Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income	$ 64,916	$ 46,209	$ 44,239
Adjustments to reconcile net income to net cash provided by operating activities:
Benefit for loan losses	0	(956)	(6,021)
Depreciation and amortization of bank premises and equipment	4,450	3,579	2,813
Net gain on sales of loans (including delinquent loans)	(584)	(422)	(67)
Net gain on sales of securities	(1,524)	(167)	(2,875)
Net gain on sales of buildings	(48,018)	(6,537)	0
Amortization of premium, net of accretion of discount	8,453	8,986	7,292
Fair value adjustment for financial assets and financial liabilities	3,434	1,841	2,568
Income from bank owned life insurance	(2,797)	(2,880)	(3,050)
Gain from life insurance proceeds	(460)	0	0
Stock-based compensation expense	5,884	4,845	4,263
Deferred compensation	(4,033)	(3,561)	(2,514)
Excess tax benefits from stock-based payment arrangements	(712)	(574)	(846)
Deferred income tax provision (benefit)	(1,540)	(5,210)	4,154
(Increase) decrease in other assets	5,170	(5,284)	8,110
Increase (decrease) in other liabilities	9,756	4,861	(690)
Net cash provided by operating activities	42,395	44,730	57,376
Investing Activities
Purchases of premises and equipment	(6,655)	(11,089)	(4,325)
Net purchases of Federal Home Loan Bank-NY shares	(3,107)	(9,142)	(899)
Purchases of securities held-to-maturity	(40,205)	(5,100)	0
Proceeds from maturities of securities held-to-maturity	8,515	3,430	0
Purchases of securities available for sale	(139,186)	(313,822)	(162,830)
Proceeds from sales and calls of securities available for sale	143,819	163,158	115,294
Proceeds from maturities and prepayments of securities available for sale	118,498	114,097	112,137
Proceeds from sale of buildings	49,284	20,209
Purchase of Bank Owned Life Insurance	(16,000)	0	0
Proceeds from Life Insurance	2,432	0	0
Net originations of loans	(267,446)	(301,766)	(248,073)
Purchases of loans	(186,717)	(278,928)	(169,860)
Proceeds from sale of loans	11,499	16,252	15,857
Proceeds from sale of Other Real Estate Owned, net	3,037	2,185	3,123
Net cash used in investing activities	(322,232)	(600,516)	(339,576)
Financing Activities
Net increase in non interest-bearing deposits	63,694	13,635	58,491
Net increase in interest-bearing deposits	245,271	368,137	213,502
Net increase in mortgagors' escrow deposits	3,372	1,165	2,881
Net proceeds from short-term borrowed funds	178,500	30,000	30,500
Proceeds from long-term borrowings	300,000	310,000	180,000
Repayment of long-term borrowings	(562,401)	(125,551)	(167,081)
Issuance of subordinated debentures, net of issuance costs of $1,598	73,402	0	0
Purchases of treasury stock	(9,858)	(15,605)	(18,872)
Excess tax benefits from stock-based payment arrangements	712	574	846
Proceeds from issuance of common stock upon exercise of stock options	328	145	565
Cash dividends paid	(19,689)	(18,616)	(17,852)
Net cash provided by financing activities	273,331	563,884	282,980
Net (decrease) increase in cash and cash equivalents	(6,506)	8,098	780
Cash and cash equivalents, beginning of year	42,363	34,265	33,485
Cash and cash equivalents, end of year	35,857	42,363	34,265
Supplemental Cash Flow Disclosure
Interest paid	53,755	48,467	53,965
Income taxes paid	36,813	32,574	24,943
Taxes paid if excess tax benefits on stock-based compensation were not tax deductible	37,525	33,148	25,789
Non-cash activities:
Securities transferred from available for sale to held-to-maturity	0	4,510	0
Loans transferred to Other Real Estate Owned	639	1,667	7,112
Loans provided for the sale of Other Real Estate Owned	0	280	712
Loans held for investment transferred to loans held for sale	$ 0	$ 300	$ 1,150