Loans and Allowance for Credit Losses - Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	$ 1,995	$ 705	$ 530
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	79,173	54,299	44,923
Financing Receivable, Nonaccrual	91,756	61,456
Financing Receivable, Nonaccrual, Related Allowance	9,836	7,965
Financing Receivable, Nonaccrual, Unpaid Principal Balance	118,901	89,536
Commercial Financial Agricultural And Other With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	135	41	143
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	12,445	6,580	7,895
Financing Receivable, Nonaccrual	22,422	5,619
Financing Receivable, Nonaccrual, Unpaid Principal Balance	31,583	21,745
Commercial Financial Agricultural And Other With No Related Allowance [Member] | Time and demand loans
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	135	41	143
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	11,467	5,481	7,569
Financing Receivable, Nonaccrual	21,092	4,813
Financing Receivable, Nonaccrual, Unpaid Principal Balance	30,253	20,939
Commercial Financial Agricultural And Other With No Related Allowance [Member] | Equipment Finance
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	978	1,099	326
Financing Receivable, Nonaccrual	1,330	806
Financing Receivable, Nonaccrual, Unpaid Principal Balance	1,330	806
Commercial Financial Agricultural And Other With No Related Allowance [Member] | Time and Demand Loans Other
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Real Estate Construction With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	106	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	1,986	4,498	1,096
Financing Receivable, Nonaccrual	1,475	2,529
Financing Receivable, Nonaccrual, Unpaid Principal Balance	1,475	2,581
Real Estate Construction With No Related Allowance [Member] | Construction Other
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	106	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	1,720	4,498	1,096
Financing Receivable, Nonaccrual	1,475	2,529
Financing Receivable, Nonaccrual, Unpaid Principal Balance	1,475	2,581
Real Estate Construction With No Related Allowance [Member] | Construction Residential
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	266	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Residential real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	125	133	136
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	11,664	8,360	6,440
Financing Receivable, Nonaccrual	11,874	8,875
Financing Receivable, Nonaccrual, Unpaid Principal Balance	13,678	10,524
Residential real estate with no related allowance recorded [Member] | Senior Lien
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	108	118	129
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	7,147	5,134	3,760
Financing Receivable, Nonaccrual	7,219	6,020
Financing Receivable, Nonaccrual, Unpaid Principal Balance	8,148	6,993
Residential real estate with no related allowance recorded [Member] | Junior Lien
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	17	15	7
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	4,517	3,226	2,680
Financing Receivable, Nonaccrual	4,655	2,855
Financing Receivable, Nonaccrual, Unpaid Principal Balance	5,530	3,531
Commercial Real Estate With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	1,624	453	260
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	21,659	16,759	20,715
Financing Receivable, Nonaccrual	17,853	18,346
Financing Receivable, Nonaccrual, Unpaid Principal Balance	23,807	24,047
Commercial Real Estate With No Related Allowance [Member] | Multifamily
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	252	34	37
Financing Receivable, Nonaccrual	10	20
Financing Receivable, Nonaccrual, Unpaid Principal Balance	12	21
Commercial Real Estate With No Related Allowance [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	1,425	173	122
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	12,854	15,657	18,454
Financing Receivable, Nonaccrual	8,799	16,948
Financing Receivable, Nonaccrual, Unpaid Principal Balance	12,879	22,372
Commercial Real Estate With No Related Allowance [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	199	280	138
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	8,553	1,068	2,224
Financing Receivable, Nonaccrual	9,044	1,378
Financing Receivable, Nonaccrual, Unpaid Principal Balance	10,916	1,654
Loans To Individuals With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	5	7	7
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	143	146	365
Financing Receivable, Nonaccrual	32	250
Financing Receivable, Nonaccrual, Unpaid Principal Balance	78	2,237
Loans To Individuals With No Related Allowance [Member] | Other consumer loans
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	21	11	66
Financing Receivable, Nonaccrual	2	103
Financing Receivable, Nonaccrual, Unpaid Principal Balance	16	157
