Loans and Leases - Allowance for Credit Losses, Loans and Leases, Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 82,709	$ 72,011	$ 79,004	$ 71,924
Provision for credit losses	2,097	4,114	9,156	5,992
Charge-offs	(1,057)	(1,458)	(4,887)	(3,581)
Recoveries	88	262	564	594
Ending balance	83,837	74,929	83,837	74,929
Commercial Financial And Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,871	13,004	16,920	13,538
Provision for credit losses	979	2,110	937	1,560
Charge-offs	(744)	(310)	(3,891)	(524)
Recoveries	30	181	170	411
Ending balance	14,136	14,985	14,136	14,985
Real-Estate Commercial [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	44,757	41,678	41,673	41,095
Provision for credit losses	519	1,286	3,647	3,559
Charge-offs	0	(999)	(50)	(2,689)
Recoveries	3	3	9	3
Ending balance	45,279	41,968	45,279	41,968
Real-Estate Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,433	4,223	4,952	4,575
Provision for credit losses	298	(376)	986	(728)
Charge-offs	0		(207)	0
Recoveries	1		1	0
Ending balance	5,732	3,847	5,732	3,847
Real Estate Residential Secured For Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,696	6,420	7,054	6,482
Provision for credit losses	(44)	433	1,417	320
Charge-offs	0	0	0	0
Recoveries	4	2	185	53
Ending balance	8,656	6,855	8,656	6,855
Real Estate Residential Secured For Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,588	2,937	3,685	2,403
Provision for credit losses	254	419	2,157	953
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	5,842	3,356	5,842	3,356
Real Estate Home Equity Secured For Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,296	1,074	1,287	1,028
Provision for credit losses	(38)	73	6	130
Charge-offs	0		(85)	0
Recoveries	33	49	83	38
Ending balance	1,291	1,196	1,291	1,196
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	560	376	351	363
Provision for credit losses	(61)	54	314	125
Charge-offs	(124)	(79)	(340)	(181)
Recoveries	12	21	62	65
Ending balance	387	372	387	372
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,508	2,299	3,082	2,290
Provision for credit losses	190	115	(308)	223
Charge-offs	(189)	(70)	(314)	(187)
Recoveries	5	6	54	24
Ending balance	2,514	2,350	2,514	2,350
Unallocated [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0	150
Provision for credit losses	0	0	0	(150)
Ending balance	$ 0	$ 0	$ 0	$ 0