Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net income		$ 154,885	$ 104,388	$ 121,021
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	[1]	(8,257)	51,134	25,412
Depreciation and amortization of premises and equipment		9,896	9,772	9,497
Net amortization on securities		5,832	4,369	3,375
Amortization of intangible assets		2,808	3,395	3,579
Amortization of operating lease right-of-use assets		7,176	7,382	7,239
Excess tax benefit on stock-based compensation		(385)	(181)	(409)
Stock-based compensation expense		4,414	4,581	4,210
Bank owned life insurance income		(6,217)	(5,743)	(5,355)
Amortization of subordinated debt issuance costs		438	230	0
Proceeds from sale of loans held for sale		55,065	168,707	175,829
Originations of loans held for sale		(54,608)	(158,279)	(181,261)
Net gains on sale of loans held for sale		(361)	(1,989)	(786)
Net security (gains) losses		(566)	388	(4,213)
Net losses (gains) on sale of other real estate owned		182	(96)	227
Lease termination losses		0	4,284	1,872
Net change in other assets and other liabilities		(12,667)	(49,930)	(6,774)
Net cash provided by operating activities		157,635	142,412	153,463
Investing activities
Net cash used in acquisitions		0	(3,899)	0
Securities available for sale:
Proceeds from maturities, calls and principal paydowns		395,386	336,410	273,578
Proceeds from sales		0	0	26,203
Purchases		(775,963)	(689,932)	(252,963)
Securities held to maturity:
Proceeds from maturities, calls and principal paydowns		181,620	243,136	223,733
Proceeds from sales		0	996	0
Purchases		(299,014)	(230,951)	(70,660)
Equity securities:
Proceeds from calls		1,000	2,000	0
Proceeds from sales		0	0	3,966
Purchases		0	0	(93)
Other:
Net increase in loans		(9,305)	(378,765)	(272,698)
Proceeds from Federal Home Loan Bank stock redemption		2,422	63,305	182,752
Purchases of Federal Reserve Bank and Federal Home Loan Bank stock		(167)	(46,038)	(174,143)
Proceeds from settlement of bank owned life insurance		4,413	1,057	1,086
Purchase of bank owned life insurance		(40,000)	0	0
Purchases of premises and equipment, net		(7,740)	(8,157)	(6,647)
Proceeds from sales of other real estate owned		1,290	1,113	1,543
Net cash provided by (used in) investing activities		(546,058)	(709,725)	(64,343)
Financing activities
Net increase in deposits		1,152,777	1,493,872	219,609
Net decrease in short-term borrowings		(70,592)	(486,889)	(216,421)
Proceeds from issuance of subordinated debt		0	100,000	0
Payment of subordinated debt issuance costs		0	(2,178)	0
Proceeds from issuance of long-term debt		0	0	10,598
Repayments of long-term debt		(25,101)	(25,114)	(20,111)
Proceeds from the issuance of shares to employee and other stock plans		112	184	725
Cash paid by employer for tax-withholding on stock issuance		(2,931)	(1,537)	(1,622)
Purchase of treasury stock		(21,714)	(7,980)	0
Cash dividends		(47,738)	(47,207)	(46,010)
Net cash provided by (used in) financing activities		984,813	1,023,151	(53,232)
Net increase in cash and cash equivalents		596,390	455,838	35,888
Cash and cash equivalents at beginning of year		672,681	216,843	180,955
Cash and cash equivalents at end of year		1,269,071	672,681	216,843
Cash paid during the period for:
Interest expense		20,285	31,692	55,908
Income taxes paid, net of refund		46,097	45,790	28,374
Noncash investing activities:
Loans transferred to other real estate owned		181	1,017	787
Acquisitions:
Fair value of assets acquired		$ 0	$ 3,328	$ 0

[1] Beginning January 1, 2020, calculation is based on current expected loss methodology. Prior to January 1, 2020, calculation was based on incurred loss methodology.