CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income		$ 69,829	$ 69,118	$ 68,432
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses		12,342	1,575	1,550
Depreciation of premises and equipment		3,176	3,291	3,282
Net amortization of premiums and discounts on securities and loans		5,720	4,492	2,865
Amortization of intangibles		914	943	979
Share–based compensation		3,766	3,124	2,602
Tax (expense) benefit from stock option exercises and other equity awards		(103)	248	496
Deferred income tax benefit		(3,130)	(1,491)	(63)
Income from bank-owned life insurance	[1]	(2,491)	(2,354)	(2,196)
Net gains on loan sales, including fair value adjustments		(48,005)	(14,332)	(9,749)
Net realized losses on securities	[1]	0	53	0
Proceeds from sales of loans, net		1,117,188	530,713	391,960
Loans originated for sale		(1,114,448)	(525,675)	(378,896)
Change in fair value of contingent consideration liability		0	0	(187)
(Increase) decrease in operating lease right-of-use assets		(2,729)	2,131	0
Increase (decrease) in operating lease liabilities		2,856	(1,992)	0
Increase in other assets		(57,730)	(27,961)	(7,456)
Increase in other liabilities		49,323	31,552	9,257
Net cash provided by (used in) operating activities		36,478	73,435	82,876
Cash flows from investing activities:
Purchases of mortgage-backed available for sale debt securities		(369,166)	(178,797)	(175,539)
Purchases of other available for sale debt securities		(149,899)	(27,520)	(76,264)
Proceeds from sale of other available for sale debt securities		0	11,877	0
Maturities and principal payments of mortgage-backed available for sale debt securities		351,161	147,620	83,197
Maturities and principal payments of other available for sale debt securities		176,000	108,306	7,301
Maturities, calls and principal payments of held-to-maturity debt securities: MBS		0	0	2,029
Net redemption (purchases) of Federal Home Loan Bank stock		20,568	(4,785)	(5,551)
Net increase in loans		(241,418)	(154,502)	(306,299)
Purchases of loans		(51,659)	(60,465)	(1,780)
Proceeds from the sale of property acquired through foreclosure or repossession		1,392	2,000	49
Purchases of premises and equipment		(3,406)	(3,132)	(3,974)
Proceeds from sale of premises		0	213	0
Purchases of bank-owned life insurance		0	0	(5,000)
Proceeds from sale of equity investment in real estate limited partnership		1,400	0	0
Proceeds from bank-owned life insurance		787	326	0
Equity investment in real estate limited partnership		0	(1,256)	0
Net cash provided by (used in) investing activities		(264,240)	(160,115)	(481,831)
Cash flows from financing activities:
Net increase (decrease) in deposits		879,471	(25,166)	281,341
Proceeds from Federal Home Loan Bank advances		1,988,500	1,982,000	2,040,000
Repayment of Federal Home Loan Bank advances		(2,536,105)	(1,791,258)	(1,880,634)
Proceeds from Payment Protection Program Lending Facility		200,628	0	0
Repayment of Payment Protection Program Lending Facility		(200,628)	0	0
Payment of contingent consideration liability		0	0	(1,217)
Treasury stock purchased		(4,322)	0	0
Net proceeds from stock option exercises and issuance of other equity awards, net of awards surrendered		(470)	273	(671)
Cash dividends paid		(35,499)	(34,189)	(29,312)
Net cash provided by (used in) financing activities		291,575	131,660	409,507
Net increase in cash and cash equivalents		63,813	44,980	10,552
Cash and cash equivalents at beginning of year		138,455	93,475	82,923
Cash and cash equivalents at end of year		202,268	138,455	93,475
Noncash Activities:
Loans charged-off		1,317	2,020	1,187
Loans transferred to property acquired through foreclosure or repossession		313	2,000	3,074
Operating lease right-of-use assets		0	28,923	0
Operating lease liabilities		0	30,853	0
Fair value of held-to-maturity securities transferred to available for sale		0	10,316	0
Supplemental Disclosures:
Interest payments		45,294	64,496	41,285
Income tax payments		$ 21,094	$ 19,759	$ 17,148

[1] As reported in the Consolidated Statements of Income.