with early adoption permitted and will require transition using a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The Company has not yet concluded whether it will adopt the standard prior to January 1, 2019; however, if the standard were effective at December 31, 2017, it would not have had an impact on any borrowings or covenants that are relevant to the Company and management estimates that the impact to the Bank’s and the Company’s regulatory capital ratios would be approximately five basis points. ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 amends current guidance on the impairment of financial instruments. ASU 2016-13 adds an impairment model known as the current expected credit loss (“CECL”) model that is based on expected losses rather than incurred losses. For the Company, the CECL model will apply mainly to held-to-maturity investment securities, loans and loan commitments. ASU 2016-13 will be effective for the Company for fiscal years beginning after December 15, 2019, and the Company is permitted to early adopt the new guidance for fiscal years beginning after December 15, 2018. ASU 2016-13 will significantly change the accounting for credit impairment. The new guidance will require the Company to modify current processes and systems for establishing the allowance for loan losses and OTTI to ensure they comply with the requirements of the new standard. As as result, the Company has engaged a nationally recognized accounting firm to advise and assist management in performing an implementation readiness assessment and adopt the standard. During the 2017, the Company performed the following: • in conjunction with its advisor, established a CECL program steering committee, identified significant work streams and created a CECL program project timeline; • evaluated several third-party models in order to determine the CECL modeling approach that will be used for the Company’s loan portfolios; • selected vendors that will assist in data analytics and modeling; and • evaluated data, gaps in data and mitigation strategies. The Company is unable to estimate the impact of adopting ASU 2016-13 at this time; however, it anticipates the allowance for loan losses will be greater under the CECL model compared to the current incurred loss model and that the composition of the loan and securities portfolio as well as the status of the economic environment, will be significant factors that impact the balance at date of adoption. ASU 2017-08, “Premium Amortization on Purchased Callable Debt Securities.” ASU 2017-08 shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. Today, entities generally amortize the premium over the contractual life of the security. The new guidance does not change the accounting for purchased callable debt securities held at a discount as discounts continue to be amortized to maturity. ASU No. 2017-08 is effective for interim and annual reporting periods beginning after December 15, 2018 and early adoption is permitted. The guidance includes a modified retrospective transition approach under which a cumulative-effect adjustment will be made to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. Management intends to adopt this standard effective January 1, 2018 and the impact of adoption is not expected to have a significant impact on the Company’s financial statements. ASU 2017-09, “Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting.” ASU 2017-09 clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under ASU 2017-09, an entity will not apply modification accounting to a share-based payment award if all of the following are the same immediately before and after the change: (i) the fair value of the award, (ii) the vesting conditions of the award and (iii) the classification of the award as an equity or liability instrument. ASU 2017-09 will be effective for the Company on January 1, 2018 and is not expected to have a significant impact on its financial statements. ASU 2017-12, “Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities.” ASU 2017-12 amends the hedge accounting recognition and presentation requirements in ASC 815 to improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities to better align the entity’s financial reporting for hedging relationships with those risk management activities and to reduce the complexity of and simplify the application of hedge accounting. ASU 2017-12 will be effective for the Company on January 1, 2019 and is not expected to have a significant impact on the Company’s financial statements. ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” ASU 2018-02 allows the Company to reclassify from accumulated other comprehensive income (loss) to retained earnings for the stranded tax effect resulting from the Tax Act. ASU 2018-02 is required to be adopted by the Company no later than January 1, 2019. The company expects to adopt ASU 2018-02 in the first quarter of 2018, which is not expected to have a significant impact on its financial statements. See Note 1. “Basis of Financial Statement Presentation and Summary of Significant Accounting Policies” for a discussion of the adoption of new accounting standards that affected the consolidated financial statements contained in this report.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Acquired loan portfolio data in the Astoria Merger is presented below: Fair value of acquired loans at acquisition date Gross contractual amounts receivable at acquisition date Best estimate at acquisition date of contractual cash flows not expected to be collected Acquired loans with evidence of deterioration since origination $ 167,614 $ 221,550 $ 44,545 Acquired loans with no evidence of deterioration since origination 9,041,784 11,509,782 NA The table below summarizes the amounts recognized as of the HVB Merger date for each major class of assets acquired and liabilities assumed, the estimated fair value adjustments and the amounts recorded in the Company’s financial statements at fair value at the HVB Merger date: Acquired from HVHC Fair value adjustments As recorded by the Company Cash and cash equivalents $ 878,988 $ — $ 878,988 Investment securities 713,625 217 (a) 713,842 Loans 1,816,767 (24,248 ) (b) 1,792,519 Federal Reserve Bank stock 5,830 — 5,830 Bank owned life insurance 44,231 — 44,231 Premises and equipment 11,918 4,925 (c) 16,843 Accrued interest receivable 7,392 — 7,392 Core deposits and other intangibles — 33,839 (d) 33,839 Other real estate owned 222 — 222 Other assets 32,639 (7,931 ) (e) 24,708 Deposits (3,160,746 ) — (3,160,746 ) Other borrowings (25,366 ) — (25,366 ) Other liabilities (37,292 ) 1,540 (f) (35,752 ) Total identifiable net assets acquired $ 288,208 $ 8,342 296,550 Purchase price 566,307 Goodwill recorded in the HVB Merger $ 269,757 Explanation of certain fair value related adjustments: (a) Represents the fair value adjustment on investment securities held to maturity. (b) Represents the elimination of HVHC ’ s allowance for loan losses and an adjustment of the net book value of loans to estimated fair value, which includes an interest rate mark and credit mark adjustment. (c) Represents an adjustment to reflect the fair value of HVHC owned real estate, as determined by independent appraisals, which will be amortized on a straight-line basis over the estimated useful lives of the individual assets. (d) Represents intangible assets recorded to reflect the fair value of core deposits. The core deposit asset was recorded as an identifiable intangible asset and will be amortized on an accelerated basis over the estimated average life of the deposit base. (e) Represents an adjustment in net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangibles recorded. (f) Represents the elimination of HVHC’s deferred rent liability. Acquired loan portfolio data in the HVB Merger is presented below: Fair value of acquired loans at acquisition date Gross contractual amounts receivable at acquisition date Best estimate at acquisition date of contractual cash flows not expected to be collected Acquired loans with evidence of deterioration since origination $ 96,973 $ 122,104 $ 12,604 Acquired loans with no evidence of deterioration since origination 1,695,546 1,974,740 NA As recorded by Astoria Fair value adjustments As recorded at acquisition Cash and cash equivalents $ 275,409 $ — $ 275,409 Investment securities 3,144,111 (42,318 ) (a) 3,101,793 Loans held for sale 497 — 497 Loans 9,546,307 (336,909 ) (b) 9,209,398 Allowance for loan losses (79,293 ) 79,293 (c) — Bank owned life insurance 447,518 — 447,518 Premises and equipment 90,678 177,137 (d) 267,815 Accrued interest receivable 34,094 — 34,094 Goodwill 185,151 (185,151 ) (e) — Core deposit and other intangibles — 99,938 (f) 99,938 Other real estate owned 17,705 (1,600 ) (g) 16,105 Other assets 288,075 47,537 (h) 335,612 Total assets acquired 13,950,252 (162,073 ) 13,788,179 Deposits (9,029,303 ) (14,758 ) (i) (9,044,061 ) FHLB borrowings (1,550,000 ) (39,464 ) (j) (1,589,464 ) Repurchase agreements (1,100,000 ) (43,279 ) (k) (1,143,279 ) Senior notes (198,044 ) (3,476 ) (l) (201,520 ) Other liabilities (354,725 ) (9,322 ) (m) (364,047 ) Total liabilities assumed (12,232,072 ) (110,299 ) (12,342,371 ) Preferred stock assumed (129,796 ) (9,616 ) (n) (139,412 ) Total liabilities and preferred stock assumed $ (12,361,868 ) $ (119,915 ) (12,481,783 ) Net assets acquired 1,306,396 Purchase price 2,189,687 Goodwill recorded in the Merger $ 883,291 Explanation of certain fair value related adjustments: (a) Represents the fair value adjustment on investment securities held to maturity. (b) Represents the fair value adjustment to the net book value of loans, which includes an interest rate mark and credit mark adjustment. (c) Represents the elimination of Astoria’s allowance for loan losses. (d) Represents the fair value adjustment to reflect the fair value of land and buildings, which will be amortized on a straight-line basis over the estimated useful lives of the individual assets. (e) Represents the elimination of Astoria’s goodwill. (f) Represents intangible assets recorded to reflect the fair value of core deposits. The core deposit asset was recorded as an identifiable intangible asset and will be amortized on an accelerated basis over the estimated average life of the deposit base. (g) Represents an adjustment to reduce the carrying value of other real estate owned to fair value. (h) Represents an adjustment to net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangible assets recorded. (i) Represents the fair value adjustment on time deposits, which will be accreted as a reduction of interest expense over the remaining term of the time deposits. (j) Represents the fair value adjustment on FHLB borrowings, which was equal to the price paid to terminate Astoria’s long-term FHLB borrowings. (k) Represents the fair value adjustment on repurchase agreements, which was equal to the price paid to various counterparties to terminate these agreements. (l) Represents the fair value adjustment on senior notes, as determined by quoted market prices, which will be accreted as a reduction of interest expense through maturity of the notes. (m) Represents the fair value adjustment to other liabilities assumed in the merger including actuarially determined liabilities of Astoria. (n) Represents the fair value adjustment on preferred stock, as determined by quoted market prices, which will be accreted as a reduction in the preferred stock dividends over the five-year call period ending on October 15, 2022.
Business Acquisition, Unaudited Pro Forma Information	Pro forma information For the year ended December 31, 2017 2016 Net interest income $ 939,036 $ 818,906 Non-interest income 98,726 121,949 Non-interest expense 516,333 544,821 Net income available to common stockholders 316,657 242,398 Pro forma earnings per common share from continuing operations: Basic $ 1.41 $ 1.11 Diluted 1.41 1.11 The unaudited pro forma information for calendar 2015 set forth below reflects adjustments related to (a) purchase accounting fair value adjustments; (b) amortization of core deposit and other intangibles; and (c) adjustments to interest income and expense due to amortization of premiums and accretion of discounts. Direct merger-related expenses and charges incurred in calendar 2015 and costs incurred to write-down assets and accrue for systems integration, retention and severance compensation are assumed to have occurred prior to January 1, 2015. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated potential cost savings for periods that include data as of June 30, 2015 or earlier. Pro forma information For the year ended December 31, 2015 Net interest income $ 360,271 Non-interest income 66,686 Non-interest expense 261,453 Net income 100,086 Pro forma earnings per share from continuing operations: Basic $ 0.78 Diluted 0.78

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of securities available for sale	A summary of amortized cost and estimated fair value of our securities is presented below: December 31, 2017 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 2,171,044 $ 1,570 $ (21,965 ) $ 2,150,649 $ 355,013 $ 978 $ (2,504 ) $ 353,487 CMO/Other MBS 656,514 31 (7,142 ) 649,403 33,496 26 (760 ) 32,762 Total residential MBS 2,827,558 1,601 (29,107 ) 2,800,052 388,509 1,004 (3,264 ) 386,249 Other securities: Federal agencies 409,322 — (9,326 ) 399,996 58,640 949 — 59,589 Corporate bonds 147,781 1,421 (976 ) 148,226 56,663 1,255 (103 ) 57,815 State and municipal 264,310 1,380 (1,892 ) 263,798 2,342,927 12,396 (10,900 ) 2,344,423 Other — — — — 15,750 83 — 15,833 Total other securities 821,413 2,801 (12,194 ) 812,020 2,473,980 14,683 (11,003 ) 2,477,660 Total securities $ 3,648,971 $ 4,402 $ (41,301 ) $ 3,612,072 $ 2,862,489 $ 15,687 $ (14,267 ) $ 2,863,909 December 31, 2016 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 1,213,733 $ 569 $ (20,821 ) $ 1,193,481 $ 277,539 $ 1,353 $ (3,625 ) $ 275,267 CMO/Other MBS 57,563 44 (926 ) 56,681 40,594 74 (572 ) 40,096 Total residential MBS 1,271,296 613 (21,747 ) 1,250,162 318,133 1,427 (4,197 ) 315,363 Other securities: Federal agencies 204,770 2 (10,793 ) 193,979 58,200 1,392 — 59,592 Corporate 43,464 150 (1,108 ) 42,506 35,048 431 (11 ) 35,468 State and municipal 245,304 739 (5,273 ) 240,770 974,290 3,571 (36,232 ) 941,629 Other — — — — 5,750 195 — 5,945 Total other securities 493,538 891 (17,174 ) 477,255 1,073,288 5,589 (36,243 ) 1,042,634 Total securities $ 1,764,834 $ 1,504 $ (38,921 ) $ 1,727,417 $ 1,391,421 $ 7,016 $ (40,440 ) $ 1,357,997
Summary of securities held-to-maturity	A summary of amortized cost and estimated fair value of our securities is presented below: December 31, 2017 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 2,171,044 $ 1,570 $ (21,965 ) $ 2,150,649 $ 355,013 $ 978 $ (2,504 ) $ 353,487 CMO/Other MBS 656,514 31 (7,142 ) 649,403 33,496 26 (760 ) 32,762 Total residential MBS 2,827,558 1,601 (29,107 ) 2,800,052 388,509 1,004 (3,264 ) 386,249 Other securities: Federal agencies 409,322 — (9,326 ) 399,996 58,640 949 — 59,589 Corporate bonds 147,781 1,421 (976 ) 148,226 56,663 1,255 (103 ) 57,815 State and municipal 264,310 1,380 (1,892 ) 263,798 2,342,927 12,396 (10,900 ) 2,344,423 Other — — — — 15,750 83 — 15,833 Total other securities 821,413 2,801 (12,194 ) 812,020 2,473,980 14,683 (11,003 ) 2,477,660 Total securities $ 3,648,971 $ 4,402 $ (41,301 ) $ 3,612,072 $ 2,862,489 $ 15,687 $ (14,267 ) $ 2,863,909 December 31, 2016 Available for Sale Held to Maturity Amortized cost Gross unrealized gains Gross unrealized losses Fair value Amortized cost Gross unrealized gains Gross unrealized losses Fair value Residential MBS: Agency-backed $ 1,213,733 $ 569 $ (20,821 ) $ 1,193,481 $ 277,539 $ 1,353 $ (3,625 ) $ 275,267 CMO/Other MBS 57,563 44 (926 ) 56,681 40,594 74 (572 ) 40,096 Total residential MBS 1,271,296 613 (21,747 ) 1,250,162 318,133 1,427 (4,197 ) 315,363 Other securities: Federal agencies 204,770 2 (10,793 ) 193,979 58,200 1,392 — 59,592 Corporate 43,464 150 (1,108 ) 42,506 35,048 431 (11 ) 35,468 State and municipal 245,304 739 (5,273 ) 240,770 974,290 3,571 (36,232 ) 941,629 Other — — — — 5,750 195 — 5,945 Total other securities 493,538 891 (17,174 ) 477,255 1,073,288 5,589 (36,243 ) 1,042,634 Total securities $ 1,764,834 $ 1,504 $ (38,921 ) $ 1,727,417 $ 1,391,421 $ 7,016 $ (40,440 ) $ 1,357,997
Summary of amortized cost and fair value of investment securities available for sale by remaining period to contractual maturity	The amortized cost and estimated fair value of securities at December 31, 2017 are presented below by contractual maturity. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Residential mortgage-backed securities are shown separately since they are not due at a single maturity date. December 31, 2017 Available for sale Held to maturity Amortized cost Fair value Amortized cost Fair value Other securities remaining period to contractual maturity: One year or less $ 11,994 $ 12,003 $ 89,155 $ 88,949 One to five years 146,471 145,499 83,615 84,742 Five to ten years 526,968 520,904 387,647 390,749 Greater than ten years 135,980 133,614 1,913,563 1,913,220 Total other securities 821,413 812,020 2,473,980 2,477,660 Residential MBS 2,827,558 2,800,052 388,509 386,249 Total securities $ 3,648,971 $ 3,612,072 $ 2,862,489 $ 2,863,909
Sale of securities	Sales of securities for the periods indicated below were as follows: Year ended December 31, 2017 2016 2015 Available for sale: Proceeds from sales $ 2,516,308 $ 858,531 $ 893,610 Gross realized gains 8 10,665 6,018 Gross realized losses (352 ) (3,143 ) (1,181 ) Income tax (benefit) expense on realized net (losses) gains (91 ) 2,445 1,572
Securities available for sale with unrealized losses, by length of time in continuous unrealized loss position	The following table summarizes securities available for sale with unrealized losses, segregated by the length of time in a continuous unrealized loss position: Continuous unrealized loss position Less than 12 months 12 months or longer Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses Available for sale December 31, 2017 Residential MBS: Agency-backed $ 1,349,217 $ (10,550 ) $ 486,948 $ (11,415 ) $ 1,836,165 $ (21,965 ) CMO/Other MBS 605,200 (6,064 ) 36,107 (1,078 ) 641,307 (7,142 ) Total residential MBS 1,954,417 (16,614 ) 523,055 (12,493 ) 2,477,472 (29,107 ) Other securities: Federal agencies 243,476 (1,955 ) 156,520 (7,371 ) 399,996 (9,326 ) Corporate 65,056 (397 ) 15,268 (579 ) 80,324 (976 ) State and municipal 97,307 (757 ) 56,324 (1,135 ) 153,631 (1,892 ) Total other securities 405,839 (3,109 ) 228,112 (9,085 ) 633,951 (12,194 ) Total $ 2,360,256 $ (19,723 ) $ 751,167 $ (21,578 ) $ 3,111,423 $ (41,301 ) December 31, 2016 Residential MBS: Agency-backed $ 1,101,641 $ (20,816 ) $ 686 $ (5 ) $ 1,102,327 $ (20,821 ) CMO/Other MBS 38,841 (506 ) 15,239 (420 ) 54,080 (926 ) Total residential MBS 1,140,482 (21,322 ) 15,925 (425 ) 1,156,407 (21,747 ) Other securities: Federal agencies 185,504 (10,793 ) 4 — 185,508 (10,793 ) Corporate 10,399 (137 ) 14,942 (971 ) 25,341 (1,108 ) State and municipal 173,062 (5,196 ) 3,733 (77 ) 176,795 (5,273 ) Total other securities 368,965 (16,126 ) 18,679 (1,048 ) 387,644 (17,174 ) Total $ 1,509,447 $ (37,448 ) $ 34,604 $ (1,473 ) $ 1,544,051 $ (38,921 )
Securities held to maturity with unrealized losses, by length of time in continuous unrealized loss position	The following table summarizes securities held to maturity with unrealized losses, segregated by the length of time in a continuous unrealized loss position: Continuous unrealized loss position Less than 12 months 12 months or longer Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses Held to maturity December 31, 2017 Residential MBS: Agency-backed $ 136,679 $ (572 ) $ 74,303 $ (1,932 ) $ 210,982 $ (2,504 ) CMO/Other MBS 10,314 (129 ) 20,160 (631 ) 30,474 (760 ) Total residential MBS 146,993 (701 ) 94,463 (2,563 ) 241,456 (3,264 ) Other securities: Corporate 16,560 (103 ) — — 16,560 (103 ) State and municipal 860,536 (5,310 ) 393,200 (5,590 ) 1,253,736 (10,900 ) Total other securities 877,096 (5,413 ) 393,200 (5,590 ) 1,270,296 (11,003 ) Total $ 1,024,089 $ (6,114 ) $ 487,663 $ (8,153 ) $ 1,511,752 $ (14,267 ) December 31, 2016 Residential MBS: Agency-backed $ 185,116 $ (3,623 ) $ 213 $ (2 ) $ 185,329 $ (3,625 ) CMO/Other MBS 34,786 (572 ) — — 34,786 (572 ) Total residential MBS 219,902 (4,195 ) 213 (2 ) 220,115 (4,197 ) Other securities: Corporate — — 5,037 (11 ) 5,037 (11 ) State and municipal 758,690 (36,169 ) 2,816 (63 ) 761,506 (36,232 ) Total other securities 758,690 (36,169 ) 7,853 (74 ) 766,543 (36,243 ) Total $ 978,592 $ (40,364 ) $ 8,066 $ (76 ) $ 986,658 $ (40,440 )
Securities pledged for borrowings at FHLB and other institutions, and securities pledged for municipal deposits and other purposes	Securities pledged for borrowings at FHLB and other institutions, and securities pledged for municipal deposits and other purposes were as follows: December 31, 2017 2016 Available for sale securities pledged for borrowings, at fair value $ 10,225 $ 67,599 Available for sale securities pledged for municipal deposits, at fair value 323,341 398,961 Available for sale securities pledged for customer back-to-back swaps, at fair value — 126 Held to maturity securities pledged for borrowings, at amortized cost 35,047 55,343 Held to maturity securities pledged for municipal deposits, at amortized cost 1,182,674 958,246 Total securities pledged $ 1,551,287 $ 1,480,275

Portfolio Loans (Tables)