Loans To Individuals With No Related Allowance [Member] | Automobile Loan
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	5	7	7
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	122	135	299
Financing Receivable, Nonaccrual	30	147
Financing Receivable, Nonaccrual, Unpaid Principal Balance	62	2,080
Subtotal with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	1,995	634	546
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	47,897	36,343	36,511
Financing Receivable, Nonaccrual	53,656	35,619
Financing Receivable, Nonaccrual, Unpaid Principal Balance	70,621	61,134
Commercial, financial, agricultural and other With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	71	(16)
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	23,517	5,378	6,574
Financing Receivable, Nonaccrual	24,196	9,368
Financing Receivable, Nonaccrual, Related Allowance	6,959	4,724
Financing Receivable, Nonaccrual, Unpaid Principal Balance	34,249	10,459
Commercial, financial, agricultural and other With an allowance recorded [Member] | Time and demand loans
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	71	(16)
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	23,517	5,378	6,574
Financing Receivable, Nonaccrual	24,196	9,368
Financing Receivable, Nonaccrual, Related Allowance	6,959	4,724
Financing Receivable, Nonaccrual, Unpaid Principal Balance	34,249	10,459
Commercial, financial, agricultural and other With an allowance recorded [Member] | Equipment Finance
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Commercial, financial, agricultural and other With an allowance recorded [Member] | Time and Demand Loans Other
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Real estate construction with an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Real estate construction with an allowance recorded [Member] | Construction Other
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Real estate construction with an allowance recorded [Member] | Construction Residential
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Residential real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	888	1,486	1,183
Financing Receivable, Nonaccrual	1,145	2,712
Financing Receivable, Nonaccrual, Related Allowance	162	369
Financing Receivable, Nonaccrual, Unpaid Principal Balance	1,160	2,885
Residential real estate With an allowance recorded [Member] | Senior Lien
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	888	205	47
Financing Receivable, Nonaccrual	1,145	1,114
Financing Receivable, Nonaccrual, Related Allowance	162	47
Financing Receivable, Nonaccrual, Unpaid Principal Balance	1,160	1,113
Residential real estate With an allowance recorded [Member] | Junior Lien
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	1,281	1,136
Financing Receivable, Nonaccrual	0	1,598
Financing Receivable, Nonaccrual, Related Allowance	0	322
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	1,772
Commercial real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	6,871	11,092	655
Financing Receivable, Nonaccrual	12,759	13,757
Financing Receivable, Nonaccrual, Related Allowance	2,715	2,872
Financing Receivable, Nonaccrual, Unpaid Principal Balance	12,871	15,058
Commercial real estate With an allowance recorded [Member] | Multifamily
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Commercial real estate With an allowance recorded [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	2,860	6,634	397
Financing Receivable, Nonaccrual	5,357	7,602
Financing Receivable, Nonaccrual, Related Allowance	2,280	2,093
Financing Receivable, Nonaccrual, Unpaid Principal Balance	5,357	8,686
Commercial real estate With an allowance recorded [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	4,011	4,458	258
Financing Receivable, Nonaccrual	7,402	6,155
Financing Receivable, Nonaccrual, Related Allowance	435	779
Financing Receivable, Nonaccrual, Unpaid Principal Balance	7,514	6,372
Loans to individuals With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Loans to individuals With an allowance recorded [Member] | Other consumer loans
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Loans to individuals With an allowance recorded [Member] | Automobile Loan
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	0	0
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	0	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Financing Receivable, Nonaccrual, Unpaid Principal Balance	0	0
Subtotal With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual, Interest Income	0	71	(16)
Financing Receivables, before Allowance for Credit Loss, Average Amount Outstanding	31,276	17,956	$ 8,412
Financing Receivable, Nonaccrual	38,100	25,837
Financing Receivable, Nonaccrual, Related Allowance	9,836	7,965
Financing Receivable, Nonaccrual, Unpaid Principal Balance	$ 48,280	$ 28,402