Loans and ACL - Summary of Aging of loans held for investment by loan category (Detail) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Days past due	$ 1,911,528	$ 2,110,755
Nonaccrual	24,327	22,957
Deferred costs, net of loan fees	1,198	1,042
Total	1,912,726	2,111,797
Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	24,327	22,957
Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	9,055	2,447
Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	15,272	20,510
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	3,552	7,130
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	3,528	2,041
Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total	4,252	2,486
Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	1,877,067	2,077,183
Deferred costs, net of loan fees	1,198	1,042
Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Days past due	276,609	354,904
Nonaccrual	8,449	10,185
Commercial and Industrial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	481	778
Commercial and Industrial [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	7,968	9,407
Commercial and Industrial [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,328	1,335
Commercial and Industrial [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,171	1,232
Commercial and Industrial [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,700	2,259
Commercial and Industrial [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	263,961	339,893
Construction, Commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	73,473	114,491
Nonaccrual		220
Construction, Commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual		220
Construction, Commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	236
Construction, Commercial [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		33
Construction, Commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	73,237	114,238
Construction, Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	50,892	51,807
Construction, Residential [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	154
Construction, Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	50,738	51,807
Commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	818,101	847,842
Nonaccrual	7,751	4,235
Commercial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,699
Commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	2,052	4,235
Commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	303	625
Commercial [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	831
Commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	809,216	842,982
Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	654,030	692,253
Nonaccrual	7,552	7,497
Residential [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	2,875	1,669
Residential [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	4,677	5,828
Residential [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	536	3,874
Residential [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,351	476
Residential [Member] \| Greater than 90 Days Past Due & Accruing [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	2,350
Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	642,241	680,406
Farmland [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	4,645	5,520
Farmland [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	4,645	5,520
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Days past due	33,778	43,938
Nonaccrual	575	820
Consumer [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	575	820
Consumer [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	995	1,296
Consumer [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	175	300
Consumer [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	202	227
Consumer [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	$ 31,831	$ 41,295