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	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 219,263	$ 176,213	$ 175,139
Loans collectively evaluated for credit losses	7,300,470	6,972,578	6,602,431
Total Loans	7,519,733	7,148,791	6,777,570
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	42,542	22,765	28,100
Loans collectively evaluated for credit losses	1,099,448	1,142,046	993,763
Total Loans	1,141,990	1,164,811	1,021,863
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	559	733	1,507
Loans collectively evaluated for credit losses	358,565	214,117	214,470
Total Loans	359,124	214,850	215,977
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	26,681	23,989	24,622
Loans collectively evaluated for credit losses	959,713	939,169	890,599
Total Loans	986,394	963,158	915,221
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	9,795	6,166	7,739
Loans collectively evaluated for credit losses	308,802	338,788	327,905
Total Loans	318,597	344,954	335,644
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	30,496	37,139	32,441
Loans collectively evaluated for credit losses	785,217	790,830	778,906
Total Loans	815,713	827,969	811,347
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	67,453	42,568	39,178
Loans collectively evaluated for credit losses	982,262	994,713	972,333
Total Loans	1,049,715	1,037,281	1,011,511
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	34,643	37,906	36,692
Loans collectively evaluated for credit losses	1,955,961	1,796,687	1,661,987
Total Loans	1,990,604	1,834,593	1,698,679
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3,083	2,589	2,220
Loans collectively evaluated for credit losses	612,109	519,270	532,383
Total Loans	615,192	521,859	534,603
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,015	899	652
Loans collectively evaluated for credit losses	155,203	153,527	150,041
Total Loans	156,218	154,426	150,693
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,996	1,459	1,988
Loans collectively evaluated for credit losses	83,190	83,431	80,044
Total Loans	86,186	84,890	82,032
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	5,161,023	5,007,955	4,772,402
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	986,394	963,158	915,221
Real Estate [Member] | Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	318,597	344,954	335,644
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	815,713	827,969	811,347
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	1,049,715	1,037,281	1,011,511
Real Estate [Member] | Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	1,990,604	1,834,593	1,698,679
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	771,410	676,285	685,296
Consumer [Member] | Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	615,192	521,859	534,603
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	$ 156,218	$ 154,426	$ 150,693