Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 53,057	$ 41,791	$ 38,918
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of premises and equipment, amortization of securities available for sale, and amortization of discount of junior subordinated debentures	9,808	10,704	12,709
Changes in net deferred loan costs, net of amortization	(150)	(1,007)	(1,422)
Provision for loan losses	5,129	4,220	4,931
Net change in accrued interest receivable, prepaid expenses and other assets, accrued expenses and other liabilities	10,195	11,634	2,147
Stock-based compensation expense	2,744	2,103	1,840
Net excess tax benefit from exercise of stock-based compensation	0	0	(123)
Amortization of intangible assets	3,819	1,286	1,415
Origination of loans held for sale	(76,101)	(108,696)	(145,107)
Proceeds from sale of loans	79,237	121,482	148,121
Earnings on bank owned life insurance	(1,753)	(1,424)	(1,460)
Valuation adjustment on other real estate owned	49	0	383
Gain on sale of loans, net	(2,759)	(7,696)	(6,994)
Gain on sale of investment securities, net	(137)	(6)	(1,315)
Gain on sale of assets held for sale	(798)	(747)	0
Loss on sale of other real estate owned	0	(144)	(173)
Impairment of assets held for sale	75	0	0
Loss on sale or write-off of furniture, equipment and leasehold improvements	32	13	110
Net cash provided by operating activities	82,447	73,513	53,980
Cash flows from investing activities:
Loans originated, net of principal payments	(98,563)	(235,154)	(263,387)
Maturities of other interest earning deposits	0	0	6,709
Maturities, calls and payments of investment securities available for sale	92,563	98,894	129,408
Purchase of investment securities available for sale	(342,141)	(149,914)	(267,657)
Purchase of premises and equipment	(23,265)	(3,063)	(6,722)
Proceeds from sales of other loans	9,993	28,874	21,077
Proceeds from sales of other real estate owned	198	930	2,486
Proceeds from sales of investment securities available for sale	156,014	31,028	140,373
Proceeds from sales of assets held for sale	1,908	1,849	0
Proceeds from redemption of Federal Home Loan Bank stock	26,538	30,018	23,732
Purchases of Federal Home Loan Bank stock	(22,524)	(30,801)	(27,148)
Proceeds from sales of premises and equipment	28	0	659
Purchase of bank owned life insurance	(54)	(4,394)	(8,000)
Proceeds from BOLI death benefit	0	1,101	0
Capital contributions to low-income housing tax credit partnerships and new market tax credit partnerships, net	(8,303)	(10,762)	(4,456)
Net cash received from acquisitions	105,974	0	0
Net cash used in investing activities	(101,634)	(241,394)	(252,926)
Cash flows from financing activities:
Net increase in deposits	214,740	163,412	121,361
Federal Home Loan Bank advances	554,950	763,350	660,900
Repayments of Federal Home Loan Bank advances	(663,450)	(750,450)	(581,300)
Common stock cash dividends paid	(25,791)	(18,305)	(21,569)
Net (decrease)/increase in securities sold under agreement to repurchase	(796)	9,717	(1,110)
Proceeds from exercise of stock options	133	164	540
Net excess tax benefit from exercise of stock-based compensation	0	0	123
Repurchase of common stock	(1,704)	(737)	(2,894)
Net cash provided by financing activities	78,082	167,151	176,051
Net increase (decrease) in cash and cash equivalents	58,895	(730)	(22,895)
Cash and cash equivalents at beginning of year	103,015	103,745	126,640
Cash and cash equivalents at end of year	161,910	103,015	103,745
Supplemental disclosures of cash flow information:
Cash paid for interest	12,385	8,399	5,998
Cash paid for income taxes	5,634	2,045	11,500
Supplemental non-cash disclosures of cash flow information:
Transfers of loans receivable to other real estate owned	434	32	1,431
Transfers of properties held for sale recorded in premises and equipment, net to prepaid expenses and other assets	1,836	2,687	0
Transfer of BOLI to prepaid expenses and other assets	421	0	0
Investment in low income housing tax credit partnership and related funding commitment	0	33,171	19,663
Business Combinations:
Common stock issued in business combinations	230,043	0	0
Assets acquired (liabilities assumed) in acquisitions:
Investment securities available for sale	84,846	0	0
Loans receivable	718,620	0	0
Other real estate owned	1,796	0	0
Premises and equipment	3,785	0	0
Federal Home Loan Bank stock	1,743	0	0
Accrued interest receivable	2,454	0	0
Bank owned life insurance	17,116	0	0
Prepaid expenses and other assets	2,957	0	0
Other intangible assets	18,345	0	0
Goodwill	121,910	0	0
Deposits	(824,602)	0	0
Federal Home Loan Bank advances	(16,000)	0	0
Securities sold under agreement to repurchase	(462)	0	0
Accrued expenses and other liabilities	$ (8,439)	$ 0	$ 0