Allowance for Credit Losses - Troubled Debt Restructurings (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) investmentSecurity	Dec. 31, 2021 USD ($) investmentSecurity	Dec. 31, 2020 USD ($) investmentSecurity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	9	16	18
Pre-mod outstanding principal balance	$ 8,477	$ 9,083	$ 6,010
Post-mod outstanding principal balance	8,819	9,116	6,074
Financial impact due to TDR taken as additional provision	$ 0	$ 2,521	$ 471
Number that defaulted during the period (in investment securities) | investmentSecurity	3	5,000	8
Recorded investment of TDR's that defaulted during the period	$ 168	$ 1,107	$ 2,862
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ (5)	$ (90)
Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	4	8	10
Pre-mod outstanding principal balance	$ 1,228	$ 6,407	$ 3,732
Post-mod outstanding principal balance	1,570	6,401	3,827
Financial impact due to TDR taken as additional provision	$ 0	$ 1,812	$ 381
Number that defaulted during the period (in investment securities) | investmentSecurity	0	3,000	3
Recorded investment of TDR's that defaulted during the period	$ 0	$ 847	$ 1,542
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	1	2
Pre-mod outstanding principal balance	$ 0	$ 200	$ 172
Post-mod outstanding principal balance	0	247	169
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	2	0	5
Recorded investment of TDR's that defaulted during the period	$ 146	$ 0	$ 1,320
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ (90)
Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	1	7	6
Pre-mod outstanding principal balance	$ 39	$ 2,476	$ 2,106
Post-mod outstanding principal balance	39	2,468	2,078
Financial impact due to TDR taken as additional provision	$ 0	$ 709	$ 90
Number that defaulted during the period (in investment securities) | investmentSecurity	1	2,000	0
Recorded investment of TDR's that defaulted during the period	$ 22	$ 260	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ (5)	$ 0
Construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	0	0
Pre-mod outstanding principal balance	$ 0	$ 0	$ 0
Post-mod outstanding principal balance	0	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	0
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
Agriculture production
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	4	0	0
Pre-mod outstanding principal balance	$ 7,210	$ 0	$ 0
Post-mod outstanding principal balance	7,210	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	0
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
Leases
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	0	0
Pre-mod outstanding principal balance	$ 0	$ 0	$ 0
Post-mod outstanding principal balance	0	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	0
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
CRE non-owner occupied | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	5	1
Pre-mod outstanding principal balance	$ 0	$ 4,966	$ 319
Post-mod outstanding principal balance	0	4,956	314
Financial impact due to TDR taken as additional provision	$ 0	$ 1,020	$ 314
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	1
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 141
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
CRE owner occupied | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	1	1	4
Pre-mod outstanding principal balance	$ 0	$ 740	$ 1,847
Post-mod outstanding principal balance	130	742	1,877
Financial impact due to TDR taken as additional provision	$ 0	$ 742	$ 67
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	1
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 950
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
Multifamily | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	0	0
Pre-mod outstanding principal balance	$ 0	$ 0	$ 0
Post-mod outstanding principal balance	0	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	0
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
Farmland | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	3	2	5
Pre-mod outstanding principal balance	$ 1,228	$ 701	$ 1,566
Post-mod outstanding principal balance	1,440	703	1,636
Financial impact due to TDR taken as additional provision	$ 0	$ 50	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	3,000	1
Recorded investment of TDR's that defaulted during the period	$ 0	$ 847	$ 451
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
SFR 1-4 1st DT liens | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	0	0
Pre-mod outstanding principal balance	$ 0	$ 0	$ 0
Post-mod outstanding principal balance	0	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	3
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 1,180
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0
SFR HELOCs and junior liens | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	1	2
Pre-mod outstanding principal balance	$ 0	$ 200	$ 172
Post-mod outstanding principal balance	0	247	169
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	2	0	2
Recorded investment of TDR's that defaulted during the period	$ 146	$ 0	$ 140
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ (90)
Other | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number (in investments) | investmentSecurity	0	0	0
Pre-mod outstanding principal balance	$ 0	$ 0	$ 0
Post-mod outstanding principal balance	0	0	0
Financial impact due to TDR taken as additional provision	$ 0	$ 0	$ 0
Number that defaulted during the period (in investment securities) | investmentSecurity	0	0	0
Recorded investment of TDR's that defaulted during the period	$ 0	$ 0	$ 0
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions	$ 0	$ 0	$ 0