Loans and ACL - Summary of Aging of amortized cost of loans held for investment by loan category (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Days past due	$ 2,393,364	$ 2,430,117
Nonaccrual	50,874	60,026
Gross loans	2,393,364	2,430,117
Deferred loan fees, net of costs	725	830
Total	2,394,089	2,430,947
Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	50,874	60,026
Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	2,428	4,088
Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	48,446	55,938
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	19,976	14,282
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total	2,498	1,913
Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total	2,309	3,037
Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	2,318,432	2,351,689
Deferred loan fees, net of costs	725	830
Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Days past due	489,972	508,944
Nonaccrual	33,946	39,429
Gross loans	489,972	508,944
Commercial and Industrial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		180,052
Commercial and Industrial [Member] \| Nonaccrual loans with no allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual		1,487
Commercial and Industrial [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	33,946	37,942
Commercial and Industrial [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	4,357	2,235
Commercial and Industrial [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,609	632
Commercial and Industrial [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	1,904	1,709
Commercial and Industrial [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	448,156	464,939
Construction, commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	156,943
Nonaccrual	2,233	383
Gross loans	156,943	180,052
Construction, commercial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	1,863
Construction, commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	370	383
Construction, commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		2,016
Construction, commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	154,710	177,653
Construction, Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	62,947	75,832
Financing Receivable Recorded Investments Current, Total	62,947
Gross loans	62,947	75,832
Construction, Residential [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		523
Construction, Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	62,947	75,309
Commercial [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	881,798	870,540
Nonaccrual	7,441	11,880
Gross loans	881,798	870,540
Commercial [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual		2,024
Commercial [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	7,441	9,856
Commercial [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	2,297	2,109
Commercial [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		714
Commercial [Member] \| Greater than 90 Days Past Due & Accruing [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due		574
Commercial [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	872,060	855,263
Residential [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	740,249	730,110
Nonaccrual	6,464	7,580
Gross loans	740,249	730,110
Residential [Member] \| Nonaccrual loans with no allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	565	577
Residential [Member] \| Non accrual loans with an allowance \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,899	7,003
Residential [Member] \| 30-59 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	6,356	5,101
Residential [Member] \| 60-89 Days Past Due [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	419	288
Residential [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	727,010	717,141
Farmland [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Days past due	5,673	5,470
Gross loans	5,673	5,470
Farmland [Member] \| Current Loans [Member] \| Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	5,673	5,470
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Days past due	55,782	59,169
Nonaccrual	790	754
Gross loans	55,782	59,169
Consumer [Member] \| Non accrual loans with an allowance
Financing Receivable, Past Due [Line Items]
Nonaccrual	790	754
Consumer [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	6,966	2,298
Consumer [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Days past due	470	279
Consumer [Member] \| Greater than 90 Days Past Due & Accruing [Member]
Financing Receivable, Past Due [Line Items]
Days past due	405	754
Consumer [Member] \| Current Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable Recorded Investments Current, Total	$ 47,151	$ 55,084

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Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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