Related Party Transactions - Schedule Statement of Income of Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Various non-consolidated joint ventures | Interest income on securities and beneficial interest and net decrease in the net present value of expected credit losses on beneficial interests
Related Party Transaction [Line Items]
Amount of transaction	$ 4,480	$ 4,855	$ 9,050	$ 12,075
Various non-consolidated joint ventures | Loss from joint venture re-securitization on beneficial interests
Related Party Transaction [Line Items]
Amount of transaction	(8,814)	(2,142)	(9,809)	(6,115)
Servicer | Loan servicing fees
Related Party Transaction [Line Items]
Amount of transaction	1,827	2,006	3,687	4,097
Servicer | Affiliate loan interest income
Related Party Transaction [Line Items]
Amount of transaction	137	67	202	134
Servicer | Loss from equity investment
Related Party Transaction [Line Items]
Amount of transaction	(20)	(170)	(87)	(263)
Manager | Management fee
Related Party Transaction [Line Items]
Amount of transaction	2,001	2,363	3,829	4,656
Manager | Loss from equity investment
Related Party Transaction [Line Items]
Amount of transaction	(29)	(71)	(27)	(112)
AS Ajax E LLC | Loss from equity investment
Related Party Transaction [Line Items]
Amount of transaction	9	4	20	7
Loan pool LLCs | Loss from equity investment
Related Party Transaction [Line Items]
Amount of transaction	(6)	(5)	(16)	(13)
Gaea | Loss from equity investment
Related Party Transaction [Line Items]
Amount of transaction	$ (270)	$ (143)	$ (513)	$ (101)