Finance of America Companies Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Summary of Commercial Mortgage Single Rental Loans (Detail)

Fair Value - Summary of Commercial Mortgage Single Rental Loans (Detail) - Commercial Mortgage Single Rental Loans [Member]	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Minimum [Member] \| Prepayment Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Prepayment rate (CPR)	1.00%	1.00%
Minimum [Member] \| Default Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Default rate (CDR)	1.00%	1.00%
Maximum [Member] \| Prepayment Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Prepayment rate (CPR)	17.10%	17.10%
Maximum [Member] \| Default Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Default rate (CDR)	54.00%	64.90%
Weighted Average [Member] \| Prepayment Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Prepayment rate (CPR)	14.00%	15.40%
Weighted Average [Member] \| Discount rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Discount rate	3.10%	5.00%
Weighted Average [Member] \| Default Rate [Member]
Fair Value Single Rental Loan SRL Classified Under Mortgage Loans Held For Sale Measured On Recurring And Nonrecurring Basis Fair Value Measurement [Line Items]
Default rate (CDR)	2.40%	3.60%