Portfolio Loans (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Components of loan portfolio excluding loans held for sale	The composition of the Company’s loan portfolio, excluding loans held for sale, was the following: December 31, 2017 2016 Commercial: C&I: Traditional C&I $ 1,979,448 $ 1,404,774 Asset-based lending 797,570 741,942 Payroll finance 268,609 255,549 Warehouse lending 723,335 616,946 Factored receivables 220,551 214,242 Equipment financing 679,541 589,315 Public sector finance 637,767 349,182 Total C&I 5,306,821 4,171,950 Commercial mortgage: CRE 4,138,864 3,162,942 Multi-family 4,859,555 981,076 ADC 282,792 230,086 Total commercial mortgage 9,281,211 4,374,104 Total commercial 14,588,032 8,546,054 Residential mortgage 5,054,732 697,108 Consumer 366,219 284,068 Total portfolio loans 20,008,983 9,527,230 Allowance for loan losses (77,907 ) (63,622 ) Total portfolio loans, net $ 19,931,076 $ 9,463,608
Schedule of amounts and status of loans and TDRs	The following tables set forth the amounts and status of the Company’s loans and TDRs at December 31, 2017 and 2016 : December 31, 2017 Current 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 1,940,387 $ 1,232 $ 187 $ — $ 37,642 $ 1,979,448 Asset-based lending 797,570 — — — — 797,570 Payroll finance 268,609 — — — — 268,609 Warehouse lending 723,335 — — — — 723,335 Factored receivables 220,551 — — — — 220,551 Equipment financing 667,083 1,143 3,216 — 8,099 679,541 Public sector finance 637,767 — — — — 637,767 CRE 4,104,173 8,403 4,131 437 21,720 4,138,864 Multi-family 4,853,677 595 834 — 4,449 4,859,555 ADC 278,587 — — — 4,205 282,792 Residential mortgage 4,925,996 22,416 6,038 324 99,958 5,054,732 Consumer 350,502 4,364 974 95 10,284 366,219 Total loans $ 19,768,237 $ 38,153 $ 15,380 $ 856 $ 186,357 $ 20,008,983 Total TDRs included above $ 13,175 $ 389 $ — $ — $ 29,325 $ 42,889 Non-performing loans: Loans 90+ days past due and still accruing $ 856 Non-accrual loans 186,357 Total non-performing loans $ 187,213 December 31, 2016 Current 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 1,376,181 $ 835 $ 817 $ 555 $ 26,386 $ 1,404,774 Asset-based lending 741,942 — — — — 741,942 Payroll finance 254,715 — 14 621 199 255,549 Warehouse lending 616,946 — — — — 616,946 Factored receivables 213,624 — — — 618 214,242 Equipment financing 583,835 2,142 1,092 — 2,246 589,315 Public sector finance 349,182 — — — — 349,182 CRE 3,140,561 967 — 406 21,008 3,162,942 Multi-family 981,005 — — — 71 981,076 ADC 224,817 — — — 5,269 230,086 Residential mortgage 675,750 5,509 951 108 14,790 697,108 Consumer 274,719 2,423 350 — 6,576 284,068 Total loans $ 9,433,277 $ 11,876 $ 3,224 $ 1,690 $ 77,163 $ 9,527,230 Total TDRs included above $ 11,032 $ 253 $ — $ — $ 1,989 $ 13,274 Non-performing loans: Loans 90+ days past due and still accruing $ 1,690 Non-accrual loans 77,163 Total non-performing loans $ 78,853
Schedule of additional analysis of non-accrual loans	The following table provides additional analysis of the Company’s non-accrual loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Recorded investment non-accrual loans Recorded investment PCI non-accrual loans Recorded investment total non-accrual loans Unpaid principal balance non-accrual loans Recorded investment non-accrual loans Recorded investment PCI non-accrual loans Recorded investment total non-accrual loans Unpaid principal balance non-accrual loans Traditional C&I $ 33,631 $ 4,011 $ 37,642 $ 37,853 $ 22,338 $ 4,048 $ 26,386 $ 26,386 Payroll finance — — — — 199 — 199 199 Factored receivables — — — — 618 — 618 618 Equipment financing 8,099 — 8,099 8,099 2,246 — 2,246 2,246 CRE 18,762 2,958 21,720 25,739 15,063 5,945 21,008 25,619 Multi-family 4,449 — 4,449 4,705 71 — 71 71 ADC 4,205 — 4,205 4,205 5,269 — 5,269 5,398 Residential mortgage 99,644 314 99,958 113,002 13,399 1,391 14,790 18,190 Consumer 9,575 709 10,284 12,096 5,719 857 6,576 7,865 Total loans $ 178,365 $ 7,992 $ 186,357 $ 205,699 $ 64,922 $ 12,241 $ 77,163 $ 86,592
Impaired financing receivables	The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at December 31, 2016 : Loans evaluated by segment Allowance evaluated by segment Individually evaluated for impairment Collectively evaluated for impairment Purchased credit impaired loans Total loans Individually evaluated for impairment Collectively evaluated for impairment Total allowance for loan losses Traditional C&I $ 25,221 $ 1,365,466 $ 14,087 $ 1,404,774 $ — $ 12,864 $ 12,864 Asset-based lending — 724,247 17,695 741,942 — 3,316 3,316 Payroll finance 570 254,979 — 255,549 — 951 951 Warehouse lending — 616,946 — 616,946 — 1,563 1,563 Factored receivables — 214,242 — 214,242 — 1,669 1,669 Equipment financing 1,413 587,902 — 589,315 — 5,039 5,039 Public sector finance — 349,182 — 349,182 — 1,062 1,062 CRE 14,853 3,104,057 44,032 3,162,942 — 20,466 20,466 Multi-family — 976,710 4,366 981,076 — 4,991 4,991 ADC 9,025 216,094 4,967 230,086 — 1,931 1,931 Residential mortgage 2,545 692,396 2,167 697,108 — 5,864 5,864 Consumer 1,764 280,710 1,594 284,068 — 3,906 3,906 Total loans $ 55,391 $ 9,382,931 $ 88,908 $ 9,527,230 $ — $ 63,622 $ 63,622 The following table presents the carrying value of the Company’s PCI loans segregated by those PCI loans subject to accretion, and those PCI loans under the cost recovery method at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 PCI loans subject to accretion PCI loans under cost recovery method (non-accrual) Total PCI loans PCI loans subject to accretion PCI loans under cost recovery method (non-accrual) Total PCI loans Traditional C&I $ 6,361 $ 4,011 $ 10,372 $ 10,039 $ 4,048 $ 14,087 Asset-based lending — — — 17,695 — 17,695 CRE 36,100 2,958 39,058 38,087 5,945 44,032 Multi-family 15,060 — 15,060 4,366 — 4,366 ADC 262 — 262 4,967 — 4,967 Residential 151,200 314 151,514 776 1,391 2,167 Consumer 9,637 709 10,346 737 857 1,594 Total $ 218,620 $ 7,992 $ 226,612 $ 76,667 $ 12,241 $ 88,908 The following tables present the average recorded investment and interest income recognized related to loans individually evaluated for impairment by segment for 2017 , 2016 and 2015 : For the year ended December 31, 2017 December 31, 2016 December 31, 2015 YTD average recorded investment Interest income recognized YTD average recorded investment Interest income recognized YTD average recorded investment Interest income recognized With no related allowance recorded: Traditional C&I $ 26,413 $ 460 $ 25,508 $ 22 $ 2,718 $ — Payroll finance — — 71 — — — Equipment Financing 4,004 — 1,275 — 757 — CRE 11,808 374 13,625 133 12,155 102 Multi-family 399 65 — — 1,078 — ADC 5,687 206 6,132 31 8,819 234 Residential mortgage 1,068 — 768 — 515 — Consumer 1,977 — 1,530 — — — Total $ 51,356 $ 1,105 $ 48,909 $ 186 $ 26,042 $ 336 The following table presents loans individually evaluated for impairment by segment of loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Unpaid principal balance Recorded investment Unpaid principal balance Recorded investment Loans with no related allowance recorded: Traditional C&I $ 36,408 $ 35,921 $ 25,221 $ 25,221 Payroll finance — — 570 570 Equipment financing 5,341 5,341 1,413 1,413 CRE 10,128 9,663 16,365 14,853 Multi-family 1,597 1,597 — — ADC 5,474 5,208 9,025 9,025 Residential — — 2,545 2,545 Consumer 3,132 3,132 1,764 1,764 Total $ 62,080 $ 60,862 $ 56,903 $ 55,391 The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at December 31, 2017 : Loans evaluated by segment Allowance evaluated by segment Individually evaluated for impairment Collectively evaluated for impairment Purchased credit impaired loans Total loans Individually evaluated for impairment Collectively evaluated for impairment Total allowance for loan losses Traditional C&I $ 35,921 $ 1,933,155 $ 10,372 $ 1,979,448 $ — $ 19,072 $ 19,072 Asset-based lending — 797,570 — 797,570 — 6,625 6,625 Payroll finance — 268,609 — 268,609 — 1,565 1,565 Warehouse lending — 723,335 — 723,335 — 3,705 3,705 Factored receivables — 220,551 — 220,551 — 1,395 1,395 Equipment financing 5,341 674,200 — 679,541 — 4,862 4,862 Public sector finance — 637,767 — 637,767 — 1,797 1,797 CRE 9,663 4,090,143 39,058 4,138,864 — 24,945 24,945 Multi-family 1,597 4,842,898 15,060 4,859,555 — 3,261 3,261 ADC 5,208 277,322 262 282,792 — 1,680 1,680 Residential mortgage — 4,903,218 151,514 5,054,732 — 5,819 5,819 Consumer 3,132 352,741 10,346 366,219 — 3,181 3,181 Total loans $ 60,862 $ 19,721,509 $ 226,612 $ 20,008,983 $ — $ 77,907 $ 77,907
Schedule of changes in the balance of accretable yield discount for PCI loans	The following table presents the changes in the balance of the accretable yield discount for PCI loans for 2017 , 2016 , and 2015 : Year ended December 31, 2017 2016 2015 Balance at beginning of year $ 11,117 $ 11,211 $ 724 Acquisition 46,111 2,200 12,527 Accretion (7,468 ) (4,937 ) (2,229 ) Disposals (2,000 ) — (50 ) Reclassification (to) from non-accretable difference (2,178 ) 2,643 239 Balance at end of year $ 45,582 $ 11,117 $ 11,211
Troubled debt restructurings	The following tables set forth the amounts and past due status of the Company’s TDRs at December 31, 2017 and December 31, 2016 : December 31, 2017 Current loans 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 565 $ — $ — $ — $ 21,083 $ 21,648 Equipment financing 898 — — — 826 1,724 CRE 2,921 — — — 115 3,036 ADC 1,495 — — — 4,205 5,700 Residential mortgage 5,154 336 — — 2,810 8,300 Consumer 2,142 53 — — 286 2,481 Total $ 13,175 $ 389 $ — $ — $ 29,325 $ 42,889 December 31, 2016 Current loans 30-59 days past due 60-89 days past due 90+ days past due Non- accrual Total Traditional C&I $ 572 $ — $ — $ — $ 128 $ 700 Equipment financing — — — — 29 29 CRE 2,443 253 — — — 2,696 ADC 5,962 — — — 458 6,420 Residential mortgage 2,055 — — — 1,374 3,429 Total $ 11,032 $ 253 $ — $ — $ 1,989 $ 13,274 The following table identifies TDRs that occurred during 2017 and 2016: December 31, 2017 December 31, 2016 Recorded investment Recorded investment Number Pre- modification Post- modification Number Pre- modification Post- modification Traditional C&I 1 $ 23,188 $ 23,188 — $ — $ — Equipment financing 3 3,558 3,337 — — — Commercial real estate 2 1,724 1,724 — — — ADC 1 797 797 — — — Residential mortgage 4 1,140 1,033 1 469 347 Total TDRs 11 $ 30,407 $ 30,079 1 $ 469 $ 347

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Allowance for loan losses activity	Activity in the allowance for loan losses for 2017 and 2016 , and 2015 is summarized below: For the year ended December 31, 2017 Beginning Charge-offs Recoveries Net Provision Ending balance Traditional C&I $ 12,864 $ (5,489 ) $ 1,142 $ (4,347 ) $ 10,555 $ 19,072 Asset-based lending 3,316 — 5 5 3,304 6,625 Payroll finance 951 (188 ) 6 (182 ) 796 1,565 Warehouse lending 1,563 — — — 2,142 3,705 Factored receivables 1,669 (982 ) 23 (959 ) 685 1,395 Equipment financing 5,039 (3,165 ) 387 (2,778 ) 2,601 4,862 Public sector finance 1,062 — — — 735 1,797 CRE 20,466 (2,379 ) 163 (2,216 ) 6,695 24,945 Multi-family 4,991 — — — (1,730 ) 3,261 ADC 1,931 (27 ) 269 242 (493 ) 1,680 Residential mortgage 5,864 (860 ) 161 (699 ) 654 5,819 Consumer 3,906 (1,095 ) 314 (781 ) 56 3,181 Total allowance for loan losses $ 63,622 $ (14,185 ) $ 2,470 $ (11,715 ) $ 26,000 $ 77,907 Annualized net charge-offs to average loans outstanding 0.10 % For the year ended December 31, 2016 Beginning balance Charge-offs Recoveries Net charge-offs Provision Ending balance Traditional C&I $ 9,953 $ (1,707 ) $ 999 $ (708 ) $ 3,619 $ 12,864 Asset-based lending 2,762 — 62 62 492 3,316 Payroll finance 1,936 (28 ) 32 4 (989 ) 951 Warehouse lending 589 — — — 974 1,563 Factored receivables 1,457 (1,200 ) 61 (1,139 ) 1,351 1,669 Equipment financing 4,925 (1,982 ) 560 (1,422 ) 1,536 5,039 Public sector finance 547 — — — 515 1,062 CRE 11,461 (959 ) 353 (606 ) 9,611 20,466 Multi-family 5,141 (417 ) 2 (415 ) 265 4,991 ADC 2,009 — 104 104 (182 ) 1,931 Residential mortgage 5,007 (1,045 ) 30 (1,015 ) 1,872 5,864 Consumer 4,358 (1,615 ) 227 (1,388 ) 936 3,906 Total allowance for loan losses $ 50,145 $ (8,953 ) $ 2,430 $ (6,523 ) $ 20,000 $ 63,622 Annualized net charge-offs to average loans outstanding 0.08 % For the year ended December 31, 2015 Beginning balance Charge-offs Recoveries Net charge-offs Provision Ending balance Traditional C&I $ 6,966 $ (1,575 ) $ 1,720 $ 145 $ 2,842 $ 9,953 Asset-based lending 4,061 — — — (1,299 ) 2,762 Payroll finance 1,506 (406 ) 35 (371 ) 801 1,936 Warehouse lending 608 — — — (19 ) 589 Factored receivables 1,205 (291 ) 60 (231 ) 483 1,457 Equipment financing 2,569 (3,423 ) 825 (2,598 ) 4,954 4,925 Public sector finance — — — — 547 547 CRE 7,721 (1,695 ) 148 (1,547 ) 5,287 11,461 Multi-family 4,511 (17 ) 9 (8 ) 638 5,141 ADC 2,987 — 52 52 (1,030 ) 2,009 Residential mortgage 5,843 (1,251 ) 92 (1,159 ) 323 5,007 Consumer 4,397 (2,360 ) 148 (2,212 ) 2,173 4,358 Total allowance for loan losses $ 42,374 $ (11,018 ) $ 3,089 $ (7,929 ) $ 15,700 $ 50,145 Annualized net charge-offs to average loans outstanding 0.13 %
Financing receivable credit quality indicators	Loans that are risk-rated 1 through 6 as defined above are considered to be pass-rated loans. As of December 31, 2017 and 2016 the risk category of gross loans by segment was as follows: December 31, 2017 December 31, 2016 Special mention Substandard Doubtful Special mention Substandard Doubtful Traditional C&I $ 7,453 $ 53,915 $ 746 $ 12,125 $ 28,977 $ 442 Asset-based lending 30,958 3,835 — 35,373 — — Payroll finance 15,542 352 — — 820 — Factored receivables 187 — — 185 433 — Equipment financing 4,093 9,299 — 2,128 3,397 — CRE 40,438 34,529 — 39,190 29,463 — Multi-family 26,602 14,266 — 7,072 658 — ADC 4,204 4,639 — 6,899 8,870 — Residential mortgage 6,038 101,149 — 951 15,796 — Consumer 1,043 10,507 18 646 6,738 — Total $ 136,558 $ 232,491 $ 764 $ 104,569 $ 95,152 $ 442

Premises and Equipment, Net (Ta

Premises and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Premises and Equipment, Net	Premises and equipment are summarized as follows: December 31, 2017 2016 Land and land improvements $ 160,376 $ 11,679 Buildings 127,959 29,785 Leasehold improvements 40,442 33,070 Furniture, fixtures and equipment 81,424 63,877 Total premises and equipment, gross 410,201 138,411 Accumulated depreciation and amortization (88,479 ) (81,093 ) Total premises and equipment, net $ 321,722 $ 57,318

Goodwill and Other Intangible38

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The change in goodwill for the periods presented was as follows: For the year ended December 31, 2017 2016 Beginning of period balance $ 696,600 $ 670,699 Acquired goodwill 883,291 25,901 End of period balance $ 1,579,891 $ 696,600
Schedule of Finite-Lived Intangible Assets	The balance of other intangible assets for the periods presented was as follows: Gross intangible assets Accumulated amortization Net intangible assets December 31, 2017 Core deposits $ 157,959 $ (31,414 ) $ 126,545 Customer lists 10,450 (4,596 ) 5,854 Non-compete agreements 11,808 (11,516 ) 292 Trade name 20,500 — 20,500 Fair value of below market leases 725 (725 ) — $ 201,442 $ (48,251 ) $ 153,191 December 31, 2016 Core deposits $ 58,021 $ (20,566 ) $ 37,455 Customer lists 10,450 (2,767 ) 7,683 Non-compete agreements 11,808 (11,183 ) 625 Trade name 20,500 — 20,500 Fair value of below market leases 725 (635 ) 90 $ 101,504 $ (35,151 ) $ 66,353
Future amortization expense	The estimated aggregate future amortization expense for other intangible assets remaining as of December 31, 2017 was as follows: Amortization expense 2018 $ 23,646 2019 19,181 2020 16,800 2021 15,104 2022 13,703 Thereafter 44,257 Total $ 132,691

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Summary of major classification of deposits	Deposit balances at December 31, 2017 and 2016 are summarized as follows: December 31, 2017 2016 Non-interest bearing demand $ 4,080,742 $ 3,239,332 Interest bearing demand 3,882,064 2,220,456 Savings 2,758,642 747,031 Money market 7,377,118 3,277,686 Certificates of deposit 2,439,638 583,754 Total deposits $ 20,538,204 $ 10,068,259
Schedule of Maturities of Deposits	Certificates of deposit had remaining periods to contractual maturity as follows: December 31, 2017 2016 Remaining period to contractual maturity: Less than one year $ 1,270,605 $ 480,162 One to two years 525,846 47,768 Two to three years 362,233 42,492 Three to four years 160,432 7,210 Four to five years 120,522 6,122 Total certificates of deposit $ 2,439,638 $ 583,754
List of Company's Brokered deposits	Listed below are the Company’s brokered deposits: December 31, 2017 2016 Interest bearing demand $ 23,820 $ 426,437 Money market 773,804 5,560 Savings — 246,572 Reciprocal CDARs 1 102,259 153,060 CDARs one way 204,331 — Total brokered deposits $ 1,104,214 $ 831,629 1 Certificate of deposit account registry service

Borrowings, Senior Notes and 40

Borrowings, Senior Notes and Subordinated Notes (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Instruments [Abstract]
Schedule of debt	The Company’s borrowings and weighted average interest rates are summarized as follows: December 31, 2017 2016 Amount Rate Amount Rate By type of borrowing: FHLB advances and overnight $ 4,510,123 1.69 % $ 1,791,000 1.01 % Repurchase agreements 30,162 0.64 16,642 0.75 5.50% Senior Notes 76,805 5.98 76,469 5.98 3.50% Senior Notes 201,404 3.19 — — Subordinated Notes 172,716 5.45 172,501 5.45 Total borrowings $ 4,991,210 1.96 $ 2,056,612 1.56 By remaining period to maturity: Less than one year $ 2,989,093 1.69 % $ 1,397,642 0.87 % One to two years 775,714 1.79 311,469 2.53 Two to three years 802,650 2.34 75,000 1.50 Three to four years 251,037 2.04 50,000 1.38 Four to five years — — 50,000 1.68 Greater than five years 172,716 5.45 172,501 5.45 Total borrowings $ 4,991,210 1.96 $ 2,056,612 1.56

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedges, Assets [Abstract]
Summary of derivatives	Summary information as of December 31, 2017 and 2016 regarding these derivatives is presented below: Notional amount Average maturity (in years) Weighted average fixed rate Weighted average variable rate Fair value December 31, 2017 Included in other assets: Third-party interest rate swap $ 314,754 $ 1,155 Customer interest rate swap 306,529 3,302 Total $ 621,283 5.79 4.28 % 1 m Libor + 1.94% $ 4,457 Included in other liabilities: Third-party interest rate swap $ (306,529 ) $ (4,718 ) Customer interest rate swap (314,754 ) (3,262 ) $ (621,283 ) 5.79 4.28 % 1 m Libor + 1.94% $ (7,980 ) December 31, 2016 Third-party interest rate swap $ 296,282 5.63 3.94 1 m Libor + 2.29% $ 2,088 Customer interest rate swap (296,282 ) 5.63 3.94 1 m Libor + 2.29% (2,088 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense for the periods indicated consisted of the following: For the year ended December 31, 2017 2016 2015 Current tax expense: Federal $ 4,375 $ 55,418 $ 25,634 State and local 2,181 12,854 5,862 Total current tax expense 6,556 68,272 31,496 Deferred tax expense (benefit): Federal 71,536 (1,069 ) (1,406 ) State and local 9,847 179 1,745 Total deferred tax expense (benefit) 81,383 (890 ) 339 Total income tax expense $ 87,939 $ 67,382 $ 31,835
Schedule of Effective Income Tax Rate Reconciliation	Actual income tax expense differs from the tax computed based on pre-tax income and the applicable statutory Federal tax rate for the following reasons: For the year ended December 31, 2017 2016 2015 Tax at federal statutory rate of 35% $ 63,341 $ 72,574 $ 34,282 State and local income taxes, net of federal tax benefit 7,818 8,472 4,945 Tax-exempt interest, net of disallowed interest (18,948 ) (11,094 ) (5,218 ) BOLI income (2,665 ) (1,933 ) (1,853 ) Non-deductible acquisition related costs 2,965 — 700 Low income housing tax credits (1,872 ) (469 ) (215 ) Equity-based stock compensation benefit (1,528 ) — — Estimated deferred tax adjustment related to reduction in federal income tax rate 40,285 — — Other, net (1,457 ) (168 ) (806 ) Actual income tax expense $ 87,939 $ 67,382 $ 31,835 Effective income tax rate 48.6 % 32.5 % 32.5 %
Schedule of Deferred Tax Assets and Liabilities	The following table presents the Company’s deferred tax position at December 31, 2017 and 2016 : December 31, 2017 2016 Deferred tax assets: Allowance for loan losses $ 20,468 $ 25,039 Deferred compensation 315 656 Other accrued compensation and benefits 22,321 9,920 Accrued post retirement expense 7,885 2,060 Deferred rent 3,445 3,268 Intangible assets 1,612 3,108 Other comprehensive loss (securities) 11,422 16,911 Other comprehensive loss (defined benefit plans) 447 479 Pension expense 11,691 — Accrued expenses 4,923 252 State NOL carryforward 15,400 — AMT credit carryforward 4,070 — Other 3,237 3,719 Total deferred tax assets 107,236 65,412 Deferred tax liabilities: Mortgage servicing rights 2,722 403 Prepaid pension costs — 3,798 Acquisition fair value adjustments — 18,948 Depreciation of premises and equipment 1,026 809 Deferred loan fees and costs 5,001 — Other 1,154 906 Total deferred tax liabilities 9,903 24,864 Net deferred tax asset $ 97,333 $ 40,548

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Company's stock option activity	The following table summarizes the activity in the Company’s active stock-based compensation plans for the periods presented: Non-vested stock awards/stock units outstanding Stock options outstanding Shares available for grant Number of shares Weighted average grant date fair value Number of shares Weighted average exercise price Balance at December 31, 2014 1,999,022 643,887 $ 11.79 2,040,299 $ 11.10 2015 Plan 2,800,000 — — — — Granted (1) (732,023 ) 447,807 14.02 24,566 14.22 Stock awards vested — (330,384 ) 11.23 — — Exercised — — — (406,422 ) 11.58 Forfeited 192,970 (34,510 ) 12.92 (71,871 ) 12.90 Canceled/expired (134.304 ) — — — — Balance at December 31, 2015 4,125,665 726,800 $ 13.36 1,586,572 $ 10.95 Granted (515,869 ) 515,869 14.60 — — Stock awards vested — (261,989 ) 13.09 — — Exercised — — — (503,893 ) 10.47 Forfeited 130,758 (48,457 ) 13.88 (78,560 ) 13.41 Canceled/expired (100,716 ) — — — — Balance at December 31, 2016 3,639,838 932,223 $ 14.09 1,004,119 $ 11.00 Granted (610,075 ) 610,075 24.13 — — Stock awards vested — (228,661 ) 16.23 — — Exercised — — — (244,252 ) 10.52 Forfeited 76,877 (74,877 ) 18.92 (2,000 ) 13.18 Canceled/expired (5,313 ) — — — — Balance at December 31, 2017 3,101,327 1,238,760 $ 20.00 757,867 $ 11.15 Exercisable at December 31, 2017 754,678 $ 11.13 (1) Reflects certain non-vested stock awards that counted as either 3.5 shares or 3.6 shares (depending on under which stock plan the awards were granted) for each share award granted.
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Other information regarding options outstanding at December 31, 2017 follows: Outstanding Exercisable Weighted average Weighted average Number of stock options Exercise price Life (in years) Number of stock options exercise price Range of exercise prices: $6.71 to $9.00 198,278 $ 8.34 4.43 198,278 $ 8.34 9.28 to 11.36 220,862 10.86 5.07 220,862 10.86 11.36 to 13.18 91,050 12.02 4.85 91,050 12.02 13.23 to 15.01 247,677 13.33 6.85 244,488 13.31 757,867 11.15 5.46 754,678 11.13 The fair value of options granted was determined using the following weighted-average assumptions as of the grant date: For the year ended December 31, 2015 Risk-free interest rate 1.8 % Expected stock price volatility 21.2 Dividend yield (1) 3.1 Expected term in years 5.76 (1) Represents the approximate annualized cash dividend rate paid with respect to a share of common stock at or near the grant date.
Schedule of stock-based compensation expense associated with stock options and non-vested stock awards	Stock-based compensation expense associated with stock options and non-vested stock awards and the related income tax benefit was as follows: For the year ended December 31, 2017 2016 2015 Stock options $ 149 $ 404 $ 909 Non-vested stock awards/performance units 7,961 6,114 3,671 Total $ 8,110 $ 6,518 $ 4,580 Income tax benefit $ 2,149 $ 2,118 $ 1,417
Unrecognized stock-based compensation expense	Unrecognized stock-based compensation expense at December 31, 2017 was as follows: December 31, 2017 Stock options $ 2 Non-vested stock awards/performance units 13,540 Total $ 13,542

