Annual report pursuant to Section 13 and 15(d)

Concentrations of Risk - Summary of Non Agency Reverse Mortgage (Detail)

v3.22.0.1
Concentrations of Risk - Summary of Non Agency Reverse Mortgage (Detail) - Credit Concentration Risk - Non Agency Reverse Mortgage - Mortgage Loans Benchmark - Mortgage Loans Customer
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Concentration Risk [Line Items]    
Concentration Risk, Percentage 100.00% 100.00%
California    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 81.00% 84.00%
Other    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 19.00% 16.00%