Loans Held for Investment and Allowance for Loan Losses - Schedule of Investment in Loans Related to Balance in Allowance for Loan Losses on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 201,587	$ 176,213	$ 157,056
Loans collectively evaluated for credit losses	7,027,823	6,972,578	6,419,159
Total Loans	7,229,410	7,148,791	6,576,215
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	41,454	22,765	25,484
Loans collectively evaluated for credit losses	1,150,062	1,142,046	929,202
Total Loans	1,191,516	1,164,811	954,686
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	559	733	907
Loans collectively evaluated for credit losses	210,454	214,117	220,472
Total Loans	211,013	214,850	221,379
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	30,929	23,989	19,586
Loans collectively evaluated for credit losses	890,844	939,169	901,604
Total Loans	921,773	963,158	921,190
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	6,533	6,166	1,684
Loans collectively evaluated for credit losses	304,469	338,788	306,022
Total Loans	311,002	344,954	307,706
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	31,655	37,139	31,464
Loans collectively evaluated for credit losses	822,066	790,830	705,653
Total Loans	853,721	827,969	737,117
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	41,179	42,568	38,801
Loans collectively evaluated for credit losses	991,666	994,713	1,004,217
Total Loans	1,032,845	1,037,281	1,043,018
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	39,271	37,906	35,695
Loans collectively evaluated for credit losses	1,879,302	1,796,687	1,593,146
Total Loans	1,918,573	1,834,593	1,628,841
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,828	2,589	1,648
Loans collectively evaluated for credit losses	547,009	519,270	535,762
Total Loans	549,837	521,859	537,410
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,092	899	714
Loans collectively evaluated for credit losses	150,156	153,527	147,137
Total Loans	151,248	154,426	147,851
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	6,087	1,459	1,073
Loans collectively evaluated for credit losses	81,795	83,431	75,944
Total Loans	87,882	84,890	77,017
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	5,037,914	5,007,955	4,637,872
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	921,773	963,158	921,190
Real Estate [Member] | Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	311,002	344,954	307,706
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	853,721	827,969	737,117
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	1,032,845	1,037,281	1,043,018
Real Estate [Member] | Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	1,918,573	1,834,593	1,628,841
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	701,085	676,285	685,261
Consumer [Member] | Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	549,837	521,859	537,410
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	$ 151,248	$ 154,426	$ 147,851