Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 12,018	$ 4,205
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of premises and equipment	1,527	973
Allocation of ESOP stock	245	149
Stock awards	730	330
Tax expense of stock plans	3,916	(270)
Amortization of servicing asset	25	45
Net premium amortization in excess of discount accretion on securities	468	388
Net amortization of deferred costs and discounts on borrowings	32	128
Amortization of core deposit intangible	524	13
Net accretion of purchase accounting adjustments	(2,169)	(164)
Net amortization of deferred costs and discounts on loans	30	0
Provision for loan losses	700	563
Net loss on sale of other real estate owned	366	65
Net loss on sale of fixed assets	7
Net gain on sales of loans	(42)	(179)
Proceeds from sales of mortgage loans held for sale	1,949	9,080
Mortgage loans originated for sale	(639)	(9,590)
Increase in value of Bank Owned Life Insurance	(772)	(319)
Increase in interest and dividends receivable	(269)	(161)
(Increase) decrease in other assets	(5,141)	428
(Decrease) increase in other liabilities	(1,552)	2,206
Total adjustments	(65)	3,685
Net cash provided by operating activities	11,953	7,890
Cash flows from investing activities:
Net increase in loans receivable	(16,292)	(14,382)
Purchase of loans receivable	(5,029)	(12,942)
Purchase of investment securities available-for-sale	(34,770)
Purchase of investment securities held-to-maturity	(42,497)	0
Purchase of MBS securities held-to-maturity	(79,984)
Proceeds from maturities and calls of investment securities held-to-maturity	1,375	6,135
Principal repayments on mortgage-backed securities held-to-maturity	23,696	13,029
Proceeds from Bank Owned Life Insurance	155
Proceeds from the redemption of Federal Home Loan Bank of New York stock	60	5,706
Purchases of Federal Home Loan Bank of New York stock	0	(2,373)
Proceeds from sales of other real estate owned	868	208
Purchases of premises and equipment	(961)	(876)
Cash acquired, net of cash paid for branch acquisition	0	16,727
Net cash (used in) provided by investing activities	(153,379)	11,232
Cash flows from financing activities:
Increase in deposits	11,204	37,771
Increase (decrease) in short-term borrowings	7,271	(73,959)
Proceeds from Federal Home Loan Bank advances	0	10,000
Repayments of Federal Home Loan Bank advances	(477)	(468)
Increase in advances by borrowers for taxes and insurance	846	150
Exercise of stock options	2,204	95
Payment of employee taxes withheld from stock awards	(956)	(199)
Dividends paid	(4,787)	(2,197)
Net cash provided by (used in) financing activities	15,305	(28,807)
Net decrease in cash and due from banks	(126,121)	(9,685)
Cash and due from banks at beginning of period	301,373	43,946
Cash and due from banks at end of period	175,252	34,261
Supplemental Disclosure of Cash Flow Information:
Interest	5,266	2,485
Income taxes	2	0
Non-cash activities:
Accretion of unrealized loss on securities reclassified to held-to-maturity	293	366
Net loan recoveries (charge-offs)	268	(1,071)
Transfer of loans receivable to other real estate owned	$ 318	$ 475