Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest and dividend income:
Interest and fees on loans	$ 367,585	$ 372,152	$ 402,092
Taxable interest and dividends on available for sale securities	58,312	31,825	31,400
Non-taxable interest and dividends on available for sale securities	7,376	7,588	8,306
Interest on federal funds sold and other short-term investments	1,886	1,757	2,977
Interest and dividends on trading securities	0	6	242
Total interest and dividend income	435,159	413,328	445,017
Interest expense:
Interest on deposits	5,167	11,315	27,301
Interest on borrowings	165	762	6,452
Total interest expense	5,332	12,077	33,753
Net interest income	429,827	401,251	411,264
(Release of) provision for loan losses	(9,686)	38,800	6,300
Net interest income after (release of) provision for loan losses	439,513	362,451	404,964
Noninterest income:
Insurance commissions	94,704	94,495	90,587
Service charges on deposit accounts	24,271	21,560	27,043
Trust and investment advisory fees	24,588	21,102	19,653
Debit card processing fees	12,118	10,277	10,452
Interest rate swap income (losses)	5,634	(1,381)	4,362
Income from investments held in rabbi trusts	10,217	10,337	9,866
(Losses) gains on trading securities, net	0	(4)	1,297
Gains on sales of mortgage loans held for sale, net	3,605	7,066	795
Gains on sales of securities available for sale, net	1,166	288	2,016
Other	16,852	14,633	16,228
Total noninterest income	193,155	178,373	182,299
Noninterest expense:
Salaries and employee benefits	295,916	261,827	252,238
Office occupancy and equipment	40,465	33,796	36,458
Data processing	50,839	45,259	45,939
Professional services	24,477	18,902	15,958
Charitable contributions	0	95,272	12,905
Marketing	8,741	8,879	9,619
Operating Costs and Expenses	7,786	2,493	3,215
Loan expenses	6,516	6,727	4,593
FDIC insurance	4,226	3,734	1,878
Amortization of intangible assets	2,512	2,857	3,542
Other	2,478	25,177	26,339
Total noninterest expense	443,956	504,923	412,684
Income before income tax expense	188,712	35,901	174,579
Income tax expense	34,047	13,163	39,481
Net income	$ 154,665	$ 22,738	$ 135,098
Basic earnings per share (in dollars per share)	$ 0.90	$ 0.13	$ 0
Diluted earnings per share (in dollars per share)	$ 0.90	$ 0.13	$ 0