Loans and Leases - Allowance for Credit Losses, Loans and Leases Roll Forward (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2021	Jan. 01, 2020	Jan. 01, 2019
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 71,924	$ 83,044	$ 35,331
Allowance for credit losses, loans and leases	79,004	71,924	83,044
(Reversal of provision) provision for credit losses	10,975	(10,907)	39,439
Charge-offs	(4,669)	(3,013)	(5,899)
Recoveries	774	2,800	1,251
Ending balance	79,004	71,924	83,044
Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				$ 0	$ 0	$ 12,922
Commercial, Financial and Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,536	13,584	8,759
Allowance for credit losses, loans and leases	16,916	13,536	13,584
(Reversal of provision) provision for credit losses	3,703	(32)	680
Charge-offs	(887)	(1,641)	(1,884)
Recoveries	564	1,625	745
Ending balance	16,916	13,536	13,584
Commercial, Financial and Agricultural [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	5,284
Paycheck Protection Program Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2	0
Allowance for credit losses, loans and leases	4	2	0
(Reversal of provision) provision for credit losses	2	2
Charge-offs	0	0
Recoveries	0	0
Ending balance	4	2	0
Paycheck Protection Program Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0
Real Estate-Commercial [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	41,095	52,230	15,750
Allowance for credit losses, loans and leases	41,673	41,095	52,230
(Reversal of provision) provision for credit losses	3,854	(11,339)	33,090
Charge-offs	(3,282)	(594)	(2,853)
Recoveries	6	798	35
Ending balance	41,673	41,095	52,230
Real Estate-Commercial [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	6,208
Real Estate-Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,575	3,298	2,446
Allowance for credit losses, loans and leases	4,952	4,575	3,298
(Reversal of provision) provision for credit losses	377	1,277	823
Charge-offs	0	0	0
Recoveries	0	0	0
Ending balance	4,952	4,575	3,298
Real Estate-Construction [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	29
Real Estate-Residential Secured for Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	6,482	7,317	2,622
Allowance for credit losses, loans and leases	7,054	6,482	7,317
(Reversal of provision) provision for credit losses	517	(688)	2,306
Charge-offs	0	(227)	(188)
Recoveries	55	80	75
Ending balance	7,054	6,482	7,317
Real Estate-Residential Secured for Business Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	2,502
Real Estate-Residential Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,403	3,055	2,713
Allowance for credit losses, loans and leases	3,685	2,403	3,055
(Reversal of provision) provision for credit losses	1,282	(652)	1,229
Charge-offs	0	0	(181)
Recoveries	0	0	0
Ending balance	3,685	2,403	3,055
Real Estate-Residential Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	(706)
Real Estate-Home Equity Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,028	1,176	1,076
Allowance for credit losses, loans and leases	1,287	1,028	1,176
(Reversal of provision) provision for credit losses	221	(212)	449
Charge-offs	0	0	0
Recoveries	38	64	15
Ending balance	1,287	1,028	1,176
Real Estate-Home Equity Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	(364)
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	363	533	470
Allowance for credit losses, loans and leases	351	363	533
(Reversal of provision) provision for credit losses	167	(35)	146
Charge-offs	(255)	(240)	(267)
Recoveries	76	105	80
Ending balance	351	363	533
Loans to Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	104
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,290	1,701	1,311
Allowance for credit losses, loans and leases	3,082	2,290	1,701
(Reversal of provision) provision for credit losses	1,002	772	750
Charge-offs	(245)	(311)	(526)
Recoveries	35	128	301
Ending balance	3,082	2,290	1,701
Lease Financings [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				0	0	(135)
Unallocated [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	150	150	184
Allowance for credit losses, loans and leases	0	150	150
(Reversal of provision) provision for credit losses	(150)	0	(34)
Ending balance	$ 0	$ 150	$ 150
Unallocated [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for credit losses, loans and leases				$ 0	$ 0	$ 0