Loans - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
Loans - Additional Information (Detail) - USD ($)	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans serviced for others	$ 131,000,000		$ 131,000,000		$ 132,000,000
Outstanding balance of commercial loans classified under credit risk, minimum amount	500,000		500,000
Interest income recognized on nonaccrual loans			33,000	$ 28,000
Charge-offs	41,000	$ 368,000	54,000	403,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs		$ 301,000		$ 301,000
Industrial, Manufacturing and Production [Member] \| Commercial Real Estate and Commercial Lessors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral dependent exposures	82,000,000		82,000,000
Healthcare Facilities [Member] \| Commercial Real Estate and Commercial Lessors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral dependent exposures	47,000,000		47,000,000
Warehouses [Member] \| Commercial Real Estate and Commercial Lessors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral dependent exposures	38,000,000		38,000,000
Residential Investment Property [Member] \| Commercial Real Estate and Commercial Lessors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral dependent exposures	36,000,000		36,000,000
Animal Feed Production [Member] \| Commercial Real Estate and Commercial Lessors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral dependent exposures	$ 25,000,000		$ 25,000,000