Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 67,557	$ 53,057	$ 41,791
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	8,169	9,808	10,704
Changes in net deferred loan costs, net of amortization	1,068	(150)	(1,007)
Provision for loan losses	4,311	5,129	4,220
Net change in accrued interest receivable, prepaid expenses and other assets, and accrued expenses and other liabilities	5,748	10,195	11,634
Stock based compensation expense	3,231	2,744	2,103
Amortization of intangible assets	4,001	3,819	1,286
Origination of mortgage loans held for sale	(72,216)	(76,101)	(108,696)
Proceeds from sale of mortgage loans held for sale	70,397	79,237	121,482
Earnings on bank owned life insurance	(2,151)	(1,753)	(1,424)
Valuation adjustment on other real estate owned	51	49	0
Loss (gain) on sale of other real estate owned, net	227	0	(144)
Gain on sale of loans, net	(2,424)	(2,759)	(7,696)
Gain on sale of investment securities, net	(330)	(137)	(6)
Gain on sale of assets held for sale	(169)	(798)	(747)
Impairment of assets held for sale	102	75	0
Impairment of assets held for sale	117	0	0
(Gain) loss on sale of premises and equipment, net	(75)	32	13
Net cash provided by operating activities	87,614	82,447	73,513
Cash flows from investing activities:
Loans originated, net of principal payments	(121,266)	(98,563)	(235,154)
Maturities, calls and payments of investment securities available for sale	242,348	92,563	98,894
Purchase of investment securities available for sale	(242,776)	(342,141)	(149,914)
Proceeds from sales of investment securities available for sale	43,962	156,014	31,028
Purchase of premises and equipment	(13,041)	(23,265)	(3,063)
Proceeds from sales of other loans	3,562	9,993	28,874
Proceeds from sales of other real estate owned	864	198	930
Proceeds from sales of assets held for sale	1,664	1,908	1,849
Proceeds from redemption of Federal Home Loan Bank stock	18,032	26,538	30,018
Purchases of Federal Home Loan Bank stock	(18,333)	(22,524)	(30,801)
Proceeds from sales of premises and equipment	96	28	0
Purchase of bank owned life insurance	(8,053)	(54)	(4,394)
Proceeds from bank owned life insurance death benefit	0	0	1,101
Capital contributions to low-income housing tax credit partnerships and new market tax credit partnerships, net	(27,485)	(8,303)	(10,762)
Net cash received from acquisitions	0	105,974	0
Net cash used in investing activities	(120,426)	(101,634)	(241,394)
Cash flows from financing activities:
Net increase in deposits	150,274	214,740	163,412
Federal Home Loan Bank advances	445,800	554,950	763,350
Repayment of Federal Home Loan Bank advances	(445,800)	(663,450)	(750,450)
Common stock cash dividends paid	(30,908)	(25,791)	(18,305)
Net (decrease) increase in securities sold under agreement to repurchase	(11,318)	(796)	9,717
Proceeds from exercise of stock options	58	133	164
Repurchase of common stock	(8,636)	(1,704)	(737)
Net cash provided by financing activities	99,470	78,082	167,151
Net increase (decrease) in cash and cash equivalents	66,658	58,895	(730)
Cash and cash equivalents at beginning of year	161,910	103,015	103,745
Cash and cash equivalents at end of year	228,568	161,910	103,015
Supplemental disclosures of cash flow information:
Cash paid for interest	17,867	12,385	8,399
Cash paid for income taxes, net of refunds	7,528	5,634	2,045
Supplemental non-cash disclosures of cash flow information:
Transfers of loans receivable to other real estate owned	0	434	32
Transfers of properties held for sale recorded in premises and equipment, net to prepaid expenses and other assets	1,533	1,836	2,687
Investment in low income housing tax credit partnership and related funding commitment	46,677	0	33,171
Transfer of bank owned life insurance to prepaid expenses and other assets	209	421	0
Business Combinations:
Common stock issued in business combinations	0	230,043	0
Assets acquired (liabilities assumed) in acquisitions:
Investment securities available for sale	0	84,846	0
Loans receivable	0	718,620	0
Other real estate owned	0	1,796	0
Premises and equipment	0	3,785	0
Federal Home Loan Bank stock	0	1,743	0
Accrued interest receivable	0	2,454	0
Bank owned life insurance	0	17,116	0
Prepaid expenses and other assets	0	2,957	0
Other intangible assets	0	18,345	0
Goodwill	0	121,910	0
Deposits	0	(824,602)	0
Federal Home Loan Bank advances	0	(16,000)	0
Securities sold under agreement to repurchase	0	(462)	0
Accrued expenses and other liabilities	$ 0	$ (8,439)	$ 0