Pension and Other Post Retire44

Pension and Other Post Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Summary of changes in the projected benefit obligation and fair value of plan assets	The following is a summary of changes in the projected benefit obligation and fair value of pension plans and other post retirement benefits plan assets. Pension benefits Other post retirement benefits December 31, December 31, 2017 2016 2017 2016 Changes in projected benefit obligation: Beginning of year balance $ — $ — $ 12,125 $ 11,733 Benefit obligation assumed in Astoria Merger 259,152 — 21,325 — Service cost — — 22 — Interest cost 2,189 — 557 417 Actuarial loss 3,561 — 984 64 Benefits and distributions paid (11,319 ) — (236 ) (89 ) End of year balance 253,583 — 34,777 12,125 Changes in fair value of plan assets: Beginning of year balance — — — — Fair value of pension plan assets at October 2, 2017 194,010 — — — Actual gain on plan assets 6,234 — — — Employer contributions 9,470 — 236 89 Benefits and distributions paid (11,319 ) — (236 ) (89 ) End of year balance 198,395 — — — Funded status at end of year $ (55,188 ) $ — $ (34,777 ) $ (12,125 )
Schedule of pre-tax components of accumulated other comprehensive loss	The following is a summary of the pre-tax components of accumulated other comprehensive loss related to pension plans and other post retirement benefits. We do not expect that any net actuarial (gain) loss and prior service cost will be recognized as components of net periodic cost in 2018 . Pension benefits Other post retirement benefits December 31, December 31, 2017 2016 2017 2016 Net actuarial loss $ 613 $ — $ 101 $ — Total accumulated other comprehensive loss $ 613 $ — $ 101 $ —
Schedule of assumptions used for plan	The following is a summary of the assumptions used to determine the net periodic (benefit) cost for the years ended December 31, 2017 and 2016 . Discount rate Expected return on plan assets 2017 2016 2017 2016 Pension benefit plans: Astoria Bank Pension Plan 3.61 % N/A 7.00 % N/A Astoria Excess and Supplemental Benefit Plans 3.21 N/A N/A N/A Astoria Directors’ Retirement Plan 2.78 N/A N/A N/A Greater Directors’ Retirement Plan 2.96 N/A N/A N/A LIB Directors’ Retirement Plan N/A N/A N/A N/A Other post retirement benefit plans: Sterling Other Post retirement medical, dental and vision plans 2.78% to 4.15% 2.78% to 4.00% N/A N/A Astoria Bank Retiree Health Care Plan 3.58 N/A N/A N/A The following is a summary of the discount rates used to determine the benefit obligations at the dates indicated. December 31, 2017 2016 Pension benefit plans: Astoria Bank Pension Plan 3.44 % N/A Astoria Excess and Supplemental Benefit Plans 3.14 N/A Astoria Directors’ Retirement Plan 2.82 N/A Greater Directors’ Retirement Plan 2.96 N/A LIB Directors’ Retirement Plan N/A N/A Other post retirement benefit plans: Sterling Other Post retirement medical, dental and vision plans 2.80% to 3.62% 2.78% to 4.00% Astoria Bank Retiree Health Care Plan 3.42 N/A
Schedule of Health Care Cost Trend Rates	The following table presents the assumed health care cost trend rates at the dates indicated. December 31, 2017 2016 Health care cost trend rate assumed for the next year: Pre-age 65 7.00 % N/A Post-age 65 6.75 N/A Rate to which the cost trend rate is assumed to decline (the “ultimate trend rate”) 4.75 N/A Year that ultimate trend rate is reached 2026 N/A
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	The following table presents the effects on a one-percentage point change in assumed health care cost trend rates. One percentage point increase One percentage point decrease Effect on total service and interest cost components $ 25 $ (20 ) Effect on the post retirement benefit obligation 2,300 (1,896 )
Components of the net periodic pension expense (benefit)	The components of net periodic pension expense were as follows: Pension benefits Other post retirement benefits For the Year Ended December 31, For the Year Ended December 31, 2017 2016 2015 2017 2016 2015 Service cost $ — $ — $ — $ 22 $ — $ 6 Interest cost 2,189 — 1,766 557 417 373 Expected return on plan assets (3,287 ) — (2,187 ) — — — Amortization of unrecognized actuarial loss — — 272 19 — — Amortization of transition obligation — — — 2 — — Amortization of prior service cost — — — 14 64 161 Plan termination / Partial settlement charge — — 13,384 — — — Net periodic pension (benefit) expense $ (1,098 ) $ — $ 13,235 $ 614 $ 481 $ 540
Schedule of expected benefit payments	Estimated future total benefits expected to be paid are the following for the years ending December 31 : Pension benefits Other post retirement benefits 2018 $ 12,568 $ 1,270 2019 12,560 1,400 2020 12,801 1,483 2021 14,162 1,566 2022 13,241 1,562 Thereafter 67,102 16,669
Schedule of Allocation of Plan Assets	The following tables set forth the carrying values of the Astoria Bank Pension Plan’s assets measured at estimated fair value on a recurring basis and the level within the fair value for the fair value measurements. Carrying value at December 31, 2017 Total Level 1 Level 2 Level 3 PRIAC Pooled Separate Accounts (1) $ 165,315 $ 165,315 $ — $ — Sterling Bancorp common stock 20,553 20,553 — — PRIAC Guaranteed Deposit Account 12,464 — — 12,464 Cash and cash equivalents 63 63 — — Total $ 198,395 $ 185,931 $ — $ 12,464 (1) Investment allocation consists of 42% large-cap equity 33% fixed income, 11% international equity, 8% small-cap equity and 6% mid-cap equity.
Schedule of Level 3 Plan Assets	The following table sets forth a summary of changes in the estimated fair value of the Astoria Bank Pension Plan’s Level 3 assets for the period indicated. For the period from October 2, 2017 to December 31, 2017 Fair value at October 2, 2017 $ 11,888 Total net loss, realized and unrealized, included in net assets (1) (47 ) Purchases 3,375 Sales (2,752 ) Fair value at December 31, 2017 $ 12,464 (1) Includes unrealized gain related to assets held at December 31, 2017 of $153 for the period October 2, 2017 to December 31, 2017 . The following table presents information about significant unobservable inputs related to the Astoria Bank Pension Plan’s investment in Level 3 assets at the date indicated. PRIAC guaranteed deposit account range at December 31, 2017 Significant unobservable inputs: Composite market value factor 1.012 - 1.020 Gross guaranteed crediting rate (1) 2.55 % - 3.59% (1) Gross guaranteed crediting rates must be greater than or equal to contractual minimum crediting rate.

Other Non-interest Expense (Tab

Other Non-interest Expense (Tables)	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Schedule of Other Non-interest Expense	Other non-interest expense items are presented in the following table. Significant components of the aggregate of total net interest income and total non-interest income are presented separately. For the year ended December 31, 2017 2016 2015 Other non-interest expense: Advertising and promotion $ 3,682 $ 2,948 $ 2,522 Professional fees 9,982 10,276 8,308 Data and check processing 19,387 8,866 8,825 Insurance & surety bond premium 3,317 3,150 3,186 Other 22,557 18,556 17,836 Total other non-interest expense $ 58,925 $ 43,796 $ 40,677

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following is a summary of the calculation of earnings per common share (“EPS”): For the year ended December 31, 2017 2016 2015 Net income available to common stockholders $ 91,029 $ 139,972 $ 66,114 Weighted average common shares outstanding for computation of basic EPS 157,513,639 130,607,994 109,907,645 Common-equivalent shares due to the dilutive effect of stock options (1) 610,631 626,468 421,708 Weighted average common shares for computation of diluted EPS 158,124,270 131,234,462 110,329,353 Earnings per common share: Basic $ 0.58 $ 1.07 $ 0.60 Diluted 0.58 1.07 0.60 Weighted average common shares that could be exercised that were anti-dilutive for the period (2) — — 2,394 (1) Represents incremental shares computed using the treasury stock method. (2) Anti-dilutive shares are not included in determining diluted earnings per share.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following table presents actual and required capital ratios as of December 31, 2017 and December 31, 2016 for the Company and the Bank under the Basel III Capital Rules. The minimum required capital amounts presented include the minimum required capital levels as of December 31, 2017 based on the phase-in provisions of the Basel III Capital Rules and the minimum required capital levels as of January 1, 2019 when the Basel III Capital Rules have been fully phased-in. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended, to reflect the changes under the Basel III Capital Rules. Actual Minimum capital required - Basel III phase-in schedule Minimum capital required - Basel III fully phased-in Required to be considered well capitalized Capital amount Ratio Capital amount Ratio Capital amount Ratio Capital amount Ratio December 31, 2017 Common equity tier 1 to RWA: Sterling National Bank $ 2,770,381 13.95 % $ 1,142,247 5.75 % $ 1,390,561 7.00 % $ 1,291,236 6.50 % Sterling Bancorp 2,458,449 12.37 1,143,045 5.75 1,391,534 7.00 N/A N/A Tier 1 capital to RWA: Sterling National Bank 2,770,381 13.95 1,440,224 7.25 1,688,539 8.50 1,589,213 8.00 Sterling Bancorp 2,597,669 13.07 1,441,231 7.25 1,689,719 8.50 N/A N/A Total capital to RWA: Sterling National Bank 3,021,658 15.21 1,837,527 9.25 2,085,842 10.50 1,986,516 10.00 Sterling Bancorp 2,818,404 14.18 1,838,812 9.25 2,087,300 10.50 N/A N/A Tier 1 leverage ratio: Sterling National Bank 2,770,381 10.10 1,097,449 4.00 1,097,449 4.00 1,371,811 5.00 Sterling Bancorp 2,597,669 9.39 1,106,977 4.00 1,106,977 4.00 N/A N/A Actual Minimum capital required - Basel III phase-in schedule Minimum capital required - Basel III fully phased-in Required to be considered well capitalized Capital amount Ratio Capital amount Ratio Capital amount Ratio Capital amount Ratio December 31, 2016 Common equity tier 1 to RWA: Sterling National Bank $ 1,176,497 10.87 % $ 554,663 5.125 % $ 757,588 7.00 % $ 703,475 6.50 % Sterling Bancorp 1,160,739 10.73 554,474 5.125 757,330 7.00 N/A N/A Tier 1 capital to RWA: Sterling National Bank 1,176,497 10.87 717,003 6.625 919,928 8.50 865,815 8.00 Sterling Bancorp 1,160,739 10.73 716,759 6.625 919,615 8.50 N/A N/A Total capital to RWA: Sterling National Bank 1,413,165 13.06 933,457 8.625 1,136,382 10.50 1,082,269 10.00 Sterling Bancorp 1,377,547 12.73 933,139 8.625 1,135,995 10.50 N/A N/A Tier 1 leverage ratio: Sterling National Bank 1,176,497 9.08 518,308 4.00 518,308 4.00 647,885 5.00 Sterling Bancorp 1,160,739 8.95 518,733 4.00 518,733 4.00 N/A N/A
Reconciliation of Stockholders' Equity to Bank Regulatory Capital	A reconciliation of the Company’s and the Bank’s stockholders’ equity to their respective regulatory capital at December 31, 2017 and 2016 is as follows: The Company The Bank December 31, December 31, 2017 2016 2017 2016 Total U.S. GAAP stockholders’ equity $ 4,240,178 $ 1,855,183 $ 4,373,108 $ 1,843,476 Disallowed goodwill and other intangible assets (1,668,680 ) (721,079 ) (1,628,898 ) (693,614 ) Net unrealized loss on available for sale securities 22,324 22,637 22,324 22,637 Net accumulated other comprehensive income components 3,847 3,998 3,847 3,998 Tier 1 risk-based capital 2,597,669 1,160,739 2,770,381 1,176,497 Tier 2 capital 142,174 152,641 172,716 172,501 Allowance for loan losses and off-balance sheet commitments 78,561 64,167 78,561 64,167 Total risk-based capital $ 2,818,404 $ 1,377,547 $ 3,021,658 $ 1,413,165

Off-Balance-Sheet Financial I48

Off-Balance-Sheet Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of off-balance-sheet financial instruments	The contractual or notional amounts of these instruments, which reflect the extent of the Company’s involvement in particular classes of off-balance sheet financial instruments, are summarized as follows: December 31, 2017 2016 Loan origination commitments $ 510,135 $ 245,319 Unused lines of credit 1,195,656 968,288 Letters of credit 166,824 114,582

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments due	Future minimum rental payments due under non-cancellable operating leases with initial or remaining terms of more than one year at December 31, 2017 were as follows: 2018 $ 20,691 2019 18,867 2020 17,666 2021 14,966 2022 11,096 2023 and thereafter 31,682 $ 114,968

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Estimated fair value on a recurring basis	A summary of assets and liabilities at December 31, 2017 measured at estimated fair value on a recurring basis is as follows: December 31, 2017 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets: Investment securities available for sale: Residential MBS: Agency-backed $ 2,150,649 $ — $ 2,150,649 $ — CMO/Other MBS 649,403 — 649,403 — Total residential MBS 2,800,052 — 2,800,052 — Federal agencies 399,996 — 399,996 — Corporate bonds 148,226 — 148,226 — State and municipal 263,798 — 263,798 — Total other securities 812,020 — 812,020 — Total investment securities available for sale 3,612,072 — 3,612,072 — Swaps 4,457 — 4,457 — Total assets $ 3,616,529 $ — $ 3,616,529 $ — Liabilities: Swaps $ 7,980 $ — $ 7,980 $ — Total liabilities $ 7,980 $ — $ 7,980 $ — A summary of assets and liabilities at December 31, 2016 measured at estimated fair value on a recurring basis is as follows: December 31, 2016 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets: Investment securities available for sale: Residential MBS: Agency-backed $ 1,193,481 $ — $ 1,193,481 $ — CMO/Other MBS 56,681 — 56,681 — Total residential MBS 1,250,162 — 1,250,162 — Federal agencies 193,979 — 193,979 — Corporate bonds 42,506 — 42,506 — State and municipal 240,770 — 240,770 — Total investment securities available for sale 477,255 — 477,255 — Total available for sale securities 1,727,417 — 1,727,417 — Interest rate caps and swaps 2,088 — 2,088 — Total assets $ 1,729,505 $ — $ 1,729,505 $ — Liabilities: Swaps $ 2,088 $ — $ 2,088 $ — Total liabilities $ 2,088 $ — $ 2,088 $ —
Impaired loans measured at estimated fair value on nonrecurring basis	A summary of impaired loans at December 31, 2017 measured at estimated fair value on a non-recurring basis is the following: December 31, 2017 Fair value Level 1 inputs Level 2 inputs Level 3 inputs Commercial & industrial $ 114 $ — $ — $ 114 CRE 782 — — 782 Total impaired loans measured at fair value $ 896 $ — $ — $ 896 A summary of impaired loans at December 31, 2016 measured at estimated fair value on a non-recurring basis is the following: December 31, 2016 Fair value Level 1 inputs Level 2 inputs Level 3 inputs CRE $ 6,786 $ — $ — $ 6,786 Total impaired loans measured at fair value $ 6,786 $ — $ — $ 6,786
Quantitative information of Level 3 assets	The following table presents quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets at December 31, 2017 : Non-recurring fair value measurements Fair value Valuation technique Unobservable input / assumptions Discount rate/prepayment speeds(1) (weighted average) Impaired loans: C&I $ 114 Appraisal Adjustments by management to reflect current conditions/selling costs 10.0% -19.0% (14.4%) CRE 782 Appraisal Adjustments for comparable properties 22.0% Assets taken in foreclosure: Residential mortgage 17,537 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% CRE 7,271 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% ADC 2,287 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% Mortgage servicing rights 10,363 Third-party Discount rates 9.5% - 20.0% (9.9%) Third-party Prepayment speeds 9.79 - 16.76 (10.30) (1) For loans collateralized by real estate and real estate assets taken in foreclosure the discount rate represents the discount factors applied to the appraisal to determine fair value, which includes a general discount to the appraised value, and estimated costs to carry and costs of sale. The amounts used for mortgage servicing rights are discounts applied by a third-party valuation provider, which the Company believes are appropriate. The following table presents quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets at December 31, 2016 : Non-recurring fair value measurements Fair value Valuation technique Unobservable input / assumptions Discount rate/prepayment speeds(1) (weighted average) Impaired loans: CRE $ 6,786 Appraisal Adjustments for comparable properties 22.0% Assets taken in foreclosure: Residential mortgage 4,929 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% CRE (2) 3,919 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% ADC 3,737 Appraisal Adjustments by management to reflect current conditions/selling costs 22.0% Mortgage servicing rights 1,024 Third-party Discount rates 8.5% - 11.5% (9.7%) Third-party Prepayment speeds 100 - 555 (174) (1) See (1) above. (2) Excludes $1,034 of commercial buildings that are former financial centers held for sale. These assets were not taken in foreclosure and their fair value is determined by appraisal, and our internal assessment of the market for this type of real estate in these locations.
Carrying amounts and estimated fair value of financial assets and liabilities	The following is a summary of the carrying amounts and estimated fair value of financial assets and liabilities (none of which were held for trading purposes) as of December 31, 2017 : December 31, 2017 Carrying amount Level 1 inputs Level 2 inputs Level 3 inputs Financial assets: Cash and due from banks $ 479,906 $ 479,906 $ — $ — Securities available for sale 3,612,072 — 3,612,072 — Securities held to maturity 2,862,489 — 2,863,909 — Loans, net 19,931,076 — — 19,903,231 Loans held for sale 5,246 — 5,246 — Accrued interest receivable on securities 34,652 — 34,652 — Accrued interest receivable on loans 59,446 — — 59,446 FHLB stock and FRB stock 284,112 — — — Swaps 4,457 — 4,457 — Financial liabilities: Non-maturity deposits (18,098,566 ) (18,098,566 ) — — Certificates of deposit (2,439,638 ) — (2,412,495 ) — FHLB borrowings (4,510,123 ) — (4,496,184 ) — Other borrowings (30,162 ) — (30,160 ) — Senior Notes (278,209 ) — (278,968 ) — Subordinated Notes (172,716 ) — (179,619 ) — Mortgage escrow funds (122,641 ) — (117,050 ) — Accrued interest payable on deposits (1,103 ) — (1,103 ) — Accrued interest payable on borrowings (9,649 ) — (9,649 ) — Swaps (7,980 ) — (7,980 ) — The following is a summary of the carrying amounts and estimated fair value of financial assets and liabilities (none of which were held for trading purposes) as of December 31, 2016 : December 31, 2016 Carrying amount Level 1 inputs Level 2 inputs Level 3 inputs Financial assets: Cash and due from banks $ 293,646 $ 293,646 $ — $ — Securities available for sale 1,727,417 — 1,727,417 — Securities held to maturity 1,391,421 — 1,357,997 — Loans, net 9,463,608 — — 9,461,469 Loans held for sale 41,889 — 41,889 — Accrued interest receivable on securities 16,495 — 16,495 — Accrued interest receivable on loans 26,824 — — 26,824 FHLB stock and FRB stock 135,098 — — — Swaps 2,088 — 2,088 — Financial liabilities: Non-maturity deposits (9,484,505 ) (9,484,505 ) — — Certificates of deposit (583,754 ) — (582,811 ) — FHLB borrowings (1,791,000 ) — (1,788,676 ) — Other borrowings (16,642 ) — (16,642 ) — Senior Notes (76,469 ) — (79,283 ) — Mortgage escrow funds (13,572 ) — (13,572 ) — Accrued interest payable on deposits (663 ) — (663 ) — Accrued interest payable on borrowings (3,621 ) — (3,621 ) — Swaps (2,088 ) — (2,088 ) —

Accumulated Other Comprehensi51

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Components of accumulated other comprehensive income (loss) (“AOCI”) were as follows as of the dates shown below: December 31, 2017 2016 Net unrealized holding loss on available for sale securities $ (36,899 ) $ (37,417 ) Related income tax benefit 14,575 14,780 Available for sale securities AOCI, net of tax (22,324 ) (22,637 ) Net unrealized holding loss on securities transferred to held to maturity (4,426 ) (5,395 ) Related income tax benefit 1,748 2,131 Securities transferred to held to maturity AOCI, net of tax (2,678 ) (3,264 ) Net unrealized holding loss on retirement plans (1,924 ) (1,213 ) Related income tax benefit 760 479 Retirement plan AOCI, net of tax (1,164 ) (734 ) Accumulated other comprehensive loss $ (26,166 ) $ (26,635 ) The following table presents the changes in each component of AOCI for 2017 and 2016 , and 2015 : Net unrealized holding gain (loss) on AFS securities Net unrealized holding gain (loss) on securities transferred to held to maturity Net unrealized holding gain (loss) on retirement plans Total Year ended December 31, 2017 Balance at beginning of the period $ (22,637 ) $ (3,264 ) $ (734 ) $ (26,635 ) Other comprehensive income before reclassification 64 — — 64 Amounts reclassified from AOCI 249 586 (430 ) 405 Total other comprehensive income (loss) 313 586 (430 ) 469 Balance at end of period $ (22,324 ) $ (2,678 ) $ (1,164 ) $ (26,166 ) Year ended December 31, 2016 Balance at beginning of the period $ (6,999 ) $ (4,155 ) $ (970 ) $ (12,124 ) Other comprehensive (loss) before reclassification (11,087 ) — — (11,087 ) Amounts reclassified from AOCI (4,551 ) 891 236 (3,424 ) Total other comprehensive (loss) income (15,638 ) 891 236 (14,511 ) Balance at end of period $ (22,637 ) $ (3,264 ) $ (734 ) $ (26,635 ) Year ended December 31, 2015 Balance at beginning of the period $ 1,297 $ (4,967 ) $ (6,581 ) $ (10,251 ) Other comprehensive (loss) gain before reclassification (5,515 ) — 435 (5,080 ) Amounts reclassified from AOCI (2,781 ) 812 5,176 3,207 Total other comprehensive (loss) income (8,296 ) 812 5,611 (1,873 ) Balance at end of period $ (6,999 ) $ (4,155 ) $ (970 ) $ (12,124 ) Location in statement of operations where reclassification from AOCI is included Net gain (loss) on sale of securities Interest income on securities Compensation and benefits expense

