Loans and ACL - Summary of Aging of loans held for investment by loan category (Detail) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
Days past due	$ 1,832,676	$ 1,864,512
Nonaccrual	19,502	20,605
Deferred costs, net of loan fees	1,223	1,205
Total	1,833,899	1,865,717
Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	19,502	20,605
Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	8,891	9,010
Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	10,611	11,595
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	15,238	12,076
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	3,782	2,119
Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total	1,525	3,158
Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	1,793,852	1,827,759
Deferred costs, net of loan fees	1,223	1,205
Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Days past due	264,004	271,158
Nonaccrual	5,417	6,639
Commercial and Industrial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	1,736	1,774
Commercial and Industrial [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	3,681	4,865
Commercial and Industrial [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	927	1,099
Commercial and Industrial [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	647	780
Commercial and Industrial [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,408	1,508
Commercial and Industrial [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	255,605	261,132
Construction, Commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	45,831	51,738
Nonaccrual	42	236
Construction, Commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	42	236
Construction, Commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	401	62
Construction, Commercial [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	22	43
Construction, Commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	45,366	51,397
Construction, Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	33,397	31,772
Construction, Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	33,397	31,772
Commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	831,794	836,308
Nonaccrual	5,890	5,651
Commercial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,553	5,634
Commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	337	17
Commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	47	49
Commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	825,857	830,608
Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	623,591	636,743
Nonaccrual	7,116	7,379
Residential [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	1,602	1,602
Residential [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,514	5,777
Residential [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	12,472	9,840
Residential [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	2,810	1,006
Residential [Member] \| Greater than 90 Days Past Due & Accruing [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		1,575
Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	601,193	616,943
Farmland [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	4,451	4,580
Farmland [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	4,451	4,580
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Days past due	29,608	32,213
Nonaccrual	1,037	700
Consumer [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	1,037	700
Consumer [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,391	1,026
Consumer [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	303	290
Consumer [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	117	75
Consumer [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current	$ 26,760	$ 30,122