Sterling Bancorp (STL) 10-K 28 Nov 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Sep. 30, 2014	Nov. 26, 2014	Mar. 31, 2014
Document Information [Line Items]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--09-30	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'FY	'	'
Entity Registrant Name	'STERLING BANCORP	'	'
Entity Central Index Key	'0001070154	'	'
Document Period End Date	30-Sep-14	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	83,899,070	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Public Float	'	'	$1,057,670,927
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and due from banks	$177,619	$113,090
Securities	'	'
Available-for-sale Securities	1,110,813	954,393
Held to maturity, at amortized cost (fair value of $587,838 and $250,896 in 2014 and 2013, respectively)	579,075	253,999
Total securities	1,689,888	1,208,392
Loans held for sale	17,846	1,011
Gross loans	4,760,438	2,412,898
Allowance for loan losses	-40,612	-28,877
Total loans, net	4,719,826	2,384,021
Federal Home Loan Bank (“FHLB”) stock, at cost	66,085	24,312
Accrued interest receivable	19,667	11,698
Premises and equipment, net	43,286	36,520
Goodwill	388,926	163,117
Core deposit and other intangible assets	45,278	5,891
Bank owned life insurance	119,486	60,914
Other real estate owned	7,580	6,022
Other assets	41,900	34,184
Total assets	7,337,387	4,049,172
LIABILITIES:	'	'
Deposits	5,298,654	2,962,294
FHLB and other borrowings	795,028	462,953
Other borrowings (federal funds purchased and repurchase agreements)	45,639	0
Senior notes	98,402	98,033
Mortgage escrow funds	4,494	12,646
Other liabilities	134,032	30,380
Total liabilities	6,376,249	3,566,306
Commitments and Contingent liabilities	'	'
STOCKHOLDERS’ EQUITY:	'	'
Preferred stock (par value $0.01 per share; 10,000,000 shares authorized; none issued or outstanding)	0	0
Common stock (par value $0.01 per share; 190,000,000 shares authorized; 91,246,024 and 52,188,056 issued for 2014 and 2013, respectively; 83,628,267 and 44,351,046 shares outstanding in 2014 and 2013, respectively)	912	522
Additional paid-in capital	860,564	403,816
Unallocated common stock held by employee stock ownership plan (“ESOP”); 0 and 549,262 unallocated shares outstanding in 2014 and 2013, respectively	0	-5,493
Treasury stock, at cost (7,617,757 shares in 2014 and 7,837,010 shares in 2013)	-86,339	-88,538
Retained earnings	197,460	187,889
Accumulated other comprehensive (loss), net of tax (benefit) of ($8,470) in 2014 and ($10,482) in 2013	-11,459	-15,330
Total stockholders’ equity	961,138	482,866
Total liabilities and stockholders’ equity	$7,337,387	$4,049,172

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Condition (Parenthetical) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Securities held to maturity	$587,838	$250,896
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized	190,000,000	190,000,000
Common stock, shares issued	91,246,024	52,188,056
Common stock, shares outstanding	83,628,267	44,351,046
Treasury stock, shares	7,617,757	7,837,010
Unallocated ESOP Shares outstanding	0	549,262
Accumulated other comprehensive income, tax	($8,470)	($10,482)

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Interest and dividend income:	'		'		'
Loans, including fees	$202,982		$107,810		$91,010
Taxable securities	30,067		17,509		16,538
Non-taxable securities	10,453		5,682		6,497
Other earning assets	3,404		1,060		992
Total interest and dividend income	246,906		132,061		115,037
Interest expense:	'		'		'
Deposits	8,964		5,923		5,581
Borrowings	19,954		13,971		12,992
Total interest expense	28,918		19,894		18,573
Net interest income	217,988		112,167		96,464
Provisions for loan losses	19,100		12,150		10,612
Net interest income after provision for loan losses	198,888		100,017		85,852
Non-interest income:	'		'		'
Accounts receivable management / factoring commissions and other related fees	13,146		0		0
Mortgage banking income	8,086		1,979		1,897
Deposit fees and service charges	15,595		10,964		11,377
Net gain on sale of securities	641		7,391		10,452
Bank owned life insurance	3,080		1,998		2,050
Investment management fees	2,209		2,413		3,143
Other	4,613		2,947		3,233
Total non-interest income	47,370		27,692		32,152
Non-interest expense:	'		'		'
Compensation and employee benefits	94,310		47,833		46,038
Stock-based compensation plans	3,703		2,239		1,187
Occupancy and office operations	27,726		14,953		14,457
Amortization of intangible assets	9,408		1,296		1,245
FDIC insurance and regulatory assessments	6,146		3,010		3,096
Other real estate owned (income) expense, net	-237		1,562		1,618
Merger related expense	9,455		2,772		5,925
Other	57,917		17,376		18,391
Total non-interest expense	208,428		91,041		91,957
Income before income tax expense	37,830		36,668		26,047
Income tax expense	10,152		11,414		6,159
Net income	$27,678		$25,254		$19,888
Weighted average common shares:	'		'		'
Basic (in shares)	80,268,970	[1]	43,734,425	[1]	38,227,653	[1]
Diluted (in shares)	80,534,043		43,783,053		38,248,046
Earnings per common share	'		'		'
Basic (USD per share)	$0.34		$0.58		$0.52
Diluted (USD per share)	$0.34		$0.58		$0.52
[1]	Includes earned ESOP shares.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]	'	'	'
Net income	$27,678	$25,254	$19,888
Other comprehensive income (“OCI”) (loss):	'	'	'
Change in unrealized holding gains (losses) on securities available for sale	15,948	-37,324	12,866
Related income tax (expense) benefit	-6,778	15,157	-5,224
Change in net unrealized (loss) on securities transferred to held to maturity	-8,947	0	0
Related income tax benefit	3,803	0	0
Less:	'	'	'
Reclassification adjustment for net realized (gains) included in net income	-641	-7,391	-10,452
Related income tax expense	272	3,001	4,245
Reclassification adjustment for other than temporary impaired losses included in net income	0	32	47
Related income tax benefit	0	-13	-19
Total OCI securities component	3,657	-26,538	1,463
Acceleration of future amortization of accumulated other comprehensive loss on defined benefit pension plan and change in funded status of defined benefit plans	372	7,255	505
Related income tax (expense)	-158	-2,946	-205
Other comprehensive income	3,871	-22,229	1,763
Total comprehensive income	$31,549	$3,025	$21,651

Consolidated_Statement_of_Chan

Consolidated Statement of Changes In Stockholders' Equity (USD $)	Total	Common stock	Additional paid-in capital	Unallocated ESOP shares	Treasury stock	Retained earnings	Accumulated other comprehensive income (loss)
In Thousands, except Share data, unless otherwise specified
Balance at Sep. 30, 2011	$431,134	$459	$357,063	($6,138)	($90,585)	$165,199	$5,136
Balance, shares at Sep. 30, 2011	'	37,864,008	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	19,888	'	'	'	'	19,888	'
Other comprehensive income	1,763	'	'	'	'	'	1,763
Stock option & other stock transactions, net	685	0	685	0	0	0	0
Stock option & other stock transactions, net, shares	'	0	'	'	'	'	'
ESOP shares allocated or committed to be released for allocation	-543	0	-43	-500	0	0	0
ESOP shares allocated or committed to be released for allocation, shares	49,932	'	'	'	'	'	'
Restricted stock awards, net	209	0	-187	0	412	-16	0
Restricted stock awards, net, shares	'	50,958	'	'	'	'	'
Capital raise	46,000	63	45,937	'	'	'	'
Capital raise, shares	'	6,258,504	'	'	'	'	'
Cash dividends declared	-9,100	0	0	0	0	-9,100	0
Balance at Sep. 30, 2012	491,122	522	403,541	-5,638	-90,173	175,971	6,899
Balance, shares at Sep. 30, 2012	'	44,173,470	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	25,254	'	'	'	'	25,254	'
Other comprehensive income	-22,229	'	'	'	'	'	-22,229
Stock option & other stock transactions, net	792	0	730	0	95	-33	0
Stock option & other stock transactions, net, shares	'	8,250	'	'	'	'	'
ESOP shares allocated or committed to be released for allocation	-264	0	-119	-145	0	0	0
ESOP shares allocated or committed to be released for allocation, shares	49,932	'	'	'	'	'	'
Restricted stock awards, net	966	0	-574	0	1,540	0	0
Restricted stock awards, net, shares	'	169,326	'	'	'	'	'
Cash dividends declared	-13,303	0	0	0	0	-13,303	'
Balance at Sep. 30, 2013	482,866	522	403,816	-5,493	-88,538	187,889	-15,330
Balance, shares at Sep. 30, 2013	'	44,351,046	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	27,678	0	0	0	0	27,678	0
Other comprehensive income	3,871	0	0	0	0	0	3,871
Common stock issued in Legacy Sterling merger transaction	457,752	390	457,362	'	'	'	'
Common stock issued in legacy Sterling Bancorp merger transaction, shares	'	39,057,968	'	'	'	'	'
Stock option & other stock transactions, net	3,783	0	880	0	3,333	-430	0
Stock option & other stock transactions, net, shares	'	267,188	'	'	'	'	'
ESOP shares allocated or committed to be released for allocation	-790	0	-1,280	-5,493	5,983	0	0
ESOP shares allocated or committed to be released for allocation, shares	'	488,403	'	'	'	'	'
Restricted stock awards, net	2,075	0	-2,774	0	4,849	0	0
Restricted stock awards, net, shares	'	440,468	'	'	'	'	'
Cash dividends declared	-17,677	0	0	0	0	-17,677	0
Balance at Sep. 30, 2014	$961,138	$912	$860,564	$0	($86,339)	$197,460	($11,459)
Balance, shares at Sep. 30, 2014	'	83,628,267	'	'	'	'	'

Consolidated_Statement_of_Chan1

Consolidated Statement of Changes In Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Stockholders' Equity [Abstract]	'	'	'
ESOP shares allocated or committed to be released for allocation, shares	'	49,932	49,932
Cash dividends paid (USD per share)	$0.21	$0.30	$0.24

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Cash flows from operating activities:	'		'		'
Net income	$27,678		$25,254		$19,888
Adjustments to reconcile net income to net cash provided by operating activities	'		'		'
Provisions for loan losses	19,100		12,150		10,612
(Gain) loss on other real estate owned	-1,208		1,285		694
(Gain) on redemption of Subordinated Debentures	-712		0		0
Depreciation of premises and equipment	6,507		4,243		4,746
Impairment of premises and equipment	11,043		0		0
Amortization of intangibles	9,408		1,296		1,245
Amortization of low income housing tax credit	520		0		0
Net gain on sale of securities	-641		-7,391		-10,452
Net gains on loans held for sale	-8,086		-1,979		-1,897
(Gain) loss on sale of premises and equipment	-93		75		-75
Accretion of premiums on borrowings (includes calls on borrowings)	3,176		2,068		-1,006
Change in unamortized acquisition costs and premiums	1,028		1,050		0
Accretion of premiums on borrowings (includes calls on borrowings)	-446		87		-67
Amortization of payment fees on restructured borrowings	1,302		1,466		1,459
ESOP and restricted stock expense	2,803		1,544		667
Stock option compensation expense	901		695		521
Originations of loans held for sale	-462,030		-85,657		-80,579
Proceeds from sales of loans held for sale	483,622		94,130		79,147
Increase in cash surrender value of bank owned life insurance	-3,198		-1,998		-2,050
Deferred income tax (benefit) expense	-3,507		719		-64
Other adjustments (principally net changes in other assets and other liabilities)	40,497		-26,413		2,237
Net cash provided by operating activities	127,664		22,624		25,026
Cash flows from investing activities:	'		'		'
Available for sale	-407,438		-490,160		-679,553
Held to maturity	-172,899		-169,320		-95,157
Proceeds from maturities, calls and other principal payments on securities	'		'		'
Available for sale	163,199		168,771		174,497
Held to maturity	31,227		55,866		63,037
Proceeds from sales of securities available for sale	529,107		339,123		344,431
Proceeds from sales of securities available for sale	0	[1]	1,187	[1]	0	[1]
Loan originations	-659,013		-310,615		-226,616
Proceeds from sale of FHLB stock, net	-34,093		-5,063		-620
Proceeds from sales of other real estate owned	9,645		4,730		3,468
Purchases of premises and equipment	-2,584		-2,355		-1,853
Proceeds from sale of Hudson Valley Investment Advisors	0		4,738		0
Proceeds from the sale of fixed assets	310		0		75
Purchase low income housing tax credit	-1,966		0		0
Cash received from Gotham acquisition	277,798		0		126,818
Net cash provided by (used in) investing activities	-266,707		-403,098		-291,473
Cash flows from financing activities	'		'		'
Net increase in transaction, savings and money market deposits	301,028		-29,503		499,340
Net decrease in time deposits	-261,858		-119,354		-53,786
Net decrease in short-term borrowings	103,000		91,528		-5,000
Gross repayments of long-term borrowings	147,506		24,783		-5,244
Net (decrease) in repurchase agreements and other short-term borrowings	-37,177		0		0
Redemption of Subordinated Debentures	-26,140		0		0
Payments of pre-payment fees on FHLBNY advances	0		0		-278
Repayment of senior unsecured note	0		0		-51,499
Net proceeds from Senior Notes	0		97,946		0
Net (decrease) increase in mortgage escrow funds	-8,152		727		2,218
Proceeds from Stock Options Exercised	2,980		62		102
Other stock-based compensation transactions	62		35		164
Capital raise	0		0		46,000
Cash dividends paid	-17,677		-10,642		-9,100
Net cash provided by (used in) financing activities	203,572		55,582		422,917
Net increase (decrease) in cash and cash equivalents	64,529		-324,892		156,470
Cash and cash equivalents at beginning of year	113,090		437,982		281,512
Cash and cash equivalents at end of year	177,619		113,090		437,982
Supplemental cash flow information:	'		'		'
Interest payments	29,419		18,831		18,447
Income tax payments	12,473		4,475		1,873
Loans transferred to other real estate owned	2,542		5,634		6,148
Securities purchases settled in subsequent periods	0		0		41,758
Dividends declared, not yet paid	0		2,661		0
Non-cash assets acquired:	'		'		'
Investments available for sale	233,190		0		54,994
Securities held to maturity	374,721		0		0
Loans held for sale	30,341		0		0
Total loans, net	1,698,108		0		205,453
Loans FHLB Stock	7,680		0		1,045
Accrued interest receivable	6,590		0		417
Goodwill	225,809		0		5,535
Trade name	20,500		0		0
Core deposit intangibles	20,089		0		4,818
Bank owned life insurance	55,374		0		0
Premises and equipment, net	23,594		0		490
Other real estate owned	5,815		0		0
Other assets	20,933		0		1,793
Total non-cash assets acquired	2,722,744		0		274,545
Liabilities assumed:	'		'		'
Deposits	2,297,190		0		368,902
FHLB and other borrowings	100,619		0		30,784
Other borrowings	62,465		0		0
Subordinated debentures	26,527		0		0
Other liabilities	55,960		0		1,677
Total liabilities assumed	2,542,761		0		401,363
Net non-cash assets (liabilities) acquired	$179,983		$0		($126,818)
[1]	(1) During the fiscal year ended September 30, 2013, the Company sold held to maturity securities after the Company had already collected at least 85% of the principal balance outstanding at acquisition.

Basis_of_Financial_Statement_P

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2014
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
	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 (“Sterling” or the “Company”).
	•	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.
	•	Provident Municipal Bank merged into Sterling National Bank.
	We refer to the transactions detailed above collectively as the “Merger.”
	The consolidated financial statements include the accounts of Sterling; STL Holdings, Inc. (formerly PBNY Holdings, Inc.) which has an investment in Sterling Silver Title Agency L.P. (formerly PB Madison Title Agency L.P.), a company that provides title searches and title insurance for residential and commercial real estate; LandSave Development, LLC an inactive subsidiary, which was dissolved on September 30, 2014; Sterling Risk Management, Inc. (formerly Provident Risk Management, Inc., a captive insurance company); Sterling National Bank (the “Bank”) and the Bank’s wholly-owned subsidiaries. These subsidiaries included at September 30, 2014: (i) Sterling REIT, Inc. a real estate investment trust that holds a portion of the Company’s real estate loans; (ii) Provest Services Corp. I, which has invested in a low-income housing partnership; (iii) Provest Services Corp. II, which has engaged a third-party provider to sell mutual funds and annuities to the Bank’s customers and (iv) several limited liability companies which hold other real estate owned. Intercompany transactions and balances are eliminated in consolidation.
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America. Certain amounts from prior years have been reclassified to conform to the current fiscal year presentation. Reclassifications had no affect on prior year net income or stockholders’ equity.
	(a) Nature of Business
	Since October 31, 2013, Sterling 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 the Bank. Sterling is listed on the New York Stock Exchange (“NYSE”) under the symbol STL.
	The Bank, an independent, full-service bank founded in 1888, is headquartered in Montebello, New York and is the principal bank subsidiary of Sterling. The Bank accounts for substantially all of Sterling’s consolidated assets and net income. 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 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’s principal business is accepting deposits and, together with funds generated from operations and borrowings, investing in various types of loans and securities. In connection with the Merger, the Bank became a national bank and its 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.
	(b) Use of estimates
	The consolidated financial statements have been prepared in conformity with GAAP. In preparing the consolidated financial statements, the Company is required to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expense. Actual results could differ significantly from these estimates. An estimate that is particularly susceptible to significant near-term change is the allowance for loan losses, which is discussed below. Also subject to change are estimates involving goodwill impairment evaluations, mortgage servicing rights, benefit plans, deferred income taxes and fair values of financial instruments.
	(c) Cash Flows
	For purposes of reporting cash flows, cash equivalents include highly liquid, short-term investments such as overnight federal funds, as well as cash and deposits with other financial institutions. Net cash flows are reported for customer loan and deposit transactions and short-term borrowings with an original maturity of 90 days or less.
	(d) Restrictions on Cash
	The Bank was required to have $28.7 million and $14.6 million of cash on hand or on deposit with the Federal Reserve Bank to meet regulatory reserve and clearing requirements at September 30, 2014 and 2013.
	(e) Long-Term Assets
	Premises and equipment, core deposit and other intangible assets are reviewed annually for impairment or when events indicate their carrying amount may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.
	(f) Fair Values of Financial Instruments
	Fair values of financial instruments are estimated using relevant market information and other assumptions, as more fully disclosed in a separate note. 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. (See Note 17. “Fair Value Measurements”)
	(g) Adoption of New Accounting Standards
	Accounting Standards Update (ASU) 2014-01 - Investments - Equity method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects was issued. This standard provides reporting guidance for entities that invest in qualified affordable housing projects through limited liability entities that are flow through entities for tax purposes. The amendments in this ASU eliminate the effective yield election and permit the Company to make an accounting policy election to account for its investment in qualified affordable housing projects using the proportional amortization method if certain conditions are met. Under the proportional amortization method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the statement of operations as a component of income tax expense. The amendments in this ASU should be applied retrospectively to all periods presented. The Company adopted this ASU in the quarter ended March 31, 2014, which coincided with the Company’s initial recognition of low income housing tax credits. The adoption of this ASU resulted in a $508 income tax benefit and a $520 expense associated with the amortization of the Company’s investment for the fiscal year ended September 30, 2014.
	(h) Securities
	Securities include U.S. Treasury, U.S. Government Agency and Government Sponsored Agencies, municipal and corporate bonds, mortgage-backed securities, collateralized mortgage obligations and trust preferred securities.
	The Company can classify its securities among three categories: held to maturity, trading, 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.
	Trading securities are debt and equity securities held principally for the purpose of selling them in the near-term. These securities are reported at fair value, with unrealized gains and losses included in earnings. The Company does not engage in securities trading activities.
	All other debt and marketable equity securities are classified as available for sale. These 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, changes in prepayment risks, the need to increase capital, or similar factors.
	Premiums and discounts on debt securities are recognized 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 impairment at least quarterly, and more frequently when economic and market conditions warrant such an evaluation. For securities in an unrealized loss position, we consider 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 the Company does not expect to recover the entire amortized cost basis of the security, the Company does not intend to sell the security 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 other than temporary impairment is separated into a) the amount representing the credit loss and b) the amount related to all other factors. The amount of other than temporary impairment 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 September 30, 2014, the Company does 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.
	(i) Loans Held For Sale
	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. In the absence of commitments from investors, fair value is based on current investor yield requirements. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings.
	Historically mortgage loans held for sale were generally sold with servicing rights retained. The carrying value of mortgage loans sold is reduced by the amount allocated to the value of the servicing rights which is its fair value. Gains and losses on sales of mortgage loans are based on the difference between the selling price and the carrying value of the related loan sold.
	(j) Servicing Rights
	When mortgage loans are sold with servicing retained, servicing rights are initially recorded at fair value with the income statement effect recorded in gains on sales of loans. 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. All classes of servicing assets are subsequently measured using the amortization method which requires servicing rights to be amortized into non-interest income in proportion to, and over the period of, the estimated future net servicing income of the underlying loans.
	Under the amortization measurement method, the Company subsequently measures servicing rights at fair value at each reporting date and records any impairment in value of servicing assets in earnings in the period in which the impairment occurs. The fair values of servicing rights are subject to significant fluctuations as a result of changes in estimated and actual prepayment speeds and default rates and losses.
	Servicing fee income, which is reported on the income statement as other income, is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan, and are recorded as income when earned. Servicing fees totaled $911, $778 and $695 for the years ended September 30, 2014, 2013 and 2012, respectively. Late fees and ancillary fees related to loan servicing are not material. Effective October 1, 2013, the Bank outsourced servicing of residential mortgage loans to a nationally recognized mortgage loan servicing company.
	(k) 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 amortized cost less the allowance for loan losses. Interest income on loans is accrued on the unpaid principal balance.
	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, unless 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 not recognized as income unless warranted based on the borrower’s financial condition and payment record. Furthermore, negative tax escrow will be included in the unpaid principal for loans individually evaluated for impairment, as this is part of the customer’s legal obligation to the Company.
	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. If a loan is prepaid or sold, the net deferred amount is recognized in the statement of income at that time. Interest and fees on loans include prepayment fees and late charges collected.
	(l) Allowance for Loan Losses
	The allowance for loan losses is a reserve 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 allowance for loan losses is a critical accounting estimate and requires substantial judgment of management. The allowance for loan losses includes allowance allocations calculated in accordance with ASC Subtopic 450-20, “Loss Contingencies” and ASC Subtopic 310-35-2, “Loan Impairment.” The level of the allowance 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, as well as trends in the foregoing. The Company analyzes loans by two broad segments: real estate secured loans and loans that are either unsecured or secured by other collateral.
	The classes considered real estate secured are: residential mortgage loans; commercial real estate (“CRE”) loans; business banking CRE; multi-family loans; acquisition, development and construction (“ADC”) loans; homeowner loans, and home equity lines of credit. The classes considered unsecured or secured by other than real estate collateral are: commercial & industrial (“C&I”) loans; payroll finance loans, warehouse lending; factored receivables; equipment finance loans; business banking C&I loans and consumer loans. In all segments or classes, significant loans are reviewed for impairment once they are past due 90 days or more or are classified substandard or doubtful. Generally the Company considers a homogeneous residential mortgage or home equity line of credit to be significant if the Company’s investment in the loan is greater than $500. If a loan is deemed to be impaired in one of the real estate secured segment, it is generally considered collateral dependent. If the value of the collateral securing a collateral dependent impaired loan is less than the loan’s carrying value, a charge-off is recognized equal to the difference between the appraised value and the book value of the loan. Additionally, impairment reserves are recognized for estimated costs to hold and liquidate and for a 10% discount on the appraisal value. The range for costs to hold and liquidate is 12-22% for CRE, business banking CRE and ADC loans and is 7-13% for homeowner loans, home equity lines of credit, and residential mortgage loans. Impaired loans in the real estate secured segments are re-appraised using a summary or drive-by appraisal report every six to nine months.
	For loans in the business banking C&I class 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, we prepare a cash flow projection, and charge-off the difference between the net present value of the cash flows discounted at the effective note rate and the carrying value of the loan, and generally recognize a 10% impairment reserve to account for the potential imprecision of our estimates. However, on most of these cases receipt of future cash flows is too unreliable to be considered probable, resulting in the charge-off of the entire balance of the loan. For unsecured consumer loans, charg0- offs are recognized once the loan is 90 to 120 days or more past due or the borrower files for bankruptcy protection.
	Subsequent recoveries, if any, are credited to the allowance for loan losses. The allowance for loan losses consists of amounts specifically allocated to non-performing loans and other criticized or classified loans (if any), as well as allowances determined for the pass rated loans in each major loan category. After we establish an allowance for loan losses for loans that are known to be non-performing, criticized or classified, we calculate a percentage to apply to the remaining loan portfolio to estimate the probable incurred losses inherent in that portion of the portfolio. These percentages are determined by management, based on historical loss experience for the applicable loan class, and are adjusted to reflect our evaluation of:
	•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 borrower; and for commercial loans, trends in risk ratings.
	Commercial real estate loans subject us 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.
	Commercial business 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 we must gain control of assets used in the borrower’s business before foreclosing which we cannot be assured of doing, and the value in a foreclosure sale or other means of liquidation is uncertain.
	Acquisition, development and construction (“ADC”) lending is considered higher risk and exposes us 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. In the event we make a land acquisition loan on property that is not yet approved for the planned development, there is the risk that approvals will not be granted or will be delayed. These events may adversely affect the borrower and the collateral value of the property. Development and construction loans also expose us to the risk that improvements will not be completed on time or in accordance with specifications and projected costs. In addition, the ultimate sale or rental of the property may not occur as anticipated. All of these factors are considered as part of the underwriting, structuring and pricing of the loan. We have deemphasized this type of lending.
	When we evaluate residential mortgage loans and home equity loans we weigh 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 our risk. Similarly, as we obtain a mortgage on the property, if home prices decline, we are exposed to risk in both our first mortgage and equity lending programs due to declines in the value of our collateral. We are also exposed to risk because the time to foreclose is significant and has become longer under current market conditions.
	(m) 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. Not all loans that are restructured as a TDR are classified as non-accrual before the restructuring occurs. 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.
(n) 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.
(o) 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 based on the excess of the carrying amount of assets (generally assets associated with a financial center) over the fair value of the assets. Fair value is determined by third-party valuations and evaluations prepared by management. For the fiscal year ended September 30, 2014, the Company recognized premises and equipment impairment charges of $9.3 million related to financial center consolidations as a result of the Merger. These charges were included in other non-interest expense in the income statement.
(p) 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 acquired in a purchase business combination and determined to have an indefinite useful life are not amortized, but tested for impairment at least annually. Goodwill and trade name are the only intangible assets with an indefinite life on our 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 has the option to first perform a qualitative assessment to test goodwill for impairment on a reporting-unit-by-reporting-unit basis. If, after performing the qualitative assessment, the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will perform the two-step process described below:
1	Identify potential impairments by comparing the fair value of a reporting unit to its carrying amount, including goodwill. Goodwill is not considered impaired as long as the fair value of the reporting unit is greater than its carrying value. The second step is only required if a potential impairment to goodwill is identified in step one.
2	Compare the implied fair value of goodwill to its carrying amount, where the implied fair value of goodwill is computed on a residual basis, that is, by subtracting the sum of the fair values of the individual asset categories (tangible and intangible) from the indicated fair value of the reporting unit as determined under step one. If the carrying amount of goodwill exceeds its implied fair value, an impairment loss is recognized. That loss is equal to the carrying amount of goodwill that is in excess of its implied fair value, and it must be presented as a separate line item on financial statements.
At September 30, 2014, the Company assessed goodwill for impairment using qualitative factors and concluded the two-step process was unnecessary.
Core deposit intangibles recorded in acquisitions are amortized to expense using an accelerated method over their estimated lives of 8 to 10 years. Non-compete agreements are amortized on a straight line basis over their estimated life. Prior to March 31, 2014, intangibles related to the naming rights on Provident Bank Ball Park were amortized over 10 years on a straight-line basis. Impairment losses on intangible assets are charged to expense, if and when they occur.
(q) 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 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 other real state owned was included as a charge to other non-interest income in the income statement. Subsequent valuations of other real estate owned are performed by management, and the carrying amount of a property is adjusted by a charge to 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 real estate owned properties are recognized upon disposition.
(r) 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.
(s) Income Taxes
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 income tax 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 September 30, 2014. (See Note 10 “Income Taxes”).
(t) Bank Owned Life Insurance (BOLI)
The Company owns life insurance policies (purchased and acquired) on certain officers and key executives. Bank owned life insurance is recorded at its cash surrender value (or the amount that can be realized).
(u) Stock-Based Compensation Plans
Compensation expense for stock options, 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.
(v) Earnings Per Share
Basic earnings per share (“EPS”) is computed by dividing net income applicable to common stock by the weighted average number of common shares outstanding during the period.
Diluted EPS is computed in a similar manner, 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. For purposes of computing both basic and diluted EPS, outstanding shares include earned ESOP shares.
(w) 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.
(x) 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 financial statements.
(y) Derivatives
At the inception of a derivative contract, the Company designates the derivative as one of three types based on the Company’s intentions and belief as to likely effectiveness as a hedge. These three types are (1) a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (“fair value hedge”), (2) a hedge of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (“cash flow hedge”), or (3) an instrument with no hedging designation (“stand-alone derivative”). For a fair value hedge, the gain or loss on the derivative, as well as the offsetting loss or gain on the hedged item, are recognized in current earnings as fair values change. For a cash flow hedge, the gain or loss on the derivative is reported in other comprehensive income and is reclassified into earnings in the same period during which the hedged transaction affects earnings. For both types of hedges, changes in the fair value of derivatives that are not highly effective in hedging the changes in fair value or expected cash flows of the hedged item are recognized immediately in current earnings. Changes in the fair value of derivatives that do not qualify for hedge accounting are reported currently in earnings, as non-interest income. Net cash settlements on derivatives that qualify for hedge accounting are recorded in interest income or interest expense, based on the item being hedged. Net cash settlements on derivatives that do not qualify for hedge accounting are reported in non-interest income. Cash flows on hedges are classified in the cash flow statement the same as the cash flows of the items being hedged.
The Company formally documents the relationship between derivatives and hedged items, as well as the risk-management objective and the strategy for undertaking hedge transactions at the inception of the hedging relationship. This documentation includes linking fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific firm commitments or forecasted transactions. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivative instruments that are used are highly effective in offsetting changes in fair values or cash flows of the hedged items. The Company discontinues hedge accounting when it determines that the derivative is no longer effective in offsetting changes in the fair value or cash flows of the hedged item, the derivative is settled or terminates, a hedged forecasted transaction is no longer probable, a hedged firm commitment is no longer firm, or treatment of the derivative as a hedge is no longer appropriate or intended.
When hedge accounting is discontinued, subsequent changes in fair value of the derivative are recorded as non-interest income. When a fair value hedge is discontinued, the hedged asset or liability is no longer adjusted for changes in fair value and the existing basis adjustment is amortized or accreted over the remaining life of the asset or liability. When a cash flow hedge is discontinued but the hedged cash flows or forecasted transactions are still expected to occur, gains or losses that were accumulated in other comprehensive income are amortized into earnings over the same periods which the hedged transactions will affect earnings.
(z) 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.

Acquisitions

Acquisitions	12 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	On October 31, 2013, the Company completed the Merger. Under the terms of the Agreement and Plan of Merger, Legacy Sterling shareholders received 1.2625 shares of Legacy Provident’s common stock, par value $0.01 per share, for each share of Legacy Sterling common stock, which resulted in the issuance of 39,057,968 shares. Based on the closing stock price of $11.72 per share on October 31, 2013, the aggregate consideration paid to Legacy Sterling shareholders was $457,781, including $23 paid in cash for fractional shares, and $6 which represented outstanding vested stock options. Consistent with the Company’s strategy, the primary reason for the Merger was the expansion of the Company’s geographic footprint and diversification of its business 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 October 31, 2013 based on management’s best estimate using the information available as of the Merger date. The application of the acquisition method of accounting resulted in the recognition of goodwill of $225,809, a core deposit intangible of $20,089 and a trade name intangible of $20,500.  As of October 31, 2013, Legacy Sterling had assets with a book value of approximately $2,759,628, loans including loans held for sale with a book value of approximately $1,735,142, and deposits with a book value of approximately $2,296,713. The table below summarizes the amounts recognized as of the 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 Merger date:
	Consideration paid through Sterling Bancorp common stock issued to Legacy Sterling shareholders				$	457,781
		Legacy Sterling carrying value				Fair value adjustments				As recorded at acquisition
	Cash and cash equivalents	$	277,798			$	—			$	277,798
	Investment securities	613,154				(5,243		)	(a)	607,911
	Loans held for sale	30,341				—				30,341
	Loans	1,704,801				(6,693		)	(b)	1,698,108
	Federal Reserve Bank stock	7,680				—				7,680
	Bank owned life insurance	55,374				—				55,374
	Premises and equipment	21,293				2,301			(c)	23,594
	Accrued interest receivable	6,590				—				6,590
	Core deposit and other intangibles	—				20,089			(d)	20,089
	Trade name intangible	—				20,500			(e)	20,500
	Other real estate owned	1,720				4,095			(f)	5,815
	Other assets	40,877				(19,944		)	(g)	20,933
	Deposits	(2,296,713		)		(477		)	(h)	(2,297,190		)
	FHLB borrowings	(100,346		)		(273		)	(i)	(100,619		)
	Other borrowings	(62,465		)		—				(62,465		)
	Subordinated Debentures	(25,774		)		(753		)	(j)	(26,527		)
	Other liabilities	(60,462		)		4,502			(k)	(55,960		)
	Total identifiable net assets	$	213,868			$	18,104			$	231,972
	Goodwill recorded in the Merger									225,809
	Goodwill at September 30, 2013									163,117
	Goodwill at September 30, 2014									$	388,926
	Explanation of certain fair value related adjustments:
	(a)	Represents the fair value adjustment on investment securities held to maturity.
	(b)	Represents the elimination of Legacy Sterling’s allowance for loan losses and an adjustment of the amortized cost of loans to estimated fair value, which includes an interest rate mark and credit mark. Gross loans acquired were $1,723,447; of the acquired loans, $1,699,271 were not considered purchased credit impaired and we recorded a fair value adjustment of $14,440.
	(c)	Represents an adjustment to reflect the fair value of leasehold improvements.
	(d)	Represents intangible assets recorded to reflect the fair value of core deposits and below market rent on leased premises. 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. The below market rent intangible asset will be amortized on a straight-line basis over the remaining term of the leases.
	(e)	Represents the estimated fair value of Legacy Sterling’s trade name. This intangible asset will not be amortized and will be reviewed at least annually for impairment.
	(f)	Represents an adjustment to an acquired property which Legacy Sterling utilized as a financial center and recorded as premises and equipment. The Company included this asset in OREO as it was held for sale. This asset was sold during the fiscal year ended September 30, 2014.
	(g)	Consists primarily of adjustments in net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangibles recorded.
	(h)	Represents the fair value adjustment on deposits as the weighted average interest rate of deposits assumed exceeded the cost of similar funding available in the market at the time of the Merger.
	(i)	Represents the fair value adjustment on FHLB borrowings as the weighted average interest rate of FHLB borrowings assumed exceeded the cost of similar funding available in the market at the time of the Merger.
	(j)	Represents the fair value adjustment on subordinated debentures as the weighted average interest rate of the debentures assumed exceeded the cost of similar debt funding available in the market at the time of the Merger.
	(k)	Represents the fair value of other liabilities assumed at the Merger date.
	Except for collateral dependent loans with deteriorated credit quality, the fair values for loans acquired from Legacy Sterling 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 Legacy Sterling’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 Merger.
	The impaired loans acquired in the Merger as of October 31, 2013 were accounted for in accordance with ASC Topic 310-30 Accounting for Certain Loans or Debt Securities Acquired in a Transfer (“ASC 310-30”) and were comprised of collateral dependent loans with deteriorated credit quality as follows:
		ASC 310-30 loans
	Contractual principal balance at acquisition	$	24,176
	Principal not expected to be collected (non-accretable discount)	(10,927		)
	Expected cash flows at acquisition	13,249
	Interest component of expected cash flows (accretable discount)	—
	Fair value of acquired loans	$	13,249
	The core deposit intangible asset recognized is being amortized over its estimated useful life of approximately 10 years utilizing the accelerated method. Other intangibles consist of below market rents which are amortized over the remaining life of each lease using the straight-line 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 premises and equipment and other real estate owned was estimated using appraisals of like kind properties and assets. Premises, equipment and leasehold improvements will be amortized or depreciated over their estimated useful lives ranging from one to five years for equipment or over the life of the lease for leasehold improvements. Other real estate owned is not amortized and is carried at estimated fair value determined by the appraised value less costs to sell.
	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. The fair value of borrowed funds was estimated by discounting the future cash flows using market rates for similar borrowings.
	Direct acquisition and integration costs of the Merger were expensed as incurred and totaled $9,455 and $2,772, for the fiscal years ended September 30, 2014 and 2013, respectively. These items were recorded as Merger-related expenses in the income statement. Other direct integration costs of the Merger for the fiscal year ended September 30, 2014, totaled $26,591 and included a charge for asset write-downs, banking systems conversion, employee retention and severance compensation. These items were recorded in non-interest expense in the income statement.
	The following table presents selected unaudited pro forma financial information reflecting the Merger assuming it was completed as of October 1, 2012. 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 Merger actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full fiscal year period. Pro forma basic and diluted earnings per common share were calculated using the Company’s actual weighted average shares outstanding for the periods presented, plus the incremental shares issued, assuming the 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 Legacy Sterling for the 2012 period presented and in 2013 until the date of the Merger, at which time Legacy Sterling’s results of operations were included in the Company’s financial statements.
	The unaudited pro forma information set forth below for the fiscal years ended September 30, 2014 and 2013, 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 fiscal years ended September 30, 2014 and 2013 to write-down assets and accrue for retention and severance compensation are assumed to have occurred prior to October 1, 2012. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated potential cost savings.
		Pro forma for the
		fiscal year ended September 30,
		2014				2013
	Net interest income	$	198,776			$	180,030
	Non-interest income	54,396				65,749
	Non-interest expense	187,306				189,136
	Net income	44,460				39,190
	Pro forma earnings per share:
	Basic	$	0.53			$	0.47
	Diluted	0.53				0.47
On August 10, 2012, the Company acquired 100% of the outstanding common shares of Gotham Bank of New York (“Gotham”) in exchange for $40,510 in cash. Under the terms of the acquisition, common shareholders received cash equal to 125% of adjusted tangible net worth. The acquisition of Gotham provided a strategic expansion into the metropolitan New York City market, enabling the Company to grow its small-to-middle market commercial business. Gotham delivered a core asset and deposit base, long-term client relationships, an advantageous location in midtown Manhattan and an initial commercial banking team. Gotham’s results of operations are included in the Company’s results for all periods presented in these financial statements.

