Loans Held for Investment and Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 19,216		$ 14,541	$ 17,467
Loans collectively evaluated for credit losses	67,325		61,293	54,465
Total allowance for loan losses	86,541	$ 0	75,834	71,932	$ 66,913	$ 63,465
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	8,451		8,398	9,591
Loans collectively evaluated for credit losses	8,079		7,731	8,998
Total allowance for loan losses	16,530	16,083	16,129	18,589	15,737	12,280
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans collectively evaluated for credit losses	187		1,026	1,352
Total allowance for loan losses	187	1,067	1,026	1,352	1,418	348
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,209		305	386
Loans collectively evaluated for credit losses	26,757		26,138	20,699
Total allowance for loan losses	28,966	28,627	26,443	21,085	17,887	17,627
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,135		36	46
Loans collectively evaluated for credit losses	1,669		1,921	960
Total allowance for loan losses	2,804	1,937	1,957	1,006	873	663
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,923		2,357	2,843
Loans collectively evaluated for credit losses	10,548		6,718	5,567
Total allowance for loan losses	13,471	9,051	9,075	8,410	8,499	10,722
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,068		1,600	2,585
Loans collectively evaluated for credit losses	10,504		8,328	8,155
Total allowance for loan losses	12,572	11,948	9,928	10,740	11,536	10,828
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,872		1,444	1,652
Loans collectively evaluated for credit losses	7,895		7,631	6,652
Total allowance for loan losses	9,767	9,702	9,075	8,304	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	826		843	909
Total allowance for loan losses	829	857	845	912	869	896
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1		1	1
Loans collectively evaluated for credit losses	332		314	371
Total allowance for loan losses	333	332	315	372	354	371
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	554		398	360
Loans collectively evaluated for credit losses	528		643	802
Total allowance for loan losses	$ 1,082	$ 1,214	$ 1,041	$ 1,162	$ 1,911	$ 1,597