Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INTEREST INCOME:
Interest and fees on loans	$ 271,638	$ 263,320	$ 224,556
Interest on investment securities:
Taxable	47,390	51,456	55,670
Exempt from federal income tax	56,638	48,399	37,075
Interest on federal funds sold and interest-bearing deposits in banks	739	953	1,891
Total interest income	376,405	364,128	319,192
INTEREST EXPENSE:
Interest on deposits	5,705	13,118	27,122
Other	337	1,125	2,980
Total interest expense	6,042	14,243	30,102
Net interest income	370,363	349,885	289,090
PROVISION FOR CREDIT LOSSES	(1,139)	19,517	2,965
Net interest income after provisions for credit losses	371,502	330,368	286,125
NONINTEREST INCOME:
Trust fees	36,145	29,531	28,401
Service charges on deposit accounts	21,156	20,572	22,039
ATM, interchange and credit card fees	38,278	32,469	29,863
Gain on sale and fees on mortgage loans	33,245	43,872	18,144
Net gain on sale of available-for-sale securities	815	3,633	733
Net gain on sale of foreclosed assets	190	159	274
Net gain on sale of assets	210	112	319
Interest on loan recoveries	4,039	856	2,092
Other	8,098	8,731	6,563
Total noninterest income	142,176	139,935	108,428
NONINTEREST EXPENSE:
Salaries and employee benefits	142,042	135,123	112,336
Cost related to termination of pension plan			2,673
Net occupancy expense	13,009	12,388	11,156
Equipment expense	9,173	8,396	9,052
FDIC insurance premiums	3,130	1,758	1,091
ATM, interchange and credit card expenses	11,973	11,235	9,856
Professional and service fees	9,334	9,346	7,853
Printing, stationery and supplies	1,910	2,163	1,812
Operational and other losses	3,293	2,462	1,879
Software amortization and expense	11,120	8,862	7,305
Amortization of intangible assets	1,613	1,990	1,016
Other	35,111	34,215	30,492
Total noninterest expense	241,708	227,938	196,521
EARNINGS BEFORE INCOME TAXES	271,970	242,365	198,032
INCOME TAX EXPENSE	44,408	40,331	33,220
NET EARNINGS	$ 227,562	$ 202,034	$ 164,812
NET EARNINGS PER SHARE, BASIC	$ 1.60	$ 1.42	$ 1.22
NET EARNINGS PER SHARE, DILUTED	1.59	1.42	1.21
DIVIDENDS PER SHARE	$ 0.58	$ 0.51	$ 0.47