Loans And Allowance For Credit Losses - Loans Held-for-Investment by Portfolio Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	$ 5,388,972	$ 5,171,033
Less: Allowance for credit losses	63,465	66,534	$ 52,499
Net loans held – for -investment	5,325,507	5,104,499
Commercial [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	1,014,980	1,312,707
Less: Allowance for credit losses		13,609
Agricultural [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	98,089	94,864
Less: Allowance for credit losses	1,597	1,255	1,206
Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	3,746,519	3,319,265
Consumer [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	529,384	444,197
C&I [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	837,075	1,131,382
Less: Allowance for credit losses	12,280	13,609	11,010
C&I [Member] | Commercial [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	837,075	1,131,382
Muncipal [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	177,905	181,325
Less: Allowance for credit losses	348	1,552	1,112
Muncipal [Member] | Commercial [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	177,905	181,325
Construction & Development [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	749,793	553,959
Less: Allowance for credit losses	17,627	13,512	6,045
Construction & Development [Member] | Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	749,793	553,959
Farm [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	217,220	152,237
Less: Allowance for credit losses	663	1,876	663
Farm [Member] | Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	217,220	152,237
Non - Owner Occupied CRE [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	623,434	617,686
Less: Allowance for credit losses	10,722	8,391	7,341
Non - Owner Occupied CRE [Member] | Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	623,434	617,686
Owner Occupied CRE [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	821,653	746,974
Less: Allowance for credit losses	10,828	12,347	9,533
Owner Occupied CRE [Member] | Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	821,653	746,974
Residential [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	1,334,419	1,248,409
Less: Allowance for credit losses	8,133	12,601	10,392
Residential [Member] | Real Estate [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	1,334,419	1,248,409
Auto [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	405,416	353,595
Less: Allowance for credit losses	896	1,020	3,900
Auto [Member] | Consumer [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	405,416	353,595
Non - Auto [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	123,968	90,602
Less: Allowance for credit losses	371	371	$ 1,297
Non - Auto [Member] | Consumer [Member]
Loans And Leases Receivable Disclosure [Line Items]
Total Loans	$ 123,968	$ 90,602