Loans and Leases - Age Analysis of Past Due Loans and Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	$ 6,813,916	$ 6,546,695
Nonaccrual loans and leases	12,667	20,519
Total loans and leases held for investment	6,826,583	6,567,214
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	12,217	22,433
Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	4,512	2,786
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	321	534
Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	17,050	25,753
Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	6,796,866	6,520,942
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	1,034,040	987,457
Nonaccrual loans and leases	3,795	2,266
Total loans and leases held for investment	1,037,835	989,723
Commercial, Financial and Agricultural [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,750	1,355
Commercial, Financial and Agricultural [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	723	348
Commercial, Financial and Agricultural [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	285
Commercial, Financial and Agricultural [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	2,473	1,988
Commercial, Financial and Agricultural [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,031,567	985,469
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	3,527,772	3,297,089
Nonaccrual loans and leases	2,679	5,709
Total loans and leases held for investment	3,530,451	3,302,798
Real Estate-Commercial [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	415	1,763
Real Estate-Commercial [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	2,919	1,072
Real Estate-Commercial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	0
Real Estate-Commercial [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,334	2,835
Real Estate-Commercial [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,524,438	3,294,254
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	274,483	388,395
Nonaccrual loans and leases	0	6,067
Total loans and leases held for investment	274,483	394,462
Real Estate-Construction [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,659	10,022
Real Estate-Construction [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	45
Real Estate-Construction [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	0
Real Estate-Construction [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,659	10,067
Real Estate-Construction [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	270,824	378,328
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	535,509	515,912
Nonaccrual loans and leases	586	1,090
Total loans and leases held for investment	536,095	517,002
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,077	930
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	643
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	0
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,077	1,573
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	534,432	514,339
Real Estate-Residential Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	991,167	904,802
Nonaccrual loans and leases	3,805	4,213
Total loans and leases held for investment	994,972	909,015
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,040	6,464
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	76
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	0
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	3,040	6,540
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	988,127	898,262
Real Estate-Home Equity Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	185,645	178,166
Nonaccrual loans and leases	1,191	1,116
Total loans and leases held for investment	186,836	179,282
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,063	721
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	309	144
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	0	0
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,372	865
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	184,273	177,301
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	21,250	27,749
Nonaccrual loans and leases	0	0
Total loans and leases held for investment	21,250	27,749
Loans to Individuals [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	187	191
Loans to Individuals [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	59	84
Loans to Individuals [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	24	37
Loans to Individuals [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	270	312
Loans to Individuals [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	20,980	27,437
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	244,050	247,125
Nonaccrual loans and leases	611	58
Total loans and leases held for investment	244,661	247,183
Lease Financings [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,026	987
Lease Financings [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	502	374
Lease Financings [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	297	212
Lease Financings [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	1,825	1,573
Lease Financings [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment	$ 242,225	$ 245,552