Quarterly report pursuant to Section 13 or 15(d)

Servicing Assets - Additional Information (Detail)

v3.21.2
Servicing Assets - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Risks Inherent In Servicing Assets And Servicing Liabilities [Line Items]          
Serviced loans sold to unaffiliated parties $ 459,800,000   $ 459,800,000   $ 429,400,000
Amortization expense 532,000 $ 524,000 1,700,000 $ 1,600,000  
Fair value of servicing rights 8,100,000   $ 8,100,000   $ 6,900,000
Minimum          
Risks Inherent In Servicing Assets And Servicing Liabilities [Line Items]          
Discount rates ranging     8.60%   9.30%
Prepayment speeds     11.00%   11.80%
Maximum [Member]          
Risks Inherent In Servicing Assets And Servicing Liabilities [Line Items]          
Discount rates ranging     10.50%   12.20%
Prepayment speeds     17.40%   19.10%
Other Operating Income          
Risks Inherent In Servicing Assets And Servicing Liabilities [Line Items]          
Servicing fee income $ 1,100,000 $ 1,100,000 $ 3,400,000 $ 3,400,000