Consolidated Statements of Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest, fee and dividend income
Interest and fees on loans		$ 307,859	$ 321,474	$ 300,827
Securities available for sale		22,434	23,303	26,920
Securities held to maturity		15,283	19,105	13,242
Other		2,706	3,652	3,266
Total interest, fee and dividend income		348,282	367,534	344,255
Interest expense
Deposits		22,070	39,986	22,144
Short-term borrowings		3,408	9,693	10,552
Long-term debt		1,553	1,875	1,790
Subordinated debt		2,842	0	0
Junior subordinated debt		2,731	4,425	4,140
Total interest expense		32,604	55,979	38,626
Net interest income		315,678	311,555	305,629
Provision for loan losses	[1]	51,134	25,412	28,828
Net interest income after provision for loan losses		264,544	286,143	276,801
Noninterest income
Service charges on deposit accounts		13,201	17,151	17,224
ATM and debit card fees		25,960	23,893	22,699
Retirement plan administration fees		35,851	30,388	26,992
Wealth management		29,247	28,400	28,747
Insurance		14,757	15,770	15,122
Bank owned life insurance		5,743	5,355	5,091
Net securities (losses) gains		(388)	4,213	(6,341)
Other		21,905	18,853	15,228
Total noninterest income		146,276	144,023	124,762
Noninterest expense
Salaries and employee benefits		161,934	156,867	151,685
Occupancy		21,634	22,706	22,318
Data processing and communications		16,527	18,318	17,652
Professional fees and outside services		15,082	14,785	14,376
Equipment		19,889	18,583	17,037
Office supplies and postage		6,138	6,579	6,204
FDIC expenses		2,688	1,946	4,651
Advertising		2,288	2,773	2,782
Amortization of intangible assets		3,395	3,579	4,042
Loan collection and other real estate owned, net		3,295	4,158	4,217
Other		24,863	24,440	19,597
Total noninterest expense		277,733	274,734	264,561
Income before income tax expense		133,087	155,432	137,002
Income tax expense		28,699	34,411	24,436
Net income		$ 104,388	$ 121,021	$ 112,566
Earnings per share
Basic (in dollars per share)		$ 2.39	$ 2.76	$ 2.58
Diluted (in dollars per share)		$ 2.37	$ 2.74	$ 2.56

[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.