Securities

Securities	12 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Securities	'
	Securities
	A summary of amortized cost and estimated fair value of our securities is presented below:
		30-Sep-14												30-Sep-13
		Amortized			Gross			Gross			Fair			Amortized		Gross			Gross			Fair
		cost			unrealized			unrealized			value			cost		unrealized			unrealized			value
					gains			losses								gains			losses
	Available for Sale
	Residential MBS:
	Agency-backed	$	477,003		$	2,257		$	(1,555	)	$	477,705		$	284,837	$	1,849		$	(4,157	)	$	282,529
	CMO/Other MBS	115,395			242			(1,492		)	114,145			169,336		356			(3,038		)	166,654
	Total residential MBS	592,398			2,499			(3,047		)	591,850			454,173		2,205			(7,195		)	449,183
	Other securities:
	Federal agencies	158,114			3			(5,303		)	152,814			273,637		—			(12,090		)	261,547
	Corporate	195,547			149			(2,857		)	192,839			118,575		153			(3,795		)	114,933
	State and municipal	131,715			3,439			(256		)	134,898			127,324		3,447			(2,041		)	128,730
	Trust preferred	37,684			766			(38		)	38,412			—		—			—			—
	Total other securities	523,060			4,357			(8,454		)	518,963			519,536		3,600			(17,926		)	505,210
	Total available for sale	$	1,115,458		$	6,856		$	(11,501	)	$	1,110,813		$	973,709	$	5,805		$	(25,121	)	$	954,393
		September 30, 2014												30-Sep-13
		Amortized			Gross			Gross			Fair			Amortized		Gross			Gross			Fair
		cost			unrealized gains			unrealized losses			value			cost		unrealized gains			unrealized losses			value
	Held to Maturity
	Residential MBS:
	Agency-backed	$	142,329		$	1,360		$	(103	)	143,586			130,371		716			(108		)	130,979
	CMO/Other MBS	62,690			9			(1,204		)	61,495			25,776		33			(315		)	25,494
	Total residential MBS	205,019			1,369			(1,307		)	205,081			156,147		749			(423		)	156,473
	Other securities:
	Federal agencies	136,413			2,634			(962		)	138,085			77,341		—			(3,458		)	73,883
	State and municipal	232,643			6,814			(123		)	239,334			19,011		556			(546		)	19,021
	Other	5,000			338			—			5,338			1,500		19			—			1,519
	Total other securities	374,056			9,786			(1,085		)	382,757			97,852		575			(4,004		)	94,423
	Total held to maturity	$	579,075		$	11,155		$	(2,392	)	$	587,838		$	253,999	$	1,324		$	(4,427	)	$	250,896
	In accordance with ASC Subtopic 320-10-25-6, in a significant business combination a company may transfer held to maturity securities to available for sale securities to maintain the company’s existing interest rate risk position or credit risk policy. Based on management’s review of the combined investment securities portfolio and implications for asset and liability management, investment securities totaling $165,230 were transferred from held to maturity to available for sale in connection with the Merger. Investment securities that were transferred included residential mortgage-backed securities, federal agency securities and state and municipal securities and was based mainly on the premium amortization and extension risk inherent in these securities. Concurrent with this repositioning, a total of $221,904 of investment securities were also transferred from available for sale to held to maturity. Substantially all of the securities transferred from available for sale to held to maturity have a maturity date in 2020 or beyond. At the date of transfer, these securities were in an unrealized loss position of $9,657, which will be accreted into interest income using the level yield method over the life of the securities, which is estimated to be approximately 5.3 year. At September 30, 2014 the remaining unrealized loss was $8,947. The unrealized loss amount is included in accumulated other comprehensive (loss) on an after-tax basis. Management believes the transfers of investment securities discussed above maintain the Company’s interest rate risk position and credit risk profile on a combined basis post-Merger.
	The amortized cost and estimated fair value of securities at September 30, 2014 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.
		September 30, 2014
		Available for sale						Held to maturity
		Amortized			Fair			Amortized			Fair
		cost			value			cost			value
	Other securities remaining period to contractual maturity:
	One year or less	$	2,100		$	2,112		$	8,847		$	8,897
	One to five years	141,508			141,748			9,138			9,624
	Five to ten years	334,295			328,902			189,494			192,109
	Greater than ten years	45,157			46,201			166,577			172,127
	Total other securities	523,060			518,963			374,056			382,757
	Residential MBS	592,398			591,850			205,019			205,081
	Total securities	$	1,115,458		$	1,110,813		$	579,075		$	587,838
	Sales of securities for the periods indicated below were as follows:
		For the fiscal year ended September 30,
		2014			2013			2012
	Available for sale:
	Proceeds from sales	$	529,107		$	339,123		$	344,431
	Gross realized gains	1,964			7,709			10,468
	Gross realized losses	(1,323		)	(377		)	—
	Income tax expense on realized net gains	172			2,282			2,475
	Held to maturity: (1)
	Proceeds from sales	$	—		$	1,187		$	—
	Gross realized gains	—			59			—
	Income tax expense on realized gains	—			18			—
	(1) During the fiscal year ended September 30, 2013, the Company sold held to maturity securities after the Company had already collected at least 85% of the principal balance outstanding at acquisition.
	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			Unrealized			Fair			Unrealized			Fair		Unrealized
value			losses			value			losses			value		losses
Available for sale
September 30, 2014
Residential MBS:
Agency-backed	$	137,693		$	(516	)	$	41,516		$	(1,039	)	$	179,209	$	(1,555	)
CMO/other MBS	62,507			(446		)	29,499			(1,046		)	92,006		(1,492		)
Total residential MBS	200,200			(962		)	71,015			(2,085		)	271,215		(3,047		)
Other securities:
Federal agencies	6,153			(144		)	146,416			(5,159		)	152,569		(5,303		)
Corporate	97,833			(1,348		)	66,440			(1,509		)	164,273		(2,857		)
State and municipal	8,170			(58		)	12,809			(198		)	20,979		(256		)
Trust preferred	3,907			(38		)	—			—			3,907		(38		)
Total other securities	116,063			(1,588		)	225,665			(6,866		)	341,728		(8,454		)
Total	$	316,263		$	(2,550	)	$	296,680		$	(8,951	)	$	612,943	$	(11,501	)
September 30, 2013
Residential MBS:
Agency-backed	$	137,265		$	(4,157	)	$	—		$	—		$	137,265	$	(4,157	)
CMO/Other MBS	122,324			(2,742		)	7,820			(296		)	130,144		(3,038		)
Total residential MBS	259,589			(6,899		)	7,820			(296		)	267,409		(7,195		)
Other securities:
Federal agencies	261,547			(12,090		)	—			—			261,547		(12,090		)
State and municipal	43,585			(2,033		)	112			(8		)	43,697		(2,041		)
Corporate	95,013			(3,795		)	—			—			95,013		(3,795		)
Total other securities	400,145			(17,918		)	112			(8		)	400,257		(17,926		)
Total	$	659,734		$	(24,817	)	$	7,932		$	(304	)	$	667,666	$	(25,121	)
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			Unrealized			Fair			Unrealized			Fair		Unrealized
	value			losses			value			losses			value		losses
Held to maturity
30-Sep-14
Residential MBS:
Agency-backed	$	20,616		$	(103	)	$	—		$	—		$	20,616	$	(103	)
CMO/Other MBS	14,928			(368		)	42,646			(836		)	57,574		(1,204		)
Total residential MBS	35,544			(471		)	42,646			(836		)	78,190		(1,307		)
Other securities:
Federal agencies	23,756			(62		)	24,101			(900		)	47,857		(962		)
State and municipal	13,943			(100		)	1,479			(23		)	15,422		(123		)
Total other securities	37,699			(162		)	25,580			(923		)	63,279		(1,085		)
Total	$	73,243		$	(633	)	$	68,226		$	(1,759	)	$	141,469	$	(2,392	)
30-Sep-13
Residential MBS:
Agency-backed	$	10,963		$	(86	)	$	—		$	—		$	10,963	$	(86	)
CMO/Other MBS	31,412			(337		)	—			—			31,412		(337		)
Total residential MBS	42,375			(423		)	—			—			42,375		(423		)
Other securities:
Federal agencies	73,883			(3,458		)	—			—			73,883		(3,458		)
State and municipal	9,530			(546		)	—			—			9,530		(546		)
Total other securities	83,413			(4,004		)	—			—			83,413		(4,004		)
Total	$	125,788		$	(4,427	)	$	—		$	—		$	125,788	$	(4,427	)
Substantially all of the unrealized losses at September 30, 2014 relate to investment grade debt securities and are attributable to changes in market interest rates subsequent to purchase. At September 30, 2014, a total of 99 available for sale securities were in a continuous unrealized loss position for less than 12 months and 118 securities were in an unrealized loss position for 12 months or longer. For securities with fixed maturities, there are no securities past due or securities for which the Company currently believes it is not probable that it will collect all amounts due according to the contractual terms of the investment.
Declines in the fair value of available for sale and held to maturity 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 other-than-temporary impairment losses (“OTTI”), 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 the investment for a period of time sufficient to allow for an anticipated recovery in cost.
Securities pledged for borrowings at FHLB and other institutions, and securities pledged for municipal deposits and other purposes were as follows:
	September 30,
	2014			2013
Available for sale securities pledged for borrowings, at fair value	$	268,316		$	199,642
Available for sale securities pledged for municipal deposits, at fair value	532,770			580,756
Available for sale securities pledged for customer back-to-back swaps, at fair value	1,934			4,645
Held to maturity securities pledged for borrowings, at amortized cost	58,509			55,497
Held to maturity securities pledged for municipal deposits, at amortized cost	430,611			167,926
Total securities pledged	$	1,292,140		$	1,008,466

Loans

Loans	12 Months Ended
	Sep. 30, 2014
Loans [Abstract]	'
Loans	'
	Loans
	The composition of the Company’s loan portfolio, excluding loans held for sale, was the following:
		September 30,
		2014				2013
	Commercial:
	Commercial & industrial	$	1,164,537			$	439,787
	Payroll finance	145,474				—
	Warehouse lending	192,003				—
	Factored receivables	181,433				—
	Equipment financing	393,027				—
	Total commercial	2,076,474				439,787
	Commercial mortgage:
	Commercial real estate	1,449,052				969,490
	Multi-family	368,524				307,547
	Acquisition, development & construction	92,149				102,494
	Total commercial mortgage	1,909,725				1,379,531
	Total commercial and commercial mortgage	3,986,199				1,819,318
	Residential mortgage	570,431				400,009
	Consumer:
	Home equity lines of credit	159,944				156,995
	Other consumer loans	43,864				36,576
	Total consumer	203,808				193,571
	Total loans	4,760,438				2,412,898
	Allowance for loan losses	(40,612		)		(28,877		)
	Total loans, net	$	4,719,826			$	2,384,021
	Total loans include net deferred loan origination costs of $1,261 at September 30, 2014 and $1,201 at September 30, 2013.
	Loans acquired from Legacy Sterling were a total of $1,698,108, net of purchase accounting adjustments and were comprised of $1,683,454 of loans that were not considered impaired at the acquisition date and $13,249 of loans that were determined to be impaired at the time of acquisition. The impaired loans were accounted for in accordance with ASC 310-30. At September 30, 2014, the net recorded amount of loans accounted for under ASC 310-30 was $3,763.
	Loans acquired in the Merger that were determined to be purchased credit impaired were all considered collateral dependent loans. Therefore, estimated fair value calculations and projected cash flows included only return of principal and no interest income. There was no accretable yield associated with these loans during the twelve months ended September 30, 2014.
	At September 30, 2014, the Company pledged loans totaling $1,246,315 to the FHLB as collateral for certain borrowing arrangements. See Note 8. “Borrowings and Senior Notes”.
	The following tables set forth the amounts and status of the Company’s loans and TDRs at September 30, 2014 and September 30, 2013:
		September 30, 2014
		Current				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	1,150,854			$	2,316			$	7,043		$	—		$	4,324		$	1,164,537
	Payroll finance	145,029				99				—			346			—			145,474
	Warehouse lending	192,003				—				—			—			—			192,003
	Factored receivables	181,063				—				—			—			370			181,433
	Equipment financing	391,914				689				162			—			262			393,027
	Commercial real estate	1,433,805				93				4,188			521			10,445			1,449,052
	Multi-family	368,393				—				—			—			131			368,524
	Acquisition, development & construction	79,732				—				56			—			12,361			92,149
	Residential mortgage	547,912				4,023				2,036			534			15,926			570,431
	Consumer	193,491				3,087				1,487			—			5,743			203,808
	Total loans	$	4,684,196			$	10,307			$	14,972		$	1,401		$	49,562		$	4,760,438
	Total TDRs included above	$	17,138			$	346			$	169		$	—		$	11,944		$	29,597
	Non-performing loans:
	Loans 90+ days past due and still accruing															$	1,401
	Non-accrual loans															49,562
	Total non-performing loans															$	50,963
		September 30, 2013
		Current				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	438,818			$	178			$	2		$	289		$	500		439,787
	Commercial real estate	1,263,933				1,978				2,357			1,574			7,195			1,277,037
	Acquisition, development & construction	96,306				768				—			—			5,420			102,494
	Residential mortgage	390,072				354				267			1,832			7,484			400,009
	Consumer	190,393				566				—			404			2,208			193,571
	Total loans	$	2,379,522			$	3,844			$	2,626		$	4,099		$	22,807		$	2,412,898
	Total TDRs included above	$	23,754			$	—			$	—		$	141		$	2,199		$	26,094
	Non-performing loans:
	Loans 90+ days past due and still accruing															$	4,099
Non-accrual loans															22,807
Total non-performing loans															$	26,906
Activity in the allowance for loan losses for the fiscal years ended September 30, 2014, 2013 and 2012 is summarized below:
	30-Sep-14
	Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
	balance											charge-offs
Commercial & industrial	$	5,302			$	(2,901	)		$	1,073		$	(1,828	)	$	6,062		$	9,536
Payroll finance	—				(758		)		—			(758		)	2,137			1,379
Warehouse lending	—				—				—			—			630			630
Factored receivables	—				(211		)		9			(202		)	1,496			1,294
Equipment financing	—				(1,074		)		194			(880		)	3,501			2,621
Commercial real estate	9,967				(741		)		161			(580		)	1,457			10,844
Multi-family	—				(418		)		92			(326		)	2,193			1,867
Acquisition, development & construction	5,806				(1,479		)		—			(1,479		)	(2,207		)	2,120
Residential mortgage	4,474				(963		)		323			(640		)	2,003			5,837
Consumer	3,328				(786		)		114			(672		)	1,828			4,484
Total loans	$	28,877			$	(9,331	)		$	1,966		$	(7,365	)	$	19,100		$	40,612
Annualized net charge-offs to average loans outstanding																		0.24		%
	30-Sep-13
	Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
	balance											charge-offs
Commercial & industrial	$	4,603			$	(1,354	)		$	410		$	(944	)	$	1,643		$	5,302
Commercial real estate	7,230				(3,725		)		577			(3,148		)	5,885			9,967
Acquisition, development & construction	8,526				(3,422		)		182			(3,240		)	520			5,806
Residential mortgage	4,359				(2,547		)		101			(2,446		)	2,561			4,474
Consumer	3,564				(2,009		)		232			(1,777		)	1,541			3,328
Total loans	$	28,282			$	(13,057	)		$	1,502		$	(11,555	)	$	12,150		$	28,877
Annualized net charge-offs to average loans outstanding																		0.52		%
	September 30, 2012
	Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
	balance											charge-offs
Commercial & industrial	$	5,945			$	(1,526	)		$	1,116		$	(410	)	$	(932	)	$	4,603
Commercial real estate	5,568				(2,707		)		528			(2,179		)	3,841			7,230
Acquisition, development & construction	9,895				(4,124		)		299			(3,825		)	2,456			8,526
Residential mortgage	3,498				(2,551		)		356			(2,195		)	3,056			4,359
Consumer	3,011				(1,901		)		263			(1,638		)	2,191			3,564
Total loans	$	27,917			$	(12,809	)		$	2,562		$	(10,247	)	$	10,612		$	28,282
Annualized net charge-offs to average loans outstanding																		0.56		%
Management considers a loan to be impaired when, based on current information and events, it is determined that the Company will not be able to collect all amounts due according to the loan contract, including scheduled interest payments. Determination of impairment is treated the same across all classes of loans on a loan-by-loan basis, except residential mortgage loans and home equity lines of credit with an outstanding balance of $500 or less, which are evaluated for impairment on a homogeneous pool basis. When management identifies a loan as impaired, the impairment is measured based on the present value of expected future cash flows, discounted at the loan’s effective interest rate, except when the sole remaining source of repayment of the loan is the operation or liquidation of the collateral. In these cases, management uses the current fair value of the collateral, less selling costs when foreclosure is probable, instead of discounted cash flows. If management determines that the value of the impaired loan is less than the recorded investment in the loan (net of previous charge-offs, deferred loan fees or costs and unamortized premium or discount), impairment is generally recognized through a charge-off to the allowance for loan losses.
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.
The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at September 30, 2014:
	Loans evaluated by segment														Allowance evaluated by segment
	Individually				Collectively				Purchased credit impaired loans			Total			Individually			Collectively			Total allowance for loan losses
	evaluated for				evaluated for							loans			evaluated for			evaluated for
	impairment				impairment										impairment			impairment
Commercial & industrial	$	4,177			$	1,158,837			$	1,523		$	1,164,537		$	—		$	9,536		$	9,536
Payroll finance	—				145,474				—			145,474			—			1,379			1,379
Warehouse lending	—				192,003				—			192,003			—			630			630
Factored receivables	—				181,433				—			181,433			—			1,294			1,294
Equipment financing	—				393,027				—			393,027			—			2,621			2,621
Commercial real estate	13,750				1,435,163				139			1,449,052			—			10,844			10,844
Multi-family	—				368,524				—			368,524			—			1,867			1,867
Acquisition, development & construction	17,766				74,383				—			92,149			—			2,120			2,120
Residential mortgage	515				567,815				2,101			570,431			—			5,837			5,837
Consumer	—				203,808				—			203,808			—			4,484			4,484
Total loans	$	36,208			$	4,720,467			$	3,763		$	4,760,438		$	—		$	40,612		$	40,612
There was no amount included in the allowance for loan losses associated with purchased credit impaired loans at September 30, 2014, as there was no further deterioration in the credit quality of these loans since the Merger date.
The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at September 30, 2013:
	Loans evaluated by segment											Allowance evaluated by segment
	Individually				Collectively				Total			Individually			Collectively			Total allowance for loan losses
	evaluated for				evaluated for				loans			evaluated for			evaluated for
	impairment				impairment							impairment			impairment
Commercial & industrial	$	2,631			$	437,156			$	439,787		$	249		$	5,053		$	5,302
Commercial real estate	14,091				1,262,946				1,277,037			803			9,164			9,967
Acquisition, development & construction	19,582				82,912				102,494			540			5,266			5,806
Residential mortgage	515				399,494				400,009			—			4,474			4,474
Consumer	2				193,569				193,571			1			3,327			3,328
Total loans	$	36,821			$	2,376,077			$	2,412,898		$	1,593		$	27,284		$	28,877
The following table presents loans individually evaluated for impairment by segment of loans at September 30, 2014 and September 30, 2013:
	September 30, 2014											30-Sep-13
	Unpaid				Recorded				Related allowance			Unpaid			Recorded			Related allowance
	principal				investment							principal			investment
	balance											balance
With no related allowance recorded:
Commercial & industrial	$	4,177			$	4,177			$	—		$	2,175		$	2,131		$	—
Commercial real estate	13,886				13,750				—			12,451			11,820			—
Acquisition, development & construction	18,676				17,766				—			17,971			17,945			—
Residential mortgage	515				515				—			515			515			—
Subtotal	37,254				36,208				—			33,112			32,411			—
With an allowance recorded:
Commercial & industrial	—				—				—			500			500			249
Commercial real estate	—				—				—			3,150			2,271			803
Acquisition, development & construction	—				—				—			2,753			1,637			540
Consumer	—				—				—			2			2			1
Subtotal	—				—				—			6,405			4,410			1,593
Total	$	37,254			$	36,208			$	—		$	39,517		$	36,821		$	1,593
During the quarter ended March 31, 2014, the Company modified its allowance for loan loss policy to generally require a charge-off of the difference between the book balance of a collateral dependent impaired loan and the net value of the collateral securing the loan.
The following table presents the average recorded investment and interest income recognized related to loans individually evaluated for impairment by segment for the fiscal year September 30, 2014 and 2013:
	September 30, 2014											September 30, 2013
	YTD average				Interest				Cash-basis			YTD average			Interest			Cash-basis
	recorded				income				interest			recorded			income			interest
	investment				recognized				income			investment			recognized			income
									recognized									recognized
With no related allowance recorded:
Commercial & industrial	$	4,180			$	—			$	—		$	1,821		$	91		$	86
Commercial real estate	14,016				186				180			17,325			286			275
Acquisition, development & construction	20,525				239				239			12,827			631			587
Residential mortgage	515				—				—			309			—			—
Consumer	—				—				—			61			—			—
Subtotal	39,236				425				419			32,343			1,008			948
With an allowance recorded:
Commercial & industrial	—				—				—			705			—			—
Commercial real estate	—				—				—			6,646			7			7
Acquisition, development & construction	—				—				—			1,104			—			—
Residential mortgage	—				—				—			1,602			14			10
Consumer	—				—				—			228			—			—
Subtotal	—				—				—			10,285			21			17
Total	$	39,236			$	425			$	419		$	42,628		$	1,029		$	965
In the fiscal year ended September 30, 2012, the Company recognized interest income of $1,878 including cash-basis interest income recognized of $1,136 on $58,195 of average impaired loans.
Troubled Debt Restructuring:
The following tables set forth the amounts and past due status of the Company’s TDRs at September 30, 2014 and 2013:
	September 30, 2014
	Current loans				30-59				60-89			90+			Non-			Total
					days				days			days			accrual
					past due				past due			past due
Commercial & industrial	$	275			$	—			$	—		$	—		$	1,618		$	1,893
Equipment financing	435				—				—			—			—			435
Commercial real estate	4,838				—				—			—			447			5,285
Acquisition, development & construction	5,732				—				—			—			6,817			12,549
Residential mortgage	5,858				346				169			—			2,841			9,214
Consumer	—				—				—			—			221			221
Total	$	17,138			$	346			$	169		$	—		$	11,944		$	29,597
Allowance for loan losses	$	409			$	—			$	31		$	—		$	451		$	891
	30-Sep-13
	Current loans				30-59				60-89			90+			Non-			Total
					days				days			days			accrual
					past due				past due			past due
Commercial & industrial	$	1,843			$	—			$	—		$	141		$	—		$	1,984
Commercial real estate	5,305				—				—			—			—			5,305
Acquisition, development & construction	14,190				—				—			—			151			14,341
Residential mortgage	2,416				—				—			—			1,792			4,208
Consumer	—				—				—			—			256			256
Total loans	$	23,754			$	—			$	—		$	141		$	2,199		$	26,094
Allowance for loan losses	$	438			$	—			$	—		$	—		$	439		$	877
The Company had outstanding commitments to lend additional amounts of $0 and $4,101 to customers with loans classified as TDRs as of September 30, 2014 and September 30, 2013, respectively.
The following table presents loans by segment modified as TDRs that occurred during the twelve months ended September 30, 2014 and 2013:
	September 30, 2014										September 30, 2013
				Recorded investment									Recorded investment
	Number			Pre-				Post-			Number		Pre-			Post-
				modification				modification					modification			modification
Commercial & industrial	—			$	—			$	—		5		$	2,001		$	2,001
Commercial real estate	—			—				—			2		2,682			2,682
Acquisition, development & construction	2			1,060				1,060			7		5,772			5,772
Residential mortgage	—			—				—			6		1,436			1,372
Consumer	—			—				—			1		302			302
Total restructured loans	2			$	1,060			$	1,060		21		$	12,193		$	12,129
There were 12 TDRs in the fiscal year ended September 30, 2012, with a pre-modification balance of $9,160 and a post-modification balance of $8,945.
The TDRs presented above increased the allowance for loan losses by $0, $300 and $134 and resulted in charge-offs of $0, $110 and $0 for the years ended September 30, 2014, 2013, and 2012, respectively.
There were no TDRs that were modified during the last twelve months that had subsequently defaulted during the year.
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 consumer loans (residential mortgage and home equity lines of credit (“HELOC”)), (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 debt. 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 reviewed 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 injection, 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 September 30, 2014 and 2013, the risk category of gross loans by segment was as follows:
	September 30, 2014											September 30, 2013
	Special				Substandard				Doubtful			Special			Substandard			Doubtful
	mention											mention
Commercial & industrial	$	24,980			$	5,749			$	—		$	3,545		$	3,855		$	365
Payroll finance	—				346				—			—			—			—
Factored receivables	46				370				—			—			—			—
Equipment financing	—				262				—			—			—			—
Commercial real estate	8,720				26,826				—			7,279			24,561			227
Multi-family	—				131				—			—			—			—
Acquisition, development & construction	1,040				16,456				—			1,867			19,410			—
Residential mortgage	2,988				16,981				—			824			9,786			—
Consumer	1,779				5,972				—			15			2,891			—
Total	$	39,553			$	73,093			$	—		$	13,530		$	60,503		$	592

Premises_And_Equipment_Net

Premises And Equipment, Net	12 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Premises and Equipment, Net	'
	Premises and Equipment, Net
	Premises and equipment are summarized as follows:
		September 30,
		2014			2013
	Land and land improvements	$	6,048		$	7,282
	Buildings	22,888			30,558
	Leasehold improvements	32,963			8,136
	Furniture, fixtures and equipment	50,343			40,164
	Total premises and equipment, gross	112,242			86,140
	Accumulated depreciation and amortization	(68,956		)	(49,620		)
	Total premises and equipment, net	$	43,286		$	36,520

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Sep. 30, 2014
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 fiscal 2014 was related to the acquisition of Legacy Sterling, which is described more fully in Note 2. “Acquisitions.”
	Goodwill
	The change in goodwill in the fiscal years ended September 30, 2014 and 2013 was as follows:
		September 30,
		2014		2013
	Beginning of year balance	$	163,117	$	163,247
	Acquisitions	225,809		(130		)
	Disposals	—		—
	End of year balance	$	388,926	$	163,117
	During the fiscal year ended September 30, 2013, the Company decreased the goodwill recorded in connection with the Gotham Bank acquisition by $130 based on the completion of the analysis of fair value of the net assets acquired.
	Other intangible assets
	The balance of other intangible assets at September 30, 2014 and 2013 was as follows:
		Gross intangible assets		Accumulated amortization			Net intangible assets
	30-Sep-14
	Core deposits	$	24,182	$	(4,694	)	$	19,488
	Non-compete agreements	10,308		(5,490		)	4,818
	Trade name	20,500		—			20,500
	Fair value of below market leases	725		(253		)	472
	Provident Bank Ball Park naming rights	2,414		(2,414		)	—
		$	58,129	$	(12,851	)	$	45,278
	30-Sep-13
	Core deposits	$	4,818	$	(798	)	$	4,020
	Provident Bank Ball Park naming rights	2,414		(543		)	1,871
		$	7,232	$	(1,341	)	$	5,891
	Included in other intangible assets was an intangible asset associated with the naming rights to Provident Bank Ball Park which is located in Rockland County, New York. At the time of the Merger, the Company wrote-off the remaining book value.
	Other intangible assets are amortized on a straight-line or accelerated bases over their estimated useful lives, which range from one to 10 years. Amortization expense related to core deposits, non-compete agreements and naming rights totaled $9,408, $1,296 and $1,245 for the fiscal years ended September 30, 2014, 2013, and 2012, respectively. The amortization of the fair value of below market leases was included in rent expense for the fiscal year ended September 30, 2014. The estimated aggregate future amortization expense for other intangible assets remaining as of September 30, 2014 was as follows:
		Amortization expense
	2015	$	6,113
	2016	5,042
	2017	2,598
	2018	2,178
	2019	2,058
	Thereafter	6,786
		$	24,775

Deposits

Deposits	12 Months Ended
	Sep. 30, 2014
Deposits [Abstract]	'
Deposits	'
	Deposits
	Deposit balances at September 30, 2014 and 2013 are summarized as follows:
		September 30,
		2014		2013
	Non-interest bearing demand	$	1,799,685	$	943,934
	Interest bearing demand	766,852		434,398
	Savings	698,443		580,125
	Money market	1,595,803		735,709
	Certificates of deposit	437,871		268,128
	Total deposits	$	5,298,654	$	2,962,294
	Municipal deposits totaled $992,761 and $757,065 at September 30, 2014 and September 30, 2013, 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:
		September 30,
		2014		2013
	Remaining period to contractual maturity:
	Less than one year	$	340,813	$	239,104
	One to two years	53,319		17,248
	Two to three years	35,632		5,185
	Three to four years	4,000		3,062
	Four to five years	4,107		3,529
	Total certificates of deposit	$	437,871	$	268,128
	Certificates of deposit accounts with a denomination of $100 or more totaled $290,483 and $104,225 at September 30, 2014 and 2013, respectively. Listed below are the Company’s brokered deposits at September 30, 2014 and 2013:
		September 30,
		2014		2013
	Money market	$	84,022	$	34,571
	Reciprocal CDAR’s 1	34,017		1,343
	CDAR’s one way	3,028		768
	Total brokered deposits	$	121,067	$	36,682
	1 Certificate of deposit account registry service

Borrowings_and_Senior_Notes

Borrowings and Senior Notes	12 Months Ended
	Sep. 30, 2014
Debt Instruments [Abstract]	'
Borrowings and Senior Notes	'
	Borrowings and Senior Notes
	The Company’s borrowings and weighted average interest rates are summarized as follows:
		September 30,
		2014				2013
		Amount		Rate		Amount		Rate
	By type of borrowing:
	FHLB advances and overnight	$	795,028	1.75	%	$	442,602	2.77	%
	Repurchase agreements	25,639		0.39		20,351		0.88
	Fed funds purchased	20,000		0.31		—		—
	Senior notes	98,402		5.98		98,033		5.98
	Total borrowings	$	939,069	2.12	%	$	560,986	3.26	%
	By remaining period to maturity:
	Less than one year	$	370,365	0.69	%	$	158,897	0.95	%
	One to two years	140,344		0.59		78,717		1.97
	Two to three years	257,442		3.52		191		5.32
	Three to four years	168,402		4.38		202,414		4.21
	Four to five years	—		—		118,033		5.57
	Greater than five years	2,516		4.92		2,734		4.92
	Total borrowings	$	939,069	2.12	%	$	560,986	3.26	%
	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 September 30, 2014 and 2013, the Bank had pledged residential mortgage and commercial real estate loans totaling $1,246,315 and $784,422, respectively. The Bank had also pledged securities to secure borrowings, which are disclosed in Note 3. “Securities.” As of September 30, 2014, the Bank may increase its borrowing capacity by pledging securities and mortgage loans not required to be pledged for other purposes with a collateral value of $703,486.
	FHLB borrowings which are putable quarterly at the discretion of the FHLB were $200,000 at September 30, 2014 and 2013. These borrowings have a weighted average remaining term to the contractual maturity dates of approximately 2.56 years and 3.56 years and a weighted average interest rates of 4.23% at both September 30, 2014 and 2013, respectively.
	Repurchase agreements. Securities sold under agreements to repurchase at September 30, 2014 are secured short-term borrowings that mature in one to 17 days. Repurchase agreements are stated at the amount of cash received in connection with these transactions. The Bank may be required to provide additional collateral based on the fair value of the underlying securities. The Bank had two $10,000 long-term repurchase agreements which were redeemed during the fiscal year ended September 30, 2014.
	Fed funds purchased. Fed funds purchased are short-term borrowings that typically mature daily and are recorded at the amount of funds received.
	Revolving line of credit. On September 5, 2014, the Company entered into a $15,000 revolving line of credit facility with a financial institution that matures on September 5, 2015. The balance was zero at September 30, 2014. 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 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 line at September 30, 2014.
	Senior Notes. On July 2, 2013, the Company issued $100,000 principal amount of 5.50% fixed rate Senior Notes through a private placement at a discount of 1.75%. The cost of issuance was $303, and at September 30, 2014 and 2013 the unamortized discount was $1,597 and $1,967, respectively, which will be accreted to interest expense over the life of the 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. The Senior Notes were issued under an indenture (the “Indenture”) between the Company and U.S. Bank National Association, as trustee.
	The 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 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 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.
	The Senior Notes will not be registered under the Securities Act and may not be offered or sold in the U.S. absent registration or an applicable exemption from registration requirements.
	Trust preferred capital securities. In connection with the Merger, the Company assumed $25,000 of trust preferred capital securities (the “Subordinated Debentures”). The capital securities, which were due March 31, 2032 and bore interest at 8.375%, were issued by Sterling Bancorp Trust I, a wholly-owned, non-consolidated statutory business trust. The trust was formed with initial capitalization of common stock and for the exclusive purpose of issuing the capital securities. The trust used the proceeds from the issuance of the capital securities to acquire $25,774 junior subordinated debenture securities that paid interest at 8.375% issued by the Company. The Company was not considered the primary beneficiary of the trust (which is a VIE); therefore, the trust was not consolidated in the Company’s financial statements and the subordinated debentures were recorded as a liability. The debt securities were due concurrently with the capital securities.
	On June 1, 2014, the Company redeemed all of the outstanding capital securities at a redemption price equal to 100% of the liquidation amount of the securities plus accumulated and unpaid interest, with such redemption payment made on June 2, 2014. In connection with the redemption, the Company eliminated the unamortized premium recorded to reflect the fair value of the Subordinated Debentures at the date of the Merger. The balance of the unamortized premium was $712 and this amount was recognized as a gain on extinguishment of debt and recorded as a reduction of other non-interest expense in the fiscal year ended September 30, 2014.

Derivatives

Derivatives	12 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedges, Assets [Abstract]	'
Derivatives	'
	Derivatives
	The Company has two interest rate caps to offset a portion of interest rate exposure should short-term rate increases lead to rapid increases in general levels of market interest rates on deposits. These caps are linked to LIBOR and have strike prices of 3.5% and 4.0%. These caps are stand alone derivatives and therefore changes in fair value are reported in current period earnings. Losses recognized in earnings were $0 and $2 in fiscal 2014 and 2013, respectively. The fair value of the interest rate caps at September 30, 2014, is reflected in other assets with a corresponding credit (charge) to income recorded as a gain (loss) to non-interest income.
	The Company has entered into certain interest rate swap contracts that are not designated as hedging instruments. 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’s customers to effectively convert a variable rate loan to a fixed rate. Because the Company acts as an intermediary for its customer, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company’s results of operations.
	The Company pledged collateral to another financial institution in the form of investment securities with an amortized cost of $5,034 and a fair value of $4,836 as of September 30, 2014. 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. The Company may need to post additional collateral to swap counterparties in the future in proportion to potential increases in unrealized loss positions.
	Summary information as of September 30, 2014 and 2013 regarding these derivatives is presented below:
		Notional			Average	Weighted		Weighted	Fair value
		amount			maturity (in years)	average		average
						fixed rate		variable rate
	30-Sep-14
	Interest rate caps	$	50,000		0.18	3.75	%	NA	$	—
	3rd party interest rate swap	50,729			4.86	4.2		1 m Libor + 2.44	1,096
	Customer interest rate swap	(50,729		)	4.86	4.2		1 m Libor + 2.44	(1,096		)
	30-Sep-13
	Interest rate caps	$	50,000		1.18	3.75	%	NA	$	—
	3rd party interest rate swap	54,180			5.76	4.22		1 m Libor + 2.45	997
	Customer interest rate swap	(54,180		)	5.76	4.22		1 m Libor + 2.45	(997		)
	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
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Income tax expense for the periods indicated consists of the following:
		For the year ended September 30,
		2014			2013			2012
	Current tax expense:
	Federal	$	11,613		$	9,146		$	5,538
	State	1,598			1,549			685
	Total current tax expense	13,211			10,695			6,223
	Deferred tax (benefit) expense:
	Federal	(2,745		)	522			(261		)
	State	(314		)	197			197
	Total deferred tax (benefit) expense	(3,059		)	719			(64		)
	Total income tax expense	$	10,152		$	11,414		$	6,159
	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 September 30,
		2014			2013			2012
	Tax at Federal statutory rate of 35%	$	13,241		$	12,833		$	9,116
	State and local income taxes, net of Federal tax benefit	834			1,135			573
	Tax-exempt interest, net of disallowed interest	(3,824		)	(2,192		)	(2,448		)
	BOLI income	(1,110		)	(699		)	(718		)
	Non-deductible acquisition related costs	712			416			418
	Low income housing tax credits	(165		)	—			—
	Other, net	464			(79		)	(782		)
	Actual income tax expense	$	10,152		$	11,414		$	6,159
	Effective income tax rate	26.8		%	31.1		%	23.6		%
	The following table presents the Company’s deferred tax position at September 30, 2014 and 2013:
		September 30,
		2014			2013
	Deferred tax assets:
	Allowance for loan losses	$	17,272		$	11,809
	Deferred compensation	649			798
	Other accrued compensation and benefits	5,418			1,497
	Accrued post retirement expense	2,705			1,441
	Deferred rent	—			1,059
	Intangible assets	2,439			—
	Other comprehensive loss (securities)	5,777			7,844
	Other comprehensive loss (defined benefit plans)	2,371			2,638
	Depreciation of premises and equipment	433			—
	State NOL carryforward	1,431			—
	Other	3,511			2,172
	Total deferred tax assets	42,006			29,258
	Deferred tax liabilities:
	Undistributed earnings of subsidiary not consolidated for tax return purposes (income from REITs)	9,303			4,483
	Prepaid pension costs	10,579			3,758
	Purchase accounting adjustments	16,056			1,057
	Depreciation and lease adjustments	—			2,686
	Deferred rent	163			—
	Intangibles amortization	—			112
	Other	2,557			2,207
	Total deferred tax liabilities	38,658			14,303
	Net deferred tax asset	$	3,348		$	14,955
	Based on the Company’s consideration of historical and anticipated future pre-tax income, as well as the reversal period for the items giving rise to the deferred tax assets and liabilities, a valuation allowance for deferred tax assets was not considered necessary at either September 30, 2014 or 2013.
	Retained earnings at September 30, 2014 and 2013 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 September 30, 2014 and 2013 was approximately $3,260.
	At September 30, 2014 the Company has state and local NOL carryforwards that were acquired from Legacy Sterling as part of the Merger on October 31, 2013. The utilization of state and local NOLs are subject to an annual limitation. Based on our projections, we believe the state and local NOL carryforwards will be fully utilized before expiration.
	At September 30, 2014and 2013, 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 income tax expense.
	Sterling 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 no longer subject to examination by Federal and New York taxing authorities for tax years prior to 2011.

