Loans Held for Investment and Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 22,310	$ 17,573	$ 19,216
Loans collectively evaluated for credit losses	72,860	71,161	67,325
Total allowance for loan losses	95,170	88,734	86,541
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	4,830	5,858	8,451
Loans collectively evaluated for credit losses	10,421	9,840	8,079
Total allowance for loan losses	15,251	15,698	16,530
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	0
Loans collectively evaluated for credit losses	239	195	187
Total allowance for loan losses	239	195	187
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,808	2,401	2,209
Loans collectively evaluated for credit losses	21,703	26,152	26,757
Total allowance for loan losses	23,511	28,553	28,966
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	883	994	1,135
Loans collectively evaluated for credit losses	2,019	1,920	1,669
Total allowance for loan losses	2,902	2,914	2,804
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,927	3,684	2,923
Loans collectively evaluated for credit losses	10,101	9,741	10,548
Total allowance for loan losses	13,028	13,425	13,471
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	8,584	1,663	2,068
Loans collectively evaluated for credit losses	12,470	12,150	10,504
Total allowance for loan losses	21,054	13,813	12,572
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,748	2,159	1,872
Loans collectively evaluated for credit losses	13,920	9,495	7,895
Total allowance for loan losses	15,668	11,654	9,767
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	6	4	3
Loans collectively evaluated for credit losses	1,067	806	826
Total allowance for loan losses	1,073	810	829
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	119	60	1
Loans collectively evaluated for credit losses	394	331	332
Total allowance for loan losses	513	391	333
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,405	750	554
Loans collectively evaluated for credit losses	526	531	528
Total allowance for loan losses	$ 1,931	$ 1,281	$ 1,082