Loans Held for Investment and Allowance for Loan Losses - Loans Held-for-Investment by Class of Financing Receivables (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 5,566,169	$ 5,388,972	$ 5,322,562
Less: Allowance for credit losses	(66,913)	(63,465)	(62,974)	$ (66,534)
Net loans held for investment	5,499,256	5,325,507	5,259,588
C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	838,049	837,075	1,178,126
Less: Allowance for credit losses	(15,737)	(12,280)	(12,323)	(13,609)
Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	191,799	177,905	176,949
Less: Allowance for credit losses	(1,418)	(348)	(2,191)	(1,552)
Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	806,211	749,793	587,928
Less: Allowance for credit losses	(17,887)	(17,627)	(13,246)	(13,512)
Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	225,942	217,220	162,046
Less: Allowance for credit losses	(873)	(663)	(1,223)	(1,876)
Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	636,160	623,434	650,144
Less: Allowance for credit losses	(8,499)	(10,722)	(9,492)	(8,391)
Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	881,181	821,653	759,906
Less: Allowance for credit losses	(11,536)	(10,828)	(9,878)	(12,347)
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,352,162	1,334,419	1,254,727
Less: Allowance for credit losses	(7,829)	(8,133)	(11,189)	(12,601)
Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	419,818	405,416	370,027
Less: Allowance for credit losses	(869)	(896)	(1,068)	(1,020)
Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	131,964	123,968	92,343
Less: Allowance for credit losses	(354)	(371)	(379)	(371)
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,029,848	1,014,980	1,355,075
Commercial [Member] | C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	838,049	837,075	1,178,126
Commercial [Member] | Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	191,799	177,905	176,949
Agriculture [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	82,883	98,089	90,366
Less: Allowance for credit losses	(1,911)	(1,597)	(1,985)	$ (1,255)
Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	3,901,656	3,746,519	3,414,751
Real Estate [Member] | Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	806,211	749,793	587,928
Real Estate [Member] | Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	225,942	217,220	162,046
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	636,160	623,434	650,144
Real Estate [Member] | Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	881,181	821,653	759,906
Real Estate [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,352,162	1,334,419	1,254,727
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	551,782	529,384	462,370
Consumer [Member] | Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	419,818	405,416	370,027
Consumer [Member] | Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 131,964	$ 123,968	$ 92,343