Condensed Parent Company Fina52

Condensed Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheets	Set forth below is the condensed balance sheets of the Company: December 31, 2017 2016 Assets: Cash $ 88,174 $ 48,765 Investment in the Bank 4,373,108 1,843,476 Goodwill 27,910 20,023 Trade name 20,500 20,500 Other assets 16,842 3,258 Total assets $ 4,526,534 $ 1,936,022 Liabilities: Senior Notes $ 278,209 $ 76,469 Other liabilities 8,147 4,370 Total liabilities 286,356 80,839 Stockholders’ equity 4,240,178 1,855,183 Total liabilities & stockholders’ equity $ 4,526,534 $ 1,936,022
Condensed Statement of Operations	The table below presents the condensed income statement: For the year ended December 31, 2017 2016 2015 Interest income $ 29 $ 14 $ 15 Dividends from the Bank 30,000 60,000 42,500 Dividends from non-bank subsidiaries — 5,026 500 Net gain on sale of trust division — 2,255 — Interest expense (6,186 ) (5,398 ) (5,894 ) Non-interest expense (9,225 ) (12,989 ) (7,031 ) Income tax benefit 7,258 3,700 4,154 Income before equity in undistributed earnings of subsidiaries 21,876 52,608 34,244 Equity in undistributed (excess distributed) earnings of: The Bank 71,155 87,364 32,230 Non-bank subsidiaries — — (360 ) Net income 93,031 139,972 66,114 Preferred stock dividends 2,002 — — Net income available to common shareholders $ 91,029 $ 139,972 $ 66,114
Condensed Statements of Cash Flows	The table below presents the condensed statements of cash flows: For the year ended December 31, 2017 2016 2015 Cash flows from operating activities: Net income $ 93,031 $ 139,972 $ 66,114 Adjustments to reconcile net income to net cash provided by operating activities: Equity in (undistributed) excess distributed earnings of: The Bank (71,155 ) (87,364 ) (32,230 ) Non-bank subsidiaries — — 360 Loss on extinguishment of borrowings — 1,013 — Other adjustments, net 61,184 6,273 (3,123 ) Net cash provided by operating activities 83,060 59,894 31,121 Cash flows from investing activities: Sales of securities — 3 — Investment in subsidiaries — (65,000 ) (84,500 ) Net cash used for investing activities — (64,997 ) (84,500 ) Cash flows from financing activities: Equity capital raise — 90,995 85,059 Redemption of Senior Notes — (23,793 ) — Cash dividends paid (46,229 ) (36,451 ) (30,384 ) Stock-based compensation transactions 2,578 3,588 4,472 Net cash (used for) provided by financing activities (43,651 ) 34,339 59,147 Net increase in cash 39,409 29,236 5,768 Cash at beginning of the period 48,765 19,529 13,761 Cash at end of the period $ 88,174 $ 48,765 $ 19,529

Quarterly Results of Operatio53

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following is a condensed summary of quarterly results of operations for 2017 and 2016 : For the year ended December 31, 2017 Reporting period First quarter Second quarter Third quarter Fourth quarter For the quarter ended March 31 June 30 September 30 December 31 Interest and dividend income $ 126,000 $ 134,263 $ 145,692 $ 276,495 Interest expense 17,210 21,005 25,619 42,471 Net interest income 108,790 113,258 120,073 234,024 Provision for loan losses 4,500 4,500 5,000 12,000 Non-interest income 12,836 13,618 13,988 23,762 Non-interest expense 60,350 59,657 62,617 250,746 Income (loss) before income tax 56,776 62,719 66,444 (4,960 ) Income tax expense 17,709 20,319 21,592 28,319 Net income (loss) 39,067 42,400 44,852 (33,279 ) Preferred stock dividend — — — 2,002 Net income (loss) available to common stockholders $ 39,067 $ 42,400 $ 44,852 $ (35,281 ) Earnings per common share: Basic $ 0.29 $ 0.31 $ 0.33 $ (0.16 ) Diluted 0.29 0.31 0.33 (0.16 ) For the year ended December 31, 2016 Reporting period First quarter Second quarter Third quarter Fourth quarter For the quarter ended March 31 June 30 September 30 December 31 Interest and dividend income $ 106,006 $ 114,309 $ 118,161 $ 123,075 Interest expense 12,495 13,929 15,031 15,827 Net interest income 93,511 100,380 103,130 107,248 Provision for loan losses 4,000 5,000 5,500 5,500 Non-interest income 15,449 20,442 19,039 16,057 Non-interest expense 68,934 59,640 62,256 57,072 Income before income tax 36,026 56,182 54,413 60,733 Income tax expense 12,242 18,412 16,991 19,737 Net income 23,784 37,770 37,422 40,996 Preferred stock dividend — — — — Net income available to common stockholders $ 23,784 $ 37,770 $ 37,422 $ 40,996 Earnings per common share: Basic $ 0.18 $ 0.29 $ 0.29 $ 0.31 Diluted 0.18 0.29 0.29 0.31

Basis of Financial Statement 54

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 02, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Required cash on hand or on deposit with the Federal Reserve Bank	$ 118,113				$ 99,594				$ 118,113	$ 99,594
Minimum duration of performance required by loan restructures									6 months
Business Acquisition [Line Items]
Bank owned life insurance	651,638				199,889				$ 651,638	199,889
Anticipated future contribution, next fiscal year	30,000								30,000
Income tax benefit	(28,319)	$ (21,592)	$ (20,319)	$ (17,709)	$ (19,737)	$ (16,991)	$ (18,412)	$ (12,242)	(87,939)	$ (67,382)	$ (31,835)
ASU 2016-09
Business Acquisition [Line Items]
Income tax benefit									1,616
Astoria Financial Corporation
Business Acquisition [Line Items]
Bank owned life insurance	441,751								441,751			$ 447,518
Claims stabilization reserve	$ 32,624								$ 32,624

Basis of Financial Statement 55

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies - Allowance for Loan Losses (Details)	12 Months Ended
	Dec. 31, 2017
Commercial business loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Duration period past due for charge off	90 days
Consumer loans, including home equity | Minimum
Financing Receivable, Allowance for Credit Losses [Line Items]
Duration period past due for charge off	90 days
Consumer loans, including home equity | Maximum
Financing Receivable, Allowance for Credit Losses [Line Items]
Duration period past due for charge off	120 days

Basis of Financial Statement 56

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies - Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Minimum
Property, Plant and Equipment [Line Items]
Premises and equipment, useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Premises and equipment, useful life	40 years

Basis of Financial Statement 57

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies - Other Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2017reporting_unit
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reporting units	1
Minimum | Core deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, weighted average useful life	8 years
Maximum | Core deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, weighted average useful life	10 years

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details)

Oct. 02, 2017USD ($)shares

Sep. 09, 2016USD ($)

Mar. 31, 2016USD ($)

Jun. 30, 2015USD ($)$ / sharesshares

May 07, 2015USD ($)

Feb. 27, 2015USD ($)

Dec. 31, 2017USD ($)

Mar. 31, 2016USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Sep. 29, 2017$ / shares

Business Acquisition [Line Items]

Acquired goodwill

$ 883,291,000

$ 25,901,000

Portfolio loans purchased

226,831,000

163,320,000

$ 0

Discount amount on acquired loan receivable

$ 4,813,000

4,813,000

1,788,000

Goodwill

1,579,891,000

1,579,891,000

696,600,000

670,699,000

Restructuring charges

30,230,000

Consideration paid

2,189,687,000

351,452,000

592,169,000

Loans

19,931,076,000

19,931,076,000

9,463,608,000

Deposits

20,538,204,000

20,538,204,000

10,068,259,000

Merger-related expense

39,232,000

265,000

17,079,000

Charge of asset write-downs, systems integration, severance and retention

$ 104,506,000

105,110,000

4,485,000

40,350,000

Charge of asset write-downs, systems integration, severance and retention

$ 105,110,000

$ 4,485,000

$ 29,046,000

FCC, LLC

Business Acquisition [Line Items]

Outstanding factoring receivables balance acquired

$ 44,500,000

Factoring receivables, purchase price

45,500,000

Premium for factoring receivables acquired

$ 1,000,000

Minimum

Business Acquisition [Line Items]

Estimated useful life

1 year

Useful life

3 years

Maximum

Business Acquisition [Line Items]

Estimated useful life

10 years

Useful life

40 years

Traditional C&I | GE Capital

Business Acquisition [Line Items]

Portfolio loan acquired, unpaid principal balance

$ 169,760,000

Portfolio loans purchased

$ 163,282,000

Discount rate on acquired portfolio loan

4.00%

Discount amount on acquired loan receivable

$ 6,790,000

Astoria Financial Corporation

Business Acquisition [Line Items]

Number of shares received by acquiree for each share of acquiree's stock

0.875

Acquired goodwill

$ 883,291,000

Liabilities assumed

12,342,371,000

Goodwill

$ 185,151,000

Common stock issued as consideration, shares | shares

88,829,776

Consideration paid

$ 2,189,687,000

Loans

9,546,307,000

Deposits

9,029,303,000

Closing share price (in dollars per share) | $ / shares

$ 24.65

Net assets acquired, book value

13,788,179,000

Astoria Financial Corporation | Core deposits

Business Acquisition [Line Items]

Acquired intangible assets

$ 99,938,000

NSBC

Business Acquisition [Line Items]

Percentage of outstanding common stock acquired

100.00%

Loans receivable acquired

$ 320,447,000

Premium paid for loans receivable acquired as a percent of gross loans acquired

5.90%

Premium paid for loans receivable acquired

$ 18,906,000

Liabilities assumed

4,839,000

Goodwill

25,698,000

Restructuring charges

$ 1,500,000

NSBC | Customer lists

Business Acquisition [Line Items]

Estimated useful life

24 months

Restructuring charges

$ 1,500

HVB Merger

Business Acquisition [Line Items]

Number of shares received by acquiree for each share of acquiree's stock

1.92

Acquired goodwill

$ 269,757,000

Common stock issued as consideration, shares | shares

38,525,154

Consideration paid

$ 566,307,000

Loans

1,816,767,000

Deposits

$ 3,160,746,000

Merger-related expense

$ 0

14,381,000

Charge of asset write-downs, systems integration, severance and retention

$ 28,055,000

Closing share price (in dollars per share) | $ / shares

$ 14.63

HVB Merger | Buildings

Business Acquisition [Line Items]

Useful life

30 years

HVB Merger | Building Improvements and Equipment | Minimum

Business Acquisition [Line Items]

Useful life

1 year

HVB Merger | Building Improvements and Equipment | Maximum

Business Acquisition [Line Items]

Useful life

5 years

HVB Merger | Core deposits

Business Acquisition [Line Items]

Estimated useful life

10 years

Damian

Business Acquisition [Line Items]

Percentage of outstanding common stock acquired

100.00%

Liabilities assumed

$ 14,560,000

Goodwill

11,930,000

Restructuring charges

$ 1,500,000

Merger-related expense

300,000

Cash consideration

24,670,000

Outstanding finance loans acquired

22,307,000

Damian | Customer lists

Business Acquisition [Line Items]

Intangible asset acquired

$ 8,950,000

Estimated useful life

16 years

Acquisitions - Consideration (D

Acquisitions - Consideration (Details) - USD ($) $ in Thousands	Oct. 02, 2017	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Cash and cash equivalents			$ 479,906	$ 293,646	$ 229,513	$ 121,520
Investment securities			6,474,561	3,118,838
Loans			19,931,076	9,463,608
Allowance for loan losses			(77,907)	(63,622)	(50,145)	$ (42,374)
Bank owned life insurance			651,638	199,889
Premises and equipment			321,722	57,318
Accrued interest receivable			94,098	43,319
Goodwill			1,579,891	696,600	670,699
Intangible assets			153,191	66,353
Other real estate owned			27,095	13,619
Other assets			357,005	48,270
Total assets			30,359,541	14,178,447
Deposits			(20,538,204)	(10,068,259)
Other borrowings (repurchase agreements)			(30,162)	(16,642)
Senior notes			(278,209)	(76,469)
Other liabilities			(467,308)	(184,821)
Liabilities			(26,119,363)	(12,323,264)
Preferred stock			(139,220)	0
Total liabilities and stockholders’ equity			(30,359,541)	(14,178,447)
As recorded by the Company
Consideration paid through common stock			2,189,687	351,452	$ 592,169
Goodwill recorded in the Merger			883,291	$ 25,901
Astoria Financial Corporation
Business Acquisition [Line Items]
Cash and cash equivalents	$ 275,409
Investment securities	3,144,111
Loans held for sale	497
Loans	9,546,307
Allowance for loan losses	(79,293)
Bank owned life insurance	447,518		$ 441,751
Premises and equipment	90,678
Accrued interest receivable	34,094
Goodwill	185,151
Intangible assets	0
Other real estate owned	17,705
Other assets	288,075
Total assets	13,950,252
Deposits	(9,029,303)
FHLB borrowings	(1,550,000)
Other borrowings (repurchase agreements)	(1,100,000)
Senior notes	(198,044)
Other liabilities	(354,725)
Liabilities	(12,232,072)
Preferred stock	(129,796)
Total liabilities and stockholders’ equity	(12,361,868)
As recorded by the Company
Cash and cash equivalents	275,409
Investment securities	3,101,793
Loans held for sale	497
Loans	9,209,398
Bank owned life insurance	447,518
Premises and equipment	267,815
Accrued interest receivable	34,094
Core deposit and other intangibles	99,938
Other real estate owned	16,105
Other assets	335,612
Total assets acquired	13,788,179
Deposits	(9,044,061)
FHLB borrowings	(1,589,464)
Repurchase agreements	(1,143,279)
Senior notes	(201,520)
Other liabilities	(364,047)
Total liabilities assumed	12,342,371
Preferred stock assumed	(139,412)
Total liabilities and preferred stock assumed	12,481,783
Net assets acquired	1,306,396
Consideration paid through common stock	2,189,687
Goodwill recorded in the Merger	883,291
Astoria Financial Corporation | Fair value adjustments
Business Acquisition [Line Items]
Cash and cash equivalents	0
Investment securities	(42,318)
Loans held for sale	0
Loans	(336,909)
Allowance for loan losses	79,293
Bank owned life insurance	0
Premises and equipment	177,137
Accrued interest receivable	0
Goodwill	(185,151)
Intangible assets	99,938
Other real estate owned	(1,600)
Other assets	47,537
Total assets	(162,073)
Deposits	(14,758)
FHLB borrowings	(39,464)
Other borrowings (repurchase agreements)	(43,279)
Senior notes	(3,476)
Other liabilities	(9,322)
Liabilities	(110,299)
Preferred stock	(9,616)
Total liabilities and stockholders’ equity	$ (119,915)
HVB Merger
Business Acquisition [Line Items]
Cash and cash equivalents		$ 878,988
Investment securities		713,625
Loans		1,816,767
Federal Reserve Bank stock		5,830
Bank owned life insurance		44,231
Premises and equipment		11,918
Accrued interest receivable		7,392
Intangible assets		0
Other real estate owned		222
Other assets		32,639
Total assets		288,208
Deposits		(3,160,746)
Other borrowings		(25,366)
Other liabilities		(37,292)
As recorded by the Company
Cash and cash equivalents		878,988
Investment securities		713,842
Loans		1,792,519
Federal Reserve Bank stock		5,830
Bank owned life insurance		44,231
Premises and equipment		16,843
Accrued interest receivable		7,392
Core deposit and other intangibles		33,839
Other real estate owned		222
Other assets		24,708
Deposits		(3,160,746)
Other borrowings		(25,366)
Other liabilities		(35,752)
Total identifiable net assets acquired		296,550
Consideration paid through common stock		566,307
Goodwill recorded in the Merger		269,757
HVB Merger | Fair value adjustments
Business Acquisition [Line Items]
Cash and cash equivalents		0
Investment securities		217
Loans		(24,248)
Federal Reserve Bank stock		0
Bank owned life insurance		0
Premises and equipment		4,925
Accrued interest receivable		0
Intangible assets		33,839
Other real estate owned		0
Other assets		(7,931)
Total assets		8,342
Deposits		0
Other borrowings		0
Other liabilities		$ 1,540

Acquisitions - Acquired Loan Po

Acquisitions - Acquired Loan Portfolio Data (Details) - USD ($) $ in Thousands	Oct. 02, 2017	Dec. 31, 2015
Astoria Financial Corporation
Business Acquisition [Line Items]
Fair value of acquired loans at acquisition date	$ 9,041,784
Gross contractual amounts receivable at acquisition date	11,509,782
Astoria Financial Corporation | PCI Loans
Business Acquisition [Line Items]
Fair value of acquired loans at acquisition date	167,614
Gross contractual amounts receivable at acquisition date	221,550
Best estimate at acquisition date of contractual cash flows not expected to be collected	$ 44,545
HVB Merger
Business Acquisition [Line Items]
Fair value of acquired loans at acquisition date		$ 1,695,546
Gross contractual amounts receivable at acquisition date		1,974,740
HVB Merger | PCI Loans
Business Acquisition [Line Items]
Fair value of acquired loans at acquisition date		96,973
Gross contractual amounts receivable at acquisition date		122,104
Best estimate at acquisition date of contractual cash flows not expected to be collected		$ 12,604

Acquisitions Acquisitions - Pro

Acquisitions Acquisitions - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Astoria Financial Corporation
Business Acquisition [Line Items]
Net interest income	$ 939,036	$ 818,906
Non-interest income	98,726	121,949
Non-interest expense	516,333	544,821
Net income	$ 316,657	$ 242,398
Pro forma earnings per share from continuing operations:
Basic (in dollars per share)	$ 1.41	$ 1.11
Diluted (in dollars per share)	$ 1.41	$ 1.11
HVB Merger
Business Acquisition [Line Items]
Net interest income		$ 360,271
Non-interest income		66,686
Non-interest expense		261,453
Net income		$ 100,086
Pro forma earnings per share from continuing operations:
Basic (in dollars per share)		$ 0.78
Diluted (in dollars per share)		$ 0.78

Securities - Amortized Cost to

Securities - Amortized Cost to Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available for Sale
Amortized cost	$ 3,648,971	$ 1,764,834
Gross unrealized gains	4,402	1,504
Gross unrealized losses	(41,301)	(38,921)
Available for sale, at fair value	3,612,072	1,727,417
Held to Maturity
Amortized cost	2,862,489	1,391,421
Gross unrealized gains	15,687	7,016
Gross unrealized losses	(14,267)	(40,440)
Fair value	2,863,909	1,357,997
Residential MBS
Available for Sale
Amortized cost	2,827,558	1,271,296
Gross unrealized gains	1,601	613
Gross unrealized losses	(29,107)	(21,747)
Available for sale, at fair value	2,800,052	1,250,162
Held to Maturity
Amortized cost	388,509	318,133
Gross unrealized gains	1,004	1,427
Gross unrealized losses	(3,264)	(4,197)
Fair value	386,249	315,363
Other securities
Available for Sale
Amortized cost	821,413	493,538
Gross unrealized gains	2,801	891
Gross unrealized losses	(12,194)	(17,174)
Available for sale, at fair value	812,020	477,255
Held to Maturity
Amortized cost	2,473,980	1,073,288
Gross unrealized gains	14,683	5,589
Gross unrealized losses	(11,003)	(36,243)
Fair value	2,477,660	1,042,634
Agency-backed | Residential MBS
Available for Sale
Amortized cost	2,171,044	1,213,733
Gross unrealized gains	1,570	569
Gross unrealized losses	(21,965)	(20,821)
Available for sale, at fair value	2,150,649	1,193,481
Held to Maturity
Amortized cost	355,013	277,539
Gross unrealized gains	978	1,353
Gross unrealized losses	(2,504)	(3,625)
Fair value	353,487	275,267
CMO/Other MBS | Residential MBS
Available for Sale
Amortized cost	656,514	57,563
Gross unrealized gains	31	44
Gross unrealized losses	(7,142)	(926)
Available for sale, at fair value	649,403	56,681
Held to Maturity
Amortized cost	33,496	40,594
Gross unrealized gains	26	74
Gross unrealized losses	(760)	(572)
Fair value	32,762	40,096
Federal agencies | Other securities
Available for Sale
Amortized cost	409,322	204,770
Gross unrealized gains	0	2
Gross unrealized losses	(9,326)	(10,793)
Available for sale, at fair value	399,996	193,979
Held to Maturity
Amortized cost	58,640	58,200
Gross unrealized gains	949	1,392
Gross unrealized losses	0	0
Fair value	59,589	59,592
Corporate | Other securities
Available for Sale
Amortized cost	147,781	43,464
Gross unrealized gains	1,421	150
Gross unrealized losses	(976)	(1,108)
Available for sale, at fair value	148,226	42,506
Held to Maturity
Amortized cost	56,663	35,048
Gross unrealized gains	1,255	431
Gross unrealized losses	(103)	(11)
Fair value	57,815	35,468
State and municipal | Other securities
Available for Sale
Amortized cost	264,310	245,304
Gross unrealized gains	1,380	739
Gross unrealized losses	(1,892)	(5,273)
Available for sale, at fair value	263,798	240,770
Held to Maturity
Amortized cost	2,342,927	974,290
Gross unrealized gains	12,396	3,571
Gross unrealized losses	(10,900)	(36,232)
Fair value	2,344,423	941,629
Other | Other securities
Available for Sale
Amortized cost	0	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Available for sale, at fair value	0	0
Held to Maturity
Amortized cost	15,750	5,750
Gross unrealized gains	83	195
Gross unrealized losses	0	0
Fair value	$ 15,833	$ 5,945

Securities - Future Maturity (D

Securities - Future Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available for Sale
Amortized cost, One year or less	$ 11,994
Amortized cost, One to five years	146,471
Amortized cost, Five to ten years	526,968
Amortized cost, Greater than ten years	135,980
Amortized cost, Total securities with a stated maturity date	821,413
Amortized cost, Available for sale securities	3,648,971	$ 1,764,834
Fair value, One year or less	12,003
Fair value, One to five years	145,499
Fair value, Five to ten years	520,904
Fair value, Greater than ten years	133,614
Fair value, Total securities with a stated maturity date	812,020
Fair value, Available for sale securities	3,612,072	1,727,417
Held to Maturity
Amortized cost, One year or less	89,155
Amortized cost, One to five years	83,615
Amortized cost, Five to ten years	387,647
Amortized cost, Greater than ten years	1,913,563
Amortized cost, Total securities with a stated maturity date	2,473,980
Amortized cost, Held to maturity securities	2,862,489	1,391,421
Fair value, One year or less	88,949
Fair value, One to five years	84,742
Fair value, Five to ten years	390,749
Fair value, Greater than ten years	1,913,220
Fair value, Total securities with a stated maturity date	2,477,660
Fair value	2,863,909	1,357,997
Residential MBS
Available for Sale
Amortized cost, Available for sale securities	2,827,558	1,271,296
Fair value, Available for sale securities	2,800,052	1,250,162
Held to Maturity
Amortized cost, Held to maturity securities	388,509	318,133
Fair value	$ 386,249	$ 315,363

Securities - Sale of Securities

Securities - Sale of Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 2,516,308	$ 858,531	$ 893,610
Gross realized gains	8	10,665	6,018
Gross realized losses	(352)	(3,143)	(1,181)
Income tax (benefit) expense on realized net (losses) gains	$ (91)	$ 2,445	$ 1,572

