Loans Held for Investment and Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 16,845	$ 14,541	$ 18,744
Loans collectively evaluated for credit losses	63,973	61,293	48,169
Total allowance for loan losses	80,818	75,834	66,913	$ 63,465
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	7,523	8,398	7,793
Loans collectively evaluated for credit losses	8,560	7,731	7,944
Total allowance for loan losses	16,083	16,129	15,737	12,280
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans collectively evaluated for credit losses	1,067	1,026	1,418
Total allowance for loan losses	1,067	1,026	1,418	348
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,397	305	1,490
Loans collectively evaluated for credit losses	26,230	26,138	16,397
Total allowance for loan losses	28,627	26,443	17,887	17,627
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		36	0
Loans collectively evaluated for credit losses	1,937	1,921	873
Total allowance for loan losses	1,937	1,957	873	663
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,081	2,357	3,016
Loans collectively evaluated for credit losses	6,970	6,718	5,483
Total allowance for loan losses	9,051	9,075	8,499	10,722
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,605	1,600	3,245
Loans collectively evaluated for credit losses	9,343	8,328	8,291
Total allowance for loan losses	11,948	9,928	11,536	10,828
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,663	1,444	1,974
Loans collectively evaluated for credit losses	8,039	7,631	5,855
Total allowance for loan losses	9,702	9,075	7,829	8,133
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3	2	3
Loans collectively evaluated for credit losses	854	843	866
Total allowance for loan losses	857	845	869	896
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2	1	1
Loans collectively evaluated for credit losses	330	314	353
Total allowance for loan losses	332	315	354	371
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	571	398	1,222
Loans collectively evaluated for credit losses	643	643	689
Total allowance for loan losses	$ 1,214	$ 1,041	$ 1,911	$ 1,597