Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Summary of HECM Buyouts Securitized (Detail)

v3.21.2
Fair Value - Summary of HECM Buyouts Securitized (Detail) - HECM Buyouts Securitized [Member]
 9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Minimum [Member] | Loss severity [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Loss severity 4.10% 5.10%
Maximum [Member] | Loss severity [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Loss severity 11.80% 13.30%
Weighted Average [Member] | Conditional repayment rate [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Conditional repayment rate 12.80% 14.70%
Weighted Average [Member] | Loss severity [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Loss severity 8.60% 7.70%
Weighted Average [Member] | Discount rate [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Discount rate 3.60% 3.50%
Weighted Average [Member] | Weighted average remaining life in years [Member]    
Fair Value HECM Buyouts Securitized Performing Mortgage Loans Held For Investment Subject To Nonrecourse Debt Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]    
Weighted average remaining life in years 9 years 3 months 18 days 8 years 6 months