Securities - Available-for-sale

Securities - Available-for-sale Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	$ 2,360,256	$ 1,509,447
Unrealized losses, Less than 12 months	(19,723)	(37,448)
Fair value, 12 months or longer	751,167	34,604
Unrealized losses, 12 months or longer	(21,578)	(1,473)
Fair value, Total	3,111,423	1,544,051
Unrealized losses, Total	(41,301)	(38,921)
Residential MBS
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	1,954,417
Unrealized losses, Less than 12 months	(16,614)
Fair value, 12 months or longer	523,055
Unrealized losses, 12 months or longer	(12,493)
Fair value, Total	2,477,472	1,156,407
Unrealized losses, Total	(29,107)	(21,747)
Other securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	405,839	368,965
Unrealized losses, Less than 12 months	(3,109)	(16,126)
Fair value, 12 months or longer	228,112	18,679
Unrealized losses, 12 months or longer	(9,085)	(1,048)
Fair value, Total	633,951	387,644
Unrealized losses, Total	(12,194)	(17,174)
Agency-backed | Residential MBS
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	1,349,217	1,101,641
Unrealized losses, Less than 12 months	(10,550)	(20,816)
Fair value, 12 months or longer	486,948	686
Unrealized losses, 12 months or longer	(11,415)	(5)
Fair value, Total	1,836,165	1,102,327
Unrealized losses, Total	(21,965)	(20,821)
CMO/Other MBS | Residential MBS
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	605,200	38,841
Unrealized losses, Less than 12 months	(6,064)	(506)
Fair value, 12 months or longer	36,107	15,239
Unrealized losses, 12 months or longer	(1,078)	(420)
Fair value, Total	641,307	54,080
Unrealized losses, Total	(7,142)	(926)
Federal agencies | Other securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	243,476	185,504
Unrealized losses, Less than 12 months	(1,955)	(10,793)
Fair value, 12 months or longer	156,520	4
Unrealized losses, 12 months or longer	(7,371)	0
Fair value, Total	399,996	185,508
Unrealized losses, Total	(9,326)	(10,793)
Corporate | Other securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	65,056	10,399
Unrealized losses, Less than 12 months	(397)	(137)
Fair value, 12 months or longer	15,268	14,942
Unrealized losses, 12 months or longer	(579)	(971)
Fair value, Total	80,324	25,341
Unrealized losses, Total	(976)	(1,108)
State and municipal | Other securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, Less than 12 months	97,307	173,062
Unrealized losses, Less than 12 months	(757)	(5,196)
Fair value, 12 months or longer	56,324	3,733
Unrealized losses, 12 months or longer	(1,135)	(77)
Fair value, Total	153,631	176,795
Unrealized losses, Total	$ (1,892)	$ (5,273)

Securities - Held to Maturity S

Securities - Held to Maturity Securities with Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	$ 1,024,089	$ 978,592
Unrealized losses, Less than 12 months	(6,114)	(40,364)
Fair value, 12 months or longer	487,663	8,066
Unrealized losses, 12 months or longer	(8,153)	(76)
Fair value, Total	1,511,752	986,658
Unrealized losses, Total	(14,267)	(40,440)
Residential MBS
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	146,993	219,902
Unrealized losses, Less than 12 months	(701)	(4,195)
Fair value, 12 months or longer	94,463	213
Unrealized losses, 12 months or longer	(2,563)	(2)
Fair value, Total	241,456	220,115
Unrealized losses, Total	(3,264)	(4,197)
Residential MBS | Agency-backed
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	136,679	185,116
Unrealized losses, Less than 12 months	(572)	(3,623)
Fair value, 12 months or longer	74,303	213
Unrealized losses, 12 months or longer	(1,932)	(2)
Fair value, Total	210,982	185,329
Unrealized losses, Total	(2,504)	(3,625)
Residential MBS | CMO/Other MBS
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	10,314	34,786
Unrealized losses, Less than 12 months	(129)	(572)
Fair value, 12 months or longer	20,160	0
Unrealized losses, 12 months or longer	(631)	0
Fair value, Total	30,474	34,786
Unrealized losses, Total	(760)	(572)
Other securities
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	877,096	758,690
Unrealized losses, Less than 12 months	(5,413)	(36,169)
Fair value, 12 months or longer	393,200	7,853
Unrealized losses, 12 months or longer	(5,590)	(74)
Fair value, Total	1,270,296	766,543
Unrealized losses, Total	(11,003)	(36,243)
Other securities | Corporate
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	16,560	0
Unrealized losses, Less than 12 months	(103)	0
Fair value, 12 months or longer	0	5,037
Unrealized losses, 12 months or longer	0	(11)
Fair value, Total	16,560	5,037
Unrealized losses, Total	(103)	(11)
Other securities | State and municipal
Schedule of Held-to-maturity Securities [Line Items]
Fair value, Less than 12 months	860,536	758,690
Unrealized losses, Less than 12 months	(5,310)	(36,169)
Fair value, 12 months or longer	393,200	2,816
Unrealized losses, 12 months or longer	(5,590)	(63)
Fair value, Total	1,253,736	761,506
Unrealized losses, Total	$ (10,900)	$ (36,232)

Securities - Securities Pledged

Securities - Securities Pledged for Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total securities pledged	$ 1,551,287	$ 1,480,275
Federal Home Loan Bank Borrowings
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	10,225	67,599
Held-to-maturity securities pledged as collateral	35,047	55,343
Municipal Deposits
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	323,341	398,961
Held-to-maturity securities pledged as collateral	1,182,674	958,246
Interest Rate Swap
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	$ 0	$ 126

Securities - Narrative (Details

Securities - Narrative (Details)	12 Months Ended
	Dec. 31, 2017security
Investments, Debt and Equity Securities [Abstract]
Number of securities which were in continuous unrealized loss position for less than 12 months	321
Number of securities which were in continuous unrealized loss position for 12 months or more	155

Portfolio Loans - Composition o

Portfolio Loans - Composition of Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	$ 20,008,983	$ 9,527,230
Allowance for loan losses	(77,907)	(63,622)	$ (50,145)	$ (42,374)
Portfolio loans, net	19,931,076	9,463,608
Traditional C&I
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	1,979,448	1,404,774
Allowance for loan losses	(19,072)	(12,864)	(9,953)	(6,966)
Asset-based lending
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	797,570	741,942
Allowance for loan losses	(6,625)	(3,316)	(2,762)	(4,061)
Payroll finance
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	268,609	255,549
Allowance for loan losses	(1,565)	(951)	(1,936)	(1,506)
Warehouse lending
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	723,335	616,946
Allowance for loan losses	(3,705)	(1,563)	(589)	(608)
Public sector finance
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	637,767	349,182
Allowance for loan losses	(1,797)	(1,062)	(547)	0
ADC
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	282,792	230,086
Allowance for loan losses	(1,680)	(1,931)	$ (2,009)	$ (2,987)
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	14,588,032	8,546,054
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	5,054,732	697,108
Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	366,219	284,068
Commercial & Industrial (C&I) | Commercial
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	5,306,821	4,171,950
Commercial & Industrial (C&I) | Commercial | Traditional C&I
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	1,979,448	1,404,774
Commercial & Industrial (C&I) | Commercial | Asset-based lending
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	797,570	741,942
Commercial & Industrial (C&I) | Commercial | Payroll finance
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	268,609	255,549
Commercial & Industrial (C&I) | Commercial | Warehouse lending
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	723,335	616,946
Commercial & Industrial (C&I) | Commercial | Factored receivables
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	220,551	214,242
Commercial & Industrial (C&I) | Commercial | Equipment financing
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	679,541	589,315
Commercial & Industrial (C&I) | Commercial | Public sector finance
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	637,767	349,182
Commercial mortgage | Commercial
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	9,281,211	4,374,104
Commercial mortgage | Commercial | CRE
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	4,138,864	3,162,942
Commercial mortgage | Commercial | ADC
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	282,792	230,086
Commercial mortgage | Commercial | Multi-family | Real estate loan
Loans and Leases Receivable Disclosure [Line Items]
Total portfolio loans	$ 4,859,555	$ 981,076

Portfolio Loans - Status of Loa

Portfolio Loans - Status of Loans and TDRs (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Non-Performing loans:
Current loans	$ 19,768,237	$ 9,433,277
Non accrual loans	186,357	77,163
Total portfolio loans	20,008,983	9,527,230
TDRs, Current	13,175	11,032
Troubled debt restructurings	42,889	13,274
TDRs, Non-accrual	29,325	1,989
Nonperforming loans
Non-Performing loans:
Non accrual loans	186,357	77,163
Non-performing loans:
Loans 90 days past due and still accruing	856	1,690
Total non-performing loans	187,213	78,853
Traditional C&I
Non-Performing loans:
Current loans	1,940,387	1,376,181
Non accrual loans	37,642	26,386
Total portfolio loans	1,979,448	1,404,774
TDRs, Current	565	572
Troubled debt restructurings	21,648	700
TDRs, Non-accrual	21,083	128
Asset-based lending
Non-Performing loans:
Current loans	797,570	741,942
Non accrual loans	0	0
Total portfolio loans	797,570	741,942
Payroll finance
Non-Performing loans:
Current loans	268,609	254,715
Non accrual loans	0	199
Total portfolio loans	268,609	255,549
Warehouse lending
Non-Performing loans:
Current loans	723,335	616,946
Non accrual loans	0	0
Total portfolio loans	723,335	616,946
Factored receivables
Non-Performing loans:
Current loans	220,551	213,624
Non accrual loans	0	618
Total portfolio loans	220,551	214,242
Equipment financing
Non-Performing loans:
Current loans	667,083	583,835
Non accrual loans	8,099	2,246
Total portfolio loans	679,541	589,315
TDRs, Current	898	0
Troubled debt restructurings	1,724	29
TDRs, Non-accrual	826	29
Public sector finance
Non-Performing loans:
Current loans	637,767	349,182
Non accrual loans	0	0
Total portfolio loans	637,767	349,182
CRE
Non-Performing loans:
Current loans	4,104,173	3,140,561
Non accrual loans	21,720	21,008
Total portfolio loans	4,138,864	3,162,942
TDRs, Current	2,921	2,443
Troubled debt restructurings	3,036	2,696
TDRs, Non-accrual	115	0
Multi-family
Non-Performing loans:
Current loans	4,853,677	981,005
Non accrual loans	4,449	71
Total portfolio loans	4,859,555	981,076
ADC
Non-Performing loans:
Current loans	278,587	224,817
Non accrual loans	4,205	5,269
Total portfolio loans	282,792	230,086
TDRs, Current	1,495	5,962
Troubled debt restructurings	5,700	6,420
TDRs, Non-accrual	4,205	458
Residential mortgage
Non-Performing loans:
Current loans	4,925,996	675,750
Non accrual loans	99,958	14,790
Total portfolio loans	5,054,732	697,108
TDRs, Current	5,154	2,055
Troubled debt restructurings	8,300	3,429
TDRs, Non-accrual	2,810	1,374
Consumer
Non-Performing loans:
Current loans	350,502	274,719
Non accrual loans	10,284	6,576
Total portfolio loans	366,219	284,068
TDRs, Current	2,142
Troubled debt restructurings	2,481
TDRs, Non-accrual	286
30-59 days past due
Non-Performing loans:
Past due loans	38,153	11,876
Troubled debt restructurings	389	253
30-59 days past due | Traditional C&I
Non-Performing loans:
Past due loans	1,232	835
Troubled debt restructurings	0	0
30-59 days past due | Asset-based lending
Non-Performing loans:
Past due loans	0	0
30-59 days past due | Payroll finance
Non-Performing loans:
Past due loans	0	0
30-59 days past due | Warehouse lending
Non-Performing loans:
Past due loans	0	0
30-59 days past due | Factored receivables
Non-Performing loans:
Past due loans	0	0
30-59 days past due | Equipment financing
Non-Performing loans:
Past due loans	1,143	2,142
Troubled debt restructurings	0	0
30-59 days past due | Public sector finance
Non-Performing loans:
Past due loans	0	0
30-59 days past due | CRE
Non-Performing loans:
Past due loans	8,403	967
Troubled debt restructurings	0	253
30-59 days past due | Multi-family
Non-Performing loans:
Past due loans	595	0
30-59 days past due | ADC
Non-Performing loans:
Past due loans	0	0
Troubled debt restructurings	0	0
30-59 days past due | Residential mortgage
Non-Performing loans:
Past due loans	22,416	5,509
Troubled debt restructurings	336	0
30-59 days past due | Consumer
Non-Performing loans:
Past due loans	4,364	2,423
Troubled debt restructurings	53
60-89 days past due
Non-Performing loans:
Past due loans	15,380	3,224
Troubled debt restructurings	0	0
60-89 days past due | Traditional C&I
Non-Performing loans:
Past due loans	187	817
Troubled debt restructurings	0	0
60-89 days past due | Asset-based lending
Non-Performing loans:
Past due loans	0	0
60-89 days past due | Payroll finance
Non-Performing loans:
Past due loans	0	14
60-89 days past due | Warehouse lending
Non-Performing loans:
Past due loans	0	0
60-89 days past due | Factored receivables
Non-Performing loans:
Past due loans	0	0
60-89 days past due | Equipment financing
Non-Performing loans:
Past due loans	3,216	1,092
Troubled debt restructurings	0	0
60-89 days past due | Public sector finance
Non-Performing loans:
Past due loans	0	0
60-89 days past due | CRE
Non-Performing loans:
Past due loans	4,131	0
Troubled debt restructurings	0	0
60-89 days past due | Multi-family
Non-Performing loans:
Past due loans	834	0
60-89 days past due | ADC
Non-Performing loans:
Past due loans	0	0
Troubled debt restructurings	0	0
60-89 days past due | Residential mortgage
Non-Performing loans:
Past due loans	6,038	951
Troubled debt restructurings	0	0
60-89 days past due | Consumer
Non-Performing loans:
Past due loans	974	350
Troubled debt restructurings	0
90 days past due
Non-Performing loans:
Past due loans	856	1,690
Troubled debt restructurings	0	0
90 days past due | Traditional C&I
Non-Performing loans:
Past due loans	0	555
Troubled debt restructurings	0	0
90 days past due | Asset-based lending
Non-Performing loans:
Past due loans	0	0
90 days past due | Payroll finance
Non-Performing loans:
Past due loans	0	621
90 days past due | Warehouse lending
Non-Performing loans:
Past due loans	0	0
90 days past due | Factored receivables
Non-Performing loans:
Past due loans	0	0
90 days past due | Equipment financing
Non-Performing loans:
Past due loans	0	0
Troubled debt restructurings	0	0
90 days past due | Public sector finance
Non-Performing loans:
Past due loans	0	0
90 days past due | CRE
Non-Performing loans:
Past due loans	437	406
Troubled debt restructurings	0	0
90 days past due | Multi-family
Non-Performing loans:
Past due loans	0	0
90 days past due | ADC
Non-Performing loans:
Past due loans	0	0
Troubled debt restructurings	0	0
90 days past due | Residential mortgage
Non-Performing loans:
Past due loans	324	108
Troubled debt restructurings	0	0
90 days past due | Consumer
Non-Performing loans:
Past due loans	95	$ 0
Troubled debt restructurings	$ 0

Portfolio Loans - Nonaccrual Lo

Portfolio Loans - Nonaccrual Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	$ 186,357	$ 77,163
Non-accrual loans, unpaid principal balance	205,699	86,592
Traditional C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	37,642	26,386
Non-accrual loans, unpaid principal balance	37,853	26,386
Payroll finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	199
Non-accrual loans, unpaid principal balance	0	199
Factored receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	618
Non-accrual loans, unpaid principal balance	0	618
Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	8,099	2,246
Non-accrual loans, unpaid principal balance	8,099	2,246
CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	21,720	21,008
Non-accrual loans, unpaid principal balance	25,739	25,619
Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	4,449	71
Non-accrual loans, unpaid principal balance	4,705	71
ADC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	4,205	5,269
Non-accrual loans, unpaid principal balance	4,205	5,398
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	99,958	14,790
Non-accrual loans, unpaid principal balance	113,002	18,190
Loans formally in process of foreclosure	76,712	9,263
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	10,284	6,576
Non-accrual loans, unpaid principal balance	12,096	7,865
Receivables without deteriorated credit quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	178,365	64,922
Receivables without deteriorated credit quality | Traditional C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	33,631	22,338
Receivables without deteriorated credit quality | Payroll finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	199
Receivables without deteriorated credit quality | Factored receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	618
Receivables without deteriorated credit quality | Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	8,099	2,246
Receivables without deteriorated credit quality | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	18,762	15,063
Receivables without deteriorated credit quality | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	4,449	71
Receivables without deteriorated credit quality | ADC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	4,205	5,269
Receivables without deteriorated credit quality | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	99,644	13,399
Receivables without deteriorated credit quality | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	9,575	5,719
Receivables acquired with deteriorated credit quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	7,992	12,241
Receivables acquired with deteriorated credit quality | Traditional C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	4,011	4,048
Receivables acquired with deteriorated credit quality | Payroll finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	0
Receivables acquired with deteriorated credit quality | Factored receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	0
Receivables acquired with deteriorated credit quality | Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	0
Receivables acquired with deteriorated credit quality | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	2,958	5,945
Receivables acquired with deteriorated credit quality | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	0
Receivables acquired with deteriorated credit quality | ADC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	0	0
Receivables acquired with deteriorated credit quality | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	314	1,391
Receivables acquired with deteriorated credit quality | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non accrual loans	$ 709	$ 857

Portfolio Loans - Loans Evaluat

Portfolio Loans - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans evaluated by segment
Individually evaluated for impairment	$ 60,862	$ 55,391
Collectively evaluated for impairment	19,721,509	9,382,931
Total portfolio loans	20,008,983	9,527,230
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	77,907	63,622
Total allowance for loan losses	77,907	63,622
Traditional C&I
Loans evaluated by segment
Individually evaluated for impairment	35,921	25,221
Collectively evaluated for impairment	1,933,155	1,365,466
Total portfolio loans	1,979,448	1,404,774
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	19,072	12,864
Total allowance for loan losses	19,072	12,864
Asset-based lending
Loans evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	797,570	724,247
Total portfolio loans	797,570	741,942
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	6,625	3,316
Total allowance for loan losses	6,625	3,316
Payroll finance
Loans evaluated by segment
Individually evaluated for impairment	0	570
Collectively evaluated for impairment	268,609	254,979
Total portfolio loans	268,609	255,549
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,565	951
Total allowance for loan losses	1,565	951
Warehouse lending
Loans evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	723,335	616,946
Total portfolio loans	723,335	616,946
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,705	1,563
Total allowance for loan losses	3,705	1,563
Factored receivables
Loans evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	220,551	214,242
Total portfolio loans	220,551	214,242
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,395	1,669
Total allowance for loan losses	1,395	1,669
Equipment financing
Loans evaluated by segment
Individually evaluated for impairment	5,341	1,413
Collectively evaluated for impairment	674,200	587,902
Total portfolio loans	679,541	589,315
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	4,862	5,039
Total allowance for loan losses	4,862	5,039
Public sector finance
Loans evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	637,767	349,182
Total portfolio loans	637,767	349,182
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,797	1,062
Total allowance for loan losses	1,797	1,062
CRE
Loans evaluated by segment
Individually evaluated for impairment	9,663	14,853
Collectively evaluated for impairment	4,090,143	3,104,057
Total portfolio loans	4,138,864	3,162,942
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	24,945	20,466
Total allowance for loan losses	24,945	20,466
Multi-family
Loans evaluated by segment
Individually evaluated for impairment	1,597	0
Collectively evaluated for impairment	4,842,898	976,710
Total portfolio loans	4,859,555	981,076
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,261	4,991
Total allowance for loan losses	3,261	4,991
ADC
Loans evaluated by segment
Individually evaluated for impairment	5,208	9,025
Collectively evaluated for impairment	277,322	216,094
Total portfolio loans	282,792	230,086
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,680	1,931
Total allowance for loan losses	1,680	1,931
Residential mortgage
Loans evaluated by segment
Individually evaluated for impairment	0	2,545
Collectively evaluated for impairment	4,903,218	692,396
Total portfolio loans	5,054,732	697,108
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	5,819	5,864
Total allowance for loan losses	5,819	5,864
Consumer
Loans evaluated by segment
Individually evaluated for impairment	3,132	1,764
Collectively evaluated for impairment	352,741	280,710
Total portfolio loans	366,219	284,068
Allowance evaluated by segment
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,181	3,906
Total allowance for loan losses	3,181	3,906
Receivables acquired with deteriorated credit quality
Loans evaluated by segment
Purchased credit impaired loans	226,612	88,908
Receivables acquired with deteriorated credit quality | Traditional C&I
Loans evaluated by segment
Purchased credit impaired loans	10,372	14,087
Receivables acquired with deteriorated credit quality | Asset-based lending
Loans evaluated by segment
Purchased credit impaired loans	0	17,695
Receivables acquired with deteriorated credit quality | Payroll finance
Loans evaluated by segment
Purchased credit impaired loans	0	0
Receivables acquired with deteriorated credit quality | Warehouse lending
Loans evaluated by segment
Purchased credit impaired loans	0	0
Receivables acquired with deteriorated credit quality | Factored receivables
Loans evaluated by segment
Purchased credit impaired loans	0	0
Receivables acquired with deteriorated credit quality | Equipment financing
Loans evaluated by segment
Purchased credit impaired loans	0	0
Receivables acquired with deteriorated credit quality | Public sector finance
Loans evaluated by segment
Purchased credit impaired loans	0	0
Receivables acquired with deteriorated credit quality | CRE
Loans evaluated by segment
Purchased credit impaired loans	39,058	44,032
Receivables acquired with deteriorated credit quality | Multi-family
Loans evaluated by segment
Purchased credit impaired loans	15,060	4,366
Receivables acquired with deteriorated credit quality | ADC
Loans evaluated by segment
Purchased credit impaired loans	262	4,967
Receivables acquired with deteriorated credit quality | Residential mortgage
Loans evaluated by segment
Purchased credit impaired loans	151,514	2,167
Receivables acquired with deteriorated credit quality | Consumer
Loans evaluated by segment
Purchased credit impaired loans	$ 10,346	$ 1,594

Portfolio Loans - Accretable Yi

Portfolio Loans - Accretable Yield Discount for PCI Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of year	$ 11,117	$ 11,211	$ 724
Acquisition	46,111	2,200	12,527
Accretion	(7,468)	(4,937)	(2,229)
Disposals	(2,000)	0	(50)
Reclassification (to) from non-accretable difference	(2,178)	2,643	239
Balance at end of year	$ 45,582	$ 11,117	$ 11,211

Portfolio Loans - PCI Loans Sep

Portfolio Loans - PCI Loans Separated by Whether or Not Subject to Accretion (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	$ 186,357	$ 77,163
Traditional C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	37,642	26,386
Asset-based lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	0	0
CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	21,720	21,008
Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	4,449	71
ADC
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	4,205	5,269
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	99,958	14,790
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans under cost recovery method (non-accrual)	10,284	6,576
Receivables acquired with deteriorated credit quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	218,620	76,667
PCI loans under cost recovery method (non-accrual)	7,992	12,241
Total PCI loans	226,612	88,908
Receivables acquired with deteriorated credit quality | Traditional C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	6,361	10,039
PCI loans under cost recovery method (non-accrual)	4,011	4,048
Total PCI loans	10,372	14,087
Receivables acquired with deteriorated credit quality | Asset-based lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	0	17,695
PCI loans under cost recovery method (non-accrual)	0	0
Total PCI loans	0	17,695
Receivables acquired with deteriorated credit quality | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	36,100	38,087
PCI loans under cost recovery method (non-accrual)	2,958	5,945
Total PCI loans	39,058	44,032
Receivables acquired with deteriorated credit quality | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	15,060	4,366
PCI loans under cost recovery method (non-accrual)	0	0
Total PCI loans	15,060	4,366
Receivables acquired with deteriorated credit quality | ADC
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	262	4,967
PCI loans under cost recovery method (non-accrual)	0	0
Total PCI loans	262	4,967
Receivables acquired with deteriorated credit quality | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	151,200	776
PCI loans under cost recovery method (non-accrual)	314	1,391
Total PCI loans	151,514	2,167
Receivables acquired with deteriorated credit quality | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans subject to accretion	9,637	737
PCI loans under cost recovery method (non-accrual)	709	857
Total PCI loans	$ 10,346	$ 1,594

