Fair Value - Schedule of Assets and Liabilities at Fair Value (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment
Mortgage loans, net	[1],[2]	1,098,629	$ 1,151,469
Investment in debt securities	[3]	247,372	231,685
Investments in beneficial interests	[4]	64,703	57,954
Not recognized on consolidated balance sheet at fair value (liabilities)
Secured borrowings, net		630,938	652,747
Borrowings under repurchase transactions		431,091	414,114
Convertible senior notes, net	[5]	111,420	118,784
Carrying value
Consolidated balance sheet at fair value disclosure (assets)
Mortgage loans, net		1,098,629	1,151,469
Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Mortgage loans, net fair value		0	0
Investment In Debt Securities, Fairvalue Disclosure		0	0
Not recognized on consolidated balance sheet at fair value (liabilities)
Secured borrowings, fair value		0	0
Borrowings under repurchase agreement, fair value		0	0
Convertible senior notes, net, fair value		87,073	132,173
Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Mortgage loans, net fair value		0	0
Investment In Debt Securities, Fairvalue Disclosure		247,372	231,685
Not recognized on consolidated balance sheet at fair value (liabilities)
Secured borrowings, fair value		0	0
Borrowings under repurchase agreement, fair value		431,091	414,114
Convertible senior notes, net, fair value		0	0
Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Mortgage loans, net fair value		1,098,638	1,260,385
Investment In Debt Securities, Fairvalue Disclosure		0	0
Not recognized on consolidated balance sheet at fair value (liabilities)
Secured borrowings, fair value		568,525	657,918
Borrowings under repurchase agreement, