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 the fair value and unpaid principal balance ("UPB") (Detail)

Fair Value - Summary of the fair value and unpaid principal balance ("UPB") (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Estimated Fair Value
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	$ 10,347,459	$ 9,929,163
Unpaid Principal Balance
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	9,617,079	9,045,104
Mortgage Loans Held For Investment Subject To Nonrecourse Debt [Member] \| Estimated Fair Value \| Reverse Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	5,665,424	5,057,624
Mortgage Loans Held For Investment Subject To Nonrecourse Debt [Member] \| Estimated Fair Value \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	274,227	338,543
Mortgage Loans Held For Investment Subject To Nonrecourse Debt [Member] \| Unpaid Principal Balance \| Reverse Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	4,986,876	4,457,805
Mortgage Loans Held For Investment Subject To Nonrecourse Debt [Member] \| Unpaid Principal Balance \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	268,288	333,344
Mortgage Loans Held For Investment [Member] \| Estimated Fair Value \| Reverse Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	842,268	661,790
Mortgage Loans Held For Investment [Member] \| Estimated Fair Value \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	235,402	69,031
Mortgage Loans Held For Investment [Member] \| Unpaid Principal Balance \| Reverse Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	721,012	589,429
Mortgage Loans Held For Investment [Member] \| Unpaid Principal Balance \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	233,101	69,127
Mortgage Loans Held For Sale [Member] \| Estimated Fair Value \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	142,906	142,226
Mortgage Loans Held For Sale [Member] \| Estimated Fair Value \| Residential Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	1,904,109	2,080,585
Mortgage Loans Held For Sale [Member] \| Unpaid Principal Balance \| Commercial Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	138,101	140,693
Mortgage Loans Held For Sale [Member] \| Unpaid Principal Balance \| Residential Mortgage Loans [Member]
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	1,859,842	2,000,795
HMBS Related Obligations [Member] \| Estimated Fair Value
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	10,216,310	9,788,668
HMBS Related Obligations [Member] \| Unpaid Principal Balance
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	9,617,079	9,045,104
Non Recourse Debt [Member] \| Estimated Fair Value
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Estimated Fair Value	5,735,010	5,257,754
Non Recourse Debt [Member] \| Unpaid Principal Balance
Fair Value Summary Of The Fair Value And Unpaid Principal Balance Upb [Line Items]
Unpaid Principal Balance	$ 5,654,826	$ 5,155,017