Portfolio Loans - Loans Individ

Portfolio Loans - Loans Individually Evaluated for Impairment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
With no related allowance recorded:
Unpaid principal balance	$ 62,080,000	$ 56,903,000
Recorded investment	60,862,000	55,391,000
Average recorded investment	51,356,000	48,909,000	$ 26,042,000
Interest income recognized	1,105,000	186,000	336,000
Cash-basis interest income recognized	0	0
Traditional C&I
With no related allowance recorded:
Unpaid principal balance	36,408,000	25,221,000
Recorded investment	35,921,000	25,221,000
Average recorded investment	26,413,000	25,508,000	2,718,000
Interest income recognized	460,000	22,000	0
Payroll finance
With no related allowance recorded:
Unpaid principal balance	0	570,000
Recorded investment	0	570,000
Average recorded investment	0	71,000	0
Interest income recognized	0	0	0
Equipment financing
With no related allowance recorded:
Unpaid principal balance	5,341,000	1,413,000
Recorded investment	5,341,000	1,413,000
Average recorded investment	4,004,000	1,275,000	757,000
Interest income recognized	0	0	0
CRE
With no related allowance recorded:
Unpaid principal balance	10,128,000	16,365,000
Recorded investment	9,663,000	14,853,000
Average recorded investment	11,808,000	13,625,000	12,155,000
Interest income recognized	374,000	133,000	102,000
Multi-family
With no related allowance recorded:
Unpaid principal balance	1,597,000	0
Recorded investment	1,597,000	0
Average recorded investment	399,000	0	1,078,000
Interest income recognized	65,000	0	0
ADC
With no related allowance recorded:
Unpaid principal balance	5,474,000	9,025,000
Recorded investment	5,208,000	9,025,000
Average recorded investment	5,687,000	6,132,000	8,819,000
Interest income recognized	206,000	31,000	234,000
Residential mortgage
With no related allowance recorded:
Unpaid principal balance	0	2,545,000
Recorded investment	0	2,545,000
Average recorded investment	1,068,000	768,000	515,000
Interest income recognized	0	0	0
Consumer
With no related allowance recorded:
Unpaid principal balance	3,132,000	1,764,000
Recorded investment	3,132,000	1,764,000
Average recorded investment	1,977,000	1,530,000	0
Interest income recognized	$ 0	$ 0	$ 0

Portfolio Loans - Past Due Stat

Portfolio Loans - Past Due Status (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Current loans	$ 13,175	$ 11,032
Troubled debt restructurings	42,889	13,274
Non-accrual	29,325	1,989
Traditional C&I
Financing Receivable, Modifications [Line Items]
Current loans	565	572
Troubled debt restructurings	21,648	700
Non-accrual	21,083	128
Equipment financing
Financing Receivable, Modifications [Line Items]
Current loans	898	0
Troubled debt restructurings	1,724	29
Non-accrual	826	29
CRE
Financing Receivable, Modifications [Line Items]
Current loans	2,921	2,443
Troubled debt restructurings	3,036	2,696
Non-accrual	115	0
ADC
Financing Receivable, Modifications [Line Items]
Current loans	1,495	5,962
Troubled debt restructurings	5,700	6,420
Non-accrual	4,205	458
Residential mortgage
Financing Receivable, Modifications [Line Items]
Current loans	5,154	2,055
Troubled debt restructurings	8,300	3,429
Non-accrual	2,810	1,374
Consumer
Financing Receivable, Modifications [Line Items]
Current loans	2,142
Troubled debt restructurings	2,481
Non-accrual	286
30-59 days past due
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	389	253
30-59 days past due | Traditional C&I
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
30-59 days past due | Equipment financing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
30-59 days past due | CRE
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	253
30-59 days past due | ADC
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
30-59 days past due | Residential mortgage
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	336	0
30-59 days past due | Consumer
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	53
60-89 days past due
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | Traditional C&I
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | Equipment financing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | CRE
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | ADC
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | Residential mortgage
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
60-89 days past due | Consumer
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0
90 days past due
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
90 days past due | Traditional C&I
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
90 days past due | Equipment financing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
90 days past due | CRE
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
90 days past due | ADC
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	0
90 days past due | Residential mortgage
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	0	$ 0
90 days past due | Consumer
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 0

Portfolio Loans - Troubled Debt

Portfolio Loans - Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)loan	Dec. 31, 2015loan	Sep. 30, 2014USD ($)
Financing Receivable, Modifications [Line Items]
Number | loan	11	1	0
Recorded investment, Pre-modification	$ 30,407	$ 469
Recorded investment, Post-modification	$ 30,079	$ 347
ADC
Financing Receivable, Modifications [Line Items]
Number | loan	1	0
Recorded investment, Pre-modification	$ 797	$ 0
Recorded investment, Post-modification	$ 797	$ 0		$ 1,060
Equipment financing
Financing Receivable, Modifications [Line Items]
Number | loan	3	0
Recorded investment, Pre-modification	$ 3,558	$ 0
Recorded investment, Post-modification	$ 3,337	$ 0
Traditional C&I
Financing Receivable, Modifications [Line Items]
Number | loan	1	0
Recorded investment, Pre-modification	$ 23,188	$ 0
Recorded investment, Post-modification	$ 23,188	$ 0
CRE
Financing Receivable, Modifications [Line Items]
Number | loan	2	0
Recorded investment, Pre-modification	$ 1,724	$ 0
Recorded investment, Post-modification	$ 1,724	$ 0
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number | loan	4	1
Recorded investment, Pre-modification	$ 1,140	$ 469
Recorded investment, Post-modification	$ 1,033	$ 347

Portfolio Loans - Narrative (De

Portfolio Loans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Cash-basis interest income recognized	$ 0	$ 0
Net deferred loan origination costs	4,813,000	1,788,000
Pledged loans	9,123,601,000	2,349,604,000
Allowance for loan losses	77,907,000	63,622,000	$ 50,145,000	$ 42,374,000
Impaired loans with related allowance recorded	0	0
Charge-offs	585,000	286,000	74,000
Residential mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans formally in process of foreclosure	76,712,000	9,263,000
Allowance for loan losses	5,819,000	5,864,000	$ 5,007,000	$ 5,843,000
Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Purchased credit impaired loans	226,612,000	88,908,000
Receivables acquired with deteriorated credit quality | Residential mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Purchased credit impaired loans	$ 151,514,000	$ 2,167,000

Allowance for Loan Losses - All

Allowance for Loan Losses - Allowance Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	$ 63,622	$ 50,145	$ 42,374
Charge-offs	(14,185)	(8,953)	(11,018)
Recoveries	2,470	2,430	3,089
Net charge-offs	(11,715)	(6,523)	(7,929)
Provision	26,000	20,000	15,700
Ending balance	$ 77,907	$ 63,622	$ 50,145
Annualized net charge-offs to average loans outstanding	0.10%	0.08%	0.13%
Traditional C&I
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	$ 12,864	$ 9,953	$ 6,966
Charge-offs	(5,489)	(1,707)	(1,575)
Recoveries	1,142	999	1,720
Net charge-offs	(4,347)	(708)	145
Provision	10,555	3,619	2,842
Ending balance	19,072	12,864	9,953
Asset-based lending
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	3,316	2,762	4,061
Charge-offs	0	0	0
Recoveries	5	62	0
Net charge-offs	5	62	0
Provision	3,304	492	(1,299)
Ending balance	6,625	3,316	2,762
Payroll finance
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	951	1,936	1,506
Charge-offs	(188)	(28)	(406)
Recoveries	6	32	35
Net charge-offs	(182)	4	(371)
Provision	796	(989)	801
Ending balance	1,565	951	1,936
Warehouse lending
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	1,563	589	608
Charge-offs	0	0	0
Recoveries	0	0	0
Net charge-offs	0	0	0
Provision	2,142	974	(19)
Ending balance	3,705	1,563	589
Factored receivables
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	1,669	1,457	1,205
Charge-offs	(982)	(1,200)	(291)
Recoveries	23	61	60
Net charge-offs	(959)	(1,139)	(231)
Provision	685	1,351	483
Ending balance	1,395	1,669	1,457
Equipment financing
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	5,039	4,925	2,569
Charge-offs	(3,165)	(1,982)	(3,423)
Recoveries	387	560	825
Net charge-offs	(2,778)	(1,422)	(2,598)
Provision	2,601	1,536	4,954
Ending balance	4,862	5,039	4,925
Public sector finance
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	1,062	547	0
Charge-offs	0	0	0
Recoveries	0	0	0
Net charge-offs	0	0	0
Provision	735	515	547
Ending balance	1,797	1,062	547
CRE
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	20,466	11,461	7,721
Charge-offs	(2,379)	(959)	(1,695)
Recoveries	163	353	148
Net charge-offs	(2,216)	(606)	(1,547)
Provision	6,695	9,611	5,287
Ending balance	24,945	20,466	11,461
Multi-family
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	4,991	5,141	4,511
Charge-offs	0	(417)	(17)
Recoveries	0	2	9
Net charge-offs	0	(415)	(8)
Provision	(1,730)	265	638
Ending balance	3,261	4,991	5,141
ADC
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	1,931	2,009	2,987
Charge-offs	(27)	0	0
Recoveries	269	104	52
Net charge-offs	242	104	52
Provision	(493)	(182)	(1,030)
Ending balance	1,680	1,931	2,009
Residential mortgage
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	5,864	5,007	5,843
Charge-offs	(860)	(1,045)	(1,251)
Recoveries	161	30	92
Net charge-offs	(699)	(1,015)	(1,159)
Provision	654	1,872	323
Ending balance	5,819	5,864	5,007
Consumer
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method
Beginning balance	3,906	4,358	4,397
Charge-offs	(1,095)	(1,615)	(2,360)
Recoveries	314	227	148
Net charge-offs	(781)	(1,388)	(2,212)
Provision	56	936	2,173
Ending balance	$ 3,181	$ 3,906	$ 4,358

Allowance for Loan Losses - Nar

Allowance for Loan Losses - Narrative (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Receivables [Abstract]
Maximum loan balance for credit risk to be evaluated on a homogeneous basis	$ 500

Allowance for Loan Losses - Ris

Allowance for Loan Losses - Risk Category of Gross Loans by Segment (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Special mention
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	$ 136,558,000	$ 104,569,000
Special mention | Traditional C&I
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	7,453,000	12,125,000
Special mention | Asset-based lending
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	30,958,000	35,373,000
Special mention | Payroll finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	15,542,000	0
Special mention | Factored receivables
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	187,000	185,000
Special mention | Equipment financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	4,093,000	2,128,000
Special mention | CRE
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	40,438,000	39,190,000
Special mention | Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	26,602,000	7,072,000
Special mention | ADC
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	4,204,000	6,899,000
Special mention | Residential mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	6,038,000	951,000
Special mention | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	1,043,000	646,000
Substandard
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	232,491,000	95,152,000
Substandard | Traditional C&I
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	53,915,000	28,977,000
Substandard | Asset-based lending
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	3,835,000	0
Substandard | Payroll finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	352,000	820,000
Substandard | Factored receivables
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	433,000
Substandard | Equipment financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	9,299,000	3,397,000
Substandard | CRE
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	34,529,000	29,463,000
Substandard | Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	14,266,000	658,000
Substandard | ADC
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	4,639,000	8,870,000
Substandard | Residential mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	101,149,000	15,796,000
Substandard | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	10,507,000	6,738,000
Doubtful
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	764,000	442,000
Doubtful | Traditional C&I
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	746,000	442,000
Doubtful | Asset-based lending
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Payroll finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Factored receivables
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Equipment financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | CRE
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | ADC
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Residential mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	0	0
Doubtful | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	18,000	0
Loss
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans by segment	$ 0	$ 0

Premises and Equipment, Net (De

Premises and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 410,201	$ 138,411
Accumulated depreciation and amortization	(88,479)	(81,093)
Total premises and equipment, net	321,722	57,318
Depreciation and amortization of premises and equipment	11,670	8,375	$ 7,476
Land and land improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	160,376	11,679
Buildings
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	127,959	29,785
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	40,442	33,070
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 81,424	$ 63,877

Goodwill and Other Intangible83

Goodwill and Other Intangible Assets - Goodwill Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning of period balance	$ 696,600	$ 670,699
Acquired goodwill	883,291	25,901
End of period balance	$ 1,579,891	$ 696,600

Goodwill and Other Intangible84

Goodwill and Other Intangible Assets - Balance of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 201,442	$ 101,504
Accumulated amortization	(48,251)	(35,151)
Net intangible assets	153,191	66,353
Amortization of intangible assets	$ 13,008	12,416	$ 10,043
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	10 years
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 157,959	58,021
Accumulated amortization	(31,414)	(20,566)
Net intangible assets	126,545	37,455
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	10,450	10,450
Accumulated amortization	(4,596)	(2,767)
Net intangible assets	5,854	7,683
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	11,808	11,808
Accumulated amortization	(11,516)	(11,183)
Net intangible assets	292	625
Trade name
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	20,500	20,500
Accumulated amortization	0	0
Net intangible assets	20,500	20,500
Fair value of below market leases
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	725	725
Accumulated amortization	(725)	(635)
Net intangible assets	$ 0	$ 90

Goodwill and Other Intangible85

Goodwill and Other Intangible Assets - Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 23,646
2,019	19,181
2,020	16,800
2,021	15,104
2,022	13,703
Thereafter	44,257
Total	$ 132,691

Deposits - Deposit Balances (De

Deposits - Deposit Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Non-interest bearing demand	$ 4,080,742	$ 3,239,332
Interest bearing demand	3,882,064	2,220,456
Savings	2,758,642	747,031
Money market	7,377,118	3,277,686
Certificates of deposit	2,439,638	583,754
Total deposits	$ 20,538,204	$ 10,068,259

Deposits - Remaining Period to

Deposits - Remaining Period to Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Less than one year	$ 1,270,605	$ 480,162
One to two years	525,846	47,768
Two to three years	362,233	42,492
Three to four years	160,432	7,210
Four to five years	120,522	6,122
Total certificates of deposit	$ 2,439,638	$ 583,754

Deposits - Brokered Deposits (D

Deposits - Brokered Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
List of Company's Brokered deposits
Brokered deposits	$ 1,104,214	$ 831,629
Interest bearing demand
List of Company's Brokered deposits
Brokered deposits	23,820	426,437
Money market
List of Company's Brokered deposits
Brokered deposits	773,804	5,560
Savings
List of Company's Brokered deposits
Brokered deposits	0	246,572
Reciprocal CDARs
List of Company's Brokered deposits
Brokered deposits	102,259	153,060
CDARs one way
List of Company's Brokered deposits
Brokered deposits	$ 204,331	$ 0

Deposits - Narrative (Details)

Deposits - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Municipal deposits	$ 1,585,076	$ 1,270,921
Cash in excess of FDIC insurance limits	$ 371,671	$ 132,406

Borrowings, Senior Notes and 90

Borrowings, Senior Notes and Subordinated Notes - Borrowings and Weighted Average Interest Rates (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Jul. 02, 2013
By period to maturity:
Less than one year, Amount	$ 2,989,093,000	$ 1,397,642,000
Less than one year, Rate	1.69%	0.87%
One to two years, Amount	$ 775,714,000	$ 311,469,000
One to two years, Rate	1.79%	2.53%
Two to three years, Amount	$ 802,650,000	$ 75,000,000
Two to three years, Rate	2.34%	1.50%
Three to four years, Amount	$ 251,037,000	$ 50,000,000
Three to four years, Rate	2.04%	1.38%
Four to five years, Amount	$ 0	$ 50,000,000
Four to five years, Rate	0.00%	1.68%
Greater than five years, Amount	$ 172,716,000	$ 172,501,000
Greater than five years, Rate	5.45%	5.45%
Total borrowings	$ 4,991,210,000	$ 2,056,612,000
Total borrowings, Rate	1.96%	1.56%
FHLB advances and overnight
By period to maturity:
Total borrowings	$ 4,510,123,000	$ 1,791,000,000
Total borrowings, Rate	1.69%	1.01%
Repurchase agreements
By period to maturity:
Total borrowings	$ 30,162,000	$ 16,642,000
Total borrowings, Rate	0.64%	0.75%
Senior Notes
By period to maturity:
Total borrowings			$ 100,000,000
Senior Notes | Senior Note, 5.50%
By period to maturity:
Total borrowings	$ 76,805,000	$ 76,469,000
Total borrowings, Rate	5.98%	5.98%
Senior Notes | Senior Notes, 3.50%
By period to maturity:
Total borrowings	$ 201,404,000	$ 0
Total borrowings, Rate	3.19%	0.00%
Subordinated Notes
By period to maturity:
Total borrowings	$ 172,716,000	$ 172,501,000
Total borrowings, Rate	5.45%	5.45%

Borrowings, Senior Notes and 91

Borrowings, Senior Notes and Subordinated Notes - Narrative (Details) - USD ($)	Sep. 02, 2016	Mar. 29, 2016	Jul. 02, 2013	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 02, 2017	Sep. 05, 2017
Debt Instrument [Line Items]
Bank pledged mortgages					$ 9,123,601,000	$ 2,349,604,000
Increased borrowing capacity by pledging securities					4,622,150,000
Gain (loss) on extinguishment of borrowings					0	(9,729,000)	$ 0
Long-term debt					$ 4,991,210,000	$ 2,056,612,000
Effective yield, rate					1.96%	1.56%
Minimum
Debt Instrument [Line Items]
Repurchase agreements maturity					1 day
Maximum
Debt Instrument [Line Items]
Repurchase agreements maturity					30 days
Senior Notes
Debt Instrument [Line Items]
Gain (loss) on extinguishment of borrowings				$ (1,013,000)
Long-term debt			$ 100,000,000
Fixed interest rate			5.50%
Private placement discount rate			1.75%
Debt issuance costs			$ 303,000
Unamortized discount					$ 195,000	$ 531,000
Amount of debt redeemed				$ 23,000,000
Senior Notes | Senior Note, 5.50%
Debt Instrument [Line Items]
Long-term debt					$ 76,805,000	$ 76,469,000
Effective yield, rate					5.98%	5.98%
Senior Notes | Senior Notes, 3.50%
Debt Instrument [Line Items]
Long-term debt					$ 201,404,000	$ 0
Effective yield, rate					3.19%	0.00%
Senior Notes | Senior Notes, 3.50% | Astoria Financial Corporation
Debt Instrument [Line Items]
Interest rate								3.50%
Debt, fair value								$ 0
Debt assumed								200,000,000
Effective yield, rate					3.19%
Senior Notes | Senior Notes, 3.50% | Astoria Financial Corporation | Fair value adjustments
Debt Instrument [Line Items]
Debt, fair value								$ 1,520,000
Subordinated Notes
Debt Instrument [Line Items]
Interest rate		5.25%
Long-term debt					$ 172,716,000	$ 172,501,000
Private placement discount rate	1.25%	1.25%
Debt issuance costs	$ 275,000	$ 500,000
Unamortized discount					$ 2,284,000
Effective yield, rate					5.45%	5.45%
Principal amount	$ 65,000,000	$ 110,000,000
Issue premium	0.50%
Effective yield					5.45%
Subordinated Notes | Three-month LIBOR
Debt Instrument [Line Items]
Basis spread rate		3.937%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving line of credit amount									$ 35,000,000
Revolving line of credit balance					$ 0	$ 0
Line of Credit | London Interbank Offered Rate (LIBOR) | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread rate					1.25%

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) $ in Thousands	Dec. 31, 2017USD ($)
Derivative Instruments and Hedges, Assets [Abstract]
Cash pledged as collateral for swaps	$ 3,523

Derivatives - Derivative Inform

Derivatives - Derivative Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Summary of derivatives
Derivative assets, Notional amount	$ 621,283
Derivative liabilities, Notional amount	$ (621,283)
Average maturity (in years)	5 years 9 months 15 days
Weighted average fixed rate	4.28%
Derivative assets, Fair value	$ 4,457
Swaps	$ (7,980)
One Month LIBOR
Summary of derivatives
Basis spread	1.94%
Customer Interest Rate Swap | One Month LIBOR
Summary of derivatives
Basis spread		2.29%
Customer Interest Rate Swap | Other Liabilities
Summary of derivatives
Derivative assets, Notional amount	$ 306,529
Derivative liabilities, Notional amount	(314,754)	$ (296,282)
Average maturity (in years)		5 years 7 months 18 days
Weighted average fixed rate		3.94%
Derivative assets, Fair value	3,302
Swaps	(3,262)	$ (2,088)
Third Party Interest Rate Swap | One Month LIBOR
Summary of derivatives
Basis spread		2.29%
Third Party Interest Rate Swap | Other Assets
Summary of derivatives
Derivative assets, Notional amount	314,754	$ 296,282
Average maturity (in years)		5 years 7 months 18 days
Weighted average fixed rate		3.94%
Derivative assets, Fair value	1,155	$ 2,088
Third Party Interest Rate Swap | Other Liabilities
Summary of derivatives
Derivative liabilities, Notional amount	(306,529)
Swaps	$ (4,718)

Income Taxes - Components of In

Income Taxes - Components of Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal									$ 4,375	$ 55,418	$ 25,634
State and local									2,181	12,854	5,862
Total current tax expense									6,556	68,272	31,496
Federal									71,536	(1,069)	(1,406)
State and local									9,847	179	1,745
Total deferred tax expense (benefit)									81,383	(890)	339
Total income tax expense	$ 28,319	$ 21,592	$ 20,319	$ 17,709	$ 19,737	$ 16,991	$ 18,412	$ 12,242	$ 87,939	$ 67,382	$ 31,835

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Efftective tax rate reconciliation:
Tax at federal statutory rate of 35%									$ 63,341	$ 72,574	$ 34,282
State and local income taxes, net of federal tax benefit									7,818	8,472	4,945
Tax-exempt interest, net of disallowed interest									(18,948)	(11,094)	(5,218)
BOLI income									(2,665)	(1,933)	(1,853)
Non-deductible acquisition related costs									2,965	0	700
Low income housing tax credits									(1,872)	(469)	(215)
Equity-based stock compensation benefit									(1,528)	0	0
Estimated deferred tax adjustment related to reduction in federal income tax rate	$ 40,285								40,285	0	0
Other, net									(1,457)	(168)	(806)
Total income tax expense	$ 28,319	$ 21,592	$ 20,319	$ 17,709	$ 19,737	$ 16,991	$ 18,412	$ 12,242	$ 87,939	$ 67,382	$ 31,835
Effective income tax rate									48.60%	32.50%	32.50%
Effective federal income tax rate									35.00%	35.00%	35.00%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Allowance for loan losses	$ 20,468	$ 25,039
Deferred compensation	315	656
Other accrued compensation and benefits	22,321	9,920
Accrued post retirement expense	7,885	2,060
Deferred rent	3,445	3,268
Intangible assets	1,612	3,108
Other comprehensive loss (securities)	11,422	16,911
Other comprehensive loss (defined benefit plans)	447	479
Pension expense	11,691	0
Accrued expenses	4,923	252
State NOL carryforward	15,400	0
AMT credit carryforward	4,070	0
Other	3,237	3,719
Total deferred tax assets	107,236	65,412
Deferred tax liabilities:
Mortgage servicing rights	2,722	403
Prepaid pension costs	0	3,798
Acquisition fair value adjustments	0	18,948
Depreciation of premises and equipment	1,026	809
Deferred loan fees and costs	5,001	0
Other	1,154	906
Total deferred tax liabilities	9,903	24,864
Net deferred tax asset	$ 97,333	$ 40,548

