Consolidated Statements Of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net income	$ 57,203,000	$ 53,071,000	$ 28,476,000
Adjustments to reconcile net income to net cash provided by operating activities:
Originations of mortgage loans held for sale	(282,443,000)	(202,194,000)	(211,568,000)
Proceeds from the sale of mortgage loans	281,207,000	211,397,000	224,883,000
Gain on sale of mortgage loans, net of origination costs	(6,365,000)	(5,451,000)	(6,256,000)
Provision for credit losses	2,861,000	847,000	3,035,000
Depreciation and amortization expense	3,891,000	3,765,000	3,761,000
Investment securities amortization and accretion, net	2,997,000	3,206,000	3,122,000
Stock-based compensation expense	1,885,000	1,688,000	1,469,000
Amortization of intangible assets	705,000	725,000	1,809,000
Purchase accounting accretion, net	(1,483,000)	(2,316,000)	(2,834,000)
(Increase) decrease in other assets	(22,405,000)	(6,679,000)	11,190,000
(Decrease) increase in other liabilities	(5,182,000)	6,275,000	1,247,000
Net cash provided by operating activities	32,871,000	64,334,000	58,334,000
Investing Activities
Proceeds from sales and maturities of available-for-sale securities	355,611,000	189,420,000	154,973,000
Purchase of available-for-sale securities	(339,286,000)	(232,206,000)	(170,495,000)
Proceeds from maturities of held-to-maturity securities	0	750,000	0
Net increase in loans	(70,714,000)	(243,815,000)	(187,740,000)
Purchase of bank-owned life insurance	0	0	(7,000,000)
Purchase of Federal Home Loan Bank stock	(13,688,000)	(15,127,000)	(12,290,000)
Proceeds from sale of Federal Home Loan Bank and Federal Reserve Bank stock	15,645,000	24,864,000	11,823,000
Purchase of premises and equipment	(4,267,000)	(5,021,000)	(2,844,000)
Proceeds from the sale of premises and equipment	0	749,000	137,000
Proceeds from other investments	0	1,593,000	0
Recoveries of previously charged-off loans	310,000	1,944,000	497,000
Proceeds from sale of other real estate owned	554,000	72,000	808,000
Net cash used by investing activities	(55,835,000)	(276,777,000)	(212,131,000)
Financing Activities
Net increase in deposits	73,335,000	464,132,000	172,291,000
(Repayments of) net proceeds from borrowings less than 90 days	(2,059,000)	(270,114,000)	36,699,000
Repayments of Federal Home Loan Bank long-term advances	0	0	(20,000,000)
Repayments of wholesale repurchase agreements	0	0	(5,000,000)
Common stock repurchases	(20,795,000)	(27,000)	0
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings	(202,000)	(350,000)	(606,000)
Cash dividends paid on common stock	(18,572,000)	(17,170,000)	(14,323,000)
Finance lease payments	(106,000)	0	0
Net cash provided by financing activities	31,601,000	176,471,000	169,061,000
Net increase (decrease) in cash, cash equivalents and restricted cash	8,637,000	(35,972,000)	15,264,000
Cash, cash equivalents and restricted cash at beginning of year	66,999,000	102,971,000	87,707,000
Cash, cash equivalents and restricted cash at end of year	75,636,000	66,999,000	102,971,000
Supplemental information
Interest paid	41,374,000	30,177,000	20,774,000
Income taxes paid	13,542,000	10,667,000	16,841,000
Transfer from loans to other real estate owned	$ 543,000	$ 55,000	$ 0