Affiliates - Narrative (Details)	Mar. 31, 2024 loanPool affiliate	Dec. 31, 2023 loanPool affiliate	Mar. 31, 2023 affiliate	Dec. 31, 2019 loanPool
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated affiliates | affiliate	5	5	5
AS Ajax E II LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage by parent (as percent)	53.10%	53.10%
2017-D
Schedule of Equity Method Investments [Line Items]
Ownership percentage by parent (as percent)	50.00%	50.00%
Great Ajax II REIT
Schedule of Equity Method Investments [Line Items]
Ownership percentage by parent (as percent)	99.90%	99.90%
AS Ajax E LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in percent)	16.50%	16.50%
Loan pool LLCs
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in percent)	40.00%	40.00%		40.40%
Number of entities | loanPool	1	1		3
Gaea Real Estate Corp.
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in percent)	22.20%	22.20%
Investment in Ajax E Master Trust | AS Ajax E LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest in real estate trust (in percent)	5.00%	5.00%
Thetis Asset Management LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in percent)	19.80%	19.80%
Great Ajax FS LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in percent)	9.70%	9.70%