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Estimated deferred tax adjustment related to reduction in federal income tax rate	$ 40,285,000	$ 40,285,000	$ 0	$ 0
Bad debt reserve for tax purposes	9,313,000	9,313,000
Provision for federal income tax		0	0
Deferred tax liability not recognized	3,260,000	3,260,000	3,260,000
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	0	0	$ 0
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	164,786,000	164,786,000
Operating loss carryforward, subject to expiration	$ 66,612,000	$ 66,612,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 28, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining that are authorized and available for future grant (in shares)	3,101,327	3,639,838	4,125,665		1,999,022
Grant of share options (in shares)	0	0	24,566
Exercise price (USD per share)	$ 0	$ 0	$ 14.22
Options outstanding (in shares)	757,867	1,004,119	1,586,572		2,040,299
Intrinsic value of options outstanding	$ 10,196
Intrinsic value of options exercisable	10,165
Proceeds from stock option exercises	$ 2,578	$ 3,588	$ 2,764
Weighted average fair value of options granted (USD per share)			$ 2.14
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of contract	10 years
Weighted-average period total unrecognized compensation cost related to non-vested shares granted	9 months
Stock options | Stock Compensation Grants associated with legacy Sterling Merger
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (USD per share)	$ 14.25
Stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for awards	1 year
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for awards	5 years
Fully Vested legacy Sterling options | Sterling Bancorp (Legacy)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of share options (in shares)	104,152
Restricted Stock Units (RSUs) | Stock Compensation Grants associated with legacy Sterling Merger
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (USD per share)	$ 11.72
Non-vested stock awards/performance units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period total unrecognized compensation cost related to non-vested shares granted	1 year 6 months 20 days
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				2,800,000
Number of shares granted for each share received (in shares)	1
Legacy Sterling 2013 Employment Inducement Award Plan | Fully Vested legacy Sterling options | Sterling Bancorp (Legacy)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of share options (in shares)	95,991
Prior Plan | Restricted Stock Units (RSUs) | Sterling Bancorp (Legacy)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period, other than options (in shares)	255,973

Stock-Based Compensation - Plan

Stock-Based Compensation - Plan Activity (Details)	12 Months Ended			27 Months Ended
	Dec. 31, 2017$ / sharesshares	Dec. 31, 2016$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2015$ / sharesshares
Shares available for grant (in shares)
Beginning balance (in shares)	3,639,838	4,125,665	1,999,022
Granted (in shares)	(610,075)	(515,869)	(732,023)
Stock awards vested (in shares)	0	0	0
Forfeited (in shares)	76,877	130,758	192,970
Canceled/expired (in shares)	(5,313)	(100,716)	(134,304)
Ending balance (in shares)	3,101,327	3,639,838	4,125,665	4,125,665
Stock options outstanding - Number of shares
Beginning balance (in shares)	1,004,119	1,586,572	2,040,299
Granted (in shares)	0	0	24,566
Stock awards vested (in shares)	0
Exercised (in shares)	(244,252)	(503,893)	(406,422)
Forfeited (in shares)	(2,000)	(78,560)	(71,871)
Canceled/expired (in shares)	0	0	0
Ending balance (in shares)	757,867	1,004,119	1,586,572	1,586,572
Exercisable (in shares)	754,678
Stock options outstanding - Weighted average exercise price
Beginning balance (USD per share) | $ / shares	$ 11	$ 10.95	$ 11.10
Granted (USD per share) | $ / shares	0	0	14.22
Stock awards vested (USD per share) | $ / shares	0
Exercised (USD per share) | $ / shares	10.52	10.47	11.58
Forfeited (USD per share) | $ / shares	13.18	13.41	12.90
Canceled/expired (USD per share) | $ / shares	0	0	0
Ending balance (USD per share) | $ / shares	11.15	$ 11	$ 10.95	$ 10.95
Exercisable (USD per share) | $ / shares	$ 11.13
Recognition and Retention Plan | Non-vested stock awards/performance units
Non-vested stock awards/stock units outstanding - Number of shares
Beginning balance (in shares)	932,223	726,800	643,887
Granted (in shares)	610,075	515,869	447,807
Stock awards vested (in shares)	(228,661)	(261,989)	(330,384)
Forfeited (in shares)	(74,877)	(48,457)	(34,510)
Canceled/expired (in shares)	0
Ending balance (in shares)	1,238,760	932,223	726,800	726,800
Non-vested stock awards/stock units outstanding - Weighted average grant date fair value
Beginning balance (USD per share) | $ / shares	$ 14.09	$ 13.36	$ 11.79
Granted (USD per share) | $ / shares	24.13	14.60	14.02
Stock awards vested (USD per share) | $ / shares	16.23	13.09	11.23
Forfeited (USD per share) | $ / shares	18.92	13.88	12.92
Canceled/expired (USD per share) | $ / shares	0
Ending balance (USD per share) | $ / shares	$ 20	$ 14.09	$ 13.36	$ 13.36
2014 Stock Incentive Plan
Stock options outstanding - Weighted average exercise price
Number of shares granted for each share received				3.5
2012 Stock Plan
Stock options outstanding - Weighted average exercise price
Number of shares granted for each share received				3.6
2015 Plan
Shares available for grant (in shares)
Stock Incentive Plan (in shares)			2,800,000

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Outstanding by Exercise Price Range (Details) - Stock options	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]
Outstanding, Number of stock options (in shares) | shares	757,867
Outstanding, Weighted-average exercise price (USD per share)	$ 11.15
Outstanding, Weighted-average life (in years)	5 years 5 months 16 days
Exercisable, Number of stock options (in shares) | shares	754,678
Exercisable, Weighted-average exercise price (USD per share)	$ 11.13
$6.71 to $9.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, lower range limit (USD per share)	6.71
Range of exercise price, upper range limit (USD per share)	$ 9
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]
Outstanding, Number of stock options (in shares) | shares	198,278
Outstanding, Weighted-average exercise price (USD per share)	$ 8.34
Outstanding, Weighted-average life (in years)	4 years 5 months 5 days
Exercisable, Number of stock options (in shares) | shares	198,278
Exercisable, Weighted-average exercise price (USD per share)	$ 8.34
$9.28 to $11.36
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, lower range limit (USD per share)	9.28
Range of exercise price, upper range limit (USD per share)	$ 11.36
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]
Outstanding, Number of stock options (in shares) | shares	220,862
Outstanding, Weighted-average exercise price (USD per share)	$ 10.86
Outstanding, Weighted-average life (in years)	5 years 26 days
Exercisable, Number of stock options (in shares) | shares	220,862
Exercisable, Weighted-average exercise price (USD per share)	$ 10.86
$11.36 to $13.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, lower range limit (USD per share)	11.36
Range of exercise price, upper range limit (USD per share)	$ 13.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]
Outstanding, Number of stock options (in shares) | shares	91,050
Outstanding, Weighted-average exercise price (USD per share)	$ 12.02
Outstanding, Weighted-average life (in years)	4 years 10 months 6 days
Exercisable, Number of stock options (in shares) | shares	91,050
Exercisable, Weighted-average exercise price (USD per share)	$ 12.02
$13.23 to $15.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, lower range limit (USD per share)	13.23
Range of exercise price, upper range limit (USD per share)	$ 15.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]
Outstanding, Number of stock options (in shares) | shares	247,677
Outstanding, Weighted-average exercise price (USD per share)	$ 13.33
Outstanding, Weighted-average life (in years)	6 years 10 months 6 days
Exercisable, Number of stock options (in shares) | shares	244,488
Exercisable, Weighted-average exercise price (USD per share)	$ 13.31

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value Assumptions (Details) - Stock options	12 Months Ended
	Dec. 31, 2015
Fair value of options granted determined using weighted-average assumptions as grant date
Risk-free interest rate	1.80%
Expected stock price volatility	21.20%
Dividend yield	3.10%
Expected term in years	5 years 9 months 4 days

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,110	$ 6,518	$ 4,580
Stock-based compensation expense, income tax benefit	2,149	2,118	1,417
Stock options	2
Non-vested stock awards/performance units	13,540
Total	13,542
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	149	404	909
Non-vested stock awards/performance units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,961	$ 6,114	$ 3,671

Pension and Other Post Retir103

Pension and Other Post Retirement Benefits - Narrative (Details) - USD ($) $ in Thousands	Oct. 15, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Anticipated future contribution, next fiscal year		$ 30,000
Lump sum distributions as elected by Plan participants	$ 58,171
Plan termination / Partial settlement charge	13,384	$ 0	$ 0	$ 13,384
Change in fair value of Plan assets	4,068
Remaining balance of accumulated other comprehensive loss through earnings recognized	7,936
Difference between effective tax rate and marginal tax rate	$ 1,380
Equity securities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		80.00%
Debt securities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		50.00%
Liquidity funds
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		25.00%
Any one company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		10.00%
Any one industry
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		30.00%
Funds that mirror S&P 500
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		50.00%
Large-cap equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		50.00%
Mid-cap equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		20.00%
Small-cap equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		20.00%
International equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		10.00%
Sterling Bancorp common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		15.00%
Limited Sterling Bancorp Common Stock, Due to Merger
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		10.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining reversion asset, recognition period		3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining reversion asset, recognition period		4 years
Other Assets
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining reversion asset		$ 6,648
Employee Savings Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum contribution by employee, percent		50.00%
Maximum contribution by employer, percent of employee contribution				50.00%
Maximum annual contribution per employee, percent		3.00%		3.00%
Savings plan expense		$ 3,827	$ 3,210	$ 1,769
HVB Merger | Other Liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed SERP liabilities				$ 16,059

Pension and Other Post Retir104

Pension and Other Post Retirement Benefits - Projected Benefit Obligation (Details) - USD ($) $ in Thousands	Oct. 15, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in fair value of plan assets:
Plan termination / Partial settlement	$ (58,171)
End of year balance		$ 198,395
Pension benefits
Changes in projected benefit obligation:
Beginning of year balance		0	$ 0
Obligations assumed in acquisitions		259,152	0
Service cost		0	0	$ 0
Interest cost		2,189	0	1,766
Actuarial loss		3,561	0
Benefits paid		(11,319)	0
End of year balance		253,583	0	0
Changes in fair value of plan assets:
Beginning of year balance		0	0
Fair value of pension plan assets at October 2, 2017		194,010	0
Actual gain on plan assets		6,234	0
Employer contributions		9,470	0
Benefits paid		(11,319)	0
End of year balance		198,395	0	0
Reversion asset / Funded status at end of year		(55,188)	0
Other post retirement benefits
Changes in projected benefit obligation:
Beginning of year balance		12,125	11,733
Obligations assumed in acquisitions		21,325	0
Service cost		22	0	6
Interest cost		557	417	373
Actuarial loss		984	64
Benefits paid		(236)	(89)
End of year balance		34,777	12,125	11,733
Changes in fair value of plan assets:
Beginning of year balance		0	0
Fair value of pension plan assets at October 2, 2017		0	0
Actual gain on plan assets		0	0
Employer contributions		236	89
Benefits paid		(236)	(89)
End of year balance		0	0	$ 0
Reversion asset / Funded status at end of year		$ (34,777)	$ (12,125)

Pension and Other Post Retir105

Pension and Other Post Retirement Benefits - Amounts Recognized in AOCI (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 613	$ 0
Total accumulated other comprehensive loss	613	0
Other post retirement benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	101	0
Total accumulated other comprehensive loss	$ 101	$ 0

Pension and Other Post Retir106

Pension and Other Post Retirement Benefits - Plan assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension benefits | Astoria Bank Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.44%
Discount rate used to value periodic cost	3.61%	7.00%
Pension benefits | Astoria Excess and Supplemental Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.14%
Discount rate used to value periodic cost	3.21%
Pension benefits | Astoria Directors’ Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.82%
Discount rate used to value periodic cost	2.78%
Pension benefits | Greater Directors’ Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.96%
Discount rate used to value periodic cost	2.96%
Other post retirement benefits | Sterling Other Post retirement medical, dental and vision plans | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.80%	2.78%
Discount rate used to value periodic cost	2.78%	2.78%
Other post retirement benefits | Sterling Other Post retirement medical, dental and vision plans | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.62%	4.00%
Discount rate used to value periodic cost	4.15%	4.00%
Other post retirement benefits | Astoria Bank Retiree Health Care Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.42%

Pension and Other Post Retir107

Pension and Other Post Retirement Benefits - Net Periodic Pension Expense (Details) - USD ($) $ in Thousands	Oct. 15, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Plan termination / Partial settlement charge	$ 13,384	$ 0	$ 0	$ 13,384
Pension benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		0	0	0
Interest cost		2,189	0	1,766
Expected return on plan assets		(3,287)	0	(2,187)
Amortization of unrecognized actuarial loss		0	0	272
Amortization of transition obligation		0	0	0
Amortization of prior service cost		0	0	0
Plan termination / Partial settlement charge		0	0	13,384
Net periodic pension (benefit) expense		(1,098)	0	13,235
Other post retirement benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		22	0	6
Interest cost		557	417	373
Expected return on plan assets		0	0	0
Amortization of unrecognized actuarial loss		19	0	0
Amortization of transition obligation		2	0	0
Amortization of prior service cost		14	64	161
Plan termination / Partial settlement charge		0	0	0
Net periodic pension (benefit) expense		$ 614	$ 481	$ 540

Pension and Other Post Retir108

Pension and Other Post Retirement Benefits - Cost Trend Rates (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Defined Benefit Plan Disclosure [Line Items]
Rate to which the cost trend rate is assumed to decline (the “ultimate trend rate”)	4.75%
Year that ultimate trend rate is reached	2,026
On percentage point increase, Effect on total service and interest cost components	$ 25
On percentage point increase, Effect on the post retirement benefit obligation	2,300
On percentage point decrease, Effect on total service and interest cost components	(20)
On percentage point decrease, Effect on the post retirement benefit obligation	$ (1,896)
Maximum
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for the next year	7.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for the next year	6.75%

Pension and Other Post Retir109

Pension and Other Post Retirement Benefits - Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2017USD ($)
Pension benefits
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,018	$ 12,568
2,019	12,560
2,020	12,801
2,021	14,162
2,022	13,241
Thereafter	67,102
Other post retirement benefits
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,018	1,270
2,019	1,400
2,020	1,483
2,021	1,566
2,022	1,562
Thereafter	$ 16,669

Pension and Other Post Retir110

Pension and Other Post Retirement Benefits - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 198,395
Level 1 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	185,931
Level 2 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Level 3 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,464	$ 11,888
PRIAC Pooled Separate Accounts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	165,315
PRIAC Pooled Separate Accounts | Level 1 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	165,315
PRIAC Pooled Separate Accounts | Level 2 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
PRIAC Pooled Separate Accounts | Level 3 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Sterling Bancorp common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,553
Sterling Bancorp common stock | Level 1 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,553
Sterling Bancorp common stock | Level 2 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Sterling Bancorp common stock | Level 3 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
PRIAC Guaranteed Deposit Account
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,464
PRIAC Guaranteed Deposit Account | Level 1 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
PRIAC Guaranteed Deposit Account | Level 2 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
PRIAC Guaranteed Deposit Account | Level 3 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,464
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63
Cash and cash equivalents | Level 1 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63
Cash and cash equivalents | Level 2 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash and cash equivalents | Level 3 inputs
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0
Large-cap equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	42.00%
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	33.00%
International equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	11.00%
Small-cap equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	8.00%
Mid-cap equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	6.00%

Pension and Other Post Retir111

Pension and Other Post Retirement Benefits - Fair Value of Level 3 Plan Assets (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
End of year balance	$ 198,395	$ 198,395
Maximum
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Gross guaranteed crediting rate	3.59%	3.59%
PRIAC Guaranteed Deposit Account
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
End of year balance	$ 12,464	$ 12,464
Level 3 inputs
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of year balance		11,888
Total net loss, realized and unrealized, included in net assets	153	(47)
Purchases		3,375
Sales		(2,752)
End of year balance	12,464	12,464
Level 3 inputs | PRIAC Guaranteed Deposit Account
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
End of year balance	$ 12,464	$ 12,464
Level 3 inputs | PRIAC Guaranteed Deposit Account | Minimum
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Composite market value factor	1.012	1.012
Gross guaranteed crediting rate	2.55%	2.55%
Level 3 inputs | PRIAC Guaranteed Deposit Account | Maximum
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Composite market value factor	1.020	1.020

Other Non-interest Expense (Det

Other Non-interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Income and Expenses [Abstract]
Advertising and promotion	$ 3,682	$ 2,948	$ 2,522
Professional fees	9,982	10,276	8,308
Data and check processing	19,387	8,866	8,825
Insurance & surety bond premium	3,317	3,150	3,186
Other	22,557	18,556	17,836
Total other non-interest expense	$ 58,925	$ 43,796	$ 40,677

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Computation of basic and diluted earnings per share:
Net income available to common stockholders	$ (35,281)	$ 44,852	$ 42,400	$ 39,067	$ 40,996	$ 37,422	$ 37,770	$ 23,784	$ 91,029	$ 139,972	$ 66,114
Weighted average common shares outstanding for computation of basic EPS									157,513,639	130,607,994	109,907,645
Common-equivalent shares due to the dilutive effect of stock options									610,631	626,468	421,708
Weighted average common shares for computation of diluted EPS									158,124,270	131,234,462	110,329,353
Basic (loss) earnings per common share (USD per share)	$ (0.16)	$ 0.33	$ 0.31	$ 0.29	$ 0.31	$ 0.29	$ 0.29	$ 0.18	$ 0.58	$ 1.07	$ 0.60
Diluted (loss) earnings per common share (USD per share)	$ (0.16)	$ 0.33	$ 0.31	$ 0.29	$ 0.31	$ 0.29	$ 0.29	$ 0.18	$ 0.58	$ 1.07	$ 0.60
Weighted average common shares that could be exercised that were anti-dilutive for the period									0	0	2,394

Stockholders' Equity - Complian

Stockholders' Equity - Compliance with Regulatory Capital Requirements (Schedule) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Subsidiaries [Member]
Common equity tier 1 to RWA:
Tier 1 common equity, Actual, Capital amount	$ 2,770,381	$ 1,176,497
Tier 1 common equity, Actual, Ratio	13.95%	10.87%
Tier 1 common equity required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,142,247	$ 554,663
Tier 1 common equity required for minimum capital adequacy ratio, phase-in schedule, Ratio	5.75%	5.125%
Tier 1 common equity required for minimum capital adequacy, fully phased-in, Capital amount	$ 1,390,561	$ 757,588
Tier 1 common equity required for minimum capital adequacy ratio, phase-in schedule, Ratio	7.00%	7.00%
Tier 1 common equity required to be well capitalized, Capital	$ 1,291,236	$ 703,475
Tier 1 common equity required to be well capitalized, Ratio	6.50%	6.50%
Tier 1 capital to RWA:
Tier 1 risk-based capital, Actual, Capital amount	$ 2,770,381	$ 1,176,497
Tier 1 risk-based capital, Actual, Ratio	13.95%	10.87%
Tier 1 risk-based capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,440,224	$ 717,003
Tier 1 risk-based capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	7.25%	6.625%
Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, Capital amount	$ 1,688,539	$ 919,928
Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, Ratio	8.50%	8.50%
Tier 1 risk-based capital required to be well capitalized, Capital amount	$ 1,589,213	$ 865,815
Tier 1 risk-based capital required to be well capitalized, Ratio	8.00%	8.00%
Total capital to RWA:
Total risk-based capital, Actual, Capital amount	$ 3,021,658	$ 1,413,165
Total risk-based capital, Actual, Ratio	15.21%	13.06%
Total risk-based capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,837,527	$ 933,457
Total risk-based capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	9.25%	8.625%
Total risk-based capital required for minimum capital adequacy, fully phased-in, Capital amount	$ 2,085,842	$ 1,136,382
Total risk-based capital required for minimum capital adequacy ratio, fully phased-in, Ratio	10.50%	10.50%
Total risk-based capital required to be well capitalized, Capital amount	$ 1,986,516	$ 1,082,269
Total risk-based capital required to be well capitalized, Ratio	10.00%	10.00%
Tier 1 leverage ratio:
Tier 1 leverage ratio, Actual, Capital amount	$ 2,770,381	$ 1,176,497
Tier 1 (core) capital, Actual, Ratio	10.10%	9.08%
Tier 1 (core) capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,097,449	$ 518,308
Tier 1 (core) capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	4.00%	4.00%
Tier 1 (core) capital required for minimum capital adequacy, fully phased- in, Capital amount	$ 1,097,449	$ 518,308
Tier 1 (core) capital required for minimum capital adequacy ratio, fully phased-in, Ratio	4.00%	4.00%
Tier 1 (core) capital required to be well capitalized, Capital amount	$ 1,371,811	$ 647,885
Tier 1 (core) capital required to be well capitalized, Ratio	5.00%	5.00%
Sterling Bancorp
Common equity tier 1 to RWA:
Tier 1 common equity, Actual, Capital amount	$ 2,458,449	$ 1,160,739
Tier 1 common equity, Actual, Ratio	12.37%	10.73%
Tier 1 common equity required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,143,045	$ 554,474
Tier 1 common equity required for minimum capital adequacy ratio, phase-in schedule, Ratio	5.75%	5.125%
Tier 1 common equity required for minimum capital adequacy, fully phased-in, Capital amount	$ 1,391,534	$ 757,330
Tier 1 common equity required for minimum capital adequacy ratio, phase-in schedule, Ratio	7.00%	7.00%
Tier 1 capital to RWA:
Tier 1 risk-based capital, Actual, Capital amount	$ 2,597,669	$ 1,160,739
Tier 1 risk-based capital, Actual, Ratio	13.07%	10.73%
Tier 1 risk-based capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,441,231	$ 716,759
Tier 1 risk-based capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	7.25%	6.625%
Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, Capital amount	$ 1,689,719	$ 919,615
Tier 1 risk-based capital required for minimum capital adequacy, fully phased-in, Ratio	8.50%	8.50%
Total capital to RWA:
Total risk-based capital, Actual, Capital amount	$ 2,818,404	$ 1,377,547
Total risk-based capital, Actual, Ratio	14.18%	12.73%
Total risk-based capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,838,812	$ 933,139
Total risk-based capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	9.25%	8.625%
Total risk-based capital required for minimum capital adequacy, fully phased-in, Capital amount	$ 2,087,300	$ 1,135,995
Total risk-based capital required for minimum capital adequacy ratio, fully phased-in, Ratio	10.50%	10.50%
Tier 1 leverage ratio:
Tier 1 leverage ratio, Actual, Capital amount	$ 2,597,669	$ 1,160,739
Tier 1 (core) capital, Actual, Ratio	9.39%	8.95%
Tier 1 (core) capital required for minimum capital adequacy, phase-in schedule, Capital amount	$ 1,106,977	$ 518,733
Tier 1 (core) capital required for minimum capital adequacy ratio, phase-in schedule, Ratio	4.00%	4.00%
Tier 1 (core) capital required for minimum capital adequacy, fully phased- in, Capital amount	$ 1,106,977	$ 518,733
Tier 1 (core) capital required for minimum capital adequacy ratio, fully phased-in, Ratio	4.00%	4.00%

Stockholders' Equity - Reconcil

Stockholders' Equity - Reconciliation of Stockholders' Equity to Bank Regulatory Capital (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total U.S. GAAP stockholders’ equity	$ 4,240,178	$ 1,855,183	$ 1,665,073	$ 975,200
Net accumulated other comprehensive income components	469	(14,511)	(1,873)
Allowance for loan losses and off-balance sheet commitments	77,907	63,622	$ 50,145	$ 42,374
Sterling Bancorp
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total U.S. GAAP stockholders’ equity	4,240,178	1,855,183
Disallowed goodwill and other intangible assets	(1,668,680)	(721,079)
Net unrealized loss on available for sale securities	22,324	22,637
Net accumulated other comprehensive income components	3,847	3,998
Tier 1 risk-based capital	2,597,669	1,160,739
Tier 2 capital	142,174	152,641
Allowance for loan losses and off-balance sheet commitments	78,561	64,167
Total risk-based capital	2,818,404	1,377,547
Sterling National Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total U.S. GAAP stockholders’ equity	4,373,108	1,843,476
Disallowed goodwill and other intangible assets	(1,628,898)	(693,614)
Net unrealized loss on available for sale securities	22,324	22,637
Net accumulated other comprehensive income components	3,847	3,998
Tier 1 risk-based capital	2,770,381	1,176,497
Tier 2 capital	172,716	172,501
Allowance for loan losses and off-balance sheet commitments	78,561	64,167
Total risk-based capital	$ 3,021,658	$ 1,413,165

