Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Additional Information (Detail)

v3.22.0.1
Subsequent Events - Additional Information (Detail) - USD ($)
1 Months Ended
Feb. 28, 2022
Jan. 31, 2022
Jan. 01, 2022
Dec. 31, 2021
Dec. 31, 2020
Subsequent Event [Line Items]          
Line of credit       $ 3,347,442,000 $ 2,973,743,000
Commercial Mortgage Backed Securities [Member]          
Subsequent Event [Line Items]          
Line of credit $ 150,000,000.0 $ 12,500,000      
Subsequent Event [Member] | Employee Stock [Member]          
Subsequent Event [Line Items]          
Share-based Payment Award, Maximum Employee Subscription Rate     15.00%    
Share based payment award maximum employee subscription amount     $ 50,000    
Percentage of shares to be granted under the plan     20.00%    
Subsequent Event [Member] | Commercial Mortgage Backed Securities [Member]          
Subsequent Event [Line Items]          
Repayments of line of credit 350,000,000.0        
Line of credit expiry date   Jan. 31, 2024      
Extended line of credit expiry date   Jan. 31, 2025      
Subsequent Event [Member] | Maturity On February Two Thousand Twenty Two [Member] | Commercial Mortgage Backed Securities [Member]          
Subsequent Event [Line Items]          
Reverse mortgage securities provided 638,700,000        
Mortgage backed notes issued fair value $ 639,900,000        
mortgage backed securities issued interest rate 3.50%        
Mortgage backed security weighted average price percentage 100.00%        
Subsequent Event [Member] | Matuirty On Febraury Two Thousand Thirty Seven [Member] | Commercial Mortgage Backed Securities [Member]          
Subsequent Event [Line Items]          
Reverse mortgage securities provided $ 386,100,000        
Mortgage backed notes issued fair value $ 450,100,000        
mortgage backed securities issued interest rate 2.20%        
Mortgage backed security weighted average price percentage 95.90%        
Subsequent Event [Member] | FOAMortgage Servicing Rights [Member]          
Subsequent Event [Line Items]          
Proceeds on sale of mortgage servicing rights $ 8,380,800,000        
Mortgage servicing rights $ 98,100,000