Employee_Benefit_Plans_And_Sto

Employee Benefit Plans And Stock-Based Compensation Plans	12 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plans And Stock-Based Compensation Plans	'
	Employee Benefit Plans and Stock-Based Compensation Plans
	(a) Pension Plans
	On May 31, 2014, the Company merged the Provident Bank Benefit Pension Plan (the “legacy Provident Plan”) and the Legacy Sterling/Sterling National Bank Employees’ Retirement Plan (the “Legacy Sterling Plan”) and formed the Sterling National Bank Defined Benefit Pension Plan. The legacy Provident Plan covers employees that were eligible as of September 30, 2006. The Board of Directors approved a curtailment to the legacy Provident Plan effective September 30, 2006. At that time, all benefit accruals for future service ceased and no new participants were allowed to enter the Plan. The purpose of the Plan curtailment was to afford flexibility in the retirement benefits the Company provides, while preserving all retirement plan participants’ earned and vested benefits, and to manage the increasing costs associated with the defined benefit pension plan. The Legacy Sterling Plan was a defined benefit plan that covered eligible employees of Legacy Sterling and Legacy Sterling National Bank and certain of its subsidiaries who were hired prior to January 3, 2006 and who attained age 21 prior to January 3, 2007. Effective October 31, 2013, the Legacy Sterling Plan was amended and the accrued benefit of each eligible actively employed participant that had not yet commenced benefits was increased by approximately 4.4% and the accrual of future service benefits ceased.
	The following is a summary of changes in the projected benefit obligation and fair value of plan assets. The Company uses a September 30 measurement date for its pension plans.
		September 30,
		2014				2013
	Changes in projected benefit obligation:
	Beginning of year balance	$	31,705			$	35,471
	Benefit obligation of the Legacy Sterling Plan at October 31, 2013	52,296				—
	Service cost	—				—
	Interest cost	2,779				1,452
	Actuarial loss (gain)	9,460				(3,672		)
	Partial settlement	(44,774		)		—
	Benefits and distributions paid	(1,748		)		(1,546		)
	End of year balance	49,718				31,705
	Changes in fair value of plan assets:
	Beginning of year balance	35,417				32,657
	Fair value of the Legacy Sterling Plan assets at October 31, 2013	71,538				—
	Actual gain on plan assets	8,137				4,306
	Employer contributions	—				—
	Partial settlement	(44,774		)		—
	Benefits and distributions paid	(1,748		)		(1,546		)
	End of year balance	68,570				35,417
	Funded status at end of year	$	18,852			$	3,712
	During the year ended September 30, 2014 the Company settled a portion of the pension obligation associated with retired employees in the amount of $44,774 through the purchase of annuities.
	The over-funded status of the Sterling National Bank Defined Benefit Pension Plan is included in other assets in the Consolidated Balance Sheets.
	The components of net periodic pension expense were as follows:
		For the year ended September 30,
		2014				2013				2012
	Service cost	$	—			$	—			$	—
	Interest cost	2,779				1,452				1,501
	Expected return on plan assets	(3,380		)		(2,462		)		(2,125		)
	Amortization of unrecognized actuarial loss	236				2,062				2,316
	Partial settlement charge	3,922				—				—
	Net periodic pension expense	$	3,557			$	1,052			$	1,692
	Net periodic pension expense is included in compensation and benefits in the Consolidated Income Statements.
	The amount of unrecognized actuarial loss and prior service cost that is expected to be amortized to net periodic pension expense during the fiscal year ending September 30, 2015 is $0.
	Amounts recognized in accumulated other comprehensive (loss) at September 30, 2014 and 2013 consisted of:
		September 30,
		2014				2013
	Unrecognized actuarial loss	$	(6,024	)		$	(5,479	)
	Deferred tax asset	2,556				2,225
	Net amount recognized in accumulated other comprehensive (loss)	$	(3,468	)		$	(3,254	)
	The principal actuarial assumptions used at September 30, 2014 and 2013 were as follows:
		September 30,
		2014			2013
	Projected benefit obligation:
	Discount rate	4.5	%		5.2	%
	Net periodic pension cost:
	Discount rate	4.5	%		5.2	%
	Long-term rate of return on plan assets	4	%		7.75	%
	The discount rate used in the measurement of the projected benefit obligation is determined by comparing the expected future retirement benefit payment cash flows of the Plan to the cash flows of a high-quality corporate bond portfolio as of the measurement date. The expected long-term rate of return on Plan assets reflect earnings expectations on existing Plan assets.  In estimating this rate, appropriate consideration was given to historical returns earned by Plan assets in the funds and the rates of return expected to be available for reinvestment.  The rate of return estimated at September 30, 2014 reflects the shift in the allocation of the Plan assets to a liability driven investment strategy which is more heavily weighted towards long-term fixed income assets with a similar duration profile to the Plan liabilities.
	Estimated future benefit payments are the following for the years ending September 30:
	2015	$	726
	2016	902
	2017	1,079
	2018	1,625
	2019	1,851
	2020 - 2024	13,461
	The Company’s funding policy is to contribute annually an amount sufficient to meet statutory minimum funding requirements, but not in excess of the maximum amount deductible for Federal income tax purposes. Contributions are intended to provide not only for benefits attributed to service to date, but also for benefits expected to be earned in the future.
	The following is a description of the valuation methodologies used for assets measured at fair value. There were no changes in the methodologies used at September 30, 2014 and 2013. See Note 17. “Fair Value Measurements” for a detailed discussion of the three levels of inputs that may be used to measure fair values.
	The fair value of the Plan assets is based on the lowest level of any input that is significant to the fair value measurement within the fair value hierarchy. Plan assets consisted of pooled separate accounts at September 30, 2014. The fair value of shares of units of participation in pooled separate accounts are based on the net asset values of the funds reported by the fund managers as of September 30, 2014 and recent transaction prices (Level 2 inputs). Assets allocated to these pooled separate accounts can include, but are not limited to stocks (both domestic and foreign), bonds and mutual funds. While some pooled separate accounts may have publicly quoted prices (Level 1 inputs), the units of separate accounts are not publicly quoted and are therefore classified as Level 2. The fair value of Plan assets by asset category as of September 30, 2014 and 2013, was the following:
		30-Sep-14
	Fair value				Level 1 inputs				Level 2 inputs				Level 3 inputs
Asset category:
Intermediate term bond	$	8,629			$	—			$	8,629			$	—
Long-term bond	59,892				—				59,892				—
Total assets	$	68,521			$	—			$	68,521			$	—
	30-Sep-13
	Fair value				Level 1 inputs				Level 2 inputs				Level 3 inputs
Asset category:
Large cap U.S. equity	$	16,378			$	—			$	16,378			$	—
Small and mid cap U.S. equity	4,443				—				4,443				—
International equity	3,654				—				3,654				—
Total equity	24,475				—				24,475				—
Total balanced asset allocation	1,691				—				1,691				—
High yield bond	1,018				—				1,018				—
Intermediate term bond	8,233				—				8,233				—
Total fixed income	9,251				—				9,251				—
Total assets	$	35,417			$	—			$	35,417			$	—
The Company’s policy is to invest the Plan assets in a prudent manner for the purpose of providing benefit payments to participants and offsetting reasonable expenses of administration. Historically, the Company’s investment strategy was designed to provide a total return that, over the long-term, placed a strong emphasis on the preservation of capital and compliance with applicable regulations and laws. Management intends to terminate the Plan in fiscal 2015 subject to obtaining required approvals from the Internal Revenue Service and other regulators. Therefore, the investment allocation of Plan assets was shifted in fiscal 2014 to a liability driven investment strategy which is more heavily weighted towards long-term fixed income assets with a similar duration profile to the Plan liabilities. As of September 30, 2014, the majority of the Plan assets were invested in funds specifically designed for liability driven investment strategies and had a weighted average expected rate of return of 4.0%.
The Plan’s investment policy prohibits the direct investment in real estate but allows the Plan’s mutual funds to include a small percentage of real estate related investments. The investment strategy utilizes asset allocation as a principal determinant for establishing an appropriate risk profile. Weighted average pension plan asset allocations based on the fair value of such assets at September 30, 2014 and September 30, 2013 and target allocation ranges for 2014, by asset category, are as follows:
	2014			2013			Target allocation		Weighted
							range 2014		average expected
									rate of return
Large cap U.S. equity	—	%		44	%				—	%
Small and mid cap U.S. equity	—			11					—
International equity	—			10					—
Total equity	—			65			0%		—
Total balanced asset allocation	—			5					—
High yield bond	—			3					—
Intermediate term bond	13			27					—
Long-term bond	87			—					—
Total fixed income	100			30			95% - 100%		4
Total assets	100	%		100	%				4	%
Cash	—			—			0% to 5%		—
There were no pension plan assets consisting of Sterling Bancorp equity securities (common stock) at September 30, 2014 or at September 30, 2013.
The Company makes contributions to its funded qualified pension plans as required by government regulation or as deemed appropriate by management after considering the fair value of plan assets, expected returns on such assets, and the present value of benefit obligations of the plans. At this time, the Company has not determined whether contributions in fiscal 2015 will be made.
(b) Other Post Retirement Benefit Plans
The Company provides other post retirement benefit plans, which are unfunded. Included in the tables below is information regarding the Company’s optional medical, dental and life insurance benefits to retirees plan, Supplemental Executive Retirement Plan to certain former directors and officers of the Company, life insurance benefits to certain directors, officers and former officers of Legacy Sterling.
Data relating to other post retirement benefit plans is the following:
	September 30,
	2014				2013
Changes in accumulated post retirement benefit obligation:
Beginning of year	$	3,302			$	3,103
Obligations assumed from Legacy Sterling	9,644				—
Service cost	51				48
Interest cost	683				134
Actuarial loss	79				177
Curtailment (gain)	(2,485		)		—
Benefits paid	(284		)		(160		)
End of year	10,990				3,302
Changes in fair value of plan assets:
Beginning of year	$	—			$	—
Employer contributions	284				160
Plan participants’ contributions	—				—
Benefits paid	(284		)		(160		)
End of year	—				—
Funded status	$	(10,990	)		$	(3,302	)
Components of net periodic (benefit) expense for other post retirement benefit plans was the following:
	For the year ended September 30,
	2014				2013				2012
Service cost	$	51			$	48			$	46
Interest cost	683				134				125
Amortization of transition obligation	34				24				24
Amortization of prior service cost	270				47				47
Amortization of net actuarial (gain) loss	(45		)		2				(25		)
Curtailment (gain)	(2,485		)		—				—
Total	$	(1,492	)		$	255			$	217
The Company terminated the optional medical and dental plan to retirees effective September 30, 2014 and all payments under the plan will cease on December 31, 2014. Net periodic benefit expense for other post retirement benefit plans is included in non-interest expense - compensation and employee benefits for the fiscal years ended September 30, 2014, 2013 and 2012. The Company’s liability under its other post retirement benefit plans is included in other liabilities in the balance sheet at September 30, 2014 and 2013.
Estimated future benefit payments are the following for the years ending September 30:
2015	$	660
2016	231
2017	271
2018	319
2019	373
2020 - 2024	2,370
Plan assumptions for the other post retirement medical, dental and vision plans include the following:
	For the year ended September 30,
	2014			2013
Medical trend rate next year	4.5	%		4.5	%
Ultimate trend rate	4.5			4.5
Discount rate	3.50% to 4.27%			4.2
Discount rate used to value periodic cost	3.50% to 4.20%			4.1
There is no impact of a 1% increase or decrease in health care trend rate due to the Company’s cap on cost.
(c) 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. The Company currently makes 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. Fiscal year 2014 did not include a profit sharing component. 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 $1,614, $935 and $1,029 for the years ended September 30, 2014, 2013 and 2012, respectively.
(d) Employee Stock Ownership Plan (“ESOP”)
In connection with the Second-Step Stock Conversion and Offering in January 2004, the Company established an ESOP for substantially all eligible employees who meet certain age and service requirements. The ESOP borrowed $9,987 from Sterling and used the funds to purchase 998,650 shares of common stock in the offering. The term of this ESOP loan was twenty years.
On October 30, 2013,  the Company terminated the ESOP.  In accordance with the provisions of the plan, all participants received contributions for calendar year 2013 and became 100% vested in their accounts.  On February 4, 2014, the ESOP held 499,330 shares of the Company’s common stock.  Of these shares, 488,403 were used to retire the ESOP trust outstanding loan obligation, which was $5,983 including accrued interest.  In accordance with the provisions of the ESOP, the remaining 10,927 shares were allocated ratably to ESOP participants.  ESOP expense was $295, $497, and $390 for the years ended September 30, 2014, 2013 and 2012, respectively.
(e) Stock Compensation Plans
The Company has active stock compensation plans as described below.
The Company’s stockholders approved the 2014 Stock Incentive Plan (the “2014 Plan”) on February 20, 2014. The 2014 Plan permits the grant of stock options, stock appreciation rights, restricted stock (both time-based and performance-based), restricted stock units, performance units, deferred stock, and other stock-based awards for up to 3,400,000 shares of common stock. At September 30, 2014 there were 3,350,761 shares available for future grant. The 2014 Plan replaced the Company’s 2012 Stock Incentive Plan (the “2012 Plan”) described below.
Under the 2014 Plan, any shares that are subject to stock options or stock appreciation rights are counted as one share deducted from the 2014 Plan for every one share delivered under those awards. Any shares granted under the 2014 Plan that are subject to awards other than stock options and stock appreciation rights are counted as 3.5 shares deducted from the 2014 Plan for every one share delivered under those awards.
The 2012 Plan was a shareholder-approved plan that permitted the grant of stock options, stock appreciation rights, restricted stock (both time-based and performance-based), restricted stock units, performance units, deferred stock and other stock-based awards. Prior to the approval of the 2014 Plan, there were 566,554 shares remaining for issuance under the 2012 Plan. These shares are included in the aggregate 3,400,000 shares available under the 2014 Plan. The Company will no longer make awards under the 2012 Plan.
The Company’s 2004 Stock Incentive Plan (the “2004 Plan”), was a shareholder-approved plan that permitted the grant of stock options to its employees for up to 2,796,220 shares of common stock. The Company will no longer make awards under the 2004 Plan. As of September 30, 2014, 11,533 restricted shares awarded under the 2004 Plan were potentially subject to accelerated vesting as the employees were eligible for retirement.
Stock option awards are granted with a fair value equal to the market price of the Company’s common 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 2 to 5 years and stock options have 10 year contractual terms.
The Company’s 2004 Restricted Stock Plan, which historically has been referred to as the Recognition and Retention Plan (“RRP”), provides for the issuance of shares to directors and officers. RRP shares vest annually on the anniversary of the grant date over the vesting period. There were no shares remaining that are authorized and available for future grant under the RRP at September 30, 2014.
In addition to the above plans, the Company provided awards under its 2011 Employment Inducement Stock Program which included options to purchase 107,256 shares of common stock and restricted stock awards covering 29,550 shares of common stock, both of which vest in four equal installments through July 2015, and performance-based restricted stock awards covering 11,820 shares which vest upon attainment of designated performance conditions in combination with continued service through December 31, 2014. These awards are governed by the terms of an award notice and the terms of the 2004 Plan.
In connection with the Merger, the Company granted 104,152 options at an exercise price of $14.25 per share pursuant to a Registration Statement on Form S-8 under which the Company assumed all outstanding fully vested Legacy Sterling stock options. Substantially all of these options expire March 15, 2017. During the fiscal year ended September 30, 2014, 37,873 of these awards were canceled or forfeited. The Company also granted 95,991 shares under the 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 the Company’s 2012 Plan to certain executives of Legacy Sterling. The weighted average grant date fair value was $11.72 per share and the restricted stock awards vest in equal annual installments on the anniversary date over a three-year period.
The following table summarizes the activity in the Company’s active stock-based compensation plans for September 30, 2014:
				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 October 1, 2013	2,066,184			209,697			$	8.73			2,114,509			$	10.71
2014 Stock Incentive Plan	3,400,000
2012 Stock Incentive Plan termination	(566,554	)
Grants associated with the Merger(1)	(921,503	)		351,964			11.72				104,152			14.25
Granted (1)	(719,674	)		115,145			11.53				324,862			11.45
Stock awards vested	—			(69,211	)		9.51				—			—
Exercised	—			—			—				(507,955	)		11.29
Forfeited	439,594			(18,841	)		(9.18		)		(375,235	)		12.24
Canceled/expired	(347,286	)		—			—				—
Balance at September 30, 2014	3,350,761			588,754			$	10.99			1,660,333			$	10.55
Exercisable at September 30, 2014											951,492			$	11.11
(1) Reflects certain non-vested stock awards that count as 3.5 shares or 3.6 shares for each share granted.
Other information regarding options outstanding at September 30, 2014 follows:
	Outstanding									Exercisable
				Weighted average									Weighted average
	Number of			Exercise				Life		Number of			Exercise			Life
	stock options			price				(in years)		stock options			price			(in years)
Range of exercise prices:
$6.71 to $9.00	689,711			$	8.38			7.57		322,148			$	8.36		7.57
$9.28 to $12.64	787,243			11.73				5.02		445,965			12.05			5.1
$12.84 to $13.92	183,379			13.68				2.69		183,379			13.68			2.69
	1,660,333			10.55				5.82		951,492			11.11			5.82
The total intrinsic value of outstanding in-the-money stock options and outstanding in-the-money exercisable stock options was $3.9 million and $1.8 million, at September 30, 2014.
Proceeds from stock option exercises were $2,980, $62 and $102 for fiscal 2014, 2013, and 2012, respectively.
The Company uses an option pricing model to estimate the grant date fair value of stock options granted. The weighted average estimated value per option granted was $2.51 in 2014, $2.74 in 2013, and $2.31 in 2012.
The fair value of options granted was determined using the following weighted-average assumptions as of the grant date:
	For the year ended September 30,
	2014			2013			2012
Risk-free interest rate	1.8	%		1	%		1.4	%
Expected stock price volatility	26.4			40.8			40
Dividend yield (1)	2			2.6			3
Expected term in years	5.67			5.75			5.82
(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 September 30,
	2014				2013				2012
Stock options	$	901			$	695			$	521
Non-vested stock awards/performance units	2,508				1,047				276
Total	$	3,409			$	1,742			$	797
Income tax benefit	914				542				188
Unrecognized stock-based compensation expense at September 30, 2014 was as follows:
	30-Sep-14
Stock options	$	962
Non-vested stock awards/stock units	4,013
Total	$	4,975
The weighted average period over which unrecognized stock options was expected to be recognized was 1.66 years. The weighted average period over which unrecognized non-vested awards/performance units was expected to be recognized was 1.82 years.

Other_NonInterest_Expense

Other Non-Interest Expense	12 Months Ended
	Sep. 30, 2014
Other Income and Expenses [Abstract]	'
Other Non-interest Expense	'
	Other Non-interest Expense
	Other non-interest expense items are presented in the following table. Components exceeding 1% of the aggregate of total net interest income and total non-interest income are presented separately.
		For the year ended September 30,
		2014		2013		2012
	Other non-interest expense:
	Advertising and promotion	$	2,358	$	1,502	$	1,849
	Professional fees	6,913		3,393		4,247
	Data and check processing	3,439		2,520		2,802
	ATM/debit card expense	1,249		1,722		1,711
	Insurance & surety bond premium	2,703		1,199		1,220
	Charge for asset write-downs, severance and retention	22,976		—		—
	Charge for banking systems conversion	3,249		—		—
	Other	15,030		7,040		6,562
	Total other non-interest expense	$	57,917	$	17,376	$	18,391

Earnings_Per_Common_Share

Earnings Per Common Share	12 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Common Share	'
	Earnings Per Common Share
	The following is a summary of the calculation of earnings per share (“EPS”):
		For the year ended September 30,
		2014		2013		2012
	Net income	$	27,678	$	25,254	$	19,888
	Weighted average common shares outstanding for computation of basic EPS (1)	80,268,970		43,734,425		38,227,653
	Common-equivalent shares due to the dilutive effect of stock options (2)	265,073		48,628		20,393
	Weighted average common shares for computation of diluted EPS	80,534,043		43,783,053		38,248,046
	Earnings per common share:
	Basic	$	0.34	$	0.58	$	0.52
	Diluted	0.34		0.58		0.52
	-1	Includes earned ESOP shares.
	-2	Represents incremental shares computed using the treasury stock method.
	As of September 30, 2014, 2013 and 2012 there were 697,475; 1,786,608; and 1,771,132 stock options, respectively, that were considered anti-dilutive and were not included in common-equivalent shares.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
Stockholders' Equity	'
	Stockholders’ Equity
	(a) Regulatory Capital Requirements
	In connection with the Merger, the Company became a bank holding company and a financial holding company as defined by the Bank Holding Company Act of 1956, as amended. Effective in the quarter ended December 31, 2013, Sterling Bancorp is subject to capital ratio requirements as discussed below.
	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. Quantitative measures established by regulations to ensure capital adequacy require the maintenance of minimum amounts and ratios (as forth in the table below) of Total and Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital to adjusted quarterly average assets (as defined).
	The Tier 1 and Total capital ratios are calculated by dividing the respective capital amounts by risk-weighed assets. Risk-weighted assets are calculated based on regulatory requirements and include total assets, excluding goodwill and other intangible assets, allocated by risk weight category, and certain off-balance sheet items (mainly loan commitments). Tier 1 capital to average assets is calculated by dividing Tier 1 capital by adjusted quarterly average total assets, which exclude goodwill and other intangible assets.
	Fiscal year end actual and required capital ratios for the Company and the Bank were as follows:
								Regulatory requirements
			The Bank and the Company					Minimum capital					Classification as well-
								adequacy					capitalized
			Amount			Ratio		Amount			Ratio		Amount		Ratio
		September 30, 2014
		Tier 1 leverage capital (to average assets):
		Sterling National Bank	$	636,507		9.34	%	$	272,542		4	%	$	340,677	5	%
		Sterling Bancorp	553,117			8.12		272,385			4		340,481		5
		Tier 1 capital (to risk-weighted assets):
		Sterling National Bank	636,507			11.94		213,176			4		319,763		6
		Sterling Bancorp	553,117			10.33		214,102			4		321,153		6
		Total capital (to risk-weighted assets):
		Sterling National Bank	677,514			12.71		426,351			8		532,939		10
		Sterling Bancorp	594,124			11.1		428,204			8		535,254		10
			Sterling National Bank only
		September 30, 2013
		Tier 1 leverage	$	363,274		9.33	%	$	155,670		4	%	$	194,587	5	%
		Risk-based capital:
		Tier 1	363,274			13.18		110,235			4		165,352		6
		Total	392,376			14.24		220,469			8		275,587		10
	Management believes that as of September 30, 2014, Sterling Bancorp and Sterling National Bank were “well-capitalized”.
	A reconciliation of the Company’s stockholders’ equity to its regulatory capital at September 30, 2014 and the Bank’s total stockholder’s equity to the Bank’s regulatory capital at September 30, 2014 and 2013 is as follows:
		The Company			The Bank
		September 30,			September 30,
		2014			2014			2013
	Total GAAP stockholders’ equity	$	961,138		$	1,011,973		$	516,281
	Disallowed goodwill and other intangible assets	(419,327		)	(386,766		)	(168,122		)
	Net unrealized loss on available for sale securities	7,815			7,809			11,455
	Disallowed servicing asset	(153		)	(153		)	(198		)
	Net actuarial loss on defined benefit pension plans	3,644			3,644			3,858
	Tier 1 risk-based capital	553,117			636,507			363,274
	Allowance for loan losses and off-balance sheet commitments	41,007			41,007			29,102
	Total risk-based capital	$	594,124		$	677,514		$	392,376
	(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 fiscal year combined with the retained net profits for the preceding two fiscal years. Under the foregoing dividend restrictions and while maintaining its “well-capitalized” status, at September 30, 2014, the Bank had capacity to pay aggregate dividends of up to $47,879 to the Company without prior regulatory approval.
	(c) Stock Repurchase Plans
	From time to time, the Company’s board of directors has authorized stock repurchase plans. The Company has 776,713 shares that are available to be purchased under an announced stock repurchase program. There were no shares repurchased under the repurchase programs during the fiscal years ended September 30, 2014, 2013, or 2012.
	(d) 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. 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 September 30, 2014, 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.

OffBalanceSheet_Financial_Inst

Off-Balance-Sheet Financial Instruments	12 Months Ended
	Sep. 30, 2014
Off-Balance-Sheet Financial Instruments [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 generally accepted accounting principles are not included in its consolidated balance sheet. 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 September 30, 2014, the Company had $97,468 in outstanding letters of credit, of which $21,756 were secured by cash collateral and $34,687 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:
		September 30,
		2014		2013
	Loan origination commitments	$	213,793	$	171,032
	Unused lines of credit	306,482		207,201
	Letters of credit	97,468		35,052

Commitment_and_Contingencies

Commitment and Contingencies	12 Months Ended
	Sep. 30, 2014
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 September 30, 2014 were as follows:
	2014	$	8,984
	2015	8,517
	2016	7,690
	2017	7,702
	2018	6,386
	2019 and thereafter	27,012
		$	66,291
	Occupancy and office operations expense includes net rent expense of $7,893, $3,340 and $2,952 for the years ended September 30, 2014, 2013 and 2012, respectively.
	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. It is possible the Company will be named as a defendant in shareholder litigation arising out of the announcement of the HVB Merger. The Company believes that any such claims would be without merit.
	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 us, and we intend to defend vigorously each case, other than matters we determine are appropriate to be settled. We accrue 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
	Sep. 30, 2014
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 the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There are 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. For these securities, the Company obtains fair value measurements from an independent pricing service. The fair value measurements 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 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.
	The Company reports the fair value of private label collateralized mortgage obligations or “CMOs” with a rating from a nationally recognized bond rating agency of below investment grade using Level 3 inputs. As of September 30, 2014, these securities have an amortized cost $2,866 and fair value of $2,869, representing 17 basis points of our total investment portfolio. At September 30, 2014, we do not anticipate further OTTI charges on these securities. These securities, along with all of the Company’s other securities, will be reviewed on at least a quarterly basis to assess whether the impairment, if any, is OTTI.
	Derivatives
	The fair values of derivatives are based on valuation models using current market terms (including interest rates and fees), the remaining terms of the agreements and the credit worthiness of the counterparty as of the measurement date (Level 2). The Company’s derivatives consist of two interest rate caps and twelve interest rate swaps. See Note 9. “Derivatives.”
	Commitments to Sell Real Estate Loans
	The Company enters into various commitments to sell real estate loans in the secondary market. Such commitments are considered to be derivative financial instruments and therefore are carried at estimated fair value on the consolidated balance sheets. The estimated fair values of these commitments were generally calculated by reference to quoted prices in secondary markets for commitments to sell to certain government sponsored agencies. The fair values of these commitments generally result in a Level 2 classification. The fair value of these commitments is not material.
	A summary of assets and liabilities at September 30, 2014 measured at estimated fair value on a recurring basis is as follows:
		30-Sep-14
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Asset:
	Investment securities available for sale:
	Residential MBS:
	Agency-backed	$	477,705		$	—			$	477,705		$	—
	CMO/Other MBS	111,276			—				111,276			—
	Privately issued CMOs	2,869			—				—			2,869
	Total residential MBS	591,850			—				588,981			2,869
	Federal agencies	152,814			—				152,814			—
	Corporate bonds	192,839			—				192,839			—
	State and municipal	134,898			—				134,898			—
	Trust preferred	38,412			—				38,412			—
	Total other securities	518,963			—				518,963			—
	Total investment securities available for sale	1,110,813			—				1,107,944			2,869
	Interest rate caps and swaps	1,096			—				1,096			—
	Total assets	$	1,111,909		$	—			$	1,109,040		$	2,869
	Swaps	$	1,096		$	—			$	1,096		$	—
	Total liabilities	$	1,096		$	—			$	1,096		$	—
	A summary of assets and liabilities at September 30, 2013 measured at estimated fair value on a recurring basis is the follows:
		September 30, 2013
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Available for sale securities:
	Residential MBS:
	Agency-backed	$	282,529		$	—			$	282,529		$	—
	CMO/Other MBS	163,041			—				163,041			—
	Privately issued CMOs	3,613			—				—			3,613
	Total residential MBS	449,183			—				445,570			3,613
	Investment securities
	Federal agencies	261,547			—				261,547			—
	Corporate	114,933			—				114,933			—
	State and municipal	128,730			—				128,730			—
	Total investment securities available for sale	505,210			—				505,210			—
	Total available for sale securities	954,393			—				950,780			3,613
	Interest rate caps and swaps	997			—				997			—
	Total assets	$	955,390		$	—			$	951,777		$	3,613
	Swaps	$	997		$	—			$	997		$	—
	Total liabilities	$	997		$	—			$	997		$	—
	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.
	Loans Held for Sale and Impaired Loans
	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. Fair value of loans held for sale is determined using quoted prices for similar assets (Level 2 inputs).
	When mortgage loans held for sale are sold with servicing rights retained, the carrying value of mortgage loans sold is reduced by the amount allocated to the value of the servicing rights, which is equal to its fair value. Gains and losses on sales of mortgage loans are based on the difference between the selling price and the carrying value of the related loan sold.
	The Company may record adjustments to the carrying value of loans based on fair value measurements for 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 FASB ASC Topic 310 – Receivables, when establishing the allowance for loan losses. 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 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 $36,208 and $35,228 (which equals the carrying value less the allowance for loan losses allocated to these loans) at September 30, 2014 and 2013, respectively. Changes in fair value recognized in provisions on loans held by the Company were $905 and $2,726 for the twelve months ended September 30, 2014 and 2013, respectively.
	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 September 30, 2014 measured at estimated fair value on a non-recurring basis is the following:
		September 30, 2014
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Commercial real estate	1,463			—				—			1,463
Acquisition, development and construction	2,173			—				—			2,173
Total impaired loans measured at fair value	$	3,636		$	—			$	—		$	3,636
A summary of impaired loans at September 30, 2013 measured at estimated fair value on a non-recurring basis is the following:
	September 30, 2013
	Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
Commercial real estate	3,672			—				—			3,672
Commercial & industrial	500			—				—			500
Acquisition, development and construction	1,839			—				—			1,839
Consumer	2			—				—			2
Total impaired loans measured at fair value	$	6,013		$	—			$	—		$	6,013
Mortgage Servicing Rights
When mortgage loans are sold with servicing retained, servicing rights are initially recorded at fair value with the income statement effect recorded in net gain on sales of loans. 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 FASB ASC Topic 860 - Transfers and Servicing, 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 September 30, 2014 and 2013 were $1,526 and $1,978, 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 subject to non-recurring fair value measurement were $7,580 and $6,022 at September 30, 2014 and 2013, respectively. There were write-downs of $224 and $1,978 related to changes in fair value recognized through income for those foreclosed assets held by the Company during the twelve months ending September 30, 2014 and 2013, respectively.
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 September 30, 2014:
Non-recurring fair value measurements		Fair value			Valuation technique		Unobservable input / assumptions		Range (1) (weighted average)
Impaired loans:
Commercial real estate		$	1,463		Appraisal		Adjustments for comparable properties		15.0% - 36.0% (22.0%)
Acquisition, development & construction		2,173			Appraisal		Adjustments for comparable properties		10.0% - 30.0% (13.5%)
Assets taken in foreclosure:
Residential mortgage		1,301			Appraisal		Adjustments by management to reflect current conditions/selling costs		16.0% - 59.0% (21.6%)
Commercial real estate(2)		1,910			Appraisal		Adjustments by management to reflect current conditions/selling costs		20.0% - 37.0% (24.8%)
Acquisition, development & construction		1,973			Appraisal		Adjustments by management to reflect current conditions/selling costs		25.0% - 70.0% (30.2%)
Mortgage servicing rights		1,526			Third-party		Discount rates		9.3% - 12.8%
					Third-party		Prepayment speeds		100 - 968 (224)
(1) Represents range of discount factors applied to the appraisal to determine fair value. The amounts used for mortgage servicing rights are discounts applied by a third-party valuation provider which the Company believes are appropriate.
(2) Excludes $2,396 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
FASB Codification Topic 825 - Financial Instruments, 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 statements of financial condition for interim and annual periods. Fair value is the amount for which a financial instrument could be exchanged in a current transaction between willing parties, other than in a forced sale or liquidation.
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 FASB Topic 825 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 September 30, 2014:
	September 30, 2014
	Carrying			Level 1 inputs				Level 2 inputs			Level 3 inputs
	amount
Financial assets:
Cash and due from banks	$	177,619		$	177,619			$	—		$	—
Securities available for sale	1,110,813			—				1,110,813			—
Securities held to maturity	579,075			—				587,838			—
Loans, net	4,719,826			—				—			4,758,366
Loans held for sale	17,846			—				17,846			—
Accrued interest receivable on securities	8,876			—				8,876			—
Accrued interest receivable on loans	10,791			—				—			10,791
FHLB stock and Federal Reserve Bank stock	66,085			—				—			—
Interest rate caps and swaps	1,096			—				1,096			—
Financial liabilities:
Non-maturity deposits	(4,860,783		)	(4,860,783		)		—			—
Certificates of deposit	(437,871		)	—				(438,088		)	—
FHLB borrowings	(795,028		)	—				(813,490		)	—
Other borrowings	(45,639		)	—				(45,640		)	—
Senior notes	(98,402		)	—				(100,482		)	—
Mortgage escrow funds	(4,494		)	—				(4,494		)	—
Accrued interest payable on deposits	(320		)	—				(320		)	—
Accrued interest payable on borrowings	(2,942		)	—				(2,942		)	—
Interest rate caps and swaps	(1,096		)	—				(1,096		)	—
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 September 30, 2013:
	September 30, 2013
	Carrying			Level 1 inputs				Level 2 inputs			Level 3 inputs
	amount
Financial assets:
Cash and due from banks	$	113,090		$	113,090			$	—		$	—
Securities available for sale	954,393			—				950,780			3,613
Securities held to maturity	253,999			—				250,896			—
Loans, net	2,384,021			—				—			2,422,824
Loans held for sale	1,011			—				1,011			—
Accrued interest receivable on securities	4,892			—				4,892			—
Accrued interest receivable on loans	6,805			—				—			6,805
FHLB stock	24,312			—				—			—
Interest rate caps and swaps	997			—				997			—
Financial liabilities:
Non-maturity deposits	(2,694,166		)	(2,694,166		)		—			—
Certificates of deposit	(268,128		)	—				(268,088		)	—
FHLB and other borrowings	(345,176		)	—				(488,369		)	—
Mortgage escrow funds	(12,646		)	—				(12,644		)	—
Accrued interest payable on deposits	(1,480		)	—				(1,480		)	—
Accrued interest payable on borrowings	(1,525		)	—				(1,525		)	—
Interest rate caps and swaps	(997		)	—				(997		)	—
The following paragraphs summarize the principal methods and assumptions used by the Company to estimate the fair value of the Company’s financial instruments:
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.
FHLB of New York Stock and Federal Reserve Bank Stock
The redeemable carrying amount of these securities with limited marketability approximates their fair value.
Deposits and Mortgage Escrow Funds
In accordance with FASB Codification Topic 825, deposits with no stated maturity (such as savings, demand and money market deposits) are assigned fair values equal to the carrying amounts payable on demand. Certificates of deposit and mortgage escrow funds are segregated by account type and original term, and fair values are estimated by discounting the contractual cash flows. The discount rate for each account grouping is equivalent to the current market rates for deposits of similar type and maturity.
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 and Senior notes
The estimated fair value approximates carrying value for short-term borrowings. The fair value of long-term fixed-rate borrowings is estimated using quoted market prices, if available, or by discounting future cash flows using current interest rates for similar financial instruments.
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 15. “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 September 30, 2014 and 2013, 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 as Level 2.