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 02, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 27, 2018
Class of Stock [Line Items]
Aggregate dividend capacity without prior regulatory approval		$ 190,117
Preferred stock, shares issued		135,000	0
Preferred stock		$ 139,220	$ 0
Preferred stock, par value (USD per share)	$ 1	$ 0.01	$ 0.01
Shares available for repurchase program (shares)		776,713
Percentage of common stock outstanding authorized to be repurchased		4.40%
Subsequent Event
Class of Stock [Line Items]
Shares authorized to be repurchased (in shares)					10,000,000
Sterling Bancorp
Class of Stock [Line Items]
Allowance for Subordinated Notes		$ 142,174	$ 152,641
Shares repurchased under repurchase program (shares)		0	0	0
Sterling National Bank
Class of Stock [Line Items]
Allowance for Subordinated Notes		$ 172,716	$ 172,501
Liquidation account		$ 13,300
Astoria Financial Corporation
Class of Stock [Line Items]
Preferred stock	$ 129,796
Depositary shares issued (in shares)	5,400,000
Astoria Financial Corporation | Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued	135,000
Preferred stock	$ 135,000
Preferred stock dividend rate	6.50%
Preferred stock, par value (USD per share)	$ 0.01
Preferred stock liquidation preference (USD per share)	$ 1,000,000
Astoria Financial Corporation | Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	6.50%

Off-Balance-Sheet Financial 117

Off-Balance-Sheet Financial Instruments - Contractual or Notional Amounts (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loan origination commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Lending-related instruments	$ 510,135	$ 245,319
Unused lines of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Lending-related instruments	1,195,656	968,288
Letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Lending-related instruments	$ 166,824	$ 114,582

Off-Balance-Sheet Financial 118

Off-Balance-Sheet Financial Instruments - Narrative (Details) - Letters of credit - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Lending-related instruments	$ 166,824	$ 114,582
Assets secured by cash as collateral	46,455
Assets secured by other collateral	$ 33,538

Commitments and Contingencie119

Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,018	$ 20,691
2,019	18,867
2,020	17,666
2,021	14,966
2,022	11,096
2023 and thereafter	31,682
Total future minimum payments	114,968
Rent expense	$ 10,647	$ 10,430	$ 9,566

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other securities:
Securities available for sale	$ 3,612,072	$ 1,727,417
Swaps	4,457
Swaps	7,980
Level 1 inputs
Other securities:
Securities available for sale	0	0
Swaps	0	0
Swaps	0	0
Level 2 inputs
Other securities:
Securities available for sale	3,612,072	1,727,417
Swaps	4,457	2,088
Swaps	7,980	2,088
Level 3 inputs
Other securities:
Securities available for sale	0	0
Swaps	0	0
Swaps	0	0
Fair Value, Measurements, Recurring
Residential MBS:
Mortgage-backed securities-residential	2,800,052	1,250,162
Other securities:
Total investment securities available for sale	812,020	477,255
Securities available for sale	3,612,072	1,727,417
Swaps	4,457	2,088
Total assets	3,616,529	1,729,505
Swaps	7,980	2,088
Total liabilities	7,980	2,088
Fair Value, Measurements, Recurring | Agency-backed
Residential MBS:
Mortgage-backed securities-residential	2,150,649	1,193,481
Fair Value, Measurements, Recurring | CMO/Other MBS
Residential MBS:
Mortgage-backed securities-residential	649,403	56,681
Fair Value, Measurements, Recurring | Federal agencies
Other securities:
Total investment securities available for sale	399,996	193,979
Fair Value, Measurements, Recurring | Corporate bonds
Other securities:
Total investment securities available for sale	148,226	42,506
Fair Value, Measurements, Recurring | State and municipal
Other securities:
Total investment securities available for sale	263,798	240,770
Fair Value, Measurements, Recurring | Level 1 inputs
Residential MBS:
Mortgage-backed securities-residential	0	0
Other securities:
Total investment securities available for sale	0	0
Securities available for sale	0	0
Swaps	0	0
Total assets	0	0
Swaps	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 inputs | Agency-backed
Residential MBS:
Mortgage-backed securities-residential	0	0
Fair Value, Measurements, Recurring | Level 1 inputs | CMO/Other MBS
Residential MBS:
Mortgage-backed securities-residential	0	0
Fair Value, Measurements, Recurring | Level 1 inputs | Federal agencies
Other securities:
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Level 1 inputs | Corporate bonds
Other securities:
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Level 1 inputs | State and municipal
Other securities:
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Level 2 inputs
Residential MBS:
Mortgage-backed securities-residential	2,800,052	1,250,162
Other securities:
Total investment securities available for sale	812,020	477,255
Securities available for sale	3,612,072	1,727,417
Swaps	4,457	2,088
Total assets	3,616,529	1,729,505
Swaps	7,980	2,088
Total liabilities	7,980	2,088
Fair Value, Measurements, Recurring | Level 2 inputs | Agency-backed
Residential MBS:
Mortgage-backed securities-residential	2,150,649	1,193,481
Fair Value, Measurements, Recurring | Level 2 inputs | CMO/Other MBS
Residential MBS:
Mortgage-backed securities-residential	649,403	56,681
Fair Value, Measurements, Recurring | Level 2 inputs | Federal agencies
Other securities:
Total investment securities available for sale	399,996	193,979
Fair Value, Measurements, Recurring | Level 2 inputs | Corporate bonds
Other securities:
Total investment securities available for sale	148,226	42,506
Fair Value, Measurements, Recurring | Level 2 inputs | State and municipal
Other securities:
Total investment securities available for sale	263,798	240,770
Fair Value, Measurements, Recurring | Level 3 inputs
Residential MBS:
Mortgage-backed securities-residential	0	0
Other securities:
Total investment securities available for sale	0	0
Securities available for sale	0	0
Swaps	0	0
Total assets	0	0
Swaps	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 3 inputs | Agency-backed
Residential MBS:
Mortgage-backed securities-residential	0	0
Fair Value, Measurements, Recurring | Level 3 inputs | CMO/Other MBS
Residential MBS:
Mortgage-backed securities-residential	0	0
Fair Value, Measurements, Recurring | Level 3 inputs | Federal agencies
Other securities:
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Level 3 inputs | Corporate bonds
Other securities:
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Level 3 inputs | State and municipal
Other securities:
Total investment securities available for sale	$ 0	$ 0

Fair Value Measurements - Impai

Fair Value Measurements - Impaired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Level 1 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	$ 0	$ 0
Level 2 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0	0
Level 3 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	19,903,231	9,461,469
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	896	6,786
Fair Value, Measurements, Nonrecurring | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	114
Fair Value, Measurements, Nonrecurring | CRE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	782	6,786
Fair Value, Measurements, Nonrecurring | Level 1 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0	0
Fair Value, Measurements, Nonrecurring | Level 1 inputs | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0
Fair Value, Measurements, Nonrecurring | Level 1 inputs | CRE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0	0
Fair Value, Measurements, Nonrecurring | Level 2 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0	0
Fair Value, Measurements, Nonrecurring | Level 2 inputs | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0
Fair Value, Measurements, Nonrecurring | Level 2 inputs | CRE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	0	0
Fair Value, Measurements, Nonrecurring | Level 3 inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	896	6,786
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	114
Fair Value, Measurements, Nonrecurring | Level 3 inputs | CRE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio loans, impaired, net	$ 782	$ 6,786

Fair Value Measurements - Unob

Fair Value Measurements - Unobservable Inputs to Level 3 (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)speed	Dec. 31, 2016USD ($)speed
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights	$ 10,363	$ 1,024
Level 3 inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	19,903,231	9,461,469
Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	896	6,786
Fair Value, Measurements, Nonrecurring | Level 3 inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	896	6,786
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | CRE
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net		1,034
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Impaired | Commercial and industrial
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	$ 114
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Impaired | Commercial and industrial | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Current conditions/selling cost adjustments	10.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Impaired | Commercial and industrial | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Current conditions/selling cost adjustments	19.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Impaired | Commercial and industrial | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Current conditions/selling cost adjustments	14.40%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Impaired | CRE
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	$ 782	$ 6,786
Comparability adjustments	22.00%	22.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Taken in Foreclosure | CRE
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	$ 7,271	$ 3,919
Current conditions/selling cost adjustments	22.00%	22.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Taken in Foreclosure | Residential mortgage
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	$ 17,537	$ 4,929
Current conditions/selling cost adjustments	22.00%	22.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Appraisal | Taken in Foreclosure | ADC
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans, net	$ 2,287	$ 3,737
Current conditions/selling cost adjustments	22.00%	22.00%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment speed | speed	9.79	100
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment speed | speed	16.76	555
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment speed | speed	10.30	174
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Mortgage servicing rights
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights	$ 10,363	$ 1,024
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Mortgage servicing rights | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rates	9.50%	8.50%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Mortgage servicing rights | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rates	20.00%	11.50%
Fair Value, Measurements, Nonrecurring | Level 3 inputs | Third-party | Mortgage servicing rights | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rates	9.90%	9.70%

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale	$ 3,612,072	$ 1,727,417
Securities held to maturity	2,863,909	1,357,997
Swaps	4,457
Senior Notes	(278,209)	(76,469)
Subordinated notes	172,716	172,501
Swaps	(7,980)
Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	479,906	293,646
Securities available for sale	3,612,072	1,727,417
Securities held to maturity	2,862,489	1,391,421
Loans, net	19,931,076	9,463,608
Loans held for sale	5,246	41,889
Accrued interest receivable on securities	34,652	16,495
Accrued interest receivable on loans	59,446	26,824
FHLB stock and FRB stock	284,112	135,098
Swaps	4,457	2,088
Non-maturity deposits	(18,098,566)	(9,484,505)
Certificates of deposit	(2,439,638)	(583,754)
FHLB borrowings	(4,510,123)	(1,791,000)
Other borrowings	(30,162)	(16,642)
Senior Notes	(278,209)	(76,469)
Subordinated notes	172,716
Mortgage escrow funds	(122,641)	(13,572)
Accrued interest payable on deposits	(1,103)	(663)
Accrued interest payable on borrowings	(9,649)	(3,621)
Swaps	(7,980)	(2,088)
Level 1 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	479,906	293,646
Securities available for sale	0	0
Securities held to maturity	0	0
Loans, net	0	0
Loans held for sale	0	0
Accrued interest receivable on securities	0	0
Accrued interest receivable on loans	0	0
FHLB stock and FRB stock	0	0
Swaps	0	0
Non-maturity deposits	(18,098,566)	(9,484,505)
Certificates of deposit	0	0
FHLB borrowings	0	0
Other borrowings	0	0
Senior Notes	0	0
Subordinated notes	0
Mortgage escrow funds	0	0
Accrued interest payable on deposits	0	0
Accrued interest payable on borrowings	0	0
Swaps	0	0
Level 2 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Securities available for sale	3,612,072	1,727,417
Securities held to maturity	2,863,909	1,357,997
Loans, net	0	0
Loans held for sale	5,246	41,889
Accrued interest receivable on securities	34,652	16,495
Accrued interest receivable on loans	0	0
FHLB stock and FRB stock	0	0
Swaps	4,457	2,088
Non-maturity deposits	0	0
Certificates of deposit	(2,412,495)	(582,811)
FHLB borrowings	(4,496,184)	(1,788,676)
Other borrowings	(30,160)	(16,642)
Senior Notes	(278,968)	(79,283)
Subordinated notes	179,619
Mortgage escrow funds	(117,050)	(13,572)
Accrued interest payable on deposits	(1,103)	(663)
Accrued interest payable on borrowings	(9,649)	(3,621)
Swaps	(7,980)	(2,088)
Level 3 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Securities available for sale	0	0
Securities held to maturity	0	0
Loans, net	19,903,231	9,461,469
Loans held for sale	0	0
Accrued interest receivable on securities	0	0
Accrued interest receivable on loans	59,446	26,824
FHLB stock and FRB stock	0	0
Swaps	0	0
Non-maturity deposits	0	0
Certificates of deposit	0	0
FHLB borrowings	0	0
Other borrowings	0	0
Senior Notes	0	0
Subordinated notes	0
Mortgage escrow funds	0	0
Accrued interest payable on deposits	0	0
Accrued interest payable on borrowings	0	0
Swaps	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Changes in fair value recognized on provisions on loans held by the Company	$ 280,000	$ 513,000	$ 0
Mortgage servicing rights	10,363,000	1,024,000
Assets taken in foreclosure, defaulted loans and facilities held for sale	27,095,000	13,619,000
Changes in fair value recognized through income for foreclosed assets held by the Company	2,273,000	582,000	$ 0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, net	$ 60,862,000	$ 55,391,000

Accumulated Other Comprehens125

Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, related tax benefit	$ 17,083	$ 17,390
Accumulated other comprehensive loss, net	(26,166)	(26,635)
Net unrealized holding gain (loss) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(36,899)	(37,417)
Accumulated other comprehensive loss, related tax benefit	14,575	14,780
Accumulated other comprehensive loss, net	(22,324)	(22,637)
Net unrealized holding gain (loss) on securities transferred to held to maturity
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(4,426)	(5,395)
Accumulated other comprehensive loss, related tax benefit	1,748	2,131
Accumulated other comprehensive loss, net	(2,678)	(3,264)
Net unrealized holding gain (loss) on retirement plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(1,924)	(1,213)
Accumulated other comprehensive loss, related tax benefit	760	479
Accumulated other comprehensive loss, net	$ (1,164)	$ (734)

Accumulated Other Comprehens126

Accumulated Other Comprehensive Income (Loss) - Changes in AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	$ 1,855,183	$ 1,665,073	$ 975,200
Other comprehensive income before reclassification	64	(11,087)	(5,080)
Amounts reclassified from AOCI	405	(3,424)	3,207
Total other comprehensive (loss) income	469	(14,511)	(1,873)
Balance	4,240,178	1,855,183	1,665,073
Net unrealized holding gain (loss) on AFS securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(22,637)	(6,999)	1,297
Other comprehensive income before reclassification	64	(11,087)	(5,515)
Amounts reclassified from AOCI	249	(4,551)	(2,781)
Total other comprehensive (loss) income	313	(15,638)	(8,296)
Balance	(22,324)	(22,637)	(6,999)
Net unrealized holding gain (loss) on securities transferred to held to maturity
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(3,264)	(4,155)	(4,967)
Other comprehensive income before reclassification	0	0	0
Amounts reclassified from AOCI	586	891	812
Total other comprehensive (loss) income	586	891	812
Balance	(2,678)	(3,264)	(4,155)
Net unrealized holding gain (loss) on retirement plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(734)	(970)	(6,581)
Other comprehensive income before reclassification	0	0	435
Amounts reclassified from AOCI	(430)	236	5,176
Total other comprehensive (loss) income	(430)	236	5,611
Balance	(1,164)	(734)	(970)
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(26,635)	(12,124)	(10,251)
Balance	$ (26,166)	$ (26,635)	$ (12,124)

Condensed Parent Company Fin127

Condensed Parent Company Financial Statements - Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Cash	$ 479,906	$ 293,646	$ 229,513	$ 121,520
Goodwill	1,579,891	696,600	670,699
Other assets	357,005	48,270
Total assets	30,359,541	14,178,447
Liabilities:
Senior Notes	278,209	76,469
Other liabilities	467,308	184,821
Total liabilities	26,119,363	12,323,264
Stockholders’ equity	4,240,178	1,855,183	1,665,073	975,200
Total liabilities and stockholders’ equity	30,359,541	14,178,447
Sterling Bancorp
Assets:
Cash	88,174	48,765	$ 19,529	$ 13,761
Investment in the Bank	4,373,108	1,843,476
Goodwill	27,910	20,023
Trade name	20,500	20,500
Other assets	16,842	3,258
Total assets	4,526,534	1,936,022
Liabilities:
Senior Notes	278,209	76,469
Other liabilities	8,147	4,370
Total liabilities	286,356	80,839
Stockholders’ equity	4,240,178	1,855,183
Total liabilities and stockholders’ equity	$ 4,526,534	$ 1,936,022

Condensed Parent Company Fin128

Condensed Parent Company Financial Statements - Statements of Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net gain on sale of trust division									$ (344,000)	$ 7,522,000	$ 4,837,000
Interest expense	$ (42,471,000)	$ (25,619,000)	$ (21,005,000)	$ (17,210,000)	$ (15,827,000)	$ (15,031,000)	$ (13,929,000)	$ (12,495,000)	(106,306,000)	(57,282,000)	(36,925,000)
Non-interest expense	(250,746,000)	(62,617,000)	(59,657,000)	(60,350,000)	(57,072,000)	(62,256,000)	(59,640,000)	(68,934,000)	(433,375,000)	(247,902,000)	(260,318,000)
Income tax benefit	(28,319,000)	(21,592,000)	(20,319,000)	(17,709,000)	(19,737,000)	(16,991,000)	(18,412,000)	(12,242,000)	(87,939,000)	(67,382,000)	(31,835,000)
Net income	(33,279,000)	44,852,000	42,400,000	39,067,000	40,996,000	37,422,000	37,770,000	23,784,000	93,031,000	139,972,000	66,114,000
Preferred stock dividend	2,002,000	0	0	0	0	0	0	0		0	0
Net income available to common stockholders	$ (35,281,000)	$ 44,852,000	$ 42,400,000	$ 39,067,000	$ 40,996,000	$ 37,422,000	$ 37,770,000	$ 23,784,000	91,029,000	139,972,000	66,114,000
Sterling Bancorp
Condensed Financial Statements, Captions [Line Items]
Interest income									29,000	14,000	15,000
Interest expense									(6,186,000)	(5,398,000)	(5,894,000)
Non-interest expense									(9,225,000)	(12,989,000)	(7,031,000)
Income tax benefit									7,258,000	3,700,000	4,154,000
Income before equity in undistributed earnings of subsidiaries									21,876,000	52,608,000	34,244,000
Net income									93,031,000	139,972,000	66,114,000
Preferred stock dividend									2,002,000	0	0
Net income available to common stockholders									91,029,000	139,972,000	66,114,000
Sterling Bancorp | Sterling National Bank
Condensed Financial Statements, Captions [Line Items]
Dividend income from subsidiaries									30,000,000	60,000,000	42,500,000
Equity in undistributed (excess distributed) earnings									71,155,000	87,364,000	32,230,000
Sterling Bancorp | Non-bank Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Dividend income from subsidiaries									0	5,026,000	500,000
Net gain on sale of trust division									0	2,255,000	0
Equity in undistributed (excess distributed) earnings									$ 0	$ 0	$ (360,000)

Condensed Parent Company Fin129

Condensed Parent Company Financial Statements - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ (33,279)	$ 44,852	$ 42,400	$ 39,067	$ 40,996	$ 37,422	$ 37,770	$ 23,784	$ 93,031	$ 139,972	$ 66,114
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on extinguishment of borrowings									0	9,729	0
Other adjustments, net									(105,331)	22,404	(62,977)
Net cash provided by operating activities									242,605	198,899	91,756
Cash flows from investing activities:
Net cash (used in) investing activities									(1,409,294)	(2,210,144)	(636,759)
Cash flows from financing activities:
Repayment of Senior Notes									0	(23,793)	0
Net cash provided by financing activities									1,352,949	2,075,378	652,996
Net increase in cash and cash equivalents									186,260	64,133	107,993
Cash and cash equivalents at beginning of period				293,646				229,513	293,646	229,513	121,520
Cash and cash equivalents at end of period	479,906				293,646				479,906	293,646	229,513
Sterling Bancorp
Cash flows from operating activities:
Net income									93,031	139,972	66,114
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on extinguishment of borrowings									0	1,013	0
Other adjustments, net									61,184	6,273	(3,123)
Net cash provided by operating activities									83,060	59,894	31,121
Cash flows from investing activities:
Sales of securities									0	3	0
Investment in subsidiaries									0	(65,000)	(84,500)
Net cash (used in) investing activities									0	(64,997)	(84,500)
Cash flows from financing activities:
Equity capital raise									0	90,995	85,059
Repayment of Senior Notes									0	(23,793)	0
Cash dividends paid									(46,229)	(36,451)	(30,384)
Stock-based compensation transactions									2,578	3,588	4,472
Net cash provided by financing activities									(43,651)	34,339	59,147
Net increase in cash and cash equivalents									39,409	29,236	5,768
Cash and cash equivalents at beginning of period				$ 48,765				$ 19,529	48,765	19,529	13,761
Cash and cash equivalents at end of period	$ 88,174				$ 48,765				88,174	48,765	19,529
Sterling Bancorp | Sterling National Bank
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in (undistributed) excess distributed earnings									(71,155)	(87,364)	(32,230)
Sterling Bancorp | Non-bank Subsidiaries
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in (undistributed) excess distributed earnings									$ 0	$ 0	$ 360

Quarterly Results of Operati130

Quarterly Results of Operations (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Interest and dividend income	$ 276,495,000	$ 145,692,000	$ 134,263,000	$ 126,000,000	$ 123,075,000	$ 118,161,000	$ 114,309,000	$ 106,006,000	$ 682,449,000	$ 461,551,000	$ 348,141,000
Interest expense	42,471,000	25,619,000	21,005,000	17,210,000	15,827,000	15,031,000	13,929,000	12,495,000	106,306,000	57,282,000	36,925,000
Net interest income	234,024,000	120,073,000	113,258,000	108,790,000	107,248,000	103,130,000	100,380,000	93,511,000	576,143,000	404,269,000	311,216,000
Provisions for loan losses	12,000,000	5,000,000	4,500,000	4,500,000	5,500,000	5,500,000	5,000,000	4,000,000	26,000,000	20,000,000	15,700,000
Non-interest income	23,762,000	13,988,000	13,618,000	12,836,000	16,057,000	19,039,000	20,442,000	15,449,000	64,202,000	70,987,000	62,751,000
Non-interest expense	250,746,000	62,617,000	59,657,000	60,350,000	57,072,000	62,256,000	59,640,000	68,934,000	433,375,000	247,902,000	260,318,000
Income before income taxes	(4,960,000)	66,444,000	62,719,000	56,776,000	60,733,000	54,413,000	56,182,000	36,026,000	180,970,000	207,354,000	97,949,000
Income tax expense	28,319,000	21,592,000	20,319,000	17,709,000	19,737,000	16,991,000	18,412,000	12,242,000	87,939,000	67,382,000	31,835,000
Net income	(33,279,000)	44,852,000	42,400,000	39,067,000	40,996,000	37,422,000	37,770,000	23,784,000	93,031,000	139,972,000	66,114,000
Preferred stock dividend	2,002,000	0	0	0	0	0	0	0		0	0
Net income available to common stockholders	$ (35,281,000)	$ 44,852,000	$ 42,400,000	$ 39,067,000	$ 40,996,000	$ 37,422,000	$ 37,770,000	$ 23,784,000	$ 91,029,000	$ 139,972,000	$ 66,114,000
Basic (USD per share)	$ (0.16)	$ 0.33	$ 0.31	$ 0.29	$ 0.31	$ 0.29	$ 0.29	$ 0.18	$ 0.58	$ 1.07	$ 0.60
Diluted (USD per share)	$ (0.16)	$ 0.33	$ 0.31	$ 0.29	$ 0.31	$ 0.29	$ 0.29	$ 0.18	$ 0.58	$ 1.07	$ 0.60
Estimated deferred tax adjustment related to reduction in federal income tax rate	$ 40,285,000								$ 40,285,000	$ 0	$ 0
Other restructuring charges	30,230,000
Charge of asset write-downs, systems integration, severance and retention	$ 104,506,000								$ 105,110,000	$ 4,485,000	$ 40,350,000