Quarterly report pursuant to Section 13 or 15(d)

HMBS Related Obligations, at Fair Value - Additional information (Detail)

v3.21.2
HMBS Related Obligations, at Fair Value - Additional information (Detail) - LoanPools
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Home Equity Conversion Mortgage Backed Security Related Obligations At Fair Value [Abstract]    
Ginnie Mae loan pools 1,810 1,693