Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INTEREST INCOME
Loans, including fees	$ 316,124	$ 311,987	$ 291,519
Debt securities:
Taxable	6,327	8,591	13,308
Tax-exempt	204	487	458
Federal funds sold			4
Interest-bearing deposits with banks	4,366	6,049	31,368
Total interest income	327,021	327,114	336,657
INTEREST EXPENSE
Deposits	8,232	18,472	52,738
Short-term borrowings	2	8	32
Subordinated debt	3,130	1,966	1,966
Total interest expense	11,364	20,446	54,736
Net interest income	315,657	306,668	281,921
(Benefit from) provision for credit losses	(8,690)	62,648	8,287
Net interest income after provision for credit losses	324,347	244,020	273,634
NONINTEREST INCOME
Securities transactions (includes no accumulated other comprehensive income reclassifications)	1,047	(389)	812
Income from sales of loans	7,282	6,067	3,619
Insurance commissions	23,745	20,996	20,296
Cash management	12,313	15,411	16,866
Gain/(loss) on sale of other assets	2,762	130	(39)
Other	26,546	7,439	5,495
Total noninterest income	170,032	137,222	137,229
NONINTEREST EXPENSE
Salaries and employee benefits	166,723	164,727	153,024
Occupancy, net	18,483	16,421	12,704
Depreciation	16,925	14,609	12,623
Amortization of intangible assets	3,116	3,815	3,366
Data processing services	6,735	6,753	5,843
Net expense/(income) from other real estate owned	9,089	(1,531)	(785)
Marketing and business promotion	7,403	6,996	8,554
Deposit insurance	3,456	2,081	1,143
Other	54,051	43,859	44,829
Total noninterest expense	285,981	257,730	241,301
Income before taxes	208,398	123,512	169,562
Income tax expense	40,768	23,926	34,683
Net income	$ 167,630	$ 99,586	$ 134,879
NET INCOME PER COMMON SHARE
Basic	$ 5.12	$ 3.05	$ 4.13
Diluted	$ 5.03	$ 3.00	$ 4.05
OTHER COMPREHENSIVE GAIN/(LOSS)
Unrealized (losses)/gains on securities, net of tax of $1,829, $(1,326) and $(1,918), respectively	$ (5,280)	$ 3,976	$ 5,593
Other comprehensive (loss)/gain, net of tax of $1,829, $(1,326) and $(1,918), respectively	(5,280)	3,976	5,593
Comprehensive income	162,350	103,562	140,472
Trust Revenue [Member]
NONINTEREST INCOME
Revenue	12,912	13,130	13,599
Service Charges on Deposits [Member]
NONINTEREST INCOME
Revenue	$ 83,425	$ 74,438	$ 76,581