Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 19,698	$ 7,866
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of premises and equipment	3,111	2,131
Allocation of ESOP stock	473	301
Stock awards	1,204	756
Tax expense of stock plans	0	(260)
Net excess tax benefit on stock compensation	(1,543)	0
Amortization of servicing asset	47	87
Net premium amortization in excess of discount accretion on securities	1,190	849
Net amortization of deferred costs and discounts on borrowings	64	0
Amortization of core deposit intangible	1,037	138
Net accretion of purchase accounting adjustments	(4,061)	(1,431)
Net amortization of deferred costs and discounts on loans	172	26
Provision for loan losses	1,865	1,225
Net loss on sale of other real estate owned	379	145
Write down of fixed assets held for sale to net realizable value	4,982	0
Net loss on sale of fixed assets	7	0
Net loss on sales of available-for-sale securities	0	12
Net gain on sales of loans	(57)	(349)
Proceeds from sales of mortgage loans held for sale	2,830	19,555
Mortgage loans originated for sale	(1,390)	(21,819)
Increase in value of Bank Owned Life Insurance	(1,555)	(861)
Increase in interest and dividends receivable	(1,047)	(756)
Decrease in other assets	3,754	9,172
Decrease in other liabilities	(961)	(857)
Total adjustments	10,501	8,064
Net cash provided by operating activities	30,199	15,930
Cash flows from investing activities:
Net (increase) decrease in loans receivable	(48,758)	9,648
Purchase of loans receivable	(16,627)	(12,942)
Purchase of investment securities available-for-sale	(49,812)	0
Purchase of investment securities held-to-maturity	(77,144)	0
Purchase of mortgage-backed securities held-to-maturity	(100,015)	0
Proceeds from maturities and calls of investment securities held-to-maturity	7,375	19,635
Proceeds from sales of securities available-for-sale	0	59,211
Principal repayments on mortgage-backed securities held-to-maturity	47,361	31,037
Proceeds from Bank Owned Life Insurance	155	155
Proceeds from the redemption of Federal Home Loan Bank of New York stock	3,740	26,559
Purchases of Federal Home Loan Bank of New York stock	(4,785)	(20,927)
Proceeds from sales of other real estate owned	1,500	1,714
Purchases of premises and equipment	(1,991)	(1,381)
Cash (received) acquired, net of cash consideration paid for acquisition	0	(477)
Cash acquired, net of cash paid for branch acquisition	0	16,727
Net cash (used in) provided by investing activities	(239,001)	128,959
Cash flows from financing activities:
(Decrease) increase in deposits	(10,331)	24,496
Increase (decrease) in short-term borrowings	28,114	(116,400)
Proceeds from Federal Home Loan Bank advances	5,000	55,000
Repayments of Federal Home Loan Bank advances	(957)	(73,048)
Repayments of other borrowings	0	(10,000)
Increase in advances by borrowers for taxes and insurance	1,006	1,778
Exercise of stock options	3,031	1,286
Payment of employee taxes withheld from stock awards	(1,217)	(244)
Dividends paid	(9,557)	(5,481)
Net cash provided by (used in) financing activities	15,089	(122,613)
Net (decrease) increase in cash and due from banks	(193,713)	22,276
Cash and due from banks at beginning of period	301,373	43,946
Cash and due from banks at end of period	107,660	66,222
Supplemental Disclosure of Cash Flow Information:
Interest	9,702	5,507
Income taxes	2	4,664
Non-cash activities:
Accretion of unrealized loss on securities reclassified to held-to-maturity	565	679
Net loan charge-offs		1,269
Transfer of premises and equipment to assets held-for-sale	5,754	0
Transfer of loans receivable to other real estate owned	1,317	888
Non-cash assets acquired:
Securities	0	212,156
Federal Home Loan Bank of New York stock	0	6,782
Loans	0	1,156,980
Premises & equipment	0	21,723
Other real estate owned	0	1,935
Deferred tax asset	0	22,054
Other assets	0	61,793
Goodwill and other intangible assets, net	0	68,739
Total non-cash assets acquired	0	1,552,162
Liabilities assumed:
Deposits	0	1,248,367
Federal Home Loan Bank advances	0	124,466
Other liabilities	0	12,951
Total liabilities assumed	$ 0	$ 1,385,784