Quarterly report [Sections 13 or 15(d)]

Loans - Additional Information (Detail)

v3.26.3
Loans - Additional Information (Detail)
3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
Loan
Property
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
Property
Sep. 30, 2025
USD ($)
Loan
Dec. 31, 2025
USD ($)
Property
Accounts, Notes, Loans and Financing Receivable [Line Items]          
Accrued interest receivable on loans $ 25,404,000   $ 25,404,000   $ 24,466,000
Pledged loans, carrying value 2,300,000,000   2,300,000,000   2,400,000,000
Sale of residential mortgage loans from the held for investment portfolio   $ 25,900,000   $ 36,000,000  
Interest income on nonaccrual loans       $ 370,000  
Other real estate owned ("OREO") $ 1,084,000   $ 1,084,000   $ 1,980,000
Number of real estate properties | Property 1   1   2
Number of loan modified | Loan 0     0  
Commercial and Industrial          
Accounts, Notes, Loans and Financing Receivable [Line Items]          
Payment defaults on loans modified within the preceding 12 months     $ 0 $ 0  
Loans Pledged to Secure Advances          
Accounts, Notes, Loans and Financing Receivable [Line Items]          
Pledged loans, carrying value $ 2,300,000,000   2,300,000,000   $ 2,400,000,000
Loans pledged 1,190,000,000   1,190,000,000   528,100,000
Loans | Location, Statement of Financial Position, Balance [Axis]: us-gaap:InterestReceivable          
Accounts, Notes, Loans and Financing Receivable [Line Items]          
Accrued interest receivable on loans $ 20,800,000   $ 20,800,000   $ 20,700,000