Annual report pursuant to Section 13 and 15(d)

Concentrations of Risk - Summary of Reverse Mortgages (Detail)

v3.22.0.1
Concentrations of Risk - Summary of Reverse Mortgages (Detail) - Credit Concentration Risk - 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 45.00% 44.00%
New York    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 8.00% 8.00%
Florida    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 5.00% 5.00%
Texas    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 5.00% 5.00%
Other    
Concentration Risk [Line Items]    
Concentration Risk, Percentage 37.00% 38.00%