Allowance for Credit Losses - Schedule of Non Accrual Loans (Detail) - Financial Asset Originated - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	$ 24,953	$ 21,703
Non accrual, no allowance including guaranteed loans	25,561	22,390
Non accrual including guaranteed loans	32,705	26,864
Total non accrual	31,840	26,053
Loans Insured or Guaranteed by US Government Authorities
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	608	687
Total non accrual	865	811
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Past due 90 days or more and still accruing	0	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	13,164	7,689
Total non accrual	15,642	8,709
Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	7,909	9,498
Total non accrual	9,046	11,408
Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	86	652
Total non accrual	3,615	2,183
Commercial and industrial | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Past due 90 days or more and still accruing	0	0
Construction
Financing Receivable, Past Due [Line Items]
Non accrual with no allowance for credit losses	4,402	4,546
Total non accrual	4,402	4,546
Construction | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	0	5
Total non accrual	0	18
Agriculture production | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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
Leases | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	8,515	3,110
Total non accrual	8,515	3,110
CRE non-owner occupied | Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	3,132	3,111
Total non accrual	5,610	4,061
CRE owner occupied | Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	171	0
Total non accrual	171	0
Multifamily | Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	1,346	1,468
Total non accrual	1,346	1,538
Farmland | Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	4,185	4,950
Total non accrual	4,328	5,093
SFR 1-4 1st DT liens | Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	3,677	4,480
Total non accrual	4,604	6,148
SFR HELOCs and junior liens | Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
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	47	68
Total non accrual	114	167
Other | Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Past due 90 days or more and still accruing	$ 0	$ 0