Recent_Accounting_Standards_No

Recent Accounting Standards, Not Yet Adopted	12 Months Ended
	Sep. 30, 2014
Accounting Changes and Error Corrections [Abstract]	'
Recently Issued Accounting Standards Not Yet Adopted	'
	Recently Issued Accounting Standards Not Yet Adopted
	Accounting Standards Update (“ASU”) 2014-14 Classification of Certain Government-Guaranteed Residential Mortgage Loans Upon Foreclosure. This standard provides guidance on how holders of certain government-guaranteed loans (e.g., mortgage loans guaranteed by the FHA or VA) should present such loans upon foreclosure. Specifically, the ASU provides that, upon foreclosure, government-guaranteed loans within the scope of the standard should be derecognized and re-recognized as a separate other receivable (i.e., a receivable from the government entity guaranteeing the loan). The standard does not require any new disclosures about such loans. ASU 2014-14 is effective for the Company for annual and interim periods beginning after December 15, 2014, and is not expected to have a material impact on our balance sheet or results of operations.
	ASU 2014-11 Transfers and Servicing (topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. This standard amends the guidance in ASC 860 on accounting for certain repurchase agreements (“repos”). The standard (1) requires entities to account for repurchase-to-maturity transactions as secured borrowings, (2) eliminates accounting guidance on linked repurchase financing transactions, and (3) expands disclosure requirements related to certain transfers of financial assets that are accounted for as sales and certain transfers (specifically, repos, securities lending transactions, and repurchase-to-maturity transactions) that are accounted for as secured borrowings. This standard is effective for annual periods beginning after December 15, 2014 and is not expected to have a material impact on our balance sheet or results of operations.
	ASU 2014-09 Revenue From Contracts With Customers. This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that an entity recognizes 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. The standard is effective for annual reporting periods beginning after December 15, 2016. The Company is currently evaluating the impact this standard will have on its balance sheet and results of operations.
	ASU 2014-04 Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40) - Reclassification of Residential Real Estate Collateralized Consumer Mortgage loans upon Foreclosure was issued. This standard provides clarification when a creditor should be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that the loan should be removed from the balance sheet and other real estate owned recognized. These amendments clarify that when an in-substance foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan upon either: (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure, or (2) the borrower is conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. This standard was effective for the Company on October 1, 2014 and is not expected to have a material impact on our balance sheet or results of operations.
	See Note 1. “Basis of Financial Statement Presentation and Summary of Significant Accounting Policy” for a discussion of the adoption of new accounting standards.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive (Loss) Income	12 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive (Loss) Income	'
	Accumulated Other Comprehensive (Loss) Income
	Components of accumulated other comprehensive income (loss) (“AOCI”) were as follows at September 30:
		September 30,
		2014			2013
	Net unrealized holding loss on available for sale securities	$	(4,645	)	$	(19,316	)
	Related income tax benefit	1,974			7,844
	Available for sale securities AOCI, net of tax	(2,671		)	(11,472		)
	Net unrealized holding loss on securities transferred to held to maturity	(8,947		)	—
	Related income tax benefit	3,803			—
	Securities transferred to held to maturity AOCI, net of tax	(5,144		)	—
	Net unrealized holding loss on retirement plans	(6,336		)	(6,496		)
	Related income tax benefit	2,692			2,638
	Retirement plan AOCI, net of tax	(3,644		)	(3,858		)
	Accumulated other comprehensive loss	$	(11,459	)	$	(15,330	)
	The following table presents the changes in each component of accumulated other comprehensive income for the fiscal years ended September 30, 2014, 2013 and 2012:
		Net unrealized holding gain (loss) on AFS securities			Net unrealized holding (loss) on securities transferred to held to maturity			Net unrealized holding gain (loss) on retirement plans			Total
	Fiscal year ended September 30, 2014
	Balance beginning of the year	$	(11,472	)	$	—		$	(3,858	)	$	(15,330	)
	Other comprehensive gain (loss) before reclassification	9,170			(5,144		)	—			4,026
	Amounts reclassified from AOCI	(369		)	—			214			(155		)
	Total other comprehensive income (loss)	8,801			(5,144		)	214			3,871
	Balance at end of period	$	(2,671	)	$	(5,144	)	$	(3,644	)	$	(11,459	)
	Fiscal year ended September 30, 2013
	Balance beginning of the year	$	15,066		$	—		$	(8,167	)	$	6,899
	Other comprehensive (loss) gain before reclassification	(22,167		)	—			3,041			(19,126		)
	Amounts reclassified from AOCI	(4,371		)	—			1,268			(3,103		)
	Total other comprehensive (loss) income	(26,538		)	—			4,309			(22,229		)
	Balance at end of period	$	(11,472	)	$	—		$	(3,858	)	$	(15,330	)
	Fiscal year ended September 30, 2012
	Balance beginning of the year	$	13,604		$	—		$	(8,468	)	$	5,136
	Other comprehensive gain before reclassification	7,640			—			—			7,640
	Amounts reclassified from AOCI	(6,178		)	—			301			(5,877		)
	Total other comprehensive income	1,462			$	—		301			1,763
	Balance at end of period	$	15,066		$	—		$	(8,167	)	$	6,899

Condensed_Parent_Company_Finan

Condensed Parent Company Financial Statements	12 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Parent Company Financial Statements	'
	Condensed Parent Company Financial Statements
	Set forth below are the condensed balance sheets of Sterling and the related condensed statements of income and cash flows:
		September 30,
		2014			2013
	Assets:
	Cash	$	23,369		$	56,230
	Loan receivable from ESOP	—			6,437
	Investment in Sterling National Bank	1,011,973			517,907
	Investment in non-bank subsidiaries	3,587			3,271
	Goodwill	18,970			—
	Trade name	20,500			—
	Other intangible assets, net	917			—
	Other assets	528			1,184
	Total assets	$	1,079,844		$	585,029
	Liabilities:
	Senior Notes	$	98,402		$	98,033
	Other liabilities	20,304			4,130
	Total liabilities	118,706			102,163
	Stockholders’ equity	961,138			482,866
	Total liabilities & stockholders’ equity	$	1,079,844		$	585,029
	The table  below presents the condensed statement of income:
		For the year ended September 30,
		2014			2013			2012
	Interest income	$	139		$	262		$	282
	Dividend income on equity securities	—			22			30
	Dividends from Sterling National Bank	22,500			—			6,000
	Dividends from non-bank subsidiaries	750			1,600			500
	Other	18			—			10
	Interest expense	(6,265		)	(1,431		)	—
	Non-interest expense	(5,841		)	(2,700		)	(1,838		)
	Income tax benefit	3,431			898			87
	Income (loss) before equity in undistributed earnings of subsidiaries	14,732			(1,349		)	5,071
	Equity in undistributed (excess distributed) earnings of:
	Sterling National Bank	12,590			27,174			13,739
	Non-bank subsidiaries	355			(571		)	1,078
	Net income	$	27,677		$	25,254		$	19,888
	The table below presents the condensed statement of cash flows:
		For the year ended September 30,
		2014			2013			2012
	Cash flows from operating activities:
	Net income	$	27,677		$	25,254		$	19,888
	Adjustments to reconcile net income to net cash provided by operating activities:
	Equity in (undistributed) excess distributed earnings of:
	Sterling National Bank	(12,590		)	(27,174		)	(13,739		)
	Non-bank subsidiaries	(355		)	571			(1,078		)
	(Gain) on redemption of Subordinated Debentures	(712		)	—			—
	Other adjustments, net	22,066			5,259			380
	Net cash provided by operating activities	36,086			3,910			5,451
	Cash flows from investing activities:
	Purchase of securities	—			—			(105		)
	Sales of securities	1,112			818			103
	Investment in subsidiaries	(15,000		)	(45,000		)	(44,203		)
	ESOP loan principal repayments	6,437			459			441
	Net cash (used for) investing activities	(7,451		)	(43,723		)	(43,764		)
	Cash flows from financing activities:
	Net change in other short-term borrowings	(20,659		)	—			—
	Redemption of Subordinated Debentures	(26,140		)	—			—
	Senior Notes offering	—			97,946			—
	Equity capital raise	—			—			46,000
	Cash dividends paid	(17,677		)	(10,642		)	(9,100		)
	Stock option transactions including RRP	2,980			1,758			910
	Other equity transactions	—			265			527
	Net cash (used for) provided by financing activities	(61,496		)	89,327			38,337
Net (decrease) increase in cash	(32,861		)	49,514			24
Cash at beginning of year	56,230			6,716			6,692
Cash at end of year	$	23,369		$	56,230		$	6,716

Quarterly_Results_Of_Operation

Quarterly Results Of Operations (Unaudited)	12 Months Ended
	Sep. 30, 2014
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 the fiscal years ended September 30, 2014 and 2013:
		First			Second		Third		Fourth
		quarter			quarter		quarter		quarter
	Year ended September 30, 2014
	Interest and dividend income	$	52,711		$	61,325	$	65,761	$	67,109
	Interest expense	6,835			7,297		7,310		7,476
	Net interest income	45,876			54,028		58,451		59,633
	Provision for loan losses	3,000			4,800		5,950		5,350
	Non-interest income	9,148			12,415		13,471		12,286
	Non-interest expense	72,974			46,723		44,904		43,780
	(Loss) income before income tax	(20,950		)	14,920		21,068		22,789
	Income tax (benefit) expense	(6,948		)	4,588		6,057		6,452
	Net (loss) income	$	(14,002	)	$	10,332	$	15,011	$	16,337
	Earnings per common share:
	Basic	$	(0.20	)	$	0.12	$	0.18	$	0.2
	Diluted	(0.20		)	0.12		0.18		0.19
	Year ended September 30, 2013
	Interest and dividend income	$	33,145		$	32,420	$	32,593	$	33,903
	Interest expense	5,222			4,601		4,276		5,795
	Net interest income	27,923			27,819		28,317		28,108
	Provision for loan losses	2,950			2,600		3,900		2,700
	Non-interest income	7,659			6,852		6,581		6,600
	Non-interest expense	22,546			23,339		21,789		23,367
	Income before income tax	10,086			8,732		9,209		8,641
	Income tax expense	3,066			2,203		2,833		3,312
	Net income	$	7,020		$	6,529	$	6,376	$	5,329
	Earnings per common share:
	Basic	$	0.16		$	0.15	$	0.15	$	0.12
	Diluted	0.16			0.15		0.15		0.12
	The Company incurred a net loss in the first fiscal quarter of 2014 due mainly to charges and asset write-downs associated with the Merger. The Company recognized charges of $22.2 million for asset write-downs, retention and severance compensation, a write-off of the naming rights to remaining book value of the Provident Bank Ballpark, all of which are included in other non-interest income on the income statement. The charge for asset write-downs was based on the Company’s intent to consolidate several office locations and financial centers. The Company recognized $9.1 million of Merger-related expenses, which included professional advisory fees, legal fees, a portion of change-in-control payments to Legacy Sterling executive officers, costs associated with changing signage at various office and financial center locations and other Merger-related items. In addition, the Company incurred a $2.7 million charge for the settlement of a portion of the Legacy Provident pension plan in December 2013.

Subsequent_Events

Subsequent Events	12 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events (Unaudited)	'
	Subsequent Events (Unaudited)
	On November 5, 2014, the Company announced it had entered into a definitive merger agreement with Hudson Valley Holding Corp. (NYSE: HVB). In the merger, which is a stock-for-stock transaction valued at approximately $539,234 based on the closing price of Sterling common stock on November 4, 2014, Hudson Valley Holding Corp. shareholders will receive a fixed ratio of 1.92 shares of Sterling common stock for each share of Hudson Valley Holding Corp. common stock. Upon closing, Sterling shareholders will own approximately 69% of stock in the combined company and Hudson Valley Holding Corp. shareholders will own approximately 31%. On a pro forma combined basis, for the twelve months ended September 30, 2014, the companies had revenue of $363,217 and $21,962 in net income. Upon completion of the merger the combined company is expected to have $10,703,764 in assets, $6,551,482 in gross loans, and deposits of $8,071,799. The transaction, which has been approved by the boards of directors of both companies, is expected to close in the second calendar quarter of 2015. The transaction is subject to approval by shareholders from both companies, regulatory approval and other customary closing conditions.
	The Company has engaged an independent third-party to assist management in estimating the fair value of the majority of the assets acquired and liabilities to be assumed. The Company will file a Current Report on Form 8-K (or an amendment to a prior report) no later than January 15, 2015 that will include historical and pro forma information regarding Hudson Valley Holding Corp. and the Company which is required in connection with the Merger

Basis_of_Financial_Statement_P1

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Consolidation	'
	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 (“Sterling” or the “Company”).
	•	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.
	•	Provident Municipal Bank merged into Sterling National Bank.
	We refer to the transactions detailed above collectively as the “Merger.”
	The consolidated financial statements include the accounts of Sterling; STL Holdings, Inc. (formerly PBNY Holdings, Inc.) which has an investment in Sterling Silver Title Agency L.P. (formerly PB Madison Title Agency L.P.), a company that provides title searches and title insurance for residential and commercial real estate; LandSave Development, LLC an inactive subsidiary, which was dissolved on September 30, 2014; Sterling Risk Management, Inc. (formerly Provident Risk Management, Inc., a captive insurance company); Sterling National Bank (the “Bank”) and the Bank’s wholly-owned subsidiaries. These subsidiaries included at September 30, 2014: (i) Sterling REIT, Inc. a real estate investment trust that holds a portion of the Company’s real estate loans; (ii) Provest Services Corp. I, which has invested in a low-income housing partnership; (iii) Provest Services Corp. II, which has engaged a third-party provider to sell mutual funds and annuities to the Bank’s customers and (iv) several limited liability companies which hold other real estate owned. Intercompany transactions and balances are eliminated in consolidation.
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America. Certain amounts from prior years have been reclassified to conform to the current fiscal year presentation. Reclassifications had no affect on prior year net income or stockholders’ equity.
Use of estimates	'
	Use of estimates
	The consolidated financial statements have been prepared in conformity with GAAP. In preparing the consolidated financial statements, the Company is required to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expense. Actual results could differ significantly from these estimates. An estimate that is particularly susceptible to significant near-term change is the allowance for loan losses, which is discussed below. Also subject to change are estimates involving goodwill impairment evaluations, mortgage servicing rights, benefit plans, deferred income taxes and fair values of financial instruments.
Cash Flows	'
	Cash Flows
	For purposes of reporting cash flows, cash equivalents include highly liquid, short-term investments such as overnight federal funds, as well as cash and deposits with other financial institutions. Net cash flows are reported for customer loan and deposit transactions and short-term borrowings with an original maturity of 90 days or less.
Long Term Assets	'
	Long-Term Assets
	Premises and equipment, core deposit and other intangible assets are reviewed annually for impairment or when events indicate their carrying amount may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.
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 a separate note. 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. (See Note 17. “Fair Value Measurements”)
Adoption of New Accounting Standards	'
	Adoption of New Accounting Standards
	Accounting Standards Update (ASU) 2014-01 - Investments - Equity method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects was issued. This standard provides reporting guidance for entities that invest in qualified affordable housing projects through limited liability entities that are flow through entities for tax purposes. The amendments in this ASU eliminate the effective yield election and permit the Company to make an accounting policy election to account for its investment in qualified affordable housing projects using the proportional amortization method if certain conditions are met. Under the proportional amortization method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the statement of operations as a component of income tax expense. The amendments in this ASU should be applied retrospectively to all periods presented. The Company adopted this ASU in the quarter ended March 31, 2014, which coincided with the Company’s initial recognition of low income housing tax credits. The adoption of this ASU resulted in a $508 income tax benefit and a $520 expense associated with the amortization of the Company’s investment for the fiscal year ended September 30, 2014.
	Recently Issued Accounting Standards Not Yet Adopted
	Accounting Standards Update (“ASU”) 2014-14 Classification of Certain Government-Guaranteed Residential Mortgage Loans Upon Foreclosure. This standard provides guidance on how holders of certain government-guaranteed loans (e.g., mortgage loans guaranteed by the FHA or VA) should present such loans upon foreclosure. Specifically, the ASU provides that, upon foreclosure, government-guaranteed loans within the scope of the standard should be derecognized and re-recognized as a separate other receivable (i.e., a receivable from the government entity guaranteeing the loan). The standard does not require any new disclosures about such loans. ASU 2014-14 is effective for the Company for annual and interim periods beginning after December 15, 2014, and is not expected to have a material impact on our balance sheet or results of operations.
	ASU 2014-11 Transfers and Servicing (topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. This standard amends the guidance in ASC 860 on accounting for certain repurchase agreements (“repos”). The standard (1) requires entities to account for repurchase-to-maturity transactions as secured borrowings, (2) eliminates accounting guidance on linked repurchase financing transactions, and (3) expands disclosure requirements related to certain transfers of financial assets that are accounted for as sales and certain transfers (specifically, repos, securities lending transactions, and repurchase-to-maturity transactions) that are accounted for as secured borrowings. This standard is effective for annual periods beginning after December 15, 2014 and is not expected to have a material impact on our balance sheet or results of operations.
	ASU 2014-09 Revenue From Contracts With Customers. This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that an entity recognizes 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. The standard is effective for annual reporting periods beginning after December 15, 2016. The Company is currently evaluating the impact this standard will have on its balance sheet and results of operations.
	ASU 2014-04 Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40) - Reclassification of Residential Real Estate Collateralized Consumer Mortgage loans upon Foreclosure was issued. This standard provides clarification when a creditor should be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that the loan should be removed from the balance sheet and other real estate owned recognized. These amendments clarify that when an in-substance foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan upon either: (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure, or (2) the borrower is conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. This standard was effective for the Company on October 1, 2014 and is not expected to have a material impact on our balance sheet or results of operations.
Securities	'
	Securities
	Securities include U.S. Treasury, U.S. Government Agency and Government Sponsored Agencies, municipal and corporate bonds, mortgage-backed securities, collateralized mortgage obligations and trust preferred securities.
	The Company can classify its securities among three categories: held to maturity, trading, 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.
	Trading securities are debt and equity securities held principally for the purpose of selling them in the near-term. These securities are reported at fair value, with unrealized gains and losses included in earnings. The Company does not engage in securities trading activities.
	All other debt and marketable equity securities are classified as available for sale. These 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, changes in prepayment risks, the need to increase capital, or similar factors.
	Premiums and discounts on debt securities are recognized 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 impairment at least quarterly, and more frequently when economic and market conditions warrant such an evaluation. For securities in an unrealized loss position, we consider 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 the Company does not expect to recover the entire amortized cost basis of the security, the Company does not intend to sell the security 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 other than temporary impairment is separated into a) the amount representing the credit loss and b) the amount related to all other factors. The amount of other than temporary impairment 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.
Loans Held For Sale	'
	Loans Held For Sale
	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. In the absence of commitments from investors, fair value is based on current investor yield requirements. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings.
	Historically mortgage loans held for sale were generally sold with servicing rights retained. The carrying value of mortgage loans sold is reduced by the amount allocated to the value of the servicing rights which is its fair value. Gains and losses on sales of mortgage loans are based on the difference between the selling price and the carrying value of the related loan sold.
Servicing Rights	'
	Servicing Rights
	When mortgage loans are sold with servicing retained, servicing rights are initially recorded at fair value with the income statement effect recorded in gains on sales of loans. 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. All classes of servicing assets are subsequently measured using the amortization method which requires servicing rights to be amortized into non-interest income in proportion to, and over the period of, the estimated future net servicing income of the underlying loans.
	Under the amortization measurement method, the Company subsequently measures servicing rights at fair value at each reporting date and records any impairment in value of servicing assets in earnings in the period in which the impairment occurs. The fair values of servicing rights are subject to significant fluctuations as a result of changes in estimated and actual prepayment speeds and default rates and losses.
	Servicing fee income, which is reported on the income statement as other income, is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan, and are recorded as income when earned.
Loans	'
	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 amortized cost less the allowance for loan losses. Interest income on loans is accrued on the unpaid principal balance.
	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, unless 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 not recognized as income unless warranted based on the borrower’s financial condition and payment record. Furthermore, negative tax escrow will be included in the unpaid principal for loans individually evaluated for impairment, as this is part of the customer’s legal obligation to the Company.
	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. If a loan is prepaid or sold, the net deferred amount is recognized in the statement of income at that time. Interest and fees on loans include prepayment fees and late charges collected.
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.
Allowance for Loan Losses	'
	Allowance for Loan Losses
	The allowance for loan losses is a reserve 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 allowance for loan losses is a critical accounting estimate and requires substantial judgment of management. The allowance for loan losses includes allowance allocations calculated in accordance with ASC Subtopic 450-20, “Loss Contingencies” and ASC Subtopic 310-35-2, “Loan Impairment.” The level of the allowance 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, as well as trends in the foregoing. The Company analyzes loans by two broad segments: real estate secured loans and loans that are either unsecured or secured by other collateral.
	The classes considered real estate secured are: residential mortgage loans; commercial real estate (“CRE”) loans; business banking CRE; multi-family loans; acquisition, development and construction (“ADC”) loans; homeowner loans, and home equity lines of credit. The classes considered unsecured or secured by other than real estate collateral are: commercial & industrial (“C&I”) loans; payroll finance loans, warehouse lending; factored receivables; equipment finance loans; business banking C&I loans and consumer loans. In all segments or classes, significant loans are reviewed for impairment once they are past due 90 days or more or are classified substandard or doubtful. Generally the Company considers a homogeneous residential mortgage or home equity line of credit to be significant if the Company’s investment in the loan is greater than $500. If a loan is deemed to be impaired in one of the real estate secured segment, it is generally considered collateral dependent. If the value of the collateral securing a collateral dependent impaired loan is less than the loan’s carrying value, a charge-off is recognized equal to the difference between the appraised value and the book value of the loan. Additionally, impairment reserves are recognized for estimated costs to hold and liquidate and for a 10% discount on the appraisal value. The range for costs to hold and liquidate is 12-22% for CRE, business banking CRE and ADC loans and is 7-13% for homeowner loans, home equity lines of credit, and residential mortgage loans. Impaired loans in the real estate secured segments are re-appraised using a summary or drive-by appraisal report every six to nine months.
	For loans in the business banking C&I class 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, we prepare a cash flow projection, and charge-off the difference between the net present value of the cash flows discounted at the effective note rate and the carrying value of the loan, and generally recognize a 10% impairment reserve to account for the potential imprecision of our estimates. However, on most of these cases receipt of future cash flows is too unreliable to be considered probable, resulting in the charge-off of the entire balance of the loan. For unsecured consumer loans, charg0- offs are recognized once the loan is 90 to 120 days or more past due or the borrower files for bankruptcy protection.
	Subsequent recoveries, if any, are credited to the allowance for loan losses. The allowance for loan losses consists of amounts specifically allocated to non-performing loans and other criticized or classified loans (if any), as well as allowances determined for the pass rated loans in each major loan category. After we establish an allowance for loan losses for loans that are known to be non-performing, criticized or classified, we calculate a percentage to apply to the remaining loan portfolio to estimate the probable incurred losses inherent in that portion of the portfolio. These percentages are determined by management, based on historical loss experience for the applicable loan class, and are adjusted to reflect our evaluation of:
	•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 borrower; and for commercial loans, trends in risk ratings.
	Commercial real estate loans subject us 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.
	Commercial business 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 we must gain control of assets used in the borrower’s business before foreclosing which we cannot be assured of doing, and the value in a foreclosure sale or other means of liquidation is uncertain.
	Acquisition, development and construction (“ADC”) lending is considered higher risk and exposes us 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. In the event we make a land acquisition loan on property that is not yet approved for the planned development, there is the risk that approvals will not be granted or will be delayed. These events may adversely affect the borrower and the collateral value of the property. Development and construction loans also expose us to the risk that improvements will not be completed on time or in accordance with specifications and projected costs. In addition, the ultimate sale or rental of the property may not occur as anticipated. All of these factors are considered as part of the underwriting, structuring and pricing of the loan. We have deemphasized this type of lending.
	When we evaluate residential mortgage loans and home equity loans we weigh 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 our risk. Similarly, as we obtain a mortgage on the property, if home prices decline, we are exposed to risk in both our first mortgage and equity lending programs due to declines in the value of our collateral. We are also exposed to risk because the time to foreclose is significant and has become longer under current market conditions.
Troubled Debt Restructuring	'
	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. Not all loans that are restructured as a TDR are classified as non-accrual before the restructuring occurs. 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.
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 based on the excess of the carrying amount of assets (generally assets associated with a financial center) over the fair value of the assets. Fair value is determined by third-party valuations and evaluations prepared by management.
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 acquired in a purchase business combination and determined to have an indefinite useful life are not amortized, but tested for impairment at least annually. Goodwill and trade name are the only intangible assets with an indefinite life on our 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 has the option to first perform a qualitative assessment to test goodwill for impairment on a reporting-unit-by-reporting-unit basis. If, after performing the qualitative assessment, the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will perform the two-step process described below:
	1	Identify potential impairments by comparing the fair value of a reporting unit to its carrying amount, including goodwill. Goodwill is not considered impaired as long as the fair value of the reporting unit is greater than its carrying value. The second step is only required if a potential impairment to goodwill is identified in step one.
	2	Compare the implied fair value of goodwill to its carrying amount, where the implied fair value of goodwill is computed on a residual basis, that is, by subtracting the sum of the fair values of the individual asset categories (tangible and intangible) from the indicated fair value of the reporting unit as determined under step one. If the carrying amount of goodwill exceeds its implied fair value, an impairment loss is recognized. That loss is equal to the carrying amount of goodwill that is in excess of its implied fair value, and it must be presented as a separate line item on financial statements.
	At September 30, 2014, the Company assessed goodwill for impairment using qualitative factors and concluded the two-step process was unnecessary.
	Core deposit intangibles recorded in acquisitions are amortized to expense using an accelerated method over their estimated lives of 8 to 10 years. Non-compete agreements are amortized on a straight line basis over their estimated life. Prior to March 31, 2014, intangibles related to the naming rights on Provident Bank Ball Park were amortized over 10 years on a straight-line basis. Impairment losses on intangible assets are charged to expense, if and when they occur.
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 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 other real state owned was included as a charge to other non-interest income in the income statement. Subsequent valuations of other real estate owned are performed by management, and the carrying amount of a property is adjusted by a charge to 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 real estate owned properties are recognized upon disposition.
Securities Repurchase Agreements	'
	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.
Income Taxes	'
	Income Taxes
	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 income tax 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 September 30, 2014. (See Note 10 “Income Taxes”).
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 is recorded at its cash surrender value (or the amount that can be realized).
Stock-Based Compensation Plans	'
	Stock-Based Compensation Plans
	Compensation expense for stock options, 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.
Earnings Per Share	'
	Earnings Per Share
	Basic earnings per share (“EPS”) is computed by dividing net income applicable to common stock by the weighted average number of common shares outstanding during the period.
	Diluted EPS is computed in a similar manner, 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. For purposes of computing both basic and diluted EPS, outstanding shares include earned ESOP shares.
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.
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 financial statements.
Derivatives	'
	Derivatives
	At the inception of a derivative contract, the Company designates the derivative as one of three types based on the Company’s intentions and belief as to likely effectiveness as a hedge. These three types are (1) a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (“fair value hedge”), (2) a hedge of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (“cash flow hedge”), or (3) an instrument with no hedging designation (“stand-alone derivative”). For a fair value hedge, the gain or loss on the derivative, as well as the offsetting loss or gain on the hedged item, are recognized in current earnings as fair values change. For a cash flow hedge, the gain or loss on the derivative is reported in other comprehensive income and is reclassified into earnings in the same period during which the hedged transaction affects earnings. For both types of hedges, changes in the fair value of derivatives that are not highly effective in hedging the changes in fair value or expected cash flows of the hedged item are recognized immediately in current earnings. Changes in the fair value of derivatives that do not qualify for hedge accounting are reported currently in earnings, as non-interest income. Net cash settlements on derivatives that qualify for hedge accounting are recorded in interest income or interest expense, based on the item being hedged. Net cash settlements on derivatives that do not qualify for hedge accounting are reported in non-interest income. Cash flows on hedges are classified in the cash flow statement the same as the cash flows of the items being hedged.
	The Company formally documents the relationship between derivatives and hedged items, as well as the risk-management objective and the strategy for undertaking hedge transactions at the inception of the hedging relationship. This documentation includes linking fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific firm commitments or forecasted transactions. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivative instruments that are used are highly effective in offsetting changes in fair values or cash flows of the hedged items. The Company discontinues hedge accounting when it determines that the derivative is no longer effective in offsetting changes in the fair value or cash flows of the hedged item, the derivative is settled or terminates, a hedged forecasted transaction is no longer probable, a hedged firm commitment is no longer firm, or treatment of the derivative as a hedge is no longer appropriate or intended.
	When hedge accounting is discontinued, subsequent changes in fair value of the derivative are recorded as non-interest income. When a fair value hedge is discontinued, the hedged asset or liability is no longer adjusted for changes in fair value and the existing basis adjustment is amortized or accreted over the remaining life of the asset or liability. When a cash flow hedge is discontinued but the hedged cash flows or forecasted transactions are still expected to occur, gains or losses that were accumulated in other comprehensive income are amortized into earnings over the same periods which the hedged transactions will affect earnings.
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.
Employee Benefit Plans	'
	The Company’s policy is to invest the Plan assets in a prudent manner for the purpose of providing benefit payments to participants and offsetting reasonable expenses of administration. Historically, the Company’s investment strategy was designed to provide a total return that, over the long-term, placed a strong emphasis on the preservation of capital and compliance with applicable regulations and laws. Management intends to terminate the Plan in fiscal 2015 subject to obtaining required approvals from the Internal Revenue Service and other regulators. Therefore, the investment allocation of Plan assets was shifted in fiscal 2014 to a liability driven investment strategy which is more heavily weighted towards long-term fixed income assets with a similar duration profile to the Plan liabilities. As of September 30, 2014, the majority of the Plan assets were invested in funds specifically designed for liability driven investment strategies and had a weighted average expected rate of return of 4.0%.
	The Plan’s investment policy prohibits the direct investment in real estate but allows the Plan’s mutual funds to include a small percentage of real estate related investments. The investment strategy utilizes asset allocation as a principal determinant for establishing an appropriate risk profile.

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Schedule of recognized amounts of identifiable assets acquired and liabilities assumed	'
	The table below summarizes the amounts recognized as of the 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 Merger date:
	Consideration paid through Sterling Bancorp common stock issued to Legacy Sterling shareholders				$	457,781
		Legacy Sterling carrying value				Fair value adjustments				As recorded at acquisition
	Cash and cash equivalents	$	277,798			$	—			$	277,798
	Investment securities	613,154				(5,243		)	(a)	607,911
	Loans held for sale	30,341				—				30,341
	Loans	1,704,801				(6,693		)	(b)	1,698,108
	Federal Reserve Bank stock	7,680				—				7,680
	Bank owned life insurance	55,374				—				55,374
	Premises and equipment	21,293				2,301			(c)	23,594
	Accrued interest receivable	6,590				—				6,590
	Core deposit and other intangibles	—				20,089			(d)	20,089
	Trade name intangible	—				20,500			(e)	20,500
	Other real estate owned	1,720				4,095			(f)	5,815
	Other assets	40,877				(19,944		)	(g)	20,933
	Deposits	(2,296,713		)		(477		)	(h)	(2,297,190		)
	FHLB borrowings	(100,346		)		(273		)	(i)	(100,619		)
	Other borrowings	(62,465		)		—				(62,465		)
	Subordinated Debentures	(25,774		)		(753		)	(j)	(26,527		)
	Other liabilities	(60,462		)		4,502			(k)	(55,960		)
	Total identifiable net assets	$	213,868			$	18,104			$	231,972
	Goodwill recorded in the Merger									225,809
	Goodwill at September 30, 2013									163,117
	Goodwill at September 30, 2014									$	388,926
	Explanation of certain fair value related adjustments:
	(a)	Represents the fair value adjustment on investment securities held to maturity.
	(b)	Represents the elimination of Legacy Sterling’s allowance for loan losses and an adjustment of the amortized cost of loans to estimated fair value, which includes an interest rate mark and credit mark. Gross loans acquired were $1,723,447; of the acquired loans, $1,699,271 were not considered purchased credit impaired and we recorded a fair value adjustment of $14,440.
	(c)	Represents an adjustment to reflect the fair value of leasehold improvements.
	(d)	Represents intangible assets recorded to reflect the fair value of core deposits and below market rent on leased premises. 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. The below market rent intangible asset will be amortized on a straight-line basis over the remaining term of the leases.
	(e)	Represents the estimated fair value of Legacy Sterling’s trade name. This intangible asset will not be amortized and will be reviewed at least annually for impairment.
	(f)	Represents an adjustment to an acquired property which Legacy Sterling utilized as a financial center and recorded as premises and equipment. The Company included this asset in OREO as it was held for sale. This asset was sold during the fiscal year ended September 30, 2014.
	(g)	Consists primarily of adjustments in net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangibles recorded.
	(h)	Represents the fair value adjustment on deposits as the weighted average interest rate of deposits assumed exceeded the cost of similar funding available in the market at the time of the Merger.
	(i)	Represents the fair value adjustment on FHLB borrowings as the weighted average interest rate of FHLB borrowings assumed exceeded the cost of similar funding available in the market at the time of the Merger.
	(j)	Represents the fair value adjustment on subordinated debentures as the weighted average interest rate of the debentures assumed exceeded the cost of similar debt funding available in the market at the time of the Merger.
	(k)	Represents the fair value of other liabilities assumed at the Merger date.
Purchased credit impaired loans	'
	The impaired loans acquired in the Merger as of October 31, 2013 were accounted for in accordance with ASC Topic 310-30 Accounting for Certain Loans or Debt Securities Acquired in a Transfer (“ASC 310-30”) and were comprised of collateral dependent loans with deteriorated credit quality as follows:
		ASC 310-30 loans
	Contractual principal balance at acquisition	$	24,176
	Principal not expected to be collected (non-accretable discount)	(10,927		)
	Expected cash flows at acquisition	13,249
	Interest component of expected cash flows (accretable discount)	—
	Fair value of acquired loans	$	13,249
Schedule of proforma information	'
	Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated potential cost savings.
		Pro forma for the
		fiscal year ended September 30,
		2014				2013
	Net interest income	$	198,776			$	180,030
	Non-interest income	54,396				65,749
	Non-interest expense	187,306				189,136
	Net income	44,460				39,190
	Pro forma earnings per share:
	Basic	$	0.53			$	0.47
	Diluted	0.53				0.47

Securities_Tables

Securities (Tables)	12 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Summary of securities available for sale	'
		30-Sep-14												30-Sep-13
		Amortized			Gross			Gross			Fair			Amortized		Gross			Gross			Fair
		cost			unrealized			unrealized			value			cost		unrealized			unrealized			value
					gains			losses								gains			losses
	Available for Sale
	Residential MBS:
	Agency-backed	$	477,003		$	2,257		$	(1,555	)	$	477,705		$	284,837	$	1,849		$	(4,157	)	$	282,529
	CMO/Other MBS	115,395			242			(1,492		)	114,145			169,336		356			(3,038		)	166,654
	Total residential MBS	592,398			2,499			(3,047		)	591,850			454,173		2,205			(7,195		)	449,183
	Other securities:
	Federal agencies	158,114			3			(5,303		)	152,814			273,637		—			(12,090		)	261,547
	Corporate	195,547			149			(2,857		)	192,839			118,575		153			(3,795		)	114,933
	State and municipal	131,715			3,439			(256		)	134,898			127,324		3,447			(2,041		)	128,730
	Trust preferred	37,684			766			(38		)	38,412			—		—			—			—
	Total other securities	523,060			4,357			(8,454		)	518,963			519,536		3,600			(17,926		)	505,210
	Total available for sale	$	1,115,458		$	6,856		$	(11,501	)	$	1,110,813		$	973,709	$	5,805		$	(25,121	)	$	954,393
Summary of securities held-to-maturity	'
		September 30, 2014												30-Sep-13
		Amortized			Gross			Gross			Fair			Amortized		Gross			Gross			Fair
		cost			unrealized gains			unrealized losses			value			cost		unrealized gains			unrealized losses			value
	Held to Maturity
	Residential MBS:
	Agency-backed	$	142,329		$	1,360		$	(103	)	143,586			130,371		716			(108		)	130,979
	CMO/Other MBS	62,690			9			(1,204		)	61,495			25,776		33			(315		)	25,494
	Total residential MBS	205,019			1,369			(1,307		)	205,081			156,147		749			(423		)	156,473
	Other securities:
	Federal agencies	136,413			2,634			(962		)	138,085			77,341		—			(3,458		)	73,883
	State and municipal	232,643			6,814			(123		)	239,334			19,011		556			(546		)	19,021
	Other	5,000			338			—			5,338			1,500		19			—			1,519
	Total other securities	374,056			9,786			(1,085		)	382,757			97,852		575			(4,004		)	94,423
	Total held to maturity	$	579,075		$	11,155		$	(2,392	)	$	587,838		$	253,999	$	1,324		$	(4,427	)	$	250,896
Summary of amortized cost and fair value of investment securities available for sale by remaining period to contractual maturity	'
		September 30, 2014
		Available for sale						Held to maturity
		Amortized			Fair			Amortized			Fair
		cost			value			cost			value
	Other securities remaining period to contractual maturity:
	One year or less	$	2,100		$	2,112		$	8,847		$	8,897
	One to five years	141,508			141,748			9,138			9,624
	Five to ten years	334,295			328,902			189,494			192,109
	Greater than ten years	45,157			46,201			166,577			172,127
	Total other securities	523,060			518,963			374,056			382,757
	Residential MBS	592,398			591,850			205,019			205,081
	Total securities	$	1,115,458		$	1,110,813		$	579,075		$	587,838
Sale of securities	'
	Sales of securities for the periods indicated below were as follows:
		For the fiscal year ended September 30,
		2014			2013			2012
	Available for sale:
	Proceeds from sales	$	529,107		$	339,123		$	344,431
	Gross realized gains	1,964			7,709			10,468
	Gross realized losses	(1,323		)	(377		)	—
	Income tax expense on realized net gains	172			2,282			2,475
	Held to maturity: (1)
	Proceeds from sales	$	—		$	1,187		$	—
	Gross realized gains	—			59			—
	Income tax expense on realized gains	—			18			—
	(1) During the fiscal year ended September 30, 2013, the Company sold held to maturity securities after the Company had already collected at least 85% of the principal balance outstanding at acquisition.
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			Unrealized			Fair			Unrealized			Fair		Unrealized
		value			losses			value			losses			value		losses
	Available for sale
	September 30, 2014
	Residential MBS:
	Agency-backed	$	137,693		$	(516	)	$	41,516		$	(1,039	)	$	179,209	$	(1,555	)
	CMO/other MBS	62,507			(446		)	29,499			(1,046		)	92,006		(1,492		)
	Total residential MBS	200,200			(962		)	71,015			(2,085		)	271,215		(3,047		)
	Other securities:
	Federal agencies	6,153			(144		)	146,416			(5,159		)	152,569		(5,303		)
	Corporate	97,833			(1,348		)	66,440			(1,509		)	164,273		(2,857		)
	State and municipal	8,170			(58		)	12,809			(198		)	20,979		(256		)
	Trust preferred	3,907			(38		)	—			—			3,907		(38		)
	Total other securities	116,063			(1,588		)	225,665			(6,866		)	341,728		(8,454		)
	Total	$	316,263		$	(2,550	)	$	296,680		$	(8,951	)	$	612,943	$	(11,501	)
	September 30, 2013
	Residential MBS:
	Agency-backed	$	137,265		$	(4,157	)	$	—		$	—		$	137,265	$	(4,157	)
	CMO/Other MBS	122,324			(2,742		)	7,820			(296		)	130,144		(3,038		)
	Total residential MBS	259,589			(6,899		)	7,820			(296		)	267,409		(7,195		)
	Other securities:
	Federal agencies	261,547			(12,090		)	—			—			261,547		(12,090		)
	State and municipal	43,585			(2,033		)	112			(8		)	43,697		(2,041		)
	Corporate	95,013			(3,795		)	—			—			95,013		(3,795		)
	Total other securities	400,145			(17,918		)	112			(8		)	400,257		(17,926		)
	Total	$	659,734		$	(24,817	)	$	7,932		$	(304	)	$	667,666	$	(25,121	)
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			Unrealized			Fair			Unrealized			Fair		Unrealized
		value			losses			value			losses			value		losses
	Held to maturity
	30-Sep-14
	Residential MBS:
	Agency-backed	$	20,616		$	(103	)	$	—		$	—		$	20,616	$	(103	)
	CMO/Other MBS	14,928			(368		)	42,646			(836		)	57,574		(1,204		)
	Total residential MBS	35,544			(471		)	42,646			(836		)	78,190		(1,307		)
	Other securities:
	Federal agencies	23,756			(62		)	24,101			(900		)	47,857		(962		)
	State and municipal	13,943			(100		)	1,479			(23		)	15,422		(123		)
	Total other securities	37,699			(162		)	25,580			(923		)	63,279		(1,085		)
	Total	$	73,243		$	(633	)	$	68,226		$	(1,759	)	$	141,469	$	(2,392	)
	30-Sep-13
	Residential MBS:
	Agency-backed	$	10,963		$	(86	)	$	—		$	—		$	10,963	$	(86	)
	CMO/Other MBS	31,412			(337		)	—			—			31,412		(337		)
	Total residential MBS	42,375			(423		)	—			—			42,375		(423		)
	Other securities:
	Federal agencies	73,883			(3,458		)	—			—			73,883		(3,458		)
	State and municipal	9,530			(546		)	—			—			9,530		(546		)
	Total other securities	83,413			(4,004		)	—			—			83,413		(4,004		)
	Total	$	125,788		$	(4,427	)	$	—		$	—		$	125,788	$	(4,427	)
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:
		September 30,
		2014			2013
	Available for sale securities pledged for borrowings, at fair value	$	268,316		$	199,642
	Available for sale securities pledged for municipal deposits, at fair value	532,770			580,756
	Available for sale securities pledged for customer back-to-back swaps, at fair value	1,934			4,645
	Held to maturity securities pledged for borrowings, at amortized cost	58,509			55,497
	Held to maturity securities pledged for municipal deposits, at amortized cost	430,611			167,926
	Total securities pledged	$	1,292,140		$	1,008,466

