Allowance for Credit Losses - Schedule of Non Accrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	$ 20,961	$ 18,125
Non accrual, no allowance including guaranteed loans	21,758	18,230
Non accrual including guaranteed loans	29,756	21,321
Total non accrual	28,820	21,096
Past due 90 days or more and still accruing	43	0
Loans Insured or Guaranteed by US Government Authorities
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	797	105
Total non accrual	936	225
Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	11,135	8,574
Total non accrual	16,710	8,574
Past due 90 days or more and still accruing	0	0
Consumer
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	5,716	6,662
Total non accrual	6,198	7,459
Past due 90 days or more and still accruing	0	0
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	1,479	1,224
Total non accrual	2,907	3,518
Past due 90 days or more and still accruing	43	0
Construction
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	71	491
Total non accrual	71	491
Past due 90 days or more and still accruing	0	0
Agriculture production
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	3,357	1,279
Total non accrual	3,870	1,279
Past due 90 days or more and still accruing	0	0
Leases
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	0	0
Total non accrual	0	0
Past due 90 days or more and still accruing	0	0
CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	1,105	1,739
Total non accrual	1,105	1,739
Past due 90 days or more and still accruing	0	0
CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	3,898	4,938
Total non accrual	3,898	4,938
Past due 90 days or more and still accruing	0	0
Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	0	125
Total non accrual	0	125
Past due 90 days or more and still accruing	0	0
Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	6,132	1,772
Total non accrual	11,707	1,772
Past due 90 days or more and still accruing	0	0
SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	2,883	4,117
Total non accrual	2,884	4,220
Past due 90 days or more and still accruing	0	0
SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	2,751	2,498
Total non accrual	3,158	3,155
Past due 90 days or more and still accruing	0	0
Other | Consumer
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	82	47
Total non accrual	156	84
Past due 90 days or more and still accruing	$ 0	$ 0