Loans Held-for-Investment and Allowance for Credit Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 24,534	$ 22,817	$ 22,310
Loans collectively evaluated for credit losses	78,258	75,508	72,860
Total allowance for loan losses	102,792	98,325	95,170
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	7,157	4,505	4,830
Loans collectively evaluated for credit losses	10,717	10,931	10,421
Total allowance for loan losses	17,874	15,436	15,251
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	162	0	0
Loans collectively evaluated for credit losses	199	200	239
Total allowance for loan losses	361	200	239
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,440	491	1,808
Loans collectively evaluated for credit losses	20,607	19,370	21,703
Total allowance for loan losses	22,047	19,861	23,511
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	562	450	883
Loans collectively evaluated for credit losses	2,222	2,421	2,019
Total allowance for loan losses	2,784	2,871	2,902
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3,973	4,258	2,927
Loans collectively evaluated for credit losses	10,035	10,406	10,101
Total allowance for loan losses	14,008	14,664	13,028
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	6,912	8,158	8,584
Loans collectively evaluated for credit losses	14,346	13,255	12,470
Total allowance for loan losses	21,258	21,413	21,054
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3,805	3,660	1,748
Loans collectively evaluated for credit losses	17,672	16,828	13,920
Total allowance for loan losses	21,477	20,488	15,668
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	8	6	6
Loans collectively evaluated for credit losses	1,538	1,180	1,067
Total allowance for loan losses	1,546	1,186	1,073
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3	124	119
Loans collectively evaluated for credit losses	497	429	394
Total allowance for loan losses	500	553	513
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	512	1,165	1,405
Loans collectively evaluated for credit losses	425	488	526
Total allowance for loan losses	$ 937	$ 1,653	$ 1,931