Loans_Tables

Loans (Tables)	12 Months Ended
	Sep. 30, 2014
Loans [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:
		September 30,
		2014				2013
	Commercial:
	Commercial & industrial	$	1,164,537			$	439,787
	Payroll finance	145,474				—
	Warehouse lending	192,003				—
	Factored receivables	181,433				—
	Equipment financing	393,027				—
	Total commercial	2,076,474				439,787
	Commercial mortgage:
	Commercial real estate	1,449,052				969,490
	Multi-family	368,524				307,547
	Acquisition, development & construction	92,149				102,494
	Total commercial mortgage	1,909,725				1,379,531
	Total commercial and commercial mortgage	3,986,199				1,819,318
	Residential mortgage	570,431				400,009
	Consumer:
	Home equity lines of credit	159,944				156,995
	Other consumer loans	43,864				36,576
	Total consumer	203,808				193,571
	Total loans	4,760,438				2,412,898
	Allowance for loan losses	(40,612		)		(28,877		)
	Total loans, net	$	4,719,826			$	2,384,021
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 September 30, 2014 and September 30, 2013:
		September 30, 2014
		Current				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	1,150,854			$	2,316			$	7,043		$	—		$	4,324		$	1,164,537
	Payroll finance	145,029				99				—			346			—			145,474
	Warehouse lending	192,003				—				—			—			—			192,003
	Factored receivables	181,063				—				—			—			370			181,433
	Equipment financing	391,914				689				162			—			262			393,027
	Commercial real estate	1,433,805				93				4,188			521			10,445			1,449,052
	Multi-family	368,393				—				—			—			131			368,524
	Acquisition, development & construction	79,732				—				56			—			12,361			92,149
	Residential mortgage	547,912				4,023				2,036			534			15,926			570,431
	Consumer	193,491				3,087				1,487			—			5,743			203,808
	Total loans	$	4,684,196			$	10,307			$	14,972		$	1,401		$	49,562		$	4,760,438
	Total TDRs included above	$	17,138			$	346			$	169		$	—		$	11,944		$	29,597
	Non-performing loans:
	Loans 90+ days past due and still accruing															$	1,401
	Non-accrual loans															49,562
	Total non-performing loans															$	50,963
		September 30, 2013
		Current				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	438,818			$	178			$	2		$	289		$	500		439,787
	Commercial real estate	1,263,933				1,978				2,357			1,574			7,195			1,277,037
	Acquisition, development & construction	96,306				768				—			—			5,420			102,494
	Residential mortgage	390,072				354				267			1,832			7,484			400,009
	Consumer	190,393				566				—			404			2,208			193,571
	Total loans	$	2,379,522			$	3,844			$	2,626		$	4,099		$	22,807		$	2,412,898
	Total TDRs included above	$	23,754			$	—			$	—		$	141		$	2,199		$	26,094
	Non-performing loans:
	Loans 90+ days past due and still accruing															$	4,099
	Non-accrual loans															22,807
	Total non-performing loans															$	26,906
Allowance for loan losses activity	'
	Activity in the allowance for loan losses for the fiscal years ended September 30, 2014, 2013 and 2012 is summarized below:
		30-Sep-14
		Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
		balance											charge-offs
	Commercial & industrial	$	5,302			$	(2,901	)		$	1,073		$	(1,828	)	$	6,062		$	9,536
	Payroll finance	—				(758		)		—			(758		)	2,137			1,379
	Warehouse lending	—				—				—			—			630			630
	Factored receivables	—				(211		)		9			(202		)	1,496			1,294
	Equipment financing	—				(1,074		)		194			(880		)	3,501			2,621
	Commercial real estate	9,967				(741		)		161			(580		)	1,457			10,844
	Multi-family	—				(418		)		92			(326		)	2,193			1,867
	Acquisition, development & construction	5,806				(1,479		)		—			(1,479		)	(2,207		)	2,120
	Residential mortgage	4,474				(963		)		323			(640		)	2,003			5,837
	Consumer	3,328				(786		)		114			(672		)	1,828			4,484
	Total loans	$	28,877			$	(9,331	)		$	1,966		$	(7,365	)	$	19,100		$	40,612
	Annualized net charge-offs to average loans outstanding																		0.24		%
		30-Sep-13
		Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
		balance											charge-offs
	Commercial & industrial	$	4,603			$	(1,354	)		$	410		$	(944	)	$	1,643		$	5,302
	Commercial real estate	7,230				(3,725		)		577			(3,148		)	5,885			9,967
	Acquisition, development & construction	8,526				(3,422		)		182			(3,240		)	520			5,806
	Residential mortgage	4,359				(2,547		)		101			(2,446		)	2,561			4,474
	Consumer	3,564				(2,009		)		232			(1,777		)	1,541			3,328
	Total loans	$	28,282			$	(13,057	)		$	1,502		$	(11,555	)	$	12,150		$	28,877
	Annualized net charge-offs to average loans outstanding																		0.52		%
		September 30, 2012
		Beginning				Charge-offs				Recoveries			Net			Provision			Ending balance
		balance											charge-offs
	Commercial & industrial	$	5,945			$	(1,526	)		$	1,116		$	(410	)	$	(932	)	$	4,603
	Commercial real estate	5,568				(2,707		)		528			(2,179		)	3,841			7,230
	Acquisition, development & construction	9,895				(4,124		)		299			(3,825		)	2,456			8,526
	Residential mortgage	3,498				(2,551		)		356			(2,195		)	3,056			4,359
	Consumer	3,011				(1,901		)		263			(1,638		)	2,191			3,564
	Total loans	$	27,917			$	(12,809	)		$	2,562		$	(10,247	)	$	10,612		$	28,282
	Annualized net charge-offs to average loans outstanding																		0.56		%
Impaired financing receivables	'
	The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at September 30, 2014:
		Loans evaluated by segment														Allowance evaluated by segment
		Individually				Collectively				Purchased credit impaired loans			Total			Individually			Collectively			Total allowance for loan losses
		evaluated for				evaluated for							loans			evaluated for			evaluated for
		impairment				impairment										impairment			impairment
	Commercial & industrial	$	4,177			$	1,158,837			$	1,523		$	1,164,537		$	—		$	9,536		$	9,536
	Payroll finance	—				145,474				—			145,474			—			1,379			1,379
	Warehouse lending	—				192,003				—			192,003			—			630			630
	Factored receivables	—				181,433				—			181,433			—			1,294			1,294
	Equipment financing	—				393,027				—			393,027			—			2,621			2,621
	Commercial real estate	13,750				1,435,163				139			1,449,052			—			10,844			10,844
	Multi-family	—				368,524				—			368,524			—			1,867			1,867
	Acquisition, development & construction	17,766				74,383				—			92,149			—			2,120			2,120
	Residential mortgage	515				567,815				2,101			570,431			—			5,837			5,837
	Consumer	—				203,808				—			203,808			—			4,484			4,484
	Total loans	$	36,208			$	4,720,467			$	3,763		$	4,760,438		$	—		$	40,612		$	40,612
	The following table sets forth loans evaluated for impairment by segment and the allowance evaluated by segment at September 30, 2013:
		Loans evaluated by segment											Allowance evaluated by segment
		Individually				Collectively				Total			Individually			Collectively			Total allowance for loan losses
		evaluated for				evaluated for				loans			evaluated for			evaluated for
		impairment				impairment							impairment			impairment
	Commercial & industrial	$	2,631			$	437,156			$	439,787		$	249		$	5,053		$	5,302
	Commercial real estate	14,091				1,262,946				1,277,037			803			9,164			9,967
	Acquisition, development & construction	19,582				82,912				102,494			540			5,266			5,806
	Residential mortgage	515				399,494				400,009			—			4,474			4,474
	Consumer	2				193,569				193,571			1			3,327			3,328
	Total loans	$	36,821			$	2,376,077			$	2,412,898		$	1,593		$	27,284		$	28,877
	The following table presents loans individually evaluated for impairment by segment of loans at September 30, 2014 and September 30, 2013:
		September 30, 2014											30-Sep-13
		Unpaid				Recorded				Related allowance			Unpaid			Recorded			Related allowance
		principal				investment							principal			investment
		balance											balance
	With no related allowance recorded:
	Commercial & industrial	$	4,177			$	4,177			$	—		$	2,175		$	2,131		$	—
	Commercial real estate	13,886				13,750				—			12,451			11,820			—
	Acquisition, development & construction	18,676				17,766				—			17,971			17,945			—
	Residential mortgage	515				515				—			515			515			—
	Subtotal	37,254				36,208				—			33,112			32,411			—
	With an allowance recorded:
	Commercial & industrial	—				—				—			500			500			249
	Commercial real estate	—				—				—			3,150			2,271			803
	Acquisition, development & construction	—				—				—			2,753			1,637			540
	Consumer	—				—				—			2			2			1
	Subtotal	—				—				—			6,405			4,410			1,593
	Total	$	37,254			$	36,208			$	—		$	39,517		$	36,821		$	1,593
	The following table presents the average recorded investment and interest income recognized related to loans individually evaluated for impairment by segment for the fiscal year September 30, 2014 and 2013:
		September 30, 2014											September 30, 2013
		YTD average				Interest				Cash-basis			YTD average			Interest			Cash-basis
		recorded				income				interest			recorded			income			interest
		investment				recognized				income			investment			recognized			income
										recognized									recognized
	With no related allowance recorded:
	Commercial & industrial	$	4,180			$	—			$	—		$	1,821		$	91		$	86
	Commercial real estate	14,016				186				180			17,325			286			275
	Acquisition, development & construction	20,525				239				239			12,827			631			587
	Residential mortgage	515				—				—			309			—			—
	Consumer	—				—				—			61			—			—
	Subtotal	39,236				425				419			32,343			1,008			948
	With an allowance recorded:
	Commercial & industrial	—				—				—			705			—			—
	Commercial real estate	—				—				—			6,646			7			7
	Acquisition, development & construction	—				—				—			1,104			—			—
	Residential mortgage	—				—				—			1,602			14			10
Consumer	—				—				—			228			—			—
Subtotal	—				—				—			10,285			21			17
Total	$	39,236			$	425			$	419		$	42,628		$	1,029		$	965
Troubled debt restructurings	'
	The following table presents loans by segment modified as TDRs that occurred during the twelve months ended September 30, 2014 and 2013:
		September 30, 2014										September 30, 2013
					Recorded investment									Recorded investment
		Number			Pre-				Post-			Number		Pre-			Post-
					modification				modification					modification			modification
	Commercial & industrial	—			$	—			$	—		5		$	2,001		$	2,001
	Commercial real estate	—			—				—			2		2,682			2,682
	Acquisition, development & construction	2			1,060				1,060			7		5,772			5,772
	Residential mortgage	—			—				—			6		1,436			1,372
	Consumer	—			—				—			1		302			302
	Total restructured loans	2			$	1,060			$	1,060		21		$	12,193		$	12,129
	The following tables set forth the amounts and past due status of the Company’s TDRs at September 30, 2014 and 2013:
		September 30, 2014
		Current loans				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	275			$	—			$	—		$	—		$	1,618		$	1,893
	Equipment financing	435				—				—			—			—			435
	Commercial real estate	4,838				—				—			—			447			5,285
	Acquisition, development & construction	5,732				—				—			—			6,817			12,549
	Residential mortgage	5,858				346				169			—			2,841			9,214
	Consumer	—				—				—			—			221			221
	Total	$	17,138			$	346			$	169		$	—		$	11,944		$	29,597
	Allowance for loan losses	$	409			$	—			$	31		$	—		$	451		$	891
		30-Sep-13
		Current loans				30-59				60-89			90+			Non-			Total
						days				days			days			accrual
						past due				past due			past due
	Commercial & industrial	$	1,843			$	—			$	—		$	141		$	—		$	1,984
	Commercial real estate	5,305				—				—			—			—			5,305
	Acquisition, development & construction	14,190				—				—			—			151			14,341
	Residential mortgage	2,416				—				—			—			1,792			4,208
	Consumer	—				—				—			—			256			256
	Total loans	$	23,754			$	—			$	—		$	141		$	2,199		$	26,094
	Allowance for loan losses	$	438			$	—			$	—		$	—		$	439		$	877
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 September 30, 2014 and 2013, the risk category of gross loans by segment was as follows:
		September 30, 2014											September 30, 2013
		Special				Substandard				Doubtful			Special			Substandard			Doubtful
		mention											mention
	Commercial & industrial	$	24,980			$	5,749			$	—		$	3,545		$	3,855		$	365
	Payroll finance	—				346				—			—			—			—
	Factored receivables	46				370				—			—			—			—
	Equipment financing	—				262				—			—			—			—
	Commercial real estate	8,720				26,826				—			7,279			24,561			227
	Multi-family	—				131				—			—			—			—
	Acquisition, development & construction	1,040				16,456				—			1,867			19,410			—
	Residential mortgage	2,988				16,981				—			824			9,786			—
	Consumer	1,779				5,972				—			15			2,891			—
	Total	$	39,553			$	73,093			$	—		$	13,530		$	60,503		$	592

Premises_And_Equipment_Net_Tab

Premises And Equipment, Net (Tables)	12 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Premises and Equipment, Net	'
	Premises and equipment are summarized as follows:
		September 30,
		2014			2013
	Land and land improvements	$	6,048		$	7,282
	Buildings	22,888			30,558
	Leasehold improvements	32,963			8,136
	Furniture, fixtures and equipment	50,343			40,164
	Total premises and equipment, gross	112,242			86,140
	Accumulated depreciation and amortization	(68,956		)	(49,620		)
	Total premises and equipment, net	$	43,286		$	36,520

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Change in goodwill	'
	The change in goodwill in the fiscal years ended September 30, 2014 and 2013 was as follows:
		September 30,
		2014		2013
	Beginning of year balance	$	163,117	$	163,247
	Acquisitions	225,809		(130		)
	Disposals	—		—
	End of year balance	$	388,926	$	163,117
Other intangible assets	'
	The balance of other intangible assets at September 30, 2014 and 2013 was as follows:
		Gross intangible assets		Accumulated amortization			Net intangible assets
	30-Sep-14
	Core deposits	$	24,182	$	(4,694	)	$	19,488
	Non-compete agreements	10,308		(5,490		)	4,818
	Trade name	20,500		—			20,500
	Fair value of below market leases	725		(253		)	472
	Provident Bank Ball Park naming rights	2,414		(2,414		)	—
		$	58,129	$	(12,851	)	$	45,278
	30-Sep-13
	Core deposits	$	4,818	$	(798	)	$	4,020
	Provident Bank Ball Park naming rights	2,414		(543		)	1,871
		$	7,232	$	(1,341	)	$	5,891
Future amortization expense	'
	The estimated aggregate future amortization expense for other intangible assets remaining as of September 30, 2014 was as follows:
		Amortization expense
	2015	$	6,113
	2016	5,042
	2017	2,598
	2018	2,178
	2019	2,058
	Thereafter	6,786
		$	24,775

Deposits_Tables

Deposits (Tables)	12 Months Ended
	Sep. 30, 2014
Deposits [Abstract]	'
Summary of major classification of deposits	'
	Deposit balances at September 30, 2014 and 2013 are summarized as follows:
		September 30,
		2014		2013
	Non-interest bearing demand	$	1,799,685	$	943,934
	Interest bearing demand	766,852		434,398
	Savings	698,443		580,125
	Money market	1,595,803		735,709
	Certificates of deposit	437,871		268,128
	Total deposits	$	5,298,654	$	2,962,294
Schedule of maturities of deposits	'
	Certificates of deposit had remaining periods to contractual maturity as follows:
		September 30,
		2014		2013
	Remaining period to contractual maturity:
	Less than one year	$	340,813	$	239,104
	One to two years	53,319		17,248
	Two to three years	35,632		5,185
	Three to four years	4,000		3,062
	Four to five years	4,107		3,529
	Total certificates of deposit	$	437,871	$	268,128
List of Company's Brokered deposits	'
	Listed below are the Company’s brokered deposits at September 30, 2014 and 2013:
		September 30,
		2014		2013
	Money market	$	84,022	$	34,571
	Reciprocal CDAR’s 1	34,017		1,343
	CDAR’s one way	3,028		768
	Total brokered deposits	$	121,067	$	36,682
	1 Certificate of deposit account registry service

Borrowings_and_Senior_Notes_Ta

Borrowings and Senior Notes (Tables)	12 Months Ended
	Sep. 30, 2014
Debt Instruments [Abstract]	'
Schedule of debt	'
	The Company’s borrowings and weighted average interest rates are summarized as follows:
		September 30,
		2014				2013
		Amount		Rate		Amount		Rate
	By type of borrowing:
	FHLB advances and overnight	$	795,028	1.75	%	$	442,602	2.77	%
	Repurchase agreements	25,639		0.39		20,351		0.88
	Fed funds purchased	20,000		0.31		—		—
	Senior notes	98,402		5.98		98,033		5.98
	Total borrowings	$	939,069	2.12	%	$	560,986	3.26	%
	By remaining period to maturity:
	Less than one year	$	370,365	0.69	%	$	158,897	0.95	%
	One to two years	140,344		0.59		78,717		1.97
	Two to three years	257,442		3.52		191		5.32
	Three to four years	168,402		4.38		202,414		4.21
	Four to five years	—		—		118,033		5.57
	Greater than five years	2,516		4.92		2,734		4.92
	Total borrowings	$	939,069	2.12	%	$	560,986	3.26	%

Derivatives_Tables

Derivatives (Tables)	12 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedges, Assets [Abstract]	'
Summary of derivatives	'
	Summary information as of September 30, 2014 and 2013 regarding these derivatives is presented below:
		Notional			Average	Weighted		Weighted	Fair value
		amount			maturity (in years)	average		average
						fixed rate		variable rate
	30-Sep-14
	Interest rate caps	$	50,000		0.18	3.75	%	NA	$	—
	3rd party interest rate swap	50,729			4.86	4.2		1 m Libor + 2.44	1,096
	Customer interest rate swap	(50,729		)	4.86	4.2		1 m Libor + 2.44	(1,096		)
	30-Sep-13
	Interest rate caps	$	50,000		1.18	3.75	%	NA	$	—
	3rd party interest rate swap	54,180			5.76	4.22		1 m Libor + 2.45	997
	Customer interest rate swap	(54,180		)	5.76	4.22		1 m Libor + 2.45	(997		)

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit)	'
	Income tax expense for the periods indicated consists of the following:
		For the year ended September 30,
		2014			2013			2012
	Current tax expense:
	Federal	$	11,613		$	9,146		$	5,538
	State	1,598			1,549			685
	Total current tax expense	13,211			10,695			6,223
	Deferred tax (benefit) expense:
	Federal	(2,745		)	522			(261		)
	State	(314		)	197			197
	Total deferred tax (benefit) expense	(3,059		)	719			(64		)
	Total income tax expense	$	10,152		$	11,414		$	6,159
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 September 30,
		2014			2013			2012
	Tax at Federal statutory rate of 35%	$	13,241		$	12,833		$	9,116
	State and local income taxes, net of Federal tax benefit	834			1,135			573
	Tax-exempt interest, net of disallowed interest	(3,824		)	(2,192		)	(2,448		)
	BOLI income	(1,110		)	(699		)	(718		)
	Non-deductible acquisition related costs	712			416			418
	Low income housing tax credits	(165		)	—			—
	Other, net	464			(79		)	(782		)
	Actual income tax expense	$	10,152		$	11,414		$	6,159
	Effective income tax rate	26.8		%	31.1		%	23.6		%
Schedule of Deferred Tax Assets and Liabilities	'
	The following table presents the Company’s deferred tax position at September 30, 2014 and 2013:
		September 30,
		2014			2013
	Deferred tax assets:
	Allowance for loan losses	$	17,272		$	11,809
	Deferred compensation	649			798
	Other accrued compensation and benefits	5,418			1,497
	Accrued post retirement expense	2,705			1,441
	Deferred rent	—			1,059
	Intangible assets	2,439			—
	Other comprehensive loss (securities)	5,777			7,844
	Other comprehensive loss (defined benefit plans)	2,371			2,638
	Depreciation of premises and equipment	433			—
	State NOL carryforward	1,431			—
	Other	3,511			2,172
	Total deferred tax assets	42,006			29,258
	Deferred tax liabilities:
	Undistributed earnings of subsidiary not consolidated for tax return purposes (income from REITs)	9,303			4,483
	Prepaid pension costs	10,579			3,758
	Purchase accounting adjustments	16,056			1,057
	Depreciation and lease adjustments	—			2,686
	Deferred rent	163			—
	Intangibles amortization	—			112
	Other	2,557			2,207
	Total deferred tax liabilities	38,658			14,303
	Net deferred tax asset	$	3,348		$	14,955

Employee_Benefit_Plans_And_Sto1

Employee Benefit Plans And Stock-Based Compensation Plans (Tables)	12 Months Ended
	Sep. 30, 2014
Schedule of Employee Benefit Plans And Stock-Based Compensation Plans [Line Items]	'
Summary of Company's stock option activity	'
	The following table summarizes the activity in the Company’s active stock-based compensation plans for September 30, 2014:
					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 October 1, 2013	2,066,184			209,697			$	8.73			2,114,509			$	10.71
	2014 Stock Incentive Plan	3,400,000
	2012 Stock Incentive Plan termination	(566,554	)
	Grants associated with the Merger(1)	(921,503	)		351,964			11.72				104,152			14.25
	Granted (1)	(719,674	)		115,145			11.53				324,862			11.45
	Stock awards vested	—			(69,211	)		9.51				—			—
	Exercised	—			—			—				(507,955	)		11.29
	Forfeited	439,594			(18,841	)		(9.18		)		(375,235	)		12.24
	Canceled/expired	(347,286	)		—			—				—
	Balance at September 30, 2014	3,350,761			588,754			$	10.99			1,660,333			$	10.55
	Exercisable at September 30, 2014											951,492			$	11.11
	(1) Reflects certain non-vested stock awards that count as 3.5 shares or 3.6 shares for each share granted.
Schedule of weighted-average assumptions as of grant date for options	'
	Other information regarding options outstanding at September 30, 2014 follows:
		Outstanding									Exercisable
					Weighted average									Weighted average
		Number of			Exercise				Life		Number of			Exercise			Life
		stock options			price				(in years)		stock options			price			(in years)
	Range of exercise prices:
	$6.71 to $9.00	689,711			$	8.38			7.57		322,148			$	8.36		7.57
	$9.28 to $12.64	787,243			11.73				5.02		445,965			12.05			5.1
	$12.84 to $13.92	183,379			13.68				2.69		183,379			13.68			2.69
		1,660,333			10.55				5.82		951,492			11.11			5.82
	The fair value of options granted was determined using the following weighted-average assumptions as of the grant date:
		For the year ended September 30,
		2014			2013			2012
	Risk-free interest rate	1.8	%		1	%		1.4	%
	Expected stock price volatility	26.4			40.8			40
	Dividend yield (1)	2			2.6			3
	Expected term in years	5.67			5.75			5.82
	(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 September 30,
		2014				2013				2012
	Stock options	$	901			$	695			$	521
	Non-vested stock awards/performance units	2,508				1,047				276
	Total	$	3,409			$	1,742			$	797
	Income tax benefit	914				542				188
Unrecognized stock-based compensation expense	'
	Unrecognized stock-based compensation expense at September 30, 2014 was as follows:
		30-Sep-14
	Stock options	$	962
	Non-vested stock awards/stock units	4,013
	Total	$	4,975
Pension Plans [Member]	'
Schedule of Employee Benefit Plans And Stock-Based Compensation Plans [Line Items]	'
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 plan assets. The Company uses a September 30 measurement date for its pension plans.
		September 30,
		2014				2013
	Changes in projected benefit obligation:
	Beginning of year balance	$	31,705			$	35,471
	Benefit obligation of the Legacy Sterling Plan at October 31, 2013	52,296				—
	Service cost	—				—
	Interest cost	2,779				1,452
	Actuarial loss (gain)	9,460				(3,672		)
	Partial settlement	(44,774		)		—
	Benefits and distributions paid	(1,748		)		(1,546		)
	End of year balance	49,718				31,705
	Changes in fair value of plan assets:
	Beginning of year balance	35,417				32,657
	Fair value of the Legacy Sterling Plan assets at October 31, 2013	71,538				—
	Actual gain on plan assets	8,137				4,306
	Employer contributions	—				—
	Partial settlement	(44,774		)		—
	Benefits and distributions paid	(1,748		)		(1,546		)
	End of year balance	68,570				35,417
	Funded status at end of year	$	18,852			$	3,712
Components of the net periodic pension expense (benefit)	'
	The components of net periodic pension expense were as follows:
		For the year ended September 30,
		2014				2013				2012
	Service cost	$	—			$	—			$	—
	Interest cost	2,779				1,452				1,501
	Expected return on plan assets	(3,380		)		(2,462		)		(2,125		)
	Amortization of unrecognized actuarial loss	236				2,062				2,316
	Partial settlement charge	3,922				—				—
	Net periodic pension expense	$	3,557			$	1,052			$	1,692
Schedule of amounts recognized in accumulated other comprehensive income (loss)	'
	Amounts recognized in accumulated other comprehensive (loss) at September 30, 2014 and 2013 consisted of:
		September 30,
		2014				2013
	Unrecognized actuarial loss	$	(6,024	)		$	(5,479	)
	Deferred tax asset	2,556				2,225
	Net amount recognized in accumulated other comprehensive (loss)	$	(3,468	)		$	(3,254	)
Schedule of expected benefit payments	'
	Estimated future benefit payments are the following for the years ending September 30:
	2015	$	726
	2016	902
	2017	1,079
	2018	1,625
	2019	1,851
	2020 - 2024	13,461
Schedule of fair value of plan assets and allocation	'
	Weighted average pension plan asset allocations based on the fair value of such assets at September 30, 2014 and September 30, 2013 and target allocation ranges for 2014, by asset category, are as follows:
		2014			2013			Target allocation		Weighted
								range 2014		average expected
										rate of return
	Large cap U.S. equity	—	%		44	%				—	%
	Small and mid cap U.S. equity	—			11					—
	International equity	—			10					—
	Total equity	—			65			0%		—
	Total balanced asset allocation	—			5					—
	High yield bond	—			3					—
	Intermediate term bond	13			27					—
	Long-term bond	87			—					—
	Total fixed income	100			30			95% - 100%		4
	Total assets	100	%		100	%				4	%
	Cash	—			—			0% to 5%		—
	The fair value of Plan assets by asset category as of September 30, 2014 and 2013, was the following:
		30-Sep-14
		Fair value				Level 1 inputs				Level 2 inputs				Level 3 inputs
	Asset category:
	Intermediate term bond	$	8,629			$	—			$	8,629			$	—
	Long-term bond	59,892				—				59,892				—
	Total assets	$	68,521			$	—			$	68,521			$	—
		30-Sep-13
		Fair value				Level 1 inputs				Level 2 inputs				Level 3 inputs
	Asset category:
	Large cap U.S. equity	$	16,378			$	—			$	16,378			$	—
	Small and mid cap U.S. equity	4,443				—				4,443				—
	International equity	3,654				—				3,654				—
	Total equity	24,475				—				24,475				—
	Total balanced asset allocation	1,691				—				1,691				—
	High yield bond	1,018				—				1,018				—
	Intermediate term bond	8,233				—				8,233				—
	Total fixed income	9,251				—				9,251				—
	Total assets	$	35,417			$	—			$	35,417			$	—
Schedule of assumptions used for plan	'
	The principal actuarial assumptions used at September 30, 2014 and 2013 were as follows:
		September 30,
		2014			2013
	Projected benefit obligation:
	Discount rate	4.5	%		5.2	%
	Net periodic pension cost:
	Discount rate	4.5	%		5.2	%
	Long-term rate of return on plan assets	4	%		7.75	%
Other Post retirement Benefit Plans [Member]	'
Schedule of Employee Benefit Plans And Stock-Based Compensation Plans [Line Items]	'
Summary of changes in the projected benefit obligation and fair value of plan assets	'
	Data relating to other post retirement benefit plans is the following:
		September 30,
		2014				2013
	Changes in accumulated post retirement benefit obligation:
	Beginning of year	$	3,302			$	3,103
	Obligations assumed from Legacy Sterling	9,644				—
	Service cost	51				48
	Interest cost	683				134
	Actuarial loss	79				177
	Curtailment (gain)	(2,485		)		—
	Benefits paid	(284		)		(160		)
	End of year	10,990				3,302
	Changes in fair value of plan assets:
	Beginning of year	$	—			$	—
	Employer contributions	284				160
	Plan participants’ contributions	—				—
	Benefits paid	(284		)		(160		)
	End of year	—				—
	Funded status	$	(10,990	)		$	(3,302	)
Components of the net periodic pension expense (benefit)	'
	Components of net periodic (benefit) expense for other post retirement benefit plans was the following:
		For the year ended September 30,
		2014				2013				2012
	Service cost	$	51			$	48			$	46
	Interest cost	683				134				125
	Amortization of transition obligation	34				24				24
	Amortization of prior service cost	270				47				47
	Amortization of net actuarial (gain) loss	(45		)		2				(25		)
	Curtailment (gain)	(2,485		)		—				—
	Total	$	(1,492	)		$	255			$	217
Schedule of expected benefit payments	'
	Estimated future benefit payments are the following for the years ending September 30:
	2015	$	660
	2016	231
	2017	271
	2018	319
	2019	373
	2020 - 2024	2,370
Schedule of assumptions used for plan	'
	Plan assumptions for the other post retirement medical, dental and vision plans include the following:
		For the year ended September 30,
		2014			2013
	Medical trend rate next year	4.5	%		4.5	%
	Ultimate trend rate	4.5			4.5
	Discount rate	3.50% to 4.27%			4.2
	Discount rate used to value periodic cost	3.50% to 4.20%			4.1

Other_Noninterest_Expense_Tabl

Other Non-interest Expense (Tables)	12 Months Ended
	Sep. 30, 2014
Other Income and Expenses [Abstract]	'
Schedule of Other Non-interest Expense	'
	Other non-interest expense items are presented in the following table. Components exceeding 1% of the aggregate of total net interest income and total non-interest income are presented separately.
		For the year ended September 30,
		2014		2013		2012
	Other non-interest expense:
	Advertising and promotion	$	2,358	$	1,502	$	1,849
	Professional fees	6,913		3,393		4,247
	Data and check processing	3,439		2,520		2,802
	ATM/debit card expense	1,249		1,722		1,711
	Insurance & surety bond premium	2,703		1,199		1,220
	Charge for asset write-downs, severance and retention	22,976		—		—
	Charge for banking systems conversion	3,249		—		—
	Other	15,030		7,040		6,562
	Total other non-interest expense	$	57,917	$	17,376	$	18,391

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Computation of basic and diluted earnings per share	'
	The following is a summary of the calculation of earnings per share (“EPS”):
		For the year ended September 30,
		2014		2013		2012
	Net income	$	27,678	$	25,254	$	19,888
	Weighted average common shares outstanding for computation of basic EPS (1)	80,268,970		43,734,425		38,227,653
	Common-equivalent shares due to the dilutive effect of stock options (2)	265,073		48,628		20,393
	Weighted average common shares for computation of diluted EPS	80,534,043		43,783,053		38,248,046
	Earnings per common share:
	Basic	$	0.34	$	0.58	$	0.52
	Diluted	0.34		0.58		0.52
	-1	Includes earned ESOP shares.
	-2	Represents incremental shares computed using the treasury stock method.

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	'
	Fiscal year end actual and required capital ratios for the Company and the Bank were as follows:
								Regulatory requirements
			The Bank and the Company					Minimum capital					Classification as well-
								adequacy					capitalized
			Amount			Ratio		Amount			Ratio		Amount		Ratio
		September 30, 2014
		Tier 1 leverage capital (to average assets):
		Sterling National Bank	$	636,507		9.34	%	$	272,542		4	%	$	340,677	5	%
		Sterling Bancorp	553,117			8.12		272,385			4		340,481		5
		Tier 1 capital (to risk-weighted assets):
		Sterling National Bank	636,507			11.94		213,176			4		319,763		6
		Sterling Bancorp	553,117			10.33		214,102			4		321,153		6
		Total capital (to risk-weighted assets):
		Sterling National Bank	677,514			12.71		426,351			8		532,939		10
		Sterling Bancorp	594,124			11.1		428,204			8		535,254		10
			Sterling National Bank only
		September 30, 2013
		Tier 1 leverage	$	363,274		9.33	%	$	155,670		4	%	$	194,587	5	%
		Risk-based capital:
		Tier 1	363,274			13.18		110,235			4		165,352		6
		Total	392,376			14.24		220,469			8		275,587		10
Reconciliation of Stockholders' Equity to Bank Regulatory Capital	'
	A reconciliation of the Company’s stockholders’ equity to its regulatory capital at September 30, 2014 and the Bank’s total stockholder’s equity to the Bank’s regulatory capital at September 30, 2014 and 2013 is as follows:
		The Company			The Bank
		September 30,			September 30,
		2014			2014			2013
	Total GAAP stockholders’ equity	$	961,138		$	1,011,973		$	516,281
	Disallowed goodwill and other intangible assets	(419,327		)	(386,766		)	(168,122		)
	Net unrealized loss on available for sale securities	7,815			7,809			11,455
	Disallowed servicing asset	(153		)	(153		)	(198		)
	Net actuarial loss on defined benefit pension plans	3,644			3,644			3,858
	Tier 1 risk-based capital	553,117			636,507			363,274
	Allowance for loan losses and off-balance sheet commitments	41,007			41,007			29,102
	Total risk-based capital	$	594,124		$	677,514		$	392,376

OffBalanceSheet_Financial_Inst1

Off-Balance-Sheet Financial Instruments (Tables)	12 Months Ended
	Sep. 30, 2014
Off-Balance-Sheet Financial Instruments [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:
		September 30,
		2014		2013
	Loan origination commitments	$	213,793	$	171,032
	Unused lines of credit	306,482		207,201
	Letters of credit	97,468		35,052

Commitment_and_Contingencies_T

Commitment and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases	'
	Future minimum rental payments due under non-cancellable operating leases with initial or remaining terms of more than one year at September 30, 2014 were as follows:
	2014	$	8,984
	2015	8,517
	2016	7,690
	2017	7,702
	2018	6,386
	2019 and thereafter	27,012
		$	66,291

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Estimated fair value on a recurring basis	'
	A summary of assets and liabilities at September 30, 2014 measured at estimated fair value on a recurring basis is as follows:
		30-Sep-14
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Asset:
	Investment securities available for sale:
	Residential MBS:
	Agency-backed	$	477,705		$	—			$	477,705		$	—
	CMO/Other MBS	111,276			—				111,276			—
	Privately issued CMOs	2,869			—				—			2,869
	Total residential MBS	591,850			—				588,981			2,869
	Federal agencies	152,814			—				152,814			—
	Corporate bonds	192,839			—				192,839			—
	State and municipal	134,898			—				134,898			—
	Trust preferred	38,412			—				38,412			—
	Total other securities	518,963			—				518,963			—
	Total investment securities available for sale	1,110,813			—				1,107,944			2,869
	Interest rate caps and swaps	1,096			—				1,096			—
	Total assets	$	1,111,909		$	—			$	1,109,040		$	2,869
	Swaps	$	1,096		$	—			$	1,096		$	—
	Total liabilities	$	1,096		$	—			$	1,096		$	—
	A summary of assets and liabilities at September 30, 2013 measured at estimated fair value on a recurring basis is the follows:
		September 30, 2013
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Available for sale securities:
	Residential MBS:
	Agency-backed	$	282,529		$	—			$	282,529		$	—
	CMO/Other MBS	163,041			—				163,041			—
	Privately issued CMOs	3,613			—				—			3,613
	Total residential MBS	449,183			—				445,570			3,613
	Investment securities
	Federal agencies	261,547			—				261,547			—
	Corporate	114,933			—				114,933			—
	State and municipal	128,730			—				128,730			—
	Total investment securities available for sale	505,210			—				505,210			—
	Total available for sale securities	954,393			—				950,780			3,613
	Interest rate caps and swaps	997			—				997			—
	Total assets	$	955,390		$	—			$	951,777		$	3,613
	Swaps	$	997		$	—			$	997		$	—
	Total liabilities	$	997		$	—			$	997		$	—
Impaired loans measured at estimated fair value on nonrecurring basis	'
	A summary of impaired loans at September 30, 2014 measured at estimated fair value on a non-recurring basis is the following:
		September 30, 2014
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Commercial real estate	1,463			—				—			1,463
	Acquisition, development and construction	2,173			—				—			2,173
	Total impaired loans measured at fair value	$	3,636		$	—			$	—		$	3,636
	A summary of impaired loans at September 30, 2013 measured at estimated fair value on a non-recurring basis is the following:
		September 30, 2013
		Fair value			Level 1 inputs				Level 2 inputs			Level 3 inputs
	Commercial real estate	3,672			—				—			3,672
	Commercial & industrial	500			—				—			500
	Acquisition, development and construction	1,839			—				—			1,839
	Consumer	2			—				—			2
	Total impaired loans measured at fair value	$	6,013		$	—			$	—		$	6,013
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 September 30, 2014:
	Non-recurring fair value measurements		Fair value			Valuation technique		Unobservable input / assumptions		Range (1) (weighted average)
	Impaired loans:
	Commercial real estate		$	1,463		Appraisal		Adjustments for comparable properties		15.0% - 36.0% (22.0%)
	Acquisition, development & construction		2,173			Appraisal		Adjustments for comparable properties		10.0% - 30.0% (13.5%)
	Assets taken in foreclosure:
	Residential mortgage		1,301			Appraisal		Adjustments by management to reflect current conditions/selling costs		16.0% - 59.0% (21.6%)
	Commercial real estate(2)		1,910			Appraisal		Adjustments by management to reflect current conditions/selling costs		20.0% - 37.0% (24.8%)
	Acquisition, development & construction		1,973			Appraisal		Adjustments by management to reflect current conditions/selling costs		25.0% - 70.0% (30.2%)
	Mortgage servicing rights		1,526			Third-party		Discount rates		9.3% - 12.8%
						Third-party		Prepayment speeds		100 - 968 (224)
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 September 30, 2014:
		September 30, 2014
		Carrying			Level 1 inputs				Level 2 inputs			Level 3 inputs
		amount
	Financial assets:
	Cash and due from banks	$	177,619		$	177,619			$	—		$	—
	Securities available for sale	1,110,813			—				1,110,813			—
	Securities held to maturity	579,075			—				587,838			—
	Loans, net	4,719,826			—				—			4,758,366
	Loans held for sale	17,846			—				17,846			—
	Accrued interest receivable on securities	8,876			—				8,876			—
	Accrued interest receivable on loans	10,791			—				—			10,791
	FHLB stock and Federal Reserve Bank stock	66,085			—				—			—
	Interest rate caps and swaps	1,096			—				1,096			—
	Financial liabilities:
	Non-maturity deposits	(4,860,783		)	(4,860,783		)		—			—
	Certificates of deposit	(437,871		)	—				(438,088		)	—
	FHLB borrowings	(795,028		)	—				(813,490		)	—
	Other borrowings	(45,639		)	—				(45,640		)	—
	Senior notes	(98,402		)	—				(100,482		)	—
	Mortgage escrow funds	(4,494		)	—				(4,494		)	—
	Accrued interest payable on deposits	(320		)	—				(320		)	—
	Accrued interest payable on borrowings	(2,942		)	—				(2,942		)	—
	Interest rate caps and swaps	(1,096		)	—				(1,096		)	—
	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 September 30, 2013:
		September 30, 2013
		Carrying			Level 1 inputs				Level 2 inputs			Level 3 inputs
		amount
	Financial assets:
	Cash and due from banks	$	113,090		$	113,090			$	—		$	—
	Securities available for sale	954,393			—				950,780			3,613
	Securities held to maturity	253,999			—				250,896			—
	Loans, net	2,384,021			—				—			2,422,824
	Loans held for sale	1,011			—				1,011			—
	Accrued interest receivable on securities	4,892			—				4,892			—
	Accrued interest receivable on loans	6,805			—				—			6,805
	FHLB stock	24,312			—				—			—
	Interest rate caps and swaps	997			—				997			—
	Financial liabilities:
	Non-maturity deposits	(2,694,166		)	(2,694,166		)		—			—
	Certificates of deposit	(268,128		)	—				(268,088		)	—
	FHLB and other borrowings	(345,176		)	—				(488,369		)	—
	Mortgage escrow funds	(12,646		)	—				(12,644		)	—
	Accrued interest payable on deposits	(1,480		)	—				(1,480		)	—
	Accrued interest payable on borrowings	(1,525		)	—				(1,525		)	—
	Interest rate caps and swaps	(997		)	—				(997		)	—

