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, 2022	Dec. 31, 2021	Jun. 30, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		$ 152,668	$ 161,185	$ 174,994
Loans collectively evaluated for credit losses		5,725,914	5,227,787	5,129,608
Total Loans		5,878,582	5,388,972	5,304,602
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		32,369	24,391	24,425
Loans collectively evaluated for credit losses		807,559	812,684	958,678
Total Loans		839,928	837,075	983,103
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		84	109	885
Loans collectively evaluated for credit losses		200,493	177,796	178,471
Total Loans		200,577	177,905	179,356
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		10,612	5,473	10,721
Loans collectively evaluated for credit losses		918,032	744,320	540,207
Total Loans		928,644	749,793	550,928
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		1,662	3,142	4,536
Loans collectively evaluated for credit losses		248,366	214,078	180,752
Total Loans		250,028	217,220	185,288
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		34,702	34,468	40,291
Loans collectively evaluated for credit losses		601,730	588,966	633,317
Total Loans		636,432	623,434	673,608
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		37,439	48,504	51,808
Loans collectively evaluated for credit losses		872,460	773,149	768,247
Total Loans		909,899	821,653	820,055
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		33,154	37,570	34,011
Loans collectively evaluated for credit losses		1,378,971	1,296,849	1,294,463
Total Loans		1,412,125	1,334,419	1,328,474
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		1,391	1,675	1,671
Loans collectively evaluated for credit losses		466,756	403,741	382,093
Total Loans		468,147	405,416	383,764
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		503	455	396
Loans collectively evaluated for credit losses		141,879	123,513	104,418
Total Loans		142,382	123,968	104,814
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		1,040,505	1,014,980	1,162,459
Commercial [Member] | C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans	[1]	839,928	837,075	983,103
Commercial [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		200,577	177,905	179,356
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses		752	5,398	6,250
Loans collectively evaluated for credit losses		89,668	92,691	88,962
Total Loans		90,420	98,089	95,212
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		4,137,128	3,746,519	3,558,353
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		928,644	749,793	550,928
Real Estate [Member] | Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		250,028	217,220	185,288
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		636,432	623,434	673,608
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		909,899	821,653	820,055
Real Estate [Member] | Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		1,412,125	1,334,419	1,328,474
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		610,529	529,384	488,578
Consumer [Member] | Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		468,147	405,416	383,764
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loans		$ 142,382	$ 123,968	$ 104,814

[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.