Loans Held for Investment and Allowance for Loan Losses - Schedule of loans that are individually evaluated for credit losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Financing Receivable, Impaired [Line Items]
Related Allowance	$ 17,467	$ 17,870	$ 17,186
Total Recorded Investment	152,668	161,185	174,994
Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	14,268	19,955	20,209
Recorded Investment With Allowance	11,207	11,697	9,577
Related Allowance	3,398	4,184	1,669
Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	14,069	13,686	15,517
Total Recorded Investment	127,193	129,533	145,208
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	9,591	6,627	4,863
Total Recorded Investment	32,453	24,500	25,310
Commercial [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	1,224	749	1,091
Recorded Investment With Allowance	5,471	4,621	2,496
Related Allowance	2,794	2,533	723
Commercial [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	6,797	4,094	4,140
Total Recorded Investment	25,758	19,130	21,723
Commercial [Member] | C&I [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	9,591	6,627	4,588
Total Recorded Investment	32,369	24,391	24,425
Commercial [Member] | C&I [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	1,224	749	1,091
Recorded Investment With Allowance	5,471	4,621	2,496
Related Allowance	2,794	2,533	723
Commercial [Member] | C&I [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	6,797	4,094	3,865
Total Recorded Investment	25,674	19,021	20,838
Commercial [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance			275
Total Recorded Investment	84	109	885
Commercial [Member] | Municipal [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance
Recorded Investment With Allowance
Related Allowance
Commercial [Member] | Municipal [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance			275
Total Recorded Investment	84	109	885
Agriculture [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	360	1,445	1,255
Total Recorded Investment	752	5,398	6,250
Agriculture [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	178	3,026	328
Recorded Investment With Allowance	304	1,894	727
Related Allowance	146	1,086	171
Agriculture [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	214	359	1,084
Total Recorded Investment	270	478	5,195
Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	7,512	9,793	11,061
Total Recorded Investment	117,569	129,157	141,367
Real Estate [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	12,866	16,180	18,790
Recorded Investment With Allowance	5,013	4,629	5,982
Related Allowance	457	564	774
Real Estate [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	7,055	9,229	10,287
Total Recorded Investment	99,690	108,348	116,595
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	386	225	1,099
Total Recorded Investment	10,612	5,473	10,721
Real Estate [Member] | Construction & Development [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	441	102	1,282
Recorded Investment With Allowance	549	606	238
Related Allowance	34	90	24
Real Estate [Member] | Construction & Development [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	352	135	1,075
Total Recorded Investment	9,622	4,765	9,201
Real Estate [Member] | Farm [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	46	2	9
Total Recorded Investment	1,662	3,142	4,536
Real Estate [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		997	1,697
Recorded Investment With Allowance	97	176	94
Related Allowance	3		0
Real Estate [Member] | Farm [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	43	2	9
Total Recorded Investment	1,565	1,969	2,745
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,843	4,059	4,200
Total Recorded Investment	34,702	34,468	40,291
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	2,391	2,543	6,444
Recorded Investment With Allowance	86	128	140
Related Allowance	7	15	15
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,836	4,044	4,185
Total Recorded Investment	32,225	31,797	33,707
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,585	3,481	3,144
Total Recorded Investment	37,439	48,504	51,808
Real Estate [Member] | Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	5,727	6,548	5,605
Recorded Investment With Allowance	1,096	1,349	3,371
Related Allowance	58	152	544
Real Estate [Member] | Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2,527	3,329	2,600
Total Recorded Investment	30,616	40,607	42,832
Real Estate [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,652	2,026	2,609
Total Recorded Investment	33,154	37,570	34,011
Real Estate [Member] | Residential [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance	4,307	5,990	3,762
Recorded Investment With Allowance	3,185	2,370	2,139
Related Allowance	355	307	191
Real Estate [Member] | Residential [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1,297	1,719	2,418
Total Recorded Investment	25,662	29,210	28,110
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	4	5	7
Total Recorded Investment	1,894	2,130	2,067
Consumer [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance
Recorded Investment With Allowance	419	553	372
Related Allowance	1	1	1
Consumer [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3	4	6
Total Recorded Investment	1,475	1,577	1,695
Consumer [Member] | Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	3	4	5
Total Recorded Investment	1,391	1,675	1,671
Consumer [Member] | Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance
Recorded Investment With Allowance	389	514	329
Related Allowance	1	1	1
Consumer [Member] | Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	2	3	4
Total Recorded Investment	1,002	1,161	1,342
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1	1	2
Total Recorded Investment	503	455	396
Consumer [Member] | Non-Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance
Recorded Investment With Allowance	30	39	43
Related Allowance
Consumer [Member] | Non-Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	1	1	2
Total Recorded Investment	$ 473	$ 416	$ 353