Loans Held for Investment and Allowance for Loan Losses - Schedule of loans that are individually evaluated for credit losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Financing Receivable, Impaired [Line Items]
Related Allowance	$ 18,298	$ 14,541	$ 15,455
Total Recorded Investment	179,105	150,698	143,717
Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	17,279	12,250	13,428
Recorded Investment With Allowance	21,533	12,075	11,176
Related Allowance	4,863	4,167	4,815
Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	13,435	10,374	10,640
Total Recorded Investment	140,293	126,373	119,113
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	6,676	8,398	8,439
Total Recorded Investment	25,218	29,440	26,881
Commercial [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	310	0	334
Recorded Investment With Allowance	3,055	5,057	5,632
Related Allowance	2,025	3,513	4,094
Commercial [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	4,651	4,885	4,345
Total Recorded Investment	21,853	24,383	20,915
Commercial [Member] | C&I [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	6,676	8,398	8,439
Total Recorded Investment	23,841	29,382	26,810
Commercial [Member] | C&I [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	310	0	334
Recorded Investment With Allowance	3,055	5,057	5,632
Related Allowance	2,025	3,513	4,094
Commercial [Member] | C&I [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	4,651	4,885	4,345
Total Recorded Investment	20,476	24,325	20,844
Commercial [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment	1,377	58	71
Commercial [Member] | Municipal [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment	1,377	58	71
Commercial [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance		2
Agriculture [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	652	398	350
Total Recorded Investment	2,116	679	750
Agriculture [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	215	116	116
Recorded Investment With Allowance	623	209	222
Related Allowance	58	122	103
Agriculture [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	594	276	247
Total Recorded Investment	1,278	354	412
Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	10,964	5,742	6,662
Total Recorded Investment	148,743	118,650	113,906
Real Estate [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	16,754	12,134	12,978
Recorded Investment With Allowance	17,284	6,349	4,699
Related Allowance	2,779	531	617
Real Estate [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	8,185	5,211	6,045
Total Recorded Investment	114,705	100,167	96,229
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,026	305	591
Total Recorded Investment	23,207	6,440	7,157
Real Estate [Member] | Construction & Development [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	2,678	577	919
Recorded Investment With Allowance	617	990	777
Related Allowance	139	193	207
Real Estate [Member] | Construction & Development [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,887	112	384
Total Recorded Investment	19,912	4,873	5,461
Real Estate [Member] | Farm [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,203	36	41
Total Recorded Investment	7,759	1,663	1,707
Real Estate [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	553	0	0
Recorded Investment With Allowance	4,981	85	91
Related Allowance	1,070		2
Real Estate [Member] | Farm [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	133	34	39
Total Recorded Investment	2,225	1,578	1,616
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3,554	2,357	2,329
Total Recorded Investment	36,534	38,358	35,365
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	1,991	2,062	2,230
Recorded Investment With Allowance	6,416	259	176
Related Allowance	889	16	12
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,665	2,341	2,317
Total Recorded Investment	28,127	36,037	32,959
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,035	1,600	2,061
Total Recorded Investment	42,800	36,206	36,839
Real Estate [Member] | Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	5,473	4,363	5,700
Recorded Investment With Allowance	2,339	2,728	1,003
Related Allowance	400	91	103
Real Estate [Member] | Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,635	1,509	1,958
Total Recorded Investment	34,988	29,115	30,136
Real Estate [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,146	1,444	1,640
Total Recorded Investment	38,443	35,983	32,838
Real Estate [Member] | Residential [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	6,059	5,132	4,129
Recorded Investment With Allowance	2,931	2,287	2,652
Related Allowance	281	229	293
Real Estate [Member] | Residential [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,865	1,215	1,347
Total Recorded Investment	29,453	28,564	26,057
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	6	3	4
Total Recorded Investment	3,028	1,929	2,180
Consumer [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	571	460	623
Related Allowance	1	1	1
Consumer [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	5	2	3
Total Recorded Investment	2,457	1,469	1,557
Consumer [Member] | Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	4	2	3
Total Recorded Investment	2,323	1,360	1,692
Consumer [Member] | Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	465	429	596
Related Allowance	1	1	1
Consumer [Member] | Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3	1	2
Total Recorded Investment	1,858	931	1,096
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	1	1
Total Recorded Investment	705	569	488
Consumer [Member] | Non-Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	106	31	27
Related Allowance	0
Consumer [Member] | Non-Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	1	1
Total Recorded Investment	$ 599	$ 538	$ 461