Loans Held for Investment and Allowance for Loan Losses - Loans Held-for-Investment by Class of Financing Receivables (Detail) - USD ($) $ in Thousands		Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		$ 6,255,488		$ 5,388,972	$ 5,286,494
Total Real Estate		24,585		31,652	25,210
Less: Allowance for credit losses		(74,108)	$ (71,932)	(63,465)	(63,370)	$ (62,138)	$ (66,534)
Net loans held for investment		6,181,380		5,325,507	5,223,124
C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		871,335		837,075	819,597
Less: Allowance for credit losses		(16,439)	(18,589)	(12,280)	(10,393)	(10,186)	(13,609)
Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		214,852		177,905	165,847
Less: Allowance for credit losses		(1,319)	(1,352)	(348)	(315)	(588)	(1,552)
Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		938,051		749,793	656,530
Less: Allowance for credit losses		(25,699)	(21,085)	(17,627)	(16,862)	(15,632)	(13,512)
Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		268,139		217,220	203,064
Less: Allowance for credit losses		(1,155)	(1,006)	(663)	(586)	(607)	(1,876)
Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		717,738		623,434	674,958
Less: Allowance for credit losses		(8,195)	(8,410)	(10,722)	(10,644)	(10,432)	(8,391)
Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		945,665		821,653	824,231
Less: Allowance for credit losses		(10,086)	(10,740)	(10,828)	(10,889)	(10,399)	(12,347)
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		1,536,180		1,334,419	1,328,798
Less: Allowance for credit losses		(8,954)	(8,304)	(8,133)	(10,057)	(11,234)	(12,601)
Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		538,798		405,416	394,072
Less: Allowance for credit losses		(912)	(912)	(896)	(960)	(1,266)	(1,020)
Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		147,793		123,968	120,450
Less: Allowance for credit losses		(356)	(372)	(371)	(375)	(482)	(371)
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		1,086,187		1,014,980	985,444
Total Real Estate		5,966		5,370	3,430
Commercial [Member] | C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	[1]	871,335		837,075	819,597
Total Real Estate		5,966		5,370	3,430
Commercial [Member] | Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		214,852		177,905	165,847
Agriculture [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		76,937		98,089	98,947
Total Real Estate		338		4,920	949
Less: Allowance for credit losses		(993)	$ (1,162)	(1,597)	(2,289)	$ (1,312)	$ (1,255)
Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		4,405,773		3,746,519	3,687,581
Total Real Estate		17,658		20,809	20,146
Real Estate [Member] | Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		938,051		749,793	656,530
Total Real Estate		1,696		708	1,455
Real Estate [Member] | Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		268,139		217,220	203,064
Total Real Estate		91		1,173	965
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		717,738		623,434	674,958
Total Real Estate		2,406		2,671	2,776
Real Estate [Member] | Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		945,665		821,653	824,231
Total Real Estate		6,703		7,897	6,551
Real Estate [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		1,536,180		1,334,419	1,328,798
Total Real Estate		6,762		8,360	8,399
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		686,591		529,384	514,522
Total Real Estate		623		553	685
Consumer [Member] | Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		538,798		405,416	394,072
Total Real Estate		596		514	589
Consumer [Member] | Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans		147,793		123,968	120,450
Total Real Estate		$ 27		$ 39	$ 96

[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.