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive (Loss) Income (Tables)	12 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	Components of accumulated other comprehensive income (loss) (“AOCI”) were as follows at September 30:
		September 30,
		2014			2013
	Net unrealized holding loss on available for sale securities	$	(4,645	)	$	(19,316	)
	Related income tax benefit	1,974			7,844
	Available for sale securities AOCI, net of tax	(2,671		)	(11,472		)
	Net unrealized holding loss on securities transferred to held to maturity	(8,947		)	—
	Related income tax benefit	3,803			—
	Securities transferred to held to maturity AOCI, net of tax	(5,144		)	—
	Net unrealized holding loss on retirement plans	(6,336		)	(6,496		)
	Related income tax benefit	2,692			2,638
	Retirement plan AOCI, net of tax	(3,644		)	(3,858		)
	Accumulated other comprehensive loss	$	(11,459	)	$	(15,330	)
	The following table presents the changes in each component of accumulated other comprehensive income for the fiscal years ended September 30, 2014, 2013 and 2012:
		Net unrealized holding gain (loss) on AFS securities			Net unrealized holding (loss) on securities transferred to held to maturity			Net unrealized holding gain (loss) on retirement plans			Total
	Fiscal year ended September 30, 2014
	Balance beginning of the year	$	(11,472	)	$	—		$	(3,858	)	$	(15,330	)
	Other comprehensive gain (loss) before reclassification	9,170			(5,144		)	—			4,026
	Amounts reclassified from AOCI	(369		)	—			214			(155		)
	Total other comprehensive income (loss)	8,801			(5,144		)	214			3,871
	Balance at end of period	$	(2,671	)	$	(5,144	)	$	(3,644	)	$	(11,459	)
	Fiscal year ended September 30, 2013
	Balance beginning of the year	$	15,066		$	—		$	(8,167	)	$	6,899
	Other comprehensive (loss) gain before reclassification	(22,167		)	—			3,041			(19,126		)
	Amounts reclassified from AOCI	(4,371		)	—			1,268			(3,103		)
	Total other comprehensive (loss) income	(26,538		)	—			4,309			(22,229		)
	Balance at end of period	$	(11,472	)	$	—		$	(3,858	)	$	(15,330	)
	Fiscal year ended September 30, 2012
	Balance beginning of the year	$	13,604		$	—		$	(8,468	)	$	5,136
	Other comprehensive gain before reclassification	7,640			—			—			7,640
	Amounts reclassified from AOCI	(6,178		)	—			301			(5,877		)
	Total other comprehensive income	1,462			$	—		301			1,763
	Balance at end of period	$	15,066		$	—		$	(8,167	)	$	6,899

Condensed_Parent_Company_Finan1

Condensed Parent Company Financial Statements (Tables)	12 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Statements of Financial Condition	'
	Set forth below are the condensed balance sheets of Sterling and the related condensed statements of income and cash flows:
		September 30,
		2014			2013
	Assets:
	Cash	$	23,369		$	56,230
	Loan receivable from ESOP	—			6,437
	Investment in Sterling National Bank	1,011,973			517,907
	Investment in non-bank subsidiaries	3,587			3,271
	Goodwill	18,970			—
	Trade name	20,500			—
	Other intangible assets, net	917			—
	Other assets	528			1,184
	Total assets	$	1,079,844		$	585,029
	Liabilities:
	Senior Notes	$	98,402		$	98,033
	Other liabilities	20,304			4,130
	Total liabilities	118,706			102,163
	Stockholders’ equity	961,138			482,866
	Total liabilities & stockholders’ equity	$	1,079,844		$	585,029
Condensed Income Statement	'
	The table  below presents the condensed statement of income:
		For the year ended September 30,
		2014			2013			2012
	Interest income	$	139		$	262		$	282
	Dividend income on equity securities	—			22			30
	Dividends from Sterling National Bank	22,500			—			6,000
	Dividends from non-bank subsidiaries	750			1,600			500
	Other	18			—			10
	Interest expense	(6,265		)	(1,431		)	—
	Non-interest expense	(5,841		)	(2,700		)	(1,838		)
	Income tax benefit	3,431			898			87
	Income (loss) before equity in undistributed earnings of subsidiaries	14,732			(1,349		)	5,071
	Equity in undistributed (excess distributed) earnings of:
	Sterling National Bank	12,590			27,174			13,739
	Non-bank subsidiaries	355			(571		)	1,078
	Net income	$	27,677		$	25,254		$	19,888
Condensed Statements of Cash Flows	'
	The table below presents the condensed statement of cash flows:
		For the year ended September 30,
		2014			2013			2012
	Cash flows from operating activities:
	Net income	$	27,677		$	25,254		$	19,888
	Adjustments to reconcile net income to net cash provided by operating activities:
	Equity in (undistributed) excess distributed earnings of:
	Sterling National Bank	(12,590		)	(27,174		)	(13,739		)
	Non-bank subsidiaries	(355		)	571			(1,078		)
	(Gain) on redemption of Subordinated Debentures	(712		)	—			—
	Other adjustments, net	22,066			5,259			380
	Net cash provided by operating activities	36,086			3,910			5,451
	Cash flows from investing activities:
	Purchase of securities	—			—			(105		)
	Sales of securities	1,112			818			103
	Investment in subsidiaries	(15,000		)	(45,000		)	(44,203		)
	ESOP loan principal repayments	6,437			459			441
	Net cash (used for) investing activities	(7,451		)	(43,723		)	(43,764		)
	Cash flows from financing activities:
	Net change in other short-term borrowings	(20,659		)	—			—
	Redemption of Subordinated Debentures	(26,140		)	—			—
	Senior Notes offering	—			97,946			—
	Equity capital raise	—			—			46,000
	Cash dividends paid	(17,677		)	(10,642		)	(9,100		)
	Stock option transactions including RRP	2,980			1,758			910
	Other equity transactions	—			265			527
	Net cash (used for) provided by financing activities	(61,496		)	89,327			38,337
	Net (decrease) increase in cash	(32,861		)	49,514			24
	Cash at beginning of year	56,230			6,716			6,692
	Cash at end of year	$	23,369		$	56,230		$	6,716

Quarterly_Results_Of_Operation1

Quarterly Results Of Operations (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2014
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	The following is a condensed summary of quarterly results of operations for the fiscal years ended September 30, 2014 and 2013:
		First			Second		Third		Fourth
		quarter			quarter		quarter		quarter
	Year ended September 30, 2014
	Interest and dividend income	$	52,711		$	61,325	$	65,761	$	67,109
	Interest expense	6,835			7,297		7,310		7,476
	Net interest income	45,876			54,028		58,451		59,633
	Provision for loan losses	3,000			4,800		5,950		5,350
	Non-interest income	9,148			12,415		13,471		12,286
	Non-interest expense	72,974			46,723		44,904		43,780
	(Loss) income before income tax	(20,950		)	14,920		21,068		22,789
	Income tax (benefit) expense	(6,948		)	4,588		6,057		6,452
	Net (loss) income	$	(14,002	)	$	10,332	$	15,011	$	16,337
	Earnings per common share:
	Basic	$	(0.20	)	$	0.12	$	0.18	$	0.2
	Diluted	(0.20		)	0.12		0.18		0.19
	Year ended September 30, 2013
	Interest and dividend income	$	33,145		$	32,420	$	32,593	$	33,903
	Interest expense	5,222			4,601		4,276		5,795
	Net interest income	27,923			27,819		28,317		28,108
	Provision for loan losses	2,950			2,600		3,900		2,700
	Non-interest income	7,659			6,852		6,581		6,600
	Non-interest expense	22,546			23,339		21,789		23,367
	Income before income tax	10,086			8,732		9,209		8,641
	Income tax expense	3,066			2,203		2,833		3,312
	Net income	$	7,020		$	6,529	$	6,376	$	5,329
	Earnings per common share:
	Basic	$	0.16		$	0.15	$	0.15	$	0.12
	Diluted	0.16			0.15		0.15		0.12

Basis_of_Financial_Statement_P2

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
									derivative_type
New Accounting Pronouncements or Change in Accounting Principle [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Income tax benefit	($6,452,000)	($6,057,000)	($4,588,000)	$6,948,000	($3,312,000)	($2,833,000)	($2,203,000)	($3,066,000)	($10,152,000)	($11,414,000)	($6,159,000)
Required cash on hand or on deposit with the Federal Reserve Bank	28,700,000	'	'	'	14,600,000	'	'	'	28,700,000	14,600,000	'
Servicing fees	'	'	'	'	'	'	'	'	911,000	778,000	695,000
Minimum duration of performance required by loan restructures	'	'	'	'	'	'	'	'	'6 months	'	'
Number of types of derivatives	'	'	'	'	'	'	'	'	3	'	'
Accounting Standards Update 2014-01	'	'	'	'	'	'	'	'	'	'	'
New Accounting Pronouncements or Change in Accounting Principle [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Income tax benefit	'	'	'	'	'	'	'	'	508,000	'	'
Equity in (undistributed) excess distributed earnings	'	'	'	'	'	'	'	'	$520,000	'	'

Basis_of_Financial_Statement_P3

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies Allowance for Loan Losses (Details) (USD $)	12 Months Ended
	Sep. 30, 2014
	loan_segment
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Number of Loan Segments	2
Minimum duration past due for impairment review	'90 days
Minimum investment in loan for significance	$500,000
Percentage discount of appraised value for costs to hold and liquidate	10.00%
Percentage of loan carrying value used for impairment review	10.00%
Minimum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Duration until re-appraisal	'6 months
Maximum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Duration until re-appraisal	'9 months
Commercial real estate | Minimum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Percentage of costs to hold and liquidate	12.00%
Commercial real estate | Maximum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Percentage of costs to hold and liquidate	22.00%
Commercial business loans [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Allowance for Credit Losses, Duration Past Due Until Chargeoff	'90 days
Homeowner loans [Member] | Minimum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Percentage of costs to hold and liquidate	7.00%
Homeowner loans [Member] | Maximum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Percentage of costs to hold and liquidate	13.00%
Consumer loans, including home equity [Member] | Minimum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Allowance for Credit Losses, Duration Past Due Until Chargeoff	'90 days
Consumer loans, including home equity [Member] | Maximum [Member]	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'
Allowance for Credit Losses, Duration Past Due Until Chargeoff	'120 days

Basis_of_Financial_Statement_P4

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies Premises and Equipment (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Minimum [Member]	'
Property, Plant and Equipment [Line Items]	'
Premises and equipment, useful life	'3 years
Maximum [Member]	'
Property, Plant and Equipment [Line Items]	'
Premises and equipment, useful life	'40 years
Other Non-interest Expense [Member]	'
Property, Plant and Equipment [Line Items]	'
Premises and equipment impairment charges	9.3

Basis_of_Financial_Statement_P5

Basis of Financial Statement Presentation and Summary of Significant Accounting Policies Other Intangible Assets (Details)	12 Months Ended
	Sep. 30, 2014
Naming Rights [Member]	'
Acquired Finite-Lived Intangible Assets [Line Items]	'
Estimated useful life	'10 years
Minimum [Member]	'
Acquired Finite-Lived Intangible Assets [Line Items]	'
Estimated useful life	'1 year
Minimum [Member] | Core Deposits [Member]	'
Acquired Finite-Lived Intangible Assets [Line Items]	'
Acquired intangible assets, weighted average useful life	'8 years
Maximum [Member]	'
Acquired Finite-Lived Intangible Assets [Line Items]	'
Estimated useful life	'10 years
Maximum [Member] | Core Deposits [Member]	'
Acquired Finite-Lived Intangible Assets [Line Items]	'
Acquired intangible assets, weighted average useful life	'10 years

Acquisitions_Details

Acquisitions (Details) (USD $)

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

In Thousands, unless otherwise specified

Purchased credit impaired loans

Book Value [Member]

Fair Value Adjustment [Member]

Core Deposits [Member]

Core Deposits [Member]

Core Deposits [Member]

Trade Names [Member]

Trade Names [Member]

Trade Names [Member]

Purchased credit impaired loans

Purchased credit impaired loans

Purchased credit impaired loans

Book Value [Member]

Fair Value Adjustment [Member]

Purchased credit impaired loans

Book Value [Member]

Fair Value Adjustment [Member]

Purchased credit impaired loans

Purchased credit impaired loans

Purchased credit impaired loans

Purchased credit impaired loans

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

'

'

$277,798

$277,798

$0

'

'

'

'

'

'

Investment securities

'

'

'

607,911

613,154

-5,243

[1]

'

'

'

'

'

'

Loans held for sale

'

'

'

30,341

30,341

0

'

'

'

'

'

'

Loans

'

'

'

1,698,108

1,704,801

-6,693

[2]

'

'

'

'

'

'

Federal Reserve Bank stock

'

'

'

7,680

7,680

0

'

'

'

'

'

'

Bank owned life insurance

'

'

'

55,374

55,374

0

'

'

'

'

'

'

Premises and equipment

'

'

'

23,594

21,293

2,301

[3]

'

'

'

'

'

'

Accrued interest receivable

'

'

'

6,590

6,590

0

'

'

'

'

'

'

Core deposit intangible

'

'

'

'

'

'

20,089

0

20,089

[4]

20,500

0

20,500

[5]

Other real estate owned

'

'

'

5,815

1,720

4,095

[6]

'

'

'

'

'

'

Other assets

'

'

'

20,933

40,877

-19,944

[7]

'

'

'

'

'

'

Deposits

'

'

'

-2,297,190

-2,296,713

-477

[8]

'

'

'

'

'

'

FHLB borrowings

'

'

'

-100,619

-100,346

-273

[9]

'

'

'

'

'

'

Other borrowings

'

'

'

-62,465

-62,465

0

'

'

'

'

'

'

Subordinated Debentures

'

'

'

-26,527

-25,774

-753

[10]

'

'

'

'

'

'

Other liabilities

'

'

'

-55,960

-60,462

4,502

[11]

'

'

'

'

'

'

Total identifiable net assets

130

'

'

231,972

213,868

18,104

'

'

'

'

'

'

Goodwill

$388,926

$163,117

$163,247

$225,809

'

'

'

'

'

'

'

'

[1]

Represents the fair value adjustment on investment securities held to maturity.

[2]

Represents the elimination of Legacy Sterling’s allowance for loan losses and an adjustment of the amortized cost of loans to estimated fair value, which includes an interest rate mark and credit mark. Gross loans acquired were $1,723,447; of the acquired loans, $1,699,271 were not considered purchased credit impaired and we recorded a fair value adjustment of $14,440.

[3]

Represents an adjustment to reflect the fair value of leasehold improvements.

[4]

Represents intangible assets recorded to reflect the fair value of core deposits and below market rent on leased premises. 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. The below market rent intangible asset will be amortized on a straight-line basis over the remaining term of the leases.

[5]

Represents the estimated fair value of Legacy Sterling’s trade name. This intangible asset will not be amortized and will be reviewed at least annually for impairment.

[6]

Represents an adjustment to an acquired property which Legacy Sterling utilized as a financial center and recorded as premises and equipment. The Company included this asset in OREO as it was held for sale. This asset was sold during the fiscal year ended September 30, 2014.

[7]

Consists primarily of adjustments in net deferred tax assets resulting from the fair value adjustments related to the acquired assets, liabilities assumed and identifiable intangibles recorded.

[8]

Represents the fair value adjustment on deposits as the weighted average interest rate of deposits assumed exceeded the cost of similar funding available in the market at the time of the Merger.

[9]

Represents the fair value adjustment on FHLB borrowings as the weighted average interest rate of FHLB borrowings assumed exceeded the cost of similar funding available in the market at the time of the Merger.

[10]

Represents the fair value adjustment on subordinated debentures as the weighted average interest rate of the debentures assumed exceeded the cost of similar debt funding available in the market at the time of the Merger.

[11]

Represents the fair value of other liabilities assumed at the Merger date

Acquisitions_Details_1

Acquisitions (Details 1) (Purchased credit impaired loans, USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Oct. 31, 2013
Purchased credit impaired loans	'	'	'
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'	'	'
Contractual principal balance at acquisition	'	'	$24,176,000
Principal not expected to be collected (non-accretable discount)	'	'	-10,927,000
Expected cash flows at acquisition	'	'	13,249,000
Interest component of expected cash flows (accretable discount)	'	'	0
Fair value of acquired loans	'	'	13,249,000
Net interest income	198,776,000	180,030,000	'
Non-interest income	54,396,000	65,749,000	'
Non-interest expense	187,306,000	189,136,000	'
Net income	$44,460,000	$39,190,000	'
Basic earnings per share (in dollars per share)	$0.53	$0.47	'
Diluted earnings per share (in dollars per share)	$0.53	$0.47	'

Acquisitions_Details_Textual

Acquisitions (Details Textual) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Oct. 31, 2013

Oct. 31, 2013

Sep. 30, 2014

Oct. 31, 2013

Oct. 31, 2013

Aug. 10, 2012

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Gotham Bank of New York [Member]

Book Value [Member]

Book Value [Member]

Book Value [Member]

Assets Write-down, Retention, and Severance Costs [Member]

Assets Write-down, Retention, and Severance Costs [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Core Deposits [Member]

Core Deposits [Member]

Trade Names [Member]

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Core Deposits [Member]

Equipment [Member]

Core Deposits [Member]

Equipment [Member]

Core Deposits [Member]

Trade Names [Member]

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares each shareholder received from merger

'

'

'

'

'

1.2625

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock, par value (in dollars per share)

'

$0.01

$0.01

'

$0.01

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill

'

$388,926,000

$163,117,000

$163,247,000

'

$225,809,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares issued in merger

'

'

'

'

'

39,057,968

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share price of stock issued in merger (in dollars per share)

'

'

'

'

'

$11.72

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration paid through Sterling Bancorp common stock issued to Legacy Sterling shareholders

'

'

'

'

'

457,781,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash paid for fractional shares

'

'

'

'

'

23,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration transferred for outstanding vested stock options

'

'

'

'

'

6,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangibles

'

'

'

'

'

'

'

20,089,000

20,500,000

'

'

0

0

'

'

'

'

'

'

'

'

Book value of assets

'

'

'

'

'

2,759,628,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Federal Home Loan Bank (FHLB) stock, at cost

'

'

'

'

'

1,735,142,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deposits

'

'

'

'

'

2,297,190,000

'

'

'

'

2,296,713,000

'

'

'

'

'

'

'

'

'

'

Acquired intangible assets, weighted average useful life

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'8 years

'

'

'10 years

'

Premises and equipment, useful life

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'1 year

'40 years

'

'5 years

Merger related expense

9,100,000

9,455,000

2,772,000

5,925,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of voting interests acquired

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

Percentage of tangible net worth used for calculating cash payment

'

'

'

'

'

'

'

'

'

125.00%

'

'

'

'

'

'

'

'

'

'

'

Cash paid

'

'

'

'

'

'

'

'

'

40,510,000

'

'

'

'

'

'

'

'

'

'

'

Recognized charges

'

'

'

'

'

'

'

'

'

'

'

'

'

22,200,000

26,591,000

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Gross

'

'

'

'

'

1,723,447

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans, Not Purchased Credit Impaired

'

'

'

'

'

1,699,271

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets, Fair Value Adjustment

'

'

'

'

'

$14,440

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Securities_Details

Securities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	$1,115,458	$973,709
Gross unrealized gains	6,856	5,805
Gross unrealized losses	-11,501	-25,121
Fair value	1,110,813	954,393
Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	592,398	454,173
Gross unrealized gains	2,499	2,205
Gross unrealized losses	-3,047	-7,195
Fair value	591,850	449,183
Investment securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	523,060	519,536
Gross unrealized gains	4,357	3,600
Gross unrealized losses	-8,454	-17,926
Fair value	518,963	505,210
Agency-backed [Member] | Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	477,003	284,837
Gross unrealized gains	2,257	1,849
Gross unrealized losses	-1,555	-4,157
Fair value	477,705	282,529
CMO/Other MBS [Member] | Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	115,395	169,336
Gross unrealized gains	242	356
Gross unrealized losses	-1,492	-3,038
Fair value	114,145	166,654
Federal agencies [Member] | Investment securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	158,114	273,637
Gross unrealized gains	3	0
Gross unrealized losses	-5,303	-12,090
Fair value	152,814	261,547
Corporate bonds [Member] | Investment securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	195,547	118,575
Gross unrealized gains	149	153
Gross unrealized losses	-2,857	-3,795
Fair value	192,839	114,933
State and municipal [Member] | Investment securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	131,715	127,324
Gross unrealized gains	3,439	3,447
Gross unrealized losses	-256	-2,041
Fair value	134,898	128,730
Trust preferred [Member] | Investment securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	37,684	0
Gross unrealized gains	766	0
Gross unrealized losses	-38	0
Fair value	$38,412	$0

Securities_Details_1

Securities (Details 1) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	$579,075	$253,999
Gross unrealized gains	11,155	1,324
Gross unrealized losses	-2,392	-4,427
Fair value, Held to maturity securities	587,838	250,896
Residential Mortgage Backed Securities [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	205,019	156,147
Gross unrealized gains	1,369	749
Gross unrealized losses	-1,307	-423
Fair value, Held to maturity securities	205,081	156,473
Residential Mortgage Backed Securities [Member] | Agency-backed [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	142,329	130,371
Gross unrealized gains	1,360	716
Gross unrealized losses	-103	-108
Fair value, Held to maturity securities	143,586	130,979
Residential Mortgage Backed Securities [Member] | CMO/Other MBS [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	62,690	25,776
Gross unrealized gains	9	33
Gross unrealized losses	-1,204	-315
Fair value, Held to maturity securities	61,495	25,494
Securities Investment [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	374,056	97,852
Gross unrealized gains	9,786	575
Gross unrealized losses	-1,085	-4,004
Fair value, Held to maturity securities	382,757	94,423
Securities Investment [Member] | Federal agencies [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	136,413	77,341
Gross unrealized gains	2,634	0
Gross unrealized losses	-962	-3,458
Fair value, Held to maturity securities	138,085	73,883
Securities Investment [Member] | State and municipal [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	232,643	19,011
Gross unrealized gains	6,814	556
Gross unrealized losses	-123	-546
Fair value, Held to maturity securities	239,334	19,021
Securities Investment [Member] | Other [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized cost	5,000	1,500
Gross unrealized gains	338	19
Gross unrealized losses	0	0
Fair value, Held to maturity securities	$5,338	$1,519

Securities_Details_2

Securities (Details 2) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Available-for-sale Securities [Abstract]	'	'
Amortized cost, One year or less	$2,100	'
Amortized cost, One to five years	141,508	'
Amortized cost, Five to ten years	334,295	'
Amortized cost, Greater than ten years	45,157	'
Amortized cost, Total other securities	523,060	'
Amortized cost, Available for sale securities	1,115,458	973,709
Fair value, One year or less	2,112	'
Fair value, One to five years	141,748	'
Fair value, Five to ten years	328,902	'
Fair value, Greater than ten years	46,201	'
Fair value, Total other securities	518,963	'
Fair value, Available for sale securities	1,110,813	954,393
Held-to-Maturity Securities [Abstract]	'	'
Amortized cost, One year or less	8,847	'
Amortized cost, One to five years	9,138	'
Amortized cost, Five to ten years	189,494	'
Amortized cost, Greater than ten years	166,577	'
Amortized cost, Total other securities	374,056	'
Amortized cost, Held to maturity securities	579,075	253,999
Fair value, One year or less	8,897	'
Fair value, One to five years	9,624	'
Fair value, Five to ten years	192,109	'
Fair value, Greater than ten years	172,127	'
Fair value, Total other securities	382,757	'
Fair value, Held to maturity securities	587,838	250,896
Residential Mortgage Backed Securities [Member]	'	'
Available-for-sale Securities [Abstract]	'	'
Amortized cost, Available for sale securities	592,398	454,173
Fair value, Available for sale securities	591,850	449,183
Held-to-Maturity Securities [Abstract]	'	'
Amortized cost, Held to maturity securities	205,019	'
Fair value, Held to maturity securities	$205,081	$156,473

Securities_Details_3

Securities (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Investments, Debt and Equity Securities [Abstract]	'		'		'
Proceeds from sales of securities available for sale	$529,107		$339,123		$344,431
Gross realized gains from securities available for sale	1,964		7,709		10,468
Gross realized losses from securities available for sale	-1,323		-377		0
Income tax expense on realized net gains of securities available for sale	172		2,282		2,475
Proceeds from sales of securities held to maturity	0	[1]	1,187	[1]	0	[1]
Gross realized gains from securities held to maturity	0	[1]	59	[1]	0	[1]
Income tax expense on securities held to maturity	$0	[1]	$18	[1]	$0	[1]
[1]	(1) During the fiscal year ended September 30, 2013, the Company sold held to maturity securities after the Company had already collected at least 85% of the principal balance outstanding at acquisition.

Securities_Details_4

Securities (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	$316,263	$659,734
Unrealized losses, Less than 12 months	-2,550	-24,817
Fair value, 12 months or longer	296,680	7,932
Unrealized losses, 12 months or longer	-8,951	-304
Fair value, Total	612,943	667,666
Unrealized losses, Total	-11,501	-25,121
Securities Investment [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	116,063	400,145
Unrealized losses, Less than 12 months	-1,588	-17,918
Fair value, 12 months or longer	225,665	112
Unrealized losses, 12 months or longer	-6,866	-8
Fair value, Total	341,728	400,257
Unrealized losses, Total	-8,454	-17,926
Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	200,200	259,589
Unrealized losses, Less than 12 months	-962	-6,899
Fair value, 12 months or longer	71,015	7,820
Unrealized losses, 12 months or longer	-2,085	-296
Fair value, Total	271,215	267,409
Unrealized losses, Total	-3,047	-7,195
Agency-backed [Member] | Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	137,693	137,265
Unrealized losses, Less than 12 months	-516	-4,157
Fair value, 12 months or longer	41,516	0
Unrealized losses, 12 months or longer	-1,039	0
Fair value, Total	179,209	137,265
Unrealized losses, Total	-1,555	-4,157
CMO/Other MBS [Member] | Residential Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	62,507	122,324
Unrealized losses, Less than 12 months	-446	-2,742
Fair value, 12 months or longer	29,499	7,820
Unrealized losses, 12 months or longer	-1,046	-296
Fair value, Total	92,006	130,144
Unrealized losses, Total	-1,492	-3,038
Federal agencies [Member] | Securities Investment [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	6,153	261,547
Unrealized losses, Less than 12 months	-144	-12,090
Fair value, 12 months or longer	146,416	0
Unrealized losses, 12 months or longer	-5,159	0
Fair value, Total	152,569	261,547
Unrealized losses, Total	-5,303	-12,090
State and municipal [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	8,170	'
Unrealized losses, Less than 12 months	-58	'
Fair value, 12 months or longer	12,809	'
Unrealized losses, 12 months or longer	-198	'
Fair value, Total	20,979	'
Unrealized losses, Total	-256	'
State and municipal [Member] | Securities Investment [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	'	43,585
Unrealized losses, Less than 12 months	'	-2,033
Fair value, 12 months or longer	'	112
Unrealized losses, 12 months or longer	'	-8
Fair value, Total	'	43,697
Unrealized losses, Total	'	-2,041
Trust preferred [Member] | Securities Investment [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	3,907	'
Unrealized losses, Less than 12 months	-38	'
Fair value, 12 months or longer	0	'
Unrealized losses, 12 months or longer	0	'
Fair value, Total	3,907	'
Unrealized losses, Total	-38	'
Corporate bonds [Member] | Securities Investment [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value, Less than 12 months	97,833	95,013
Unrealized losses, Less than 12 months	-1,348	-3,795
Fair value, 12 months or longer	66,440	0
Unrealized losses, 12 months or longer	-1,509	0
Fair value, Total	164,273	95,013
Unrealized losses, Total	($2,857)	($3,795)

Securities_Details_5

Securities (Details 5) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	$73,243	$125,788
Unrealized losses, Less than 12 months	-633	-4,427
Fair value, 12 months or longer	68,226	0
Unrealized losses, 12 months or longer	-1,759	0
Fair value, Total	141,469	125,788
Unrealized losses, Total	-2,392	-4,427
Securities Investment [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	37,699	83,413
Unrealized losses, Less than 12 months	-162	-4,004
Fair value, 12 months or longer	25,580	0
Unrealized losses, 12 months or longer	-923	0
Fair value, Total	63,279	83,413
Unrealized losses, Total	-1,085	-4,004
Securities Investment [Member] | Federal agencies [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	23,756	73,883
Unrealized losses, Less than 12 months	-62	-3,458
Fair value, 12 months or longer	24,101	0
Unrealized losses, 12 months or longer	-900	0
Fair value, Total	47,857	73,883
Unrealized losses, Total	-962	-3,458
Securities Investment [Member] | State and municipal [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	13,943	9,530
Unrealized losses, Less than 12 months	-100	-546
Fair value, 12 months or longer	1,479	0
Unrealized losses, 12 months or longer	-23	0
Fair value, Total	15,422	9,530
Unrealized losses, Total	-123	-546
Residential Mortgage Backed Securities [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	35,544	42,375
Unrealized losses, Less than 12 months	-471	-423
Fair value, 12 months or longer	42,646	0
Unrealized losses, 12 months or longer	-836	0
Fair value, Total	78,190	42,375
Unrealized losses, Total	-1,307	-423
Residential Mortgage Backed Securities [Member] | Agency-backed [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	20,616	10,963
Unrealized losses, Less than 12 months	-103	-86
Fair value, 12 months or longer	0	0
Unrealized losses, 12 months or longer	0	0
Fair value, Total	20,616	10,963
Unrealized losses, Total	-103	-86
Residential Mortgage Backed Securities [Member] | CMO/Other MBS [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Fair value, Less than 12 months	14,928	31,412
Unrealized losses, Less than 12 months	-368	-337
Fair value, 12 months or longer	42,646	0
Unrealized losses, 12 months or longer	-836	0
Fair value, Total	57,574	31,412
Unrealized losses, Total	($1,204)	($337)

Securities_Details_6

Securities (Details 6) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total securities pledged	$1,292,140	$1,008,466
Federal Home Loan Bank Borrowings [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Available-for-sale securities pledged as collateral	268,316	199,642
Held-to-maturity securities pledged as collateral	58,509	55,497
Municipal Deposits [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Available-for-sale securities pledged as collateral	532,770	580,756
Held-to-maturity securities pledged as collateral	430,611	167,926
Interest Rate Swap [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Available-for-sale securities pledged as collateral	$1,934	$4,645

Securities_Details_Textual

Securities (Details Textual) (USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Oct. 31, 2013	Sep. 30, 2014	Sep. 30, 2013
		Security
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Investment securities transferred from held to maturity to available for sale	$165,230	'	'
Investment securities transferred from available for sale to held to maturity	221,904	'	'
Unrealized gain(loss) on investment securities transferred	$9,657	$8,947	'
Life of investment securities transferred	'	'5 years 3 months 18 days	'
Held to maturity securities sold after the company collected principal outstanding balance	'	'	85.00%
Number of securities which were in continuous unrealized loss position for 12 months or more	'	99	'
Number of securities which were in continuous unrealized loss position for less than 12 months	'	118	'
Number of fixed maturity securities past due	'	0	'

Loans_Details

Loans (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
In Thousands, unless otherwise specified
Components of loan portfolio, excluding loans held for sale	'	'	'	'
Commercial & industrial	'	$439,787	'	'
Payroll finance	'	0	'	'
Warehouse lending	'	0	'	'
Factored receivables	'	0	'	'
Equipment financing	'	0	'	'
Total commercial	2,076,474	439,787	'	'
Commercial real estate	'	969,490	'	'
Multi-family	'	307,547	'	'
Acquisition, development & construction	'	102,494	'	'
Total commercial mortgage	1,909,725	1,379,531	'	'
Total commercial and commercial mortgage	3,986,199	1,819,318	'	'
Real estate-residential mortgage loans	'	400,009	'	'
Consumer loans:	'	'	'	'
Home equity lines of credit	159,944	156,995	'	'
Other consumer loans, including overdrafts	43,864	36,576	'	'
Total consumer	203,808	193,571	'	'
Gross loans	4,760,438	2,412,898	'	'
Allowance for loan losses	-40,612	-28,877	-28,282	-27,917
Total loans, net	$4,719,826	$2,384,021	'	'

Loans_Details_1

Loans (Details 1) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans and Lease Receivable Allowance Under Troubled Debt Restructurings	$891,000	$877,000
Non-Performing loans:	'	'
Current Loans	4,684,196,000	2,379,522,000
Non-performing loans, 30-59 Days Past Due	10,307,000	3,844,000
Non-performing loans, 60-89 Days Past Due	14,972,000	2,626,000
Non-performing loans, 90+ Days Past Due	1,401,000	4,099,000
Non accrual loans	49,562,000	22,807,000
Loans and Leases Receivable, Gross	4,760,438,000	2,412,898,000
Current loans	17,138,000	23,754,000
30-59 days past due	346,000	0
60-89 days past due	169,000	0
90 days past due	0	141,000
Non-Accrual	11,944,000	2,199,000
Total	29,597,000	26,094,000
Nonperforming loans	'	'
Non-Performing loans:	'	'
Non accrual loans	49,562,000	22,807,000
Non-performing loans:	'	'
Loans 90 days past due and still accruing	1,401,000	4,099,000
Total non-performing loans	50,963,000	26,906,000
Commercial & industrial	'	'
Non-Performing loans:	'	'
Current Loans	1,150,854,000	438,818,000
Non-performing loans, 30-59 Days Past Due	2,316,000	178,000
Non-performing loans, 60-89 Days Past Due	7,043,000	2,000
Non-performing loans, 90+ Days Past Due	0	289,000
Non accrual loans	4,324,000	500,000
Loans and Leases Receivable, Gross	1,164,537,000	439,787,000
Payroll finance	'	'
Non-Performing loans:	'	'
Current Loans	145,029,000	'
Non-performing loans, 30-59 Days Past Due	99,000	'
Non-performing loans, 60-89 Days Past Due	0	'
Non-performing loans, 90+ Days Past Due	346,000	'
Non accrual loans	0	'
Loans and Leases Receivable, Gross	145,474,000	'
Warehouse lending	'	'
Non-Performing loans:	'	'
Current Loans	192,003,000	'
Non-performing loans, 30-59 Days Past Due	0	'
Non-performing loans, 60-89 Days Past Due	0	'
Non-performing loans, 90+ Days Past Due	0	'
Non accrual loans	0	'
Loans and Leases Receivable, Gross	192,003,000	'
Factored receivables	'	'
Non-Performing loans:	'	'
Current Loans	181,063,000	'
Non-performing loans, 30-59 Days Past Due	0	'
Non-performing loans, 60-89 Days Past Due	0	'
Non-performing loans, 90+ Days Past Due	0	'
Non accrual loans	370,000	'
Loans and Leases Receivable, Gross	181,433,000	'
Equipment financing	'	'
Non-Performing loans:	'	'
Current Loans	391,914,000	'
Non-performing loans, 30-59 Days Past Due	689,000	'
Non-performing loans, 60-89 Days Past Due	162,000	'
Non-performing loans, 90+ Days Past Due	0	'
Non accrual loans	262,000	'
Loans and Leases Receivable, Gross	393,027,000	'
Commercial real estate	'	'
Non-Performing loans:	'	'
Current Loans	1,433,805,000	1,263,933,000
Non-performing loans, 30-59 Days Past Due	93,000	1,978,000
Non-performing loans, 60-89 Days Past Due	4,188,000	2,357,000
Non-performing loans, 90+ Days Past Due	521,000	1,574,000
Non accrual loans	10,445,000	7,195,000
Loans and Leases Receivable, Gross	1,449,052,000	1,277,037,000
Multi-family	'	'
Non-Performing loans:	'	'
Current Loans	368,393,000	'
Non-performing loans, 30-59 Days Past Due	0	'
Non-performing loans, 60-89 Days Past Due	0	'
Non-performing loans, 90+ Days Past Due	0	'
Non accrual loans	131,000	'
Loans and Leases Receivable, Gross	368,524,000	'
Acquisition, development & construction	'	'
Non-Performing loans:	'	'
Current Loans	79,732,000	96,306,000
Non-performing loans, 30-59 Days Past Due	0	768,000
Non-performing loans, 60-89 Days Past Due	56,000	0
Non-performing loans, 90+ Days Past Due	0	0
Non accrual loans	12,361,000	5,420,000
Loans and Leases Receivable, Gross	92,149,000	102,494,000
Residential mortgage	'	'
Non-Performing loans:	'	'
Current Loans	547,912,000	390,072,000
Non-performing loans, 30-59 Days Past Due	4,023,000	354,000
Non-performing loans, 60-89 Days Past Due	2,036,000	267,000
Non-performing loans, 90+ Days Past Due	534,000	1,832,000
Non accrual loans	15,926,000	7,484,000
Loans and Leases Receivable, Gross	570,431,000	400,009,000
Consumer	'	'
Non-Performing loans:	'	'
Current Loans	193,491,000	190,393,000
Non-performing loans, 30-59 Days Past Due	3,087,000	566,000
Non-performing loans, 60-89 Days Past Due	1,487,000	0
Non-performing loans, 90+ Days Past Due	0	404,000
Non accrual loans	5,743,000	2,208,000
Loans and Leases Receivable, Gross	$203,808,000	$193,571,000

