Loans Held for Investment and Allowance for Loan Losses - Schedule of loans that are individually evaluated for credit losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Financing Receivable, Impaired [Line Items]
Related Allowance	$ 16,845	$ 14,541	$ 18,744
Total Recorded Investment	157,056	150,698	152,160
Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	11,867	12,250	17,257
Recorded Investment With Allowance	12,304	12,075	11,486
Related Allowance	4,434	4,167	3,928
Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	12,411	10,374	14,816
Total Recorded Investment	132,885	126,373	123,417
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	7,523	8,398	7,793
Total Recorded Investment	26,391	29,440	25,427
Commercial [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		0	95
Recorded Investment With Allowance	5,343	5,057	4,616
Related Allowance	3,582	3,513	2,525
Commercial [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3,941	4,885	5,268
Total Recorded Investment	21,048	24,383	20,716
Commercial [Member] | C&I [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	7,523	8,398	7,793
Total Recorded Investment	25,484	29,382	25,331
Commercial [Member] | C&I [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		0	95
Recorded Investment With Allowance	5,343	5,057	4,616
Related Allowance	3,582	3,513	2,525
Commercial [Member] | C&I [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3,941	4,885	5,268
Total Recorded Investment	20,141	24,325	20,620
Commercial [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment	907	58	96
Commercial [Member] | Municipal [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment	907	58	96
Commercial [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance		2
Agriculture [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	571	398	1,222
Total Recorded Investment	1,073	679	4,749
Agriculture [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		116	2,349
Recorded Investment With Allowance	161	209	1,989
Related Allowance	86	122	946
Agriculture [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	485	276	276
Total Recorded Investment	912	354	411
Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	8,746	5,742	9,725
Total Recorded Investment	127,230	118,650	120,100
Real Estate [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	11,867	12,134	14,813
Recorded Investment With Allowance	6,320	6,349	4,439
Related Allowance	765	531	456
Real Estate [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	7,981	5,211	9,269
Total Recorded Investment	109,043	100,167	100,848
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,397	305	1,490
Total Recorded Investment	19,586	6,440	10,226
Real Estate [Member] | Construction & Development [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	397	577	0
Recorded Investment With Allowance	376	990	594
Related Allowance	57	193	44
Real Estate [Member] | Construction & Development [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,340	112	1,446
Total Recorded Investment	18,813	4,873	9,632
Real Estate [Member] | Farm [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance		36	0
Total Recorded Investment	1,684	1,663	2,423
Real Estate [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	452	0	1,209
Recorded Investment With Allowance		85	0
Related Allowance			0
Real Estate [Member] | Farm [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance		34	0
Total Recorded Investment	1,232	1,578	1,214
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,081	2,357	3,016
Total Recorded Investment	31,464	38,358	35,279
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	2,136	2,062	2,463
Recorded Investment With Allowance	771	259	111
Related Allowance	152	16	10
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,929	2,341	3,006
Total Recorded Investment	28,557	36,037	32,705
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,605	1,600	3,245
Total Recorded Investment	38,801	36,206	36,896
Real Estate [Member] | Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	4,111	4,363	6,187
Recorded Investment With Allowance	2,712	2,728	1,101
Related Allowance	297	91	96
Real Estate [Member] | Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,308	1,509	3,149
Total Recorded Investment	31,978	29,115	29,608
Real Estate [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,663	1,444	1,974
Total Recorded Investment	35,695	35,983	35,276
Real Estate [Member] | Residential [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	4,771	5,132	4,954
Recorded Investment With Allowance	2,461	2,287	2,633
Related Allowance	259	229	306
Real Estate [Member] | Residential [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,404	1,215	1,668
Total Recorded Investment	28,463	28,564	27,689
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	5	3	4
Total Recorded Investment	2,362	1,929	1,884
Consumer [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	480	460	442
Related Allowance	1	1	1
Consumer [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	4	2	3
Total Recorded Investment	1,882	1,469	1,442
Consumer [Member] | Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3	2	3
Total Recorded Investment	1,648	1,360	1,494
Consumer [Member] | Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	398	429	402
Related Allowance	1	1	1
Consumer [Member] | Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	1	2
Total Recorded Investment	1,250	931	1,092
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	1	1
Total Recorded Investment	714	569	390
Consumer [Member] | Non-Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance	82	31	40
Consumer [Member] | Non-Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	1	1
Total Recorded Investment	$ 632	$ 538	$ 350