Loan And Allowance For Credit Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 17,870	$ 20,637
Loans collectively evaluated for credit losses	45,595	45,897
Total allowance for loan losses	63,465	66,534	$ 52,499
Commercial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses		5,391
Loans collectively evaluated for credit losses		8,218
Total allowance for loan losses		13,609
Agricultural [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,445	982
Loans collectively evaluated for credit losses	152	273
Total allowance for loan losses	1,597	1,255	1,206
C&I [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	6,627
Loans collectively evaluated for credit losses	5,653
Total allowance for loan losses	12,280	13,609	11,010
Muncipal [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses		1,435
Loans collectively evaluated for credit losses	348	117
Total allowance for loan losses	348	1,552	1,112
Construction & Development [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	225	652
Loans collectively evaluated for credit losses	17,402	12,860
Total allowance for loan losses	17,627	13,512	6,045
Farm [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses		1,312
Loans collectively evaluated for credit losses	661	564
Total allowance for loan losses	663	1,876	663
Non - Owner Occupied CRE [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	4,059	1,921
Loans collectively evaluated for credit losses	6,663	6,470
Total allowance for loan losses	10,722	8,391	7,341
Owner Occupied CRE [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	3,481	5,829
Loans collectively evaluated for credit losses	7,347	6,518
Total allowance for loan losses	10,828	12,347	9,533
Residential [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,026	3,107
Loans collectively evaluated for credit losses	6,107	9,494
Total allowance for loan losses	8,133	12,601	10,392
Auto [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	4	6
Loans collectively evaluated for credit losses	892	1,014
Total allowance for loan losses	896	1,020	3,900
Non - Auto [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for credit losses	1	2
Loans collectively evaluated for credit losses	370	369
Total allowance for loan losses	$ 371	$ 371	$ 1,297