Loans_Details_2

Loans (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	$28,877	$28,282	$27,917
Charge-offs	-9,331	-13,057	-12,809
Recoveries	1,966	1,502	2,562
Net Charge-offs	-7,365	-11,555	-10,247
Provision	19,100	12,150	10,612
Ending Allowance for Loan Losses	40,612	28,877	28,282
Annualized net charge-offs to average loans outstanding	0.24%	0.52%	0.56%
Commercial & industrial	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	5,302	4,603	5,945
Charge-offs	-2,901	-1,354	-1,526
Recoveries	1,073	410	1,116
Net Charge-offs	-1,828	-944	-410
Provision	6,062	1,643	-932
Ending Allowance for Loan Losses	9,536	5,302	4,603
Payroll finance	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	0	'	'
Charge-offs	-758	'	'
Recoveries	0	'	'
Net Charge-offs	-758	'	'
Provision	2,137	'	'
Ending Allowance for Loan Losses	1,379	'	'
Warehouse lending	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	0	'	'
Charge-offs	0	'	'
Recoveries	0	'	'
Net Charge-offs	0	'	'
Provision	630	'	'
Ending Allowance for Loan Losses	630	'	'
Factored receivables	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	0	'	'
Charge-offs	-211	'	'
Recoveries	9	'	'
Net Charge-offs	-202	'	'
Provision	1,496	'	'
Ending Allowance for Loan Losses	1,294	'	'
Equipment financing	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	0	'	'
Charge-offs	-1,074	'	'
Recoveries	194	'	'
Net Charge-offs	-880	'	'
Provision	3,501	'	'
Ending Allowance for Loan Losses	2,621	'	'
Commercial real estate	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	9,967	7,230	5,568
Charge-offs	-741	-3,725	-2,707
Recoveries	161	577	528
Net Charge-offs	-580	-3,148	-2,179
Provision	1,457	5,885	3,841
Ending Allowance for Loan Losses	10,844	9,967	7,230
Multi-family	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	0	'	'
Charge-offs	-418	'	'
Recoveries	92	'	'
Net Charge-offs	-326	'	'
Provision	2,193	'	'
Ending Allowance for Loan Losses	1,867	'	'
Acquisition, development & construction	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	5,806	8,526	9,895
Charge-offs	-1,479	-3,422	-4,124
Recoveries	0	182	299
Net Charge-offs	-1,479	-3,240	-3,825
Provision	-2,207	520	2,456
Ending Allowance for Loan Losses	2,120	5,806	8,526
Residential mortgage	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	4,474	4,359	3,498
Charge-offs	-963	-2,547	-2,551
Recoveries	323	101	356
Net Charge-offs	-640	-2,446	-2,195
Provision	2,003	2,561	3,056
Ending Allowance for Loan Losses	5,837	4,474	4,359
Consumer	'	'	'
Summary of activity in allowance for loan losses and recorded investments in loans by portfolio segment based on impairment method	'	'	'
Beginning Allowance for loan losses	3,328	3,564	3,011
Charge-offs	-786	-2,009	-1,901
Recoveries	114	232	263
Net Charge-offs	-672	-1,777	-1,638
Provision	1,828	1,541	2,191
Ending Allowance for Loan Losses	$4,484	$3,328	$3,564

Loans_Details_3

Loans (Details 3) (USD $)	Sep. 30, 2014	Sep. 30, 2013
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	$36,208,000	$36,821,000
Loans evaluated by segment, Collectively evaluated for impairment	4,720,467,000	2,376,077,000
Total loans	4,760,438,000	2,412,898,000
Allowance evaluated by segment, Individually evaluated for impairment	0	1,593,000
Allowance evaluated by segment, Collectively evaluated for impairment	40,612,000	27,284,000
Total allowance for loan losses	40,612,000	28,877,000
Commercial & industrial	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	4,177,000	2,631,000
Loans evaluated by segment, Collectively evaluated for impairment	1,158,837,000	437,156,000
Total loans	1,164,537,000	439,787,000
Allowance evaluated by segment, Individually evaluated for impairment	0	249,000
Allowance evaluated by segment, Collectively evaluated for impairment	9,536,000	5,053,000
Total allowance for loan losses	9,536,000	5,302,000
Payroll finance	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	'
Loans evaluated by segment, Collectively evaluated for impairment	145,474,000	'
Total loans	145,474,000	'
Allowance evaluated by segment, Individually evaluated for impairment	0	'
Allowance evaluated by segment, Collectively evaluated for impairment	1,379,000	'
Total allowance for loan losses	1,379,000	'
Warehouse lending	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	'
Loans evaluated by segment, Collectively evaluated for impairment	192,003,000	'
Total loans	192,003,000	'
Allowance evaluated by segment, Individually evaluated for impairment	0	'
Allowance evaluated by segment, Collectively evaluated for impairment	630,000	'
Total allowance for loan losses	630,000	'
Factored receivables	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	'
Loans evaluated by segment, Collectively evaluated for impairment	181,433,000	'
Total loans	181,433,000	'
Allowance evaluated by segment, Individually evaluated for impairment	0	'
Allowance evaluated by segment, Collectively evaluated for impairment	1,294,000	'
Total allowance for loan losses	1,294,000	'
Equipment financing	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	'
Loans evaluated by segment, Collectively evaluated for impairment	393,027,000	'
Total loans	393,027,000	'
Allowance evaluated by segment, Individually evaluated for impairment	0	'
Allowance evaluated by segment, Collectively evaluated for impairment	2,621,000	'
Total allowance for loan losses	2,621,000	'
Commercial real estate	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	13,750,000	14,091,000
Loans evaluated by segment, Collectively evaluated for impairment	1,435,163,000	1,262,946,000
Total loans	1,449,052,000	1,277,037,000
Allowance evaluated by segment, Individually evaluated for impairment	0	803,000
Allowance evaluated by segment, Collectively evaluated for impairment	10,844,000	9,164,000
Total allowance for loan losses	10,844,000	9,967,000
Multi-family	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	'
Loans evaluated by segment, Collectively evaluated for impairment	368,524,000	'
Total loans	368,524,000	'
Allowance evaluated by segment, Individually evaluated for impairment	0	'
Allowance evaluated by segment, Collectively evaluated for impairment	1,867,000	'
Total allowance for loan losses	1,867,000	'
Acquisition, development & construction	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	17,766,000	19,582,000
Loans evaluated by segment, Collectively evaluated for impairment	74,383,000	82,912,000
Total loans	92,149,000	102,494,000
Allowance evaluated by segment, Individually evaluated for impairment	0	540,000
Allowance evaluated by segment, Collectively evaluated for impairment	2,120,000	5,266,000
Total allowance for loan losses	2,120,000	5,806,000
Residential mortgage	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	515,000	515,000
Loans evaluated by segment, Collectively evaluated for impairment	567,815,000	399,494,000
Total loans	570,431,000	400,009,000
Allowance evaluated by segment, Individually evaluated for impairment	0	0
Allowance evaluated by segment, Collectively evaluated for impairment	5,837,000	4,474,000
Total allowance for loan losses	5,837,000	4,474,000
Consumer	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Individually evaluated for impairment	0	2,000
Loans evaluated by segment, Collectively evaluated for impairment	203,808,000	193,569,000
Total loans	203,808,000	193,571,000
Allowance evaluated by segment, Individually evaluated for impairment	0	1,000
Allowance evaluated by segment, Collectively evaluated for impairment	4,484,000	3,327,000
Total allowance for loan losses	4,484,000	3,328,000
Purchased credit impaired loans	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	3,763,000	'
Purchased credit impaired loans | Commercial & industrial	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	1,523,000	'
Purchased credit impaired loans | Payroll finance	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Warehouse lending	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Factored receivables	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Equipment financing	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Commercial real estate	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	139,000	'
Purchased credit impaired loans | Multi-family	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Acquisition, development & construction	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	0	'
Purchased credit impaired loans | Residential mortgage	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	2,101,000	'
Purchased credit impaired loans | Consumer	'	'
Loans evaluated for impairment by segment	'	'
Loans evaluated by segment, Purchased credit impaired loans	$0	'

Loans_Details_4

Loans (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
With no related allowance recorded:	'	'
Unpaid principal balance with no related allowance recorded	$37,254	$33,112
Recorded investment with no related allowance recorded	36,208	32,411
With an allowance recorded:	'	'
Unpaid principal balance with an allowance recorded	0	6,405
Recorded investment with an allowance recorded	0	4,410
Allowance for loan losses allocated with an allowance recorded	0	1,593
Unpaid principal balance, total	37,254	39,517
Recorded investment total	36,208	36,821
Allowance for loan losses allocated, total	0	1,593
Commercial & industrial	'	'
With no related allowance recorded:	'	'
Unpaid principal balance with no related allowance recorded	4,177	2,175
Recorded investment with no related allowance recorded	4,177	2,131
With an allowance recorded:	'	'
Unpaid principal balance with an allowance recorded	0	500
Recorded investment with an allowance recorded	0	500
Allowance for loan losses allocated with an allowance recorded	0	249
Commercial real estate	'	'
With no related allowance recorded:	'	'
Unpaid principal balance with no related allowance recorded	13,886	12,451
Recorded investment with no related allowance recorded	13,750	11,820
With an allowance recorded:	'	'
Unpaid principal balance with an allowance recorded	0	3,150
Recorded investment with an allowance recorded	0	2,271
Allowance for loan losses allocated with an allowance recorded	0	803
Acquisition, development & construction	'	'
With no related allowance recorded:	'	'
Unpaid principal balance with no related allowance recorded	18,676	17,971
Recorded investment with no related allowance recorded	17,766	17,945
With an allowance recorded:	'	'
Unpaid principal balance with an allowance recorded	0	2,753
Recorded investment with an allowance recorded	0	1,637
Allowance for loan losses allocated with an allowance recorded	0	540
Residential mortgage	'	'
With no related allowance recorded:	'	'
Unpaid principal balance with no related allowance recorded	515	515
Recorded investment with no related allowance recorded	515	515
Consumer	'	'
With an allowance recorded:	'	'
Unpaid principal balance with an allowance recorded	0	2
Recorded investment with an allowance recorded	0	2
Allowance for loan losses allocated with an allowance recorded	$0	$1

Loans_Details_5

Loans (Details 5) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	$39,236	$32,343	'
Interest income recognized with no related allowance	425	1,008	'
Cash-basis interest income recognized with no related allowance	419	948	'
Average recorded investment with an allowance recorded	0	10,285	'
Interest income recognized with an allowance recorded	0	21	'
Cash-basis interest income recognized with an allowance recorded	0	17	'
Average recorded investment, Total	39,236	42,628	58,195
Interest income recognized, Total	425	1,029	1,878
Cash-basis interest income recognized, Total	419	965	1,136
Commercial & industrial	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	4,180	1,821	'
Interest income recognized with no related allowance	0	91	'
Cash-basis interest income recognized with no related allowance	0	86	'
Average recorded investment with an allowance recorded	0	705	'
Interest income recognized with an allowance recorded	0	0	'
Cash-basis interest income recognized with an allowance recorded	0	0	'
Commercial real estate	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	14,016	17,325	'
Interest income recognized with no related allowance	186	286	'
Cash-basis interest income recognized with no related allowance	180	275	'
Average recorded investment with an allowance recorded	0	6,646	'
Interest income recognized with an allowance recorded	0	7	'
Cash-basis interest income recognized with an allowance recorded	0	7	'
Acquisition, development & construction	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	20,525	12,827	'
Interest income recognized with no related allowance	239	631	'
Cash-basis interest income recognized with no related allowance	239	587	'
Average recorded investment with an allowance recorded	0	1,104	'
Interest income recognized with an allowance recorded	0	0	'
Cash-basis interest income recognized with an allowance recorded	0	0	'
Residential mortgage	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	515	309	'
Interest income recognized with no related allowance	0	0	'
Cash-basis interest income recognized with no related allowance	0	0	'
Average recorded investment with an allowance recorded	0	1,602	'
Interest income recognized with an allowance recorded	0	14	'
Cash-basis interest income recognized with an allowance recorded	0	10	'
Consumer	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'
Average recorded investment with no related allowance	0	61	'
Interest income recognized with no related allowance	0	0	'
Cash-basis interest income recognized with no related allowance	0	0	'
Average recorded investment with an allowance recorded	0	228	'
Interest income recognized with an allowance recorded	0	0	'
Cash-basis interest income recognized with an allowance recorded	$0	$0	'

Loans_Details_6

Loans (Details 6) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Modifications [Line Items]	'	'
Current loans	$17,138	$23,754
30-59 days past due	346	0
60-89 days past due	169	0
90 days past due	0	141
Non- accrual	11,944	2,199
Total	29,597	26,094
Allowance for loan losses, Current loans	409	438
Allowance for loan losses, 30-59 days past due	0	0
Allowance for loan losses, 60-89 days past due	31	0
Allowance for loan losses, 90 plus days past due	0	0
Allowance for loan losses, Non-accrual	451	439
Allowance for loan losses, Total	891	877
Commercial & industrial	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	275	1,843
30-59 days past due	0	0
60-89 days past due	0	0
90 days past due	0	141
Non- accrual	1,618	0
Total	1,893	1,984
Equipment financing	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	435	'
30-59 days past due	0	'
60-89 days past due	0	'
90 days past due	0	'
Non- accrual	0	'
Total	435	'
Commercial real estate	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	4,838	5,305
30-59 days past due	0	0
60-89 days past due	0	0
90 days past due	0	0
Non- accrual	447	0
Total	5,285	5,305
Acquisition, development & construction	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	5,732	14,190
30-59 days past due	0	0
60-89 days past due	0	0
90 days past due	0	0
Non- accrual	6,817	151
Total	12,549	14,341
Residential mortgage	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	5,858	2,416
30-59 days past due	346	0
60-89 days past due	169	0
90 days past due	0	0
Non- accrual	2,841	1,792
Total	9,214	4,208
Consumer	'	'
Financing Receivable, Modifications [Line Items]	'	'
Current loans	0	0
30-59 days past due	0	0
60-89 days past due	0	0
90 days past due	0	0
Non- accrual	221	256
Total	$221	$256

Loans_Details_7

Loans (Details 7) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
	loan	loan	loan
Financing Receivable, Modifications [Line Items]	'	'	'
Number	2	21	12
Recorded investment, Pre-modification	$1,060	$12,193	$9,160
Recorded investment, Post-modification	1,060	12,129	8,945
Commercial & industrial	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number	0	5	'
Recorded investment, Pre-modification	0	2,001	'
Recorded investment, Post-modification	0	2,001	'
Commercial real estate	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number	0	2	'
Recorded investment, Pre-modification	0	2,682	'
Recorded investment, Post-modification	0	2,682	'
Acquisition, development & construction	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number	2	7	'
Recorded investment, Pre-modification	1,060	5,772	'
Recorded investment, Post-modification	1,060	5,772	'
Residential mortgage	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number	0	6	'
Recorded investment, Pre-modification	0	1,436	'
Recorded investment, Post-modification	0	1,372	'
Consumer	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number	0	1	'
Recorded investment, Pre-modification	0	302	'
Recorded investment, Post-modification	$0	$302	'

Loans_Details_8

Loans (Details 8) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	$39,553	$13,530
Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	73,093	60,503
Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	592
Commercial & industrial | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	24,980	3,545
Commercial & industrial | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	5,749	3,855
Commercial & industrial | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	365
Payroll finance | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Payroll finance | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	346	0
Payroll finance | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Factored receivables | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	46	0
Factored receivables | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	370	0
Factored receivables | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Equipment financing | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Equipment financing | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	262	0
Equipment financing | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Commercial real estate | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	8,720	7,279
Commercial real estate | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	26,826	24,561
Commercial real estate | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	227
Multi-family | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Multi-family | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	131	0
Multi-family | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Acquisition, development & construction | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	1,040	1,867
Acquisition, development & construction | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	16,456	19,410
Acquisition, development & construction | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Residential mortgage | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	2,988	824
Residential mortgage | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	16,981	9,786
Residential mortgage | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	0	0
Consumer | Special mention	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	1,779	15
Consumer | Substandard	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	5,972	2,891
Consumer | Doubtful	'	'
Risk category of loans by segment of gross loans	'	'
Gross loans by segment	$0	$0

Loans_Details_Textual

Loans (Details Textual) (USD $)	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Oct. 31, 2013
		loan	loan	loan
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'	'	'
Net deferred loan origination costs	($1,261,000)	($1,261,000)	($1,201,000)	'	'
Legacy Sterling loans not considered impaired	'	'	'	'	1,683,454,000
Recorded amount of loans	3,763,000	3,763,000	'	'	'
Interest income	'	0	'	'	'
Pledged loans	1,246,315,000	1,246,315,000	784,422,000	'	'
Maximum outstanding loan balance to be evaluated for impairment on a homogeneous pool basis	'	500,000	'	'	'
Interest income recognized	'	425,000	1,029,000	1,878,000	'
Cash-basis interest income recognized	'	419,000	965,000	1,136,000	'
Average recorded investment	'	39,236,000	42,628,000	58,195,000	'
Number of TDRs	'	2	21	12	'
Recorded investment, Pre-modification	'	1,060,000	12,193,000	9,160,000	'
Recorded investment, Post-modification	'	1,060,000	12,129,000	8,945,000	'
Increased allowance for loan losses	0	'	300,000	134,000	'
Charge-offs	0	'	110,000	0	'
Maximum loan balance for credit risk to be evaluated on a homogeneous basis	'	500,000	'	'	'
Additional restricted loan [Member]	'	'	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'	'	'
Additional restricted loan	0	0	4,101,000	'	'
Sterling Bancorp (Legacy)	'	'	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'	'	'
Loans	'	'	'	'	1,698,108,000
Fair value of acquired loans	'	'	'	'	13,249,000
Accretable yield	0	0	'	'	'
Sterling Bancorp (Legacy) | Purchased credit impaired loans | Commercial & industrial	'	'	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'	'	'
Amount included in allowance for loan losses associated with purchased credit impaired loans	$0	$0	'	'	'

Premises_And_Equipment_Net_Det

Premises And Equipment, Net (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Total premises and equipment, gross	$112,242	$86,140
Accumulated depreciation and amortization	-68,956	-49,620
Total premises and equipment, net	43,286	36,520
Land and Land Improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total premises and equipment, gross	6,048	7,282
Buildings [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total premises and equipment, gross	22,888	30,558
Leasehold Improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total premises and equipment, gross	32,963	8,136
Furniture, Fixtures and Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Total premises and equipment, gross	$50,343	$40,164

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'	'
Identifiable net assets	$130	'
Goodwill [Roll Forward]	'	'
Beginning of year	163,117	163,247
Acquisitions	225,809	-130
Disposals	0	0
End of year	$388,926	$163,117

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	$58,129	$7,232	'
Accumulated amortization	-12,851	-1,341	'
Net intangible assets	45,278	5,891	'
Amortization of intangible assets	9,408	1,296	1,245
Minimum [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Estimated useful life	'1 year	'	'
Maximum [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Estimated useful life	'10 years	'	'
Core Deposits [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	24,182	4,818	'
Accumulated amortization	-4,694	-798	'
Net intangible assets	19,488	4,020	'
Amortization of intangible assets	9,408	'	'
Noncompete Agreements [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	10,308	'	'
Accumulated amortization	-5,490	'	'
Net intangible assets	4,818	'	'
Amortization of intangible assets	1,296	'	'
Trade Names [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	20,500	'	'
Accumulated amortization	0	'	'
Net intangible assets	20,500	'	'
Fair Value of Below Market Leases [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	725	'	'
Accumulated amortization	-253	'	'
Net intangible assets	472	'	'
Provident Bank Ball Park Naming Rights [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross intangible assets	2,414	2,414	'
Accumulated amortization	-2,414	-543	'
Net intangible assets	0	1,871	'
Estimated useful life	'10 years	'	'
Amortization of intangible assets	$1,245	'	'

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Details 3) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
2015	$6,113
2016	5,042
2017	2,598
2018	2,178
2019	2,058
Thereafter	6,786
Intangible assets	$24,775

Deposits_Details

Deposits (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Deposits [Abstract]	'	'
Non-interest bearing demand	$1,799,685	$943,934
Interest bearing demand	766,852	434,398
Savings	698,443	580,125
Money market	1,595,803	735,709
Certificates of deposit	437,871	268,128
Deposits	$5,298,654	$2,962,294

Deposits_Details_1

Deposits (Details 1) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Deposits [Abstract]	'	'
Less than one year	$340,813	$239,104
One to two years	53,319	17,248
Two to three years	35,632	5,185
Three to four years	4,000	3,062
Four to five years	4,107	3,529
Total certificates of deposit	$437,871	$268,128

Deposits_Details_2

Deposits (Details 2) (USD $)	Sep. 30, 2014		Sep. 30, 2013
In Thousands, unless otherwise specified
List of Company's Brokered deposits	'		'
Noninterest-bearing Domestic Deposit, Brokered	$121,067		$36,682
Money Market [Member]	'		'
List of Company's Brokered deposits	'		'
Noninterest-bearing Domestic Deposit, Brokered	84,022		34,571
Reciprocal CDAR's [Member]	'		'
List of Company's Brokered deposits	'		'
Noninterest-bearing Domestic Deposit, Brokered	34,017	[1]	1,343	[1]
CDAR's one way [Member]	'		'
List of Company's Brokered deposits	'		'
Noninterest-bearing Domestic Deposit, Brokered	$3,028		$768
[1]	Certificate of deposit account registry service

Deposits_Details_Textual

Deposits (Details Textual) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Deposits [Abstract]	'	'
Municipal deposits	$992,761	$757,065
Certificates of Deposits, $100,000 or More	$290,483	$104,225

Borrowings_and_Senior_Notes_De

Borrowings and Senior Notes (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Jul. 02, 2013
In Thousands, unless otherwise specified
By period to maturity:	'	'	'
Less than one year, Amount	$370,365	$158,897	'
Less than one year, Rate	0.69%	0.95%	'
One to two years, Amount	140,344	78,717	'
One to two years, Rate	0.59%	1.97%	'
Two to three years, Amount	257,442	191	'
Two to three years, Rate	3.52%	5.32%	'
Three to four years, Amount	168,402	202,414	'
Three to four years, Rate	4.38%	4.21%	'
Four to five years, Amount	0	118,033	'
Four to five years, Rate	0.00%	5.57%	'
Greater than five years, Amount	2,516	2,734	'
Greater than five years, Rate	4.92%	4.92%	'
Total borrowings, Amount	939,069	560,986	'
Total borrowings, Rate	2.12%	3.26%	'
FHLB Advances [Member]	'	'	'
By period to maturity:	'	'	'
Total borrowings, Amount	795,028	442,602	'
Total borrowings, Rate	1.75%	2.77%	'
FHLB Repurchase Agreements [Member]	'	'	'
By period to maturity:	'	'	'
Total borrowings, Amount	25,639	20,351	'
Total borrowings, Rate	0.39%	0.88%	'
Federal Funds Purchased [Member]	'	'	'
By period to maturity:	'	'	'
Total borrowings, Amount	20,000	0	'
Total borrowings, Rate	0.31%	0.00%	'
Senior Notes [Member]	'	'	'
By period to maturity:	'	'	'
Total borrowings, Amount	$98,402	$98,033	$100,000
Total borrowings, Rate	5.98%	5.98%	'

Borrowings_and_Senior_Notes_De1

Borrowings and Senior Notes (Details Textual) (USD $)

0 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

1 Months Ended

12 Months Ended

Jul. 02, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Feb. 28, 2002

Sep. 30, 2014

Sep. 30, 2013

Jul. 02, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 05, 2014

Sep. 05, 2014

Sep. 05, 2014

Feb. 28, 2002

Jun. 01, 2014

Sep. 30, 2014

Sep. 30, 2014

repurchase_agreement

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

FHLB Advances [Member]

FHLB Advances [Member]

FHLB Repurchase Agreements [Member]

FHLB Repurchase Agreements [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

London Interbank Offered Rate (LIBOR) [Member]

Sterling Bancorp Trust I [Member]

Trust preferred [Member]

Minimum [Member]

Maximum [Member]

Line of Credit [Member]

Line of Credit [Member]

Revolving Credit Facility [Member]

Sterling Bancorp [Member]

Line of Credit [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Bank pledged mortgages

'

$1,246,315,000

$784,422,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increased borrowing capacity by pledging securities

'

703,486,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Federal home loan bank borrowings

'

200,000,000

200,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long term debt weighted average remaining term

'

'2 years 6 months 22 days

'3 years 6 months 22 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average interest rates

'

4.23%

4.23%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase agreements maturity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 day

'17 days

Amount of repurchase agreements

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase agreements

'

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving line of credit amount

'

'

'

'

'

'

'

'

'

'

'

'

'

15,000

'

'

'

'

'

Revolving line of credit balance

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

Required balance

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

Duration of minimum outstanding balance

'

'

'

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

Basis spread on one-month LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.25%

'

'

'

'

Long-term debt

'

939,069,000

560,986,000

'

'

98,402,000

98,033,000

100,000,000

795,028,000

442,602,000

25,639,000

20,351,000

'

'

'

'

'

'

'

Fixed interest rate (percent)

'

'

'

'

'

'

'

5.50%

'

'

'

'

'

'

'

'

'

'

'

Private placement discount rate

1.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cost of issuance

'

'

'

'

'

303,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized discount

'

'

'

'

'

1,597,000

1,967,000

'

'

'

'

'

'

'

'

'

'

'

'

Interest expense cost over the life of Senior note

'

5.98%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from trust preferred capital securities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

'

'

'

Stated interest rate (percent)

'

'

'

'

8.38%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Junior Subordinated Notes

'

'

'

'

25,774,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percent of liquidation amount of securities and accumulated and unpaid interest (percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

(Gain) on redemption of Subordinated Debentures

'

$712,000

$0

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivatives_Details

Derivatives (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Interest rate caps [Member]	'	'
Summary of derivatives	'	'
Notional amount	$50,000	$50,000
Average maturity (in years)	'2 months 5 days	'1 year 2 months 5 days
Weighted average fixed rate	3.75%	3.75%
Fair value	0	0
3rd party interest rate swap [Member]	'	'
Summary of derivatives	'	'
Notional amount	50,729	54,180
Average maturity (in years)	'4 years 10 months 10 days	'5 years 9 months 4 days
Weighted average fixed rate	4.20%	4.22%
Fair value	1,096	997
3rd party interest rate swap [Member] | One Month Libor [Member]	'	'
Summary of derivatives	'	'
Weighted average variable rate	'1 m Libor + 2.44	'1 m Libor + 2.45
Basis spread	2.44%	2.45%
Customer interest rate swap [Member]	'	'
Summary of derivatives	'	'
Notional amount	50,729	54,180
Average maturity (in years)	'4 years 10 months 10 days	'5 years 9 months 4 days
Weighted average fixed rate	4.20%	4.22%
Fair value	($1,096)	($997)
Customer interest rate swap [Member] | One Month Libor [Member]	'	'
Summary of derivatives	'	'
Weighted average variable rate	'1 m Libor + 2.44	'1 m Libor + 2.45
Basis spread	2.44%	2.45%

Derivatives_Details_Textual

Derivatives (Details Textual) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
	Derivatives
Credit Derivatives [Line Items]	'	'
Amortized cost of investment securities pledged as collateral	$5,034	'
Fair value of investment securities pledged as collateral	4,836	'
Interest rate caps [Member]	'	'
Credit Derivatives [Line Items]	'	'
Number of interest rate derivatives held	2	'
Changes in fair value: loss	$0	$2
Interest Rate Cap 1 [Member]	'	'
Credit Derivatives [Line Items]	'	'
Strike price	3.50%	'
Interest Rate Cap 2 [Member]	'	'
Credit Derivatives [Line Items]	'	'
Strike price	4.00%	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Current tax expense:	'	'	'	'	'	'	'	'	'	'	'
Federal	'	'	'	'	'	'	'	'	$11,613,000	$9,146,000	$5,538,000
State	'	'	'	'	'	'	'	'	1,598,000	1,549,000	685,000
Current tax expense	'	'	'	'	'	'	'	'	13,211,000	10,695,000	6,223,000
Deferred tax expense (benefit):	'	'	'	'	'	'	'	'	'	'	'
Federal	'	'	'	'	'	'	'	'	-2,745,000	522,000	-261,000
State	'	'	'	'	'	'	'	'	-314,000	197,000	197,000
Deferred tax expense (benefit)	'	'	'	'	'	'	'	'	-3,059,000	719,000	-64,000
Total income tax expense	6,452,000	6,057,000	4,588,000	-6,948,000	3,312,000	2,833,000	2,203,000	3,066,000	10,152,000	11,414,000	6,159,000
Efftective tax rate reconciliation:	'	'	'	'	'	'	'	'	'	'	'
Tax at Federal statutory rate of 35%	'	'	'	'	'	'	'	'	13,241,000	12,833,000	9,116,000
State income taxes, net of Federal tax benefit	'	'	'	'	'	'	'	'	834,000	1,135,000	573,000
Tax-exempt interest	'	'	'	'	'	'	'	'	-3,824,000	-2,192,000	-2,448,000
BOLI income	'	'	'	'	'	'	'	'	-1,110,000	-699,000	-718,000
Non deductible acquisition costs	'	'	'	'	'	'	'	'	712,000	416,000	418,000
Low income housing tax credits	'	'	'	'	'	'	'	'	-165,000	0	0
Other, net	'	'	'	'	'	'	'	'	464,000	-79,000	-782,000
Effective income tax rate	'	'	'	'	'	'	'	'	26.80%	31.10%	23.60%
Deferred tax assets:	'	'	'	'	'	'	'	'	'	'	'
Allowance for loan losses	17,272,000	'	'	'	11,809,000	'	'	'	17,272,000	11,809,000	'
Deferred compensation	649,000	'	'	'	798,000	'	'	'	649,000	798,000	'
Other accrued compensation and benefits	5,418,000	'	'	'	1,497,000	'	'	'	5,418,000	1,497,000	'
Accrued post retirement expense	2,705,000	'	'	'	1,441,000	'	'	'	2,705,000	1,441,000	'
Deferred tax assets deferred rent	0	'	'	'	1,059,000	'	'	'	0	1,059,000	'
Core deposit intangibles	2,439,000	'	'	'	0	'	'	'	2,439,000	0	'
Other comprehensive income (defined benefits)	5,777,000	'	'	'	7,844,000	'	'	'	5,777,000	7,844,000	'
Deferred tax assets, other comprehensive loss- Defined benefit plans	2,371,000	'	'	'	2,638,000	'	'	'	2,371,000	2,638,000	'
Depreciation of premises and equipment	433,000	'	'	'	0	'	'	'	433,000	0	'
State NOL carryforward	1,431,000	'	'	'	0	'	'	'	1,431,000	0	'
Other	3,511,000	'	'	'	2,172,000	'	'	'	3,511,000	2,172,000	'
Total deferred tax assets	42,006,000	'	'	'	29,258,000	'	'	'	42,006,000	29,258,000	'
Deferred tax liabilities:	'	'	'	'	'	'	'	'	'	'	'
Undistributed earnings of subsidiary not consolidated for tax return purposes (REIT Income)	9,303,000	'	'	'	4,483,000	'	'	'	9,303,000	4,483,000	'
Deferred tax liability prepaid pension cost	10,579,000	'	'	'	3,758,000	'	'	'	10,579,000	3,758,000	'
Purchase accounting fair value adjustments	16,056,000	'	'	'	1,057,000	'	'	'	16,056,000	1,057,000	'
Depreciation of premises and equipment	0	'	'	'	2,686,000	'	'	'	0	2,686,000	'
Intangibles amortization	0	'	'	'	112,000	'	'	'	0	112,000	'
Deferred rent	163,000	'	'	'	0	'	'	'	163,000	0	'
Other	2,557,000	'	'	'	2,207,000	'	'	'	2,557,000	2,207,000	'
Total deferred tax liabilities	38,658,000	'	'	'	14,303,000	'	'	'	38,658,000	14,303,000	'
Net deferred tax asset	3,348,000	'	'	'	14,955,000	'	'	'	3,348,000	14,955,000	'
Cumulative amount of deferred tax liability not recognized	9,313,000	'	'	'	0	'	'	'	9,313,000	0	'
Provision for federal income tax	'	'	'	'	'	'	'	'	0	'	'
Unrecorded deferred tax liability	$3,260,000	'	'	'	$0	'	'	'	$3,260,000	$0	'

Employee_Benefit_Plans_And_Sto2

Employee Benefit Plans And Stock-Based Compensation Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Pension Plans [Member]	'	'	'
Changes in projected benefit obligation:	'	'	'
Beginning of year	$31,705	$35,471	'
Obligations assumed from Legacy Sterling	52,296	0	'
Service cost	0	0	0
Interest cost	2,779	1,452	1,501
Actuarial loss (gain)	9,460	-3,672	'
Partial settlement	-44,774	0	'
Benefits and distributions paid	-1,748	-1,546	'
End of year	49,718	31,705	35,471
Changes in fair value of plan assets:	'	'	'
Beginning of year	35,417	32,657	'
Fair value of the Legacy Sterling Plan assets at October 31, 2013	71,538	0	'
Actual gain (loss) on plan assets	8,137	4,306	'
Employer contributions	0	0	'
Partial settlement	-44,774	0	'
Benefits and distributions paid	-1,748	-1,546	'
End of year	68,570	35,417	32,657
Funded status at end of year	18,852	3,712	'
Other Post retirement Benefit Plans [Member]	'	'	'
Changes in projected benefit obligation:	'	'	'
Beginning of year	3,302	3,103	'
Obligations assumed from Legacy Sterling	9,644	0	'
Service cost	51	48	46
Interest cost	683	134	125
Actuarial loss (gain)	79	177	'
Amendments	-2,485	0	'
Benefits and distributions paid	-284	-160	'
End of year	10,990	3,302	3,103
Changes in fair value of plan assets:	'	'	'
Beginning of year	0	0	'
Employer contributions	284	160	'
Plan participants' contributions	0	0	'
Benefits and distributions paid	-284	-160	'
End of year	0	0	0
Funded status at end of year	($10,990)	($3,302)	'

Employee_Benefit_Plans_And_Sto3

Employee Benefit Plans And Stock-Based Compensation Plans (Details 1) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
		Pension Plans [Member]	Pension Plans [Member]	Pension Plans [Member]	Other Post retirement Benefit Plans [Member]	Other Post retirement Benefit Plans [Member]	Other Post retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'	'	'	'
Service cost	'	$0	$0	$0	$51	$48	$46
Interest cost	'	2,779	1,452	1,501	683	134	125
Expected return on plan assets	'	-3,380	-2,462	-2,125	'	'	'
Amortization of unrecognized actuarial (gain) loss	'	236	2,062	2,316	-45	2	-25
Partial settlement charge	2,700	3,922	0	0	'	'	'
Amortization of transition obligation	'	'	'	'	34	24	24
Amortization of prior service cost	'	'	'	'	270	47	47
Curtailment (gain)	'	'	'	'	-2,485	0	0
Total	'	$3,557	$1,052	$1,692	($1,492)	$255	$217

Employee_Benefit_Plans_And_Sto4

Employee Benefit Plans And Stock-Based Compensation Plans (Details 2) (Pension Plans [Member], USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Unrecognized actuarial loss	($6,024)	($5,479)
Deferred tax asset	2,556	2,225
Net amount recognized in accumulated other comprehensive income (loss)	($3,468)	($3,254)

Recovered_Sheet1

Employee Benefit Plans and Stock-Based Compensation Plans (Details 3) (Pension Plans [Member])	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Projected benefit obligation, Discount rate	4.50%	5.20%
Net periodic pension cost, Discount rate	4.50%	5.20%
Net periodic pension cost, Long-term rate of return on plan assets	4.00%	7.75%

Employee_Benefit_Plans_And_Sto5

Employee Benefit Plans And Stock-Based Compensation Plans (Details 4) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Pension Plans [Member]	'
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]	'
2015	$726
2016	902
2017	1,079
2018	1,625
2019	1,851
2020 - 2024	13,461
Other Post retirement Benefit Plans [Member]	'
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]	'
2015	660
2016	231
2017	271
2018	319
2019	373
2020 - 2024	$2,370

Employee_Benefit_Plans_And_Sto6

Employee Benefit Plans And Stock-Based Compensation Plans (Details 5) (Pension Plans [Member], USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	$68,570	$35,417	$32,657
Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	68,521	35,417	'
Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	68,521	35,417	'
Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Total Equity [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	24,475	'
Total Equity [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Total Equity [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	24,475	'
Total Equity [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Large U.S. equity [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	16,378	'
Large U.S. equity [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Large U.S. equity [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	16,378	'
Large U.S. equity [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Small Mid U.S. equity [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	4,443	'
Small Mid U.S. equity [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Small Mid U.S. equity [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	4,443	'
Small Mid U.S. equity [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
International Equity [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	3,654	'
International Equity [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
International Equity [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	3,654	'
International Equity [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Total Balanced Asset Allocation [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	1,691	'
Total Balanced Asset Allocation [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Total Balanced Asset Allocation [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	1,691	'
Total Balanced Asset Allocation [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Total Fixed Income [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	9,251	'
Total Fixed Income [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Total Fixed Income [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	9,251	'
Total Fixed Income [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
High yield bond [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	1,018	'
High yield bond [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
High yield bond [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	1,018	'
High yield bond [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	'	0	'
Intermediate term bond [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	8,629	8,233	'
Intermediate term bond [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Intermediate term bond [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	8,629	8,233	'
Intermediate term bond [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Fixed Income Funds Long Term Bond [Member] | Fair Value Measurements [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	59,892	'	'
Fixed Income Funds Long Term Bond [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	'	'
Fixed Income Funds Long Term Bond [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	59,892	'	'
Fixed Income Funds Long Term Bond [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	$0	'	'

Employee_Benefit_Plans_And_Sto7

Employee Benefit Plans And Stock-Based Compensation Plans (Details 6) (Pension Plans [Member])	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	100.00%	100.00%
Weighted average expected rate of return	4.00%	'
Total Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	65.00%
Target allocation 2014	0.00%	'
Weighted average expected rate of return	0.00%	'
Large U.S. equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	44.00%
Weighted average expected rate of return	0.00%	'
Small Mid U.S. equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	11.00%
Weighted average expected rate of return	0.00%	'
International Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	10.00%
Weighted average expected rate of return	0.00%	'
Total Balanced Asset Allocation [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	5.00%
Weighted average expected rate of return	0.00%	'
Total Fixed Income [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	100.00%	30.00%
Target allocation range 2014, minimum	95.00%	'
Target allocation range 2014, maximum	1.00%	'
Weighted average expected rate of return	4.00%	'
High yield bond [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	3.00%
Weighted average expected rate of return	0.00%	'
Intermediate term bond [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	13.00%	27.00%
Weighted average expected rate of return	0.00%	'
Fixed Income Funds Long Term Bond [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	87.00%	0.00%
Weighted average expected rate of return	0.00%	'
Cash [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Actual plan asset allocations	0.00%	0.00%
Target allocation range 2014, minimum	0.00%	'
Target allocation range 2014, maximum	5.00%	'
Weighted average expected rate of return	0.00%	'

Employee_Benefit_Plans_And_Sto8

Employee Benefit Plans And Stock-Based Compensation Plans (Details 7) (Other Post retirement Benefit Plans [Member])	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]	'	'
Medical trend rate next year	4.50%	4.50%
Ultimate trend rate	4.50%	4.50%
Discount rate	'	4.20%
Discount rate used to value periodic cost	'	4.10%
Minimum [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Discount rate	3.50%	'
Discount rate used to value periodic cost	3.50%	'
Maximum [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Discount rate	4.27%	'
Discount rate used to value periodic cost	4.20%	'

Employee_Benefit_Plans_And_Sto9

Employee Benefit Plans And Stock-Based Compensation Plans (Details 8) (USD $)	12 Months Ended
	Sep. 30, 2014
Shares available for grant (in shares)	'
Beginning balance	2,066,184
Grants	-719,674	[1]
Stock awards vested	0
Forfeited	439,594
Canceled/expired	-347,286
Ending balance	3,350,761
Stock options outstanding - Number of shares	'
Beginning balance	2,114,509
Grants	324,862	[1]
Exercised	-507,955
Forfeited	-375,235
Ending balance	1,660,333
Exercisable at September 30, 2014	951,492
Stock options outstanding - Weighted average exercise price (in usd per share)	'
Beginning balance	$10.71
Grants	$11.45	[1]
Exercised	$11.29
Forfeited	$12.24
Ending balance	$10.55
Exercisable at September 30, 2014	$11.11
Recognition and Retention Plan [Member] | Non-vested Stock Awards and Performance Units [Member]	'
Non-vested stock awards/stock units outstanding - Number of shares	'
Beginning balance	209,697
Grants	115,145	[1]
Stock awards vested	-69,211
Forfeited	-18,841
Ending balance	588,754
Non-vested stock awards/stock units outstanding - Weighted average grant date fair value (in usd per share)	'
Beginning balance	$8.73
Grants	$11.53	[1]
Stock awards vested	$9.51
Forfeited	($9.18)
Ending balance	$10.99
2014 Stock Incentive Plan [Member]	'
Shares available for grant (in shares)	'
2014 Stock Incentive Plan	3,400,000
2012 Stock Plan [Member]	'
Shares available for grant (in shares)	'
2012 Stock Incentive Plan termination	-566,554
Stock Compensation Grants associated with legacy Sterling Merger [Member]	'
Shares available for grant (in shares)	'
Grants	-921,503	[1]
Stock options outstanding - Number of shares	'
Grants	104,152	[1]
Stock options outstanding - Weighted average exercise price (in usd per share)	'
Grants	$14.25	[1]
Stock Compensation Grants associated with legacy Sterling Merger [Member] | Recognition and Retention Plan [Member] | Non-vested Stock Awards and Performance Units [Member]	'
Non-vested stock awards/stock units outstanding - Number of shares	'
Grants	351,964	[1]
Non-vested stock awards/stock units outstanding - Weighted average grant date fair value (in usd per share)	'
Grants	$11.72	[1]
[1]	(1) Reflects certain non-vested stock awards that count as 3.5 shares or 3.6 shares for each share granted.

