CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows Provided by (Used in) Operating Activities
Net income	$ 123,449	$ 100,344	$ 102,953
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	(15,101)	38,797	10,406
Amortization of intangible assets	11,274	10,008	9,547
Amortization of mortgage servicing rights	5,292	5,667	2,710
Depreciation and amortization of premises and equipment	11,610	12,273	11,879
Net amortization (accretion) on portfolio loans	(11,545)	(15,372)	(3,383)
Net amortization (accretion) of premium (discount) on investment securities	24,251	9,716	6,106
Net amortization (accretion) of premium (discount) on time deposits	(1,142)	(933)	(1,648)
Net amortization (accretion) of premium (discount) on FHLB advances and other borrowings	826	586	309
Impairment of OREO	1	68	62
Impairment of fixed assets held for sale	3,227	6,901	2,026
Impairment of mortgage servicing rights	(639)	648
Amortization of NMTC	5,563	2,311	1,200
Impairment of leases			348
Change in fair value of equity securities, net	(3,041)	393	759
(Gain) loss on sales of equity securities, net			(8)
(Gain) loss on sales of debt securities, net	(29)	(1,724)	(733)
(Gain) loss on sales of loans, net	(9,323)	(26,999)	(16,819)
(Gain) loss on sales of OREO	174	(133)	(102)
(Gain) loss on sales of premises and equipment	(1,023)	286	113
(Gain) loss on life insurance proceeds	(1,257)	(1,270)	(1,604)
(Increase) decrease in cash surrender value of bank owned life insurance	(3,909)	(4,110)	(4,191)
Provision for deferred income taxes	4,665	(5,309)	96
Stock-based compensation	7,864	7,135	3,997
Increase (decrease) in deferred compensation			(6,781)
Mortgage loans originated for sale	(274,356)	(881,398)	(667,515)
Proceeds from sales of mortgage loans	306,074	920,050	641,778
Net change in operating assets and liabilities:
(Increase) decrease in other assets	7,203	(8,210)	4,197
Increase (decrease) in other liabilities	(28,096)	(6,551)	(7,380)
Net cash provided by (used in) operating activities	162,012	163,174	88,322
Cash Flows Provided by (Used in) Investing Activities
Purchases of equity securities	(11,017)	(13,123)	(550)
Purchases of debt securities available for sale	(2,298,055)	(1,282,199)	(408,941)
Purchases of FHLB stock			(3,700)
Proceeds from sales of equity securities	7,254	13,152	1,474
Proceeds from sales of debt securities available for sale	290,955		227,371
Proceeds from paydowns and maturities of debt securities held to maturity			14,422
Proceeds from paydowns and maturities of debt securities available for sale	868,083	665,744	541,753
Proceeds from the redemption of FHLB stock			5,369
Net cash received in (paid for) acquisitions (see Note 2)	228,279		(61,481)
Net (increase) decrease in loans	76,826	(113,744)	(251,855)
Cash paid for premiums on bank-owned life insurance	(124)	(120)	(6)
Proceeds from life insurance	4,755	2,696	3,915
Purchases of premises and equipment	(5,042)	(4,198)	(13,238)
Proceeds from disposition of premises and equipment	7,306	814	424
Capitalized expenditures on OREO			(2)
Proceeds from sales of OREO	1,590	1,439	2,481
Net cash provided by (used in) investing activities	(829,190)	(729,539)	57,436
Cash Flows Provided by (Used in) Financing Activities
Net increase (decrease) in deposits	767,474	776,386	215,519
Net change in federal funds purchased and securities sold under agreements to repurchase	77,874	(29,877)	(30,904)
Proceeds from FHLB advances	5,000	4,000
Repayment of FHLB advances	(4,658)	(32,711)	(24,667)
Proceeds from other borrowings	72,500	142,634	60,000
Repayment of other borrowings	(18,500)	(74,000)	(6,000)
Cash dividends paid	(50,764)	(48,012)	(45,171)
Purchase of treasury stock	(33,043)	(12,272)	(24,292)
Cash paid for withholding taxes on stock-based payments	(997)	(635)	(863)
Proceeds from stock options exercised		101	169
Common stock issuance costs	(150)		(234)
Net cash provided by (used in) financing activities	814,736	725,614	143,557
Net increase (decrease) in cash and cash equivalents	147,558	159,249	289,315
Cash and cash equivalents, beginning of period	688,537	529,288	239,973
Cash and cash equivalents, ending of period	836,095	688,537	529,288
Cash payments for:
Interest	25,374	53,601	70,577
Income taxes	12,542	22,195	24,725
Non-cash investing and financing activities:
OREO acquired in settlement of loans	1,610	$ 2,867	4,872
Transfer of loans held for sale to portfolio loans	$ (4,808)
Transfer of debt securities held to maturity to available for sale			$ 593,548