Loans and Leases - Age Analysis of Past Due Loans and Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	$ 6,546,695	$ 6,109,877
Nonaccrual loans and leases	20,519	13,353
Total loans and leases held for investment	6,567,214	6,123,230
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	22,433	14,254
Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	2,786	1,717
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	534	875
Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	25,753	16,846
Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	6,520,942	6,093,031
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	987,457	1,083,856
Nonaccrual loans and leases	2,266	5,072
Total loans and leases held for investment	989,723	1,088,928
Commercial, Financial and Agricultural [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,355	1,616
Commercial, Financial and Agricultural [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	348	343
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]
Financial receivables, gross	285	0
Commercial, Financial and Agricultural [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,988	1,959
Commercial, Financial and Agricultural [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	985,469	1,081,897
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	3,297,089	3,023,418
Nonaccrual loans and leases	5,709	4,537
Total loans and leases held for investment	3,302,798	3,027,955
Real Estate-Commercial [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,763	3,281
Real Estate-Commercial [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,072	290
Real Estate-Commercial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	0	20
Real Estate-Commercial [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	2,835	3,591
Real Estate-Commercial [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	3,294,254	3,019,827
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	388,395	381,811
Nonaccrual loans and leases	6,067	0
Total loans and leases held for investment	394,462	381,811
Real Estate-Construction [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	10,022	315
Real Estate-Construction [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	45	0
Real Estate-Construction [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	0	0
Real Estate-Construction [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	10,067	315
Real Estate-Construction [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	378,328	381,496
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	515,912	477,241
Nonaccrual loans and leases	1,090	1,013
Total loans and leases held for investment	517,002	478,254
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]
Financial receivables, gross	930	375
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]
Financial receivables, gross	643	203
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]
Financial receivables, gross	0	263
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,573	841
Real Estate-Residential Secured for Business Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	514,339	476,400
Real Estate-Residential Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	904,802	728,406
Nonaccrual loans and leases	4,213	1,989
Total loans and leases held for investment	909,015	730,395
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]
Financial receivables, gross	6,464	4,127
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]
Financial receivables, gross	76	162
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]
Financial receivables, gross	0	319
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	6,540	4,608
Real Estate-Residential Secured for Personal Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	898,262	723,798
Real Estate-Home Equity Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	178,166	175,959
Nonaccrual loans and leases	1,116	740
Total loans and leases held for investment	179,282	176,699
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]
Financial receivables, gross	721	953
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]
Financial receivables, gross	144	225
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]
Financial receivables, gross	0	0
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	865	1,178
Real Estate-Home Equity Secured for Personal Purpose [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	177,301	174,781
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	27,749	27,873
Nonaccrual loans and leases	0	0
Total loans and leases held for investment	27,749	27,873
Loans to Individuals [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	191	32
Loans to Individuals [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	84	153
Loans to Individuals [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	37	39
Loans to Individuals [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	312	224
Loans to Individuals [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	27,437	27,649
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans and leases	247,125	211,313
Nonaccrual loans and leases	58	2
Total loans and leases held for investment	247,183	211,315
Lease Financings [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	987	3,555
Lease Financings [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	374	341
Lease Financings [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	212	234
Lease Financings [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	1,573	4,130
Lease Financings [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivables, gross	$ 245,552	$ 207,183