Recovered_Sheet2

Employee Benefit Plans And Stock-Based Compensation Plans (Details 9) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014
			Stock Option Plan [Member]	$6.71 to $9.00 [Member]	$9.28 to $12.64 [Member]	$12.84 to $13.92 [Member]
				Stock Option Plan [Member]	Stock Option Plan [Member]	Stock Option Plan [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'	'	'
Range of exercise price, lower range limit (in dollars per share)	'	'	'	$6.71	$9.28	$12.84
Range of exercise price, upper range limit (in dollars per share)	'	'	'	$9	$12.64	$13.92
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract]	'	'	'	'	'	'
Outstanding, Number of stock options	0	549,262	1,660,333	689,711	787,243	183,379
Outstanding, Weighted-average exercise price (in usd per share)	'	'	$10.55	$8.38	$11.73	$13.68
Outstanding, Weighted-average life (in years)	'	'	'5 years 9 months 26 days	'7 years 6 months 26 days	'5 years 0 months 8 days	'2 years 8 months 9 days
Exercisable, Number of stock options	'	'	951,492	322,148	445,965	183,379
Exercisable, Weighted-average exercise price (in usd per share)	'	'	$11.11	$8.36	$12.05	$13.68
Exercisable, Weighted-average life (in years)	'	'	'5 years 9 months 26 days	'7 years 6 months 26 days	'5 years 0 months 8 days	'2 years 8 months 9 days

Recovered_Sheet3

Employee Benefit Plans And Stock-Based Compensation Plans (Details 10) (Stock Options [Member], Stock Option Plan [Member])	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Stock Options [Member] | Stock Option Plan [Member]	'		'		'
Fair value of options granted determined using weighted-average assumptions as grant date	'		'		'
Risk-free interest rate	1.80%		1.00%		1.40%
Expected stock price volatility	26.40%		40.80%		40.00%
Dividend yield	2.00%	[1]	2.60%	[1]	3.00%	[1]
Expected term in years	'5 years 8 months 1 day		'5 years 9 months		'5 years 9 months 26 days
[1]	Represents the approximate annualized cash dividend rate paid with respect to a share of common stock at or near the grant date.

Recovered_Sheet4

Employee Benefit Plans and Stock-Based Compensation Plans (Details 11) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	$3,409	$1,742	$797
Stock-based compensation expense, income tax benefit	914	542	188
Unrecognized stock-based compensation, stock options	962	'	'
Unrecognized stock-based compensation, non-vested stock awards/stock units	4,013	'	'
Total unrecognized stock-based compensation expense	4,975	'	'
Stock Options [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	901	695	521
Non-vested Stock Awards and Performance Units [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	$2,508	$1,047	$276

Recovered_Sheet5

Employee Benefit Plans And Stock-Based Compensation Plans (Details Textual) (USD $)

0 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Oct. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Jan. 31, 2004

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Feb. 04, 2014

Sep. 30, 2014

Sep. 30, 2014

Feb. 28, 2010

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Feb. 04, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Oct. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Share Option Plan Two Thousand Four [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

2012 Stock Plan [Member]

Employee Savings Plan [Member]

Employee Savings Plan [Member]

Employee Savings Plan [Member]

Employee Stock Ownership Plan [Member]

Employee Stock Ownership Plan [Member]

Employee Stock Ownership Plan [Member]

Employee Stock Ownership Plan [Member]

Employee Stock Ownership Plan [Member]

2014 Stock Incentive Plan [Member]

Recognition and Retention Plan [Member]

Stock Option Plan [Member]

Stock Option Plan [Member]

Stock Option Plan [Member]

Stock Option Plan [Member]

Restricted Stock [Member]

Restricted Stock Units (RSUs) [Member]

Non-vested Stock Awards and Performance Units [Member]

Non-vested Stock Awards and Performance Units [Member]

Stock Options [Member]

Pension Plans [Member]

Pension Plans [Member]

Employee Stock Ownership Plan (ESOP) loan repayment [Member]

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Sterling Bancorp (Legacy)

Stock Compensation Grants associated with legacy Sterling Merger [Member]

Stock Compensation Grants associated with legacy Sterling Merger [Member]

Stock Compensation Grants associated with legacy Sterling Merger [Member]

Stock Compensation Grants associated with legacy Sterling Merger [Member]

Minimum [Member]

Maximum [Member]

Recognition and Retention Plan [Member]

Maximum [Member]

Sterling Bancorp 2013 Employment Inducement Award Plan [Member]

Fully Vested legacy Sterling options [Member]

Restricted Stock Units (RSUs) [Member]

legacy Sterling/ National Bank employees' Retirement Plan [Member]

Stock Options [Member]

Non-vested Stock Awards and Performance Units [Member]

Restricted Stock Units (RSUs) [Member]

2012 Stock Plan [Member]

Recognition and Retention Plan [Member]

Recognition and Retention Plan [Member]

Schedule of Employee Benefit Plans And Stock-Based Compensation Plans [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase of accrued benefit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.40%

'

'

'

'

Partial settlement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

($44,774,000)

$0

'

'

'

'

'

'

'

'

'

'

'

Unrecognized acturaial loss and prior service cost expected to be amortized

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Net periodic pension cost, Long-term rate of return on plan assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.00%

7.75%

'

'

'

'

'

'

'

'

'

'

'

Pension plan assets consisting of company common stock (in shares)

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Health care cost trend rate

'

1.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Savings plan expense

'

'

'

'

'

'

'

'

'

1,614,000

935,000

1,029,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount borrowed by ESOP

'

'

'

'

'

'

'

'

'

'

'

'

9,987,000

'

'

'

5,983,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares purchased for ESOP with borrowings

'

'

'

'

'

'

'

'

'

'

'

'

998,650

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of loan

'

'

'

'

'

'

'

'

'

'

'

'

'20 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee stock ownership plan percent automatically vested upon termination

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cumulative shares in ESOP

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

499,330

'

'

'

'

'

'

'

'

'

'

'

'

'

488,403

'

'

'

'

'

'

'

'

'

'

Number of ESPO shares allocated

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,927

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

ESOP expense (net of forfeitures)

'

'

'

'

'

'

'

'

'

'

'

'

'

295,000

497,000

390,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares authorized

'

'

'

'

2,796,220

'

'

'

'

'

'

'

'

'

'

'

'

3,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares remaining that are authorized and available for future grant

'

3,350,761

2,066,184

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares granted for each share received

'

'

'

'

'

'

'

'

3.6

'

'

'

'

'

'

'

'

3.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares remaining for issuance under the 2012 Plan

'

'

'

'

'

'

'

'

566,554

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares subject to accelerated vesting

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,533

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of contract

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vesting period for awards

'

'

'

'

'

'

'2 years

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

Grant of share options (in shares)

'

324,862

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

107,256

'

'

'

29,550

11,820

'

'

'

'

'

'

'

'

95,991

104,152

'

'

104,152

[1]

'

'

'

Exercise price (in usd per share)

'

$11.45

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$14.25

[1]

$14.25

'

'

Awards canceled of forfeited (in shares)

'

375,235

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

37,873

'

'

'

'

'

'

'

'

'

Grants in period, other than options (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

115,145

[1]

'

'

'

'

'

'

'

'

255,973

'

'

'

351,964

[1]

'

Weighted average grant date fair value (in usd per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$11.53

[1]

'

'

'

'

'

'

'

'

'

'

'

'

$11.72

[1]

$11.72

Intrinsic value of options outstanding

'

3,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options exercisable

'

1,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

651,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from stock option exercises

'

$2,980,000

$62,000

$102,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average fair value of options granted (in usd per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2.51

$2.74

$2.31

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted-average period total unrecognized compensation cost related to non-vested shares granted

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year 9 months 26 days

'

'1 year 7 months 28 days

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

(1) Reflects certain non-vested stock awards that count as 3.5 shares or 3.6 shares for each share granted.

Other_Noninterest_Expense_Deta

Other Non-interest Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Other Income and Expenses [Abstract]	'	'	'
Advertising and promotion	$2,358	$1,502	$1,849
Professional fees	6,913	3,393	4,247
Data and check processing	3,439	2,520	2,802
ATM/debit card expense	1,249	1,722	1,711
Insurance & surety bond premium	2,703	1,199	1,220
Charge for asset write-downs, severance and retention	22,976	0	0
Charge for banking systems conversion	3,249	0	0
Other	15,030	7,040	6,562
Total other non-interest expense	$57,917	$17,376	$18,391

Earnings_Per_Common_Share_Deta

Earnings Per Common Share (Details) (USD $)

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Computation of basic and diluted earnings per share:

'

'

'

'

'

'

'

'

'

'

'

Net income

$16,337

$15,011

$10,332

($14,002)

$5,329

$6,376

$6,529

$7,020

$27,678

$25,254

$19,888

Weighted average common shares outstanding for computation of basic EPS (in shares)

'

'

'

'

'

'

'

'

80,268,970

[1]

43,734,425

[1]

38,227,653

[1]

Common-equivalent shares due to the dilutive effect of stock options (in shares)

'

'

'

'

'

'

'

'

265,073

[2]

48,628

[2]

20,393

[2]

Weighted average common shares for computation of diluted EPS (in shares)

'

'

'

'

'

'

'

'

80,534,043

43,783,053

38,248,046

Basic (USD per share)

$0.20

$0.18

$0.12

($0.20)

$0.12

$0.15

$0.15

$0.16

$0.34

$0.58

$0.52

Diluted (USD per share)

$0.19

$0.18

$0.12

($0.20)

$0.12

$0.15

$0.15

$0.16

$0.34

$0.58

$0.52

Antidilutive securities excluded from earnings per share (in shares)

'

'

'

'

'

'

'

'

697,475

1,786,608

1,771,132

[1]

Includes earned ESOP shares.

[2]

Represents incremental shares computed using the treasury stock method.

Stockholders_Equity_Compliance

Stockholders' Equity - Compliance with Regulatory Capital Requirements (Schedule) (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Sterling Bancorp [Member]	'	'
Tier 1 capital (to risk-weighted assets):	'	'
Tier 1 risk-based capital	$553,117	'
Total capital (to risk-weighted assets):	'	'
Total risk-based capital	594,124	'
Sterling National Bank [Member]	'	'
Tier 1 leverage capital (to average assets):	'	'
Tier 1 (core) capital	636,507	363,274
Tier 1 (core) capital ratio	9.34%	9.33%
Tier 1 (core) capital required for minimum capital adequacy	272,542	155,670
Tier 1 (core) capital required for minimum capital adequacy ratio	4.00%	4.00%
Tier 1 (core) capital required to be well capitalized	340,677	194,587
Tier 1 (core) capital required to be well capitalized ratio	5.00%	5.00%
Tier 1 capital (to risk-weighted assets):	'	'
Tier 1 risk-based capital	636,507	363,274
Tier 1 risk-based capital ratio	11.94%	13.18%
Tier 1 risk-based capital required for minimum capital adequacy	213,176	110,235
Tier 1 risk-based capital required for minimum capital adequacy ratio	4.00%	4.00%
Tier 1 risk-based capital required to be well capitalized	319,763	165,352
Tier 1 risk-based capital required to be well capitalized ratio	6.00%	6.00%
Total capital (to risk-weighted assets):	'	'
Total risk-based capital	677,514	392,376
Total risk-based capital ratio	12.71%	14.24%
Total risk-based capital required for minimum capital adequacy	426,351	220,469
Total risk-based capital required for minimum capital adequacy ratio	8.00%	8.00%
Total risk-based capital required to be well capitalized	532,939	275,587
Total risk-based capital required to be well capitalized ratio	10.00%	10.00%
Sterling Bancorp [Member]	'	'
Tier 1 leverage capital (to average assets):	'	'
Tier 1 (core) capital	553,117	'
Tier 1 (core) capital ratio	8.12%	'
Tier 1 (core) capital required for minimum capital adequacy	272,385	'
Tier 1 (core) capital required for minimum capital adequacy ratio	4.00%	'
Tier 1 (core) capital required to be well capitalized	340,481	'
Tier 1 (core) capital required to be well capitalized ratio	5.00%	'
Tier 1 capital (to risk-weighted assets):	'	'
Tier 1 risk-based capital	553,117	'
Tier 1 risk-based capital ratio	10.33%	'
Tier 1 risk-based capital required for minimum capital adequacy	214,102	'
Tier 1 risk-based capital required for minimum capital adequacy ratio	4.00%	'
Tier 1 risk-based capital required to be well capitalized	321,153	'
Tier 1 risk-based capital required to be well capitalized ratio	6.00%	'
Total capital (to risk-weighted assets):	'	'
Total risk-based capital	594,124	'
Total risk-based capital ratio	11.10%	'
Total risk-based capital required for minimum capital adequacy	428,204	'
Total risk-based capital required for minimum capital adequacy ratio	8.00%	'
Total risk-based capital required to be well capitalized	$535,254	'
Total risk-based capital required to be well capitalized ratio	10.00%	'

Stockholders_Equity_Reconcilia

Stockholders' Equity - Reconciliation of Stockholders' Equity to Bank Regulatory Capital (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified					Sterling Bancorp [Member]	Sterling Bancorp [Member]	Sterling National Bank [Member]	Sterling National Bank [Member]
Reconciliation of Stockholders' Equity To Bank Regulatory Capital [Line Items]	'	'	'	'	'	'	'	'
Total GAAP stockholders’ equity	$961,138	$482,866	$491,122	$431,134	$961,138	$482,866	$1,011,973	$516,281
Disallowed goodwill and other intangible assets	'	'	'	'	-419,327	'	-386,766	-168,122
Net unrealized loss on available for sale securities	'	'	'	'	7,815	'	7,809	11,455
Disallowed servicing asset	'	'	'	'	-153	'	-153	-198
Net actuarial loss on defined benefit pension plans	'	'	'	'	3,644	'	3,644	3,858
Tier 1 risk-based capital	'	'	'	'	553,117	'	636,507	363,274
Allowance for loan losses and off-balance sheet commitments	40,612	28,877	28,282	27,917	41,007	'	41,007	29,102
Total risk-based capital	'	'	'	'	$594,124	'	$677,514	$392,376

Stockholders_Equity_Narrative_

Stockholders' Equity (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Class of Stock [Line Items]	'	'	'
Aggregate dividend capacity without prior regulatory approval	47,879,000	'	'
Shares available for repurchase program	776,713	'	'
Sterling Bancorp [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Shares repurchased under repurchase program	0	0	0
Sterling National Bank [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Liquidation account	13,300,000	'	'

OffBalanceSheet_Financial_Inst2

Off-Balance-Sheet Financial Instruments (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Loan origination commitments [Member]	'	'
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'
Lending-related instruments	$213,793	$171,032
Unused lines of credit [Member]	'	'
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'
Lending-related instruments	306,482	207,201
Letters of credit [Member]	'	'
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'
Lending-related instruments	$97,468	$35,052

OffBalanceSheet_Financial_Inst3

Off-Balance-Sheet Financial Instruments (Details Textual) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'
Assets secured by other collateral	$34,687	'
Letters of credit [Member]	'	'
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'
Lending-related instruments	97,468	35,052
Assets secured by cash as collateral	$21,756	'

Commitment_and_Contingencies_D

Commitment and Contingencies (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Future minimum rental payments due under non-cancelable operating leases	'	'	'
2014	$8,984	'	'
2015	8,517	'	'
2016	7,690	'	'
2017	7,702	'	'
2018	6,386	'	'
2019 and thereafter	27,012	'	'
Future minimum rental payments	66,291	'	'
Rent expense	$7,893	$3,340	$2,952

Fair_Value_Measurements_Detail

Fair Value Measurements (Details 1) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Investment securities	'	'
Securities available for sale	$1,110,813	$954,393
Fair Value Measurements [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	591,850	449,183
Investment securities	'	'
Total investment securities available for sale	518,963	505,210
Securities available for sale	1,110,813	954,393
Interest rate caps and swaps	'	-997
Total Assets	1,111,909	955,390
Swaps	1,096	997
Total Liabilities	1,096	997
Fair Value Measurements [Member] | Agency-backed [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	477,705	282,529
Fair Value Measurements [Member] | CMO/Other MBS [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	111,276	163,041
Fair Value Measurements [Member] | Privately issued collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	2,869	3,613
Fair Value Measurements [Member] | Federal agencies [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	152,814	261,547
Fair Value Measurements [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	192,839	114,933
Fair Value Measurements [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	134,898	128,730
Fair Value Measurements [Member] | Trust preferred [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	38,412	'
Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Investment securities	'	'
Securities available for sale	0	0
Interest rate caps and swaps	0	0
Swaps	'	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Investment securities	'	'
Total investment securities available for sale	0	0
Securities available for sale	0	0
Interest rate caps and swaps	0	0
Total Assets	0	0
Swaps	0	0
Total Liabilities	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Agency-backed [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | CMO/Other MBS [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Privately issued collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Federal agencies [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Quoted Prices in Active markets for Identical Assets Level 1 [Member] | Trust preferred [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	'
Significant Other Observable Inputs Level 2 [Member]	'	'
Investment securities	'	'
Securities available for sale	1,110,813	950,780
Interest rate caps and swaps	-1,096	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	588,981	445,570
Investment securities	'	'
Total investment securities available for sale	518,963	505,210
Securities available for sale	1,107,944	950,780
Interest rate caps and swaps	-1,096	-997
Total Assets	1,109,040	951,777
Swaps	1,096	997
Total Liabilities	1,096	997
Significant Other Observable Inputs Level 2 [Member] | Agency-backed [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	477,705	282,529
Significant Other Observable Inputs Level 2 [Member] | CMO/Other MBS [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	111,276	163,041
Significant Other Observable Inputs Level 2 [Member] | Privately issued collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Significant Other Observable Inputs Level 2 [Member] | Federal agencies [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	152,814	261,547
Significant Other Observable Inputs Level 2 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	192,839	114,933
Significant Other Observable Inputs Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	134,898	128,730
Significant Other Observable Inputs Level 2 [Member] | Trust preferred [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	38,412	'
Significant Unobservable Inputs Level 3 [Member]	'	'
Investment securities	'	'
Securities available for sale	0	3,613
Interest rate caps and swaps	0	0
Swaps	'	0
Significant Unobservable Inputs Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	2,869	3,613
Investment securities	'	'
Total investment securities available for sale	0	0
Securities available for sale	2,869	3,613
Interest rate caps and swaps	0	0
Total Assets	2,869	3,613
Swaps	0	0
Total Liabilities	0	0
Significant Unobservable Inputs Level 3 [Member] | Agency-backed [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Significant Unobservable Inputs Level 3 [Member] | CMO/Other MBS [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	0	0
Significant Unobservable Inputs Level 3 [Member] | Privately issued collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Mortgage-backed securities-residential	'	'
Mortgage-backed securities-residential	2,869	3,613
Significant Unobservable Inputs Level 3 [Member] | Federal agencies [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Significant Unobservable Inputs Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Significant Unobservable Inputs Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	0	0
Significant Unobservable Inputs Level 3 [Member] | Trust preferred [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Investment securities	'	'
Total investment securities available for sale	$0	'

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	$0	$0
Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	4,758,366	2,422,824
Impaired [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	3,636	6,013
Impaired [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	3,636	6,013
Impaired [Member] | Commercial Real Estate [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	1,463	3,672
Impaired [Member] | Commercial Real Estate [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Commercial Real Estate [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Commercial Real Estate [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	1,463	3,672
Impaired [Member] | Commercial & industrial | Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	500
Impaired [Member] | Commercial & industrial | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	0
Impaired [Member] | Commercial & industrial | Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	0
Impaired [Member] | Commercial & industrial | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	500
Impaired [Member] | Acquisition development and construction [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	2,173	1,839
Impaired [Member] | Acquisition development and construction [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Acquisition development and construction [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	0	0
Impaired [Member] | Acquisition development and construction [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	2,173	1,839
Impaired [Member] | Consumer loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	2
Impaired [Member] | Consumer loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active markets for Identical Assets Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	0
Impaired [Member] | Consumer loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	0
Impaired [Member] | Consumer loans [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	'	$2

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 3) (USD $)

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

In Thousands, unless otherwise specified

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Market Approach Valuation Technique [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Impaired [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Taken in Foreclosure [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Weighted Average [Member]

Weighted Average [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Weighted Average [Member]

Weighted Average [Member]

Weighted Average [Member]

Weighted Average [Member]

Real estate-commercial mortgage [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Significant Unobservable Inputs Level 3 [Member]

Real estate-commercial mortgage [Member]

Acquisition development and construction [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Real estate-commercial mortgage [Member]

Real estate-residential mortgage [Member]

Acquisition development and construction [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Fair Value, Measurements, Nonrecurring [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Real estate-commercial mortgage [Member]

Acquisition development and construction [Member]

Real estate-commercial mortgage [Member]

Acquisition development and construction [Member]

Real estate-commercial mortgage [Member]

Acquisition development and construction [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Real estate-commercial mortgage [Member]

Real estate-residential mortgage [Member]

Acquisition development and construction [Member]

Mortgage Servicing Rights [Member]

Real estate-commercial mortgage [Member]

Real estate-residential mortgage [Member]

Acquisition development and construction [Member]

Mortgage Servicing Rights [Member]

Real estate-commercial mortgage [Member]

Real estate-residential mortgage [Member]

Acquisition development and construction [Member]

Mortgage Servicing Rights [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

Significant Unobservable Inputs Level 3 [Member]

speed

speed

speed

Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loans, net

'

'

$4,758,366

$2,422,824

$2,396

$3,636

$6,013

$1,463

$2,173

'

'

'

'

'

'

$1,910

$1,301

$1,973

'

'

'

'

'

'

'

'

'

'

'

'

Mortgage servicing rights

$1,526

$1,978

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Comparability adjustments

'

'

'

'

'

'

'

'

'

15.00%

10.00%

36.00%

30.00%

22.00%

13.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Management adjustments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20.00%

16.00%

25.00%

'

37.00%

59.00%

70.00%

'

24.80%

21.60%

30.20%

'

Discount rates

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

9.30%

'

'

'

12.80%

'

'

'

'

Prepayment speed

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100

'

'

'

968

'

'

'

224

Recovered_Sheet6

Fair value Measurements (Details 4) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Securities available for sale	$1,110,813	$954,393
Securities held to maturity	587,838	250,896
Senior notes	-98,402	-98,033
Carrying Amount [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and due from banks	177,619	113,090
Securities available for sale	1,110,813	954,393
Securities held to maturity	579,075	253,999
Loans, net	4,719,826	2,384,021
Loans held for sale	17,846	1,011
Accrued interest receivable on securities	8,876	4,892
Accrued interest receivable on loans	10,791	6,805
FHLB stock and Federal Reserve Bank stock	66,085	24,312
Interest rate caps and swaps	1,096	997
Non-maturity deposits	-4,860,783	-2,694,166
Certificates of deposit	-437,871	-268,128
FHLB borrowings	-795,028	-345,176
Other borrowings	-45,639	'
Senior notes	-98,402	'
Mortgage escrow funds	-4,494	'
Accrued interest payable on deposits	-320	-12,646
Accrued interest payable on borrowings	-2,942	-1,480
Interest rate caps and swaps	-1,096	-1,525
Interest rate caps and swaps	'	-997
Fair Value, Inputs, Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and due from banks	177,619	113,090
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
Interest rate caps and swaps	0	0
Non-maturity deposits	-4,860,783	-2,694,166
Certificates of deposit	0	0
FHLB borrowings	0	0
Senior notes	0	'
Mortgage escrow funds	0	'
Accrued interest payable on deposits	0	0
Accrued interest payable on borrowings	0	0
Interest rate caps and swaps	0	0
Interest rate caps and swaps	'	0
Significant Other Observable Inputs Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and due from banks	0	0
Securities available for sale	1,110,813	950,780
Securities held to maturity	587,838	250,896
Loans, net	0	0
Loans held for sale	17,846	1,011
Accrued interest receivable on securities	8,876	4,892
Accrued interest receivable on loans	0	0
Interest rate caps and swaps	1,096	'
Non-maturity deposits	0	0
Certificates of deposit	-438,088	-268,088
FHLB borrowings	-813,490	-488,369
Other borrowings	-45,640	'
Senior notes	-100,482	'
Mortgage escrow funds	-4,494	'
Accrued interest payable on deposits	-320	-12,644
Accrued interest payable on borrowings	-2,942	-1,480
Interest rate caps and swaps	-1,096	-1,525
Significant Other Observable Inputs Level 2 [Member] | Carrying Amount [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Interest rate caps and swaps	'	997
Interest rate caps and swaps	'	-997
Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and due from banks	0	0
Securities available for sale	0	3,613
Securities held to maturity	0	0
Loans, net	4,758,366	2,422,824
Loans held for sale	0	0
Accrued interest receivable on securities	0	0
Accrued interest receivable on loans	10,791	6,805
Interest rate caps and swaps	0	0
Non-maturity deposits	0	0
Certificates of deposit	0	0
FHLB borrowings	0	0
Senior notes	0	'
Mortgage escrow funds	0	'
Accrued interest payable on deposits	0	0
Accrued interest payable on borrowings	0	0
Interest rate caps and swaps	0	0
Interest rate caps and swaps	'	$0

Recovered_Sheet7

Fair value measurements (Details Textual) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized cost	$1,115,458	$973,709
Changes in fair value recognized on provisions on loans held by the Company	905	2,726
Other real estate owned	7,580	6,022
Changes in fair value recognized through income for foreclosed assets held by the Company	224	1,978
Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	4,758,366	2,422,824
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	36,208	35,228
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Mortgage-backed securities-residential	2,869	3,613
Privately issued collateralized mortgage obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized cost	2,866	'
Privately issued collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Mortgage-backed securities-residential	2,869	3,613
Mortgage-backed securities, percent of portfolio	0.17%	'
Market Approach Valuation Technique [Member] | Commercial Real Estate [Member] | Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loans, net	$2,396	'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive (Loss) Income (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
In Thousands, unless otherwise specified
Equity [Abstract]	'	'	'	'
Net unrealized holding loss on available for sale securities	($4,645)	($19,316)	'	'
Related income tax benefit	1,974	7,844	'	'
Available for sale securities AOCI, net of tax	-2,671	-11,472	'	'
Net unrealized holding loss on securities transferred to held to maturity	-8,947	0	'	'
Related income tax benefit	3,803	0	'	'
Securities transferred to held to maturity AOCI, net of tax	-5,144	0	'	'
Net unrealized holding loss on retirement plans	-6,336	-6,496	'	'
Related income tax benefit	2,692	2,638	'	'
Retirement plan AOCI, net of tax	-3,644	-3,858	'	'
Accumulated other comprehensive loss	($11,459)	($15,330)	$6,899	$5,136

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive (Loss) Income (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'	'	'
Balance beginning of the year	($15,330)	$6,899	$5,136
Other comprehensive gain (loss) before reclassification	4,026	-19,126	7,640
Amounts reclassified from AOCI	-155	-3,103	-5,877
Other comprehensive income	3,871	-22,229	1,763
Balance at end of period	-11,459	-15,330	6,899
Net unrealized holding gain (loss) on AFS securities	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'	'	'
Balance beginning of the year	-11,472	15,066	13,604
Other comprehensive gain (loss) before reclassification	9,170	-22,167	7,640
Amounts reclassified from AOCI	-369	-4,371	-6,178
Other comprehensive income	8,801	-26,538	1,462
Balance at end of period	-2,671	-11,472	15,066
Net unrealized holding (loss) on securities transferred to held to maturity	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'	'	'
Balance beginning of the year	0	0	0
Other comprehensive gain (loss) before reclassification	-5,144	0	0
Amounts reclassified from AOCI	0	0	0
Other comprehensive income	-5,144	0	0
Balance at end of period	-5,144	0	0
Net unrealized holding gain (loss) on retirement plans	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'	'	'
Balance beginning of the year	-3,858	-8,167	-8,468
Other comprehensive gain (loss) before reclassification	0	3,041	0
Amounts reclassified from AOCI	214	1,268	301
Other comprehensive income	214	4,309	301
Balance at end of period	($3,644)	($3,858)	($8,167)

Condensed_Parent_Company_Finan2

Condensed Parent Company Financial Statements - Statements of Financial Condition (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash	$177,619,000	$113,090,000	$437,982,000	$281,512,000
Goodwill	388,926,000	163,117,000	163,247,000	'
Other assets	41,900,000	34,184,000	'	'
Total assets	7,337,387,000	4,049,172,000	'	'
Senior Notes	98,402,000	98,033,000	'	'
Other liabilities	134,032,000	30,380,000	'	'
Total liabilities	6,376,249,000	3,566,306,000	'	'
Stockholders’ equity	961,138,000	482,866,000	491,122,000	431,134,000
Total liabilities and stockholders’ equity	7,337,387,000	4,049,172,000	'	'
Sterling Bancorp [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash	23,369,000	56,230,000	6,716,000	6,692,000
Loan receivable from ESOP	0	6,437,000	'	'
Goodwill	18,970,000	0	'	'
Trade name	20,500,000	0	'	'
Other intangible assets, net	917,000	0	'	'
Other assets	528,000	1,184,000	'	'
Total assets	1,079,844,000	585,029,000	'	'
Senior Notes	98,402,000	98,033,000	'	'
Other liabilities	20,304,000	4,130,000	'	'
Total liabilities	118,706,000	102,163,000	'	'
Stockholders’ equity	961,138,000	482,866,000	'	'
Total liabilities and stockholders’ equity	1,079,844,000	585,029,000	'	'
Sterling National Bank [Member] | Sterling Bancorp [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Investment in Sterling National Bank	1,011,973,000	517,907,000	'	'
Non-bank Subsidiaries[Member] | Sterling Bancorp [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Investment in non-bank subsidiaries	$3,587,000	$3,271,000	'	'

Condensed_Parent_Company_Finan3

Condensed Parent Company Financial Statements - Statements of Income (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Other	'	'	'	'	'	'	'	'	$3,080	$1,998	$2,050
Interest expense	-7,476	-7,310	-7,297	-6,835	-5,795	-4,276	-4,601	-5,222	-28,918	-19,894	-18,573
Non-interest expense	-43,780	-44,904	-46,723	-72,974	-23,367	-21,789	-23,339	-22,546	-208,428	-91,041	-91,957
Income tax benefit	-6,452	-6,057	-4,588	6,948	-3,312	-2,833	-2,203	-3,066	-10,152	-11,414	-6,159
Net income	16,337	15,011	10,332	-14,002	5,329	6,376	6,529	7,020	27,678	25,254	19,888
Sterling Bancorp [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Interest income	'	'	'	'	'	'	'	'	139	262	282
Dividend income on equity securities	'	'	'	'	'	'	'	'	0	22	30
Other	'	'	'	'	'	'	'	'	18	0	10
Interest expense	'	'	'	'	'	'	'	'	-6,265	-1,431	0
Non-interest expense	'	'	'	'	'	'	'	'	-5,841	-2,700	-1,838
Income tax benefit	'	'	'	'	'	'	'	'	3,431	898	87
Income (loss) before equity in undistributed earnings of subsidiaries	'	'	'	'	'	'	'	'	14,732	-1,349	5,071
Net income	'	'	'	'	'	'	'	'	27,677	25,254	19,888
Sterling National Bank [Member] | Sterling Bancorp [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Dividend income from subsidiaries	'	'	'	'	'	'	'	'	22,500	0	6,000
Equity in undistributed (excess distributed) earnings	'	'	'	'	'	'	'	'	12,590	27,174	13,739
Non-bank Subsidiaries[Member] | Sterling Bancorp [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Dividend income from subsidiaries	'	'	'	'	'	'	'	'	750	1,600	500
Equity in undistributed (excess distributed) earnings	'	'	'	'	'	'	'	'	$355	($571)	$1,078

Condensed_Parent_Company_Finan4

Condensed Parent Company Financial Statements - Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'	'
Net income	$27,678	$25,254	$19,888
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
(Gain) on redemption of Subordinated Debentures	-712	0	0
Other adjustments, net	-40,497	26,413	-2,237
Net cash provided by operating activities	127,664	22,624	25,026
Cash flows from investing activities:	'	'	'
Net cash provided by (used in) investing activities	-266,707	-403,098	-291,473
Cash flows from financing activities	'	'	'
Redemption of Subordinated Debentures	-26,140	0	0
Senior Notes offering	0	97,946	0
Cash dividends paid	-17,677	-10,642	-9,100
Net increase (decrease) in cash and cash equivalents	64,529	-324,892	156,470
Cash and cash equivalents at beginning of year	113,090	437,982	281,512
Cash and cash equivalents at end of year	177,619	113,090	437,982
Sterling Bancorp [Member]	'	'	'
Cash flows from operating activities:	'	'	'
Net income	27,677	25,254	19,888
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
Other adjustments, net	-22,066	-5,259	-380
Net cash provided by operating activities	36,086	3,910	5,451
Cash flows from investing activities:	'	'	'
Purchase of securities	0	0	-105
Sales of securities	1,112	818	103
Investment in subsidiaries	-15,000	-45,000	-44,203
ESOP loan principal repayments	6,437	459	441
Net cash provided by (used in) investing activities	-7,451	-43,723	-43,764
Cash flows from financing activities	'	'	'
Net change in other short-term borrowings	-20,659	0	0
Redemption of Subordinated Debentures	-26,140	0	0
Senior Notes offering	0	97,946	0
Equity capital raise	0	0	46,000
Cash dividends paid	-17,677	-10,642	-9,100
Stock option transactions including RRP	2,980	1,758	910
Other equity transactions	0	265	527
Net cash (used for) provided by financing activities	-61,496	89,327	38,337
Net increase (decrease) in cash and cash equivalents	-32,861	49,514	24
Cash and cash equivalents at beginning of year	56,230	6,716	6,692
Cash and cash equivalents at end of year	23,369	56,230	6,716
Sterling National Bank [Member] | Sterling Bancorp [Member]	'	'	'
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
Equity in (undistributed) excess distributed earnings	-12,590	-27,174	-13,739
Non-bank Subsidiaries[Member] | Sterling Bancorp [Member]	'	'	'
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
Equity in (undistributed) excess distributed earnings	($355)	$571	($1,078)

Quarterly_Results_Of_Operation2

Quarterly Results Of Operations (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Interest and dividend income	$67,109	$65,761	$61,325	$52,711	$33,903	$32,593	$32,420	$33,145	$246,906	$132,061	$115,037
Interest expense	7,476	7,310	7,297	6,835	5,795	4,276	4,601	5,222	28,918	19,894	18,573
Net interest income	59,633	58,451	54,028	45,876	28,108	28,317	27,819	27,923	217,988	112,167	96,464
Provisions for loan losses	5,350	5,950	4,800	3,000	2,700	3,900	2,600	2,950	19,100	12,150	10,612
Non-interest income	12,286	13,471	12,415	9,148	6,600	6,581	6,852	7,659	47,370	27,692	32,152
Non-interest expense	43,780	44,904	46,723	72,974	23,367	21,789	23,339	22,546	208,428	91,041	91,957
Income before income tax expense	22,789	21,068	14,920	-20,950	8,641	9,209	8,732	10,086	37,830	36,668	26,047
Income tax expense	6,452	6,057	4,588	-6,948	3,312	2,833	2,203	3,066	10,152	11,414	6,159
Net income	16,337	15,011	10,332	-14,002	5,329	6,376	6,529	7,020	27,678	25,254	19,888
Basic (USD per share)	$0.20	$0.18	$0.12	($0.20)	$0.12	$0.15	$0.15	$0.16	$0.34	$0.58	$0.52
Diluted (USD per share)	$0.19	$0.18	$0.12	($0.20)	$0.12	$0.15	$0.15	$0.16	$0.34	$0.58	$0.52
Business Combination, Separately Recognized Transactions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Merger related expense	'	'	'	9,100	'	'	'	'	9,455	2,772	5,925
Partial settlement charge	'	'	'	2,700	'	'	'	'	'	'	'
Assets Write-down, Retention, and Severance Costs [Member]	'	'	'	'	'	'	'	'	'	'	'
Business Combination, Separately Recognized Transactions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Recognized charges	'	'	'	$22,200	'	'	'	'	'	'	'

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Nov. 05, 2014	Nov. 05, 2014
			Hudson Valley Holding Corp [Member]	Subsequent Event [Member]	Subsequent Event [Member]
				Hudson Valley Holding Corp [Member]	Hudson Valley Holding Corp [Member]
Subsequent Event [Line Items]	'	'	'	'	'
Consideration paid	'	'	'	$539,234	'
Number of shares each shareholder received from merger	'	'	'	1.92	'
Ownership percentage (percent)	'	'	'	'	69.00%
Hudson Valley Holding Corp ownership percentage (percent)	'	'	'	'	31.00%
Pro forma revenue	'	'	363,217	'	'
Net income	'	'	21,962	'	'
Total assets	7,337,387,000	4,049,172,000	'	'	10,703,764
Gross loans	4,760,438,000	2,412,898,000	'	'	6,551,482
Deposits	$5,298,654,000	$2,962,294,000	'	'	$8,071,799