Loans Held for Investment and Allowance for Loan Losses - Loans Held-for-Investment by Class of Financing Receivables (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022		Sep. 30, 2022		Jun. 30, 2022	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 6,994,696		$ 6,441,868		$ 6,255,488
Total Real Estate	38,812		24,325		24,604
Less: Allowance for credit losses	(89,714)	$ (86,541)	(75,834)		(74,108)		$ (71,932)	$ (63,465)
Net loans held for investment	6,904,982		6,366,034		6,181,380
C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,108,240		917,317		871,335
Less: Allowance for credit losses	(15,807)	(16,530)	(16,129)		(16,439)		(18,589)	(12,280)
Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	218,358		221,090		214,852
Less: Allowance for credit losses	(185)	(187)	(1,026)		(1,319)		(1,352)	(348)
Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	929,570		959,426		938,051
Less: Allowance for credit losses	(28,276)	(28,966)	(26,443)		(25,699)		(21,085)	(17,627)
Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	341,052		306,322		268,139
Less: Allowance for credit losses	(2,935)	(2,804)	(1,957)		(1,155)		(1,006)	(663)
Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	828,900		732,089		717,738
Less: Allowance for credit losses	(15,817)	(13,471)	(9,075)		(8,195)		(8,410)	(10,722)
Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,002,913		954,400		945,665
Less: Allowance for credit losses	(13,526)	(12,572)	(9,928)		(10,086)		(10,740)	(10,828)
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,788,913		1,575,758		1,536,180
Less: Allowance for credit losses	(10,798)	(9,767)	(9,075)		(8,954)		(8,304)	(8,133)
Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	540,382		550,635		538,798
Less: Allowance for credit losses	(862)	(829)	(845)		(912)		(912)	(896)
Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	154,492		147,884		147,793
Less: Allowance for credit losses	(352)	(333)	(315)		(356)		(372)	(371)
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,326,598		1,138,407		1,086,187
Commercial [Member] | C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,108,240		917,317	[1]	871,335	[1]
Commercial [Member] | Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	218,358		221,090		214,852
Agriculture [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	81,876		76,947		76,937
Less: Allowance for credit losses	(1,156)	$ (1,082)	(1,041)		(993)		$ (1,162)	$ (1,597)
Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	4,891,348		4,527,995		4,405,773
Real Estate [Member] | Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	929,570		959,426		938,051
Real Estate [Member] | Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	341,052		306,322		268,139
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	828,900		732,089		717,738
Real Estate [Member] | Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,002,913		954,400		945,665
Real Estate [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,788,913		1,575,758		1,536,180
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	694,874		698,519		686,591
Consumer [Member] | Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	540,382		550,635		538,798
Consumer [Member] | Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 154,492		$ 147,884		$ 147,793

[1] All disclosures for the C&I loan segment include PPP loan balances, net of deferred fees and costs, as disclosed on the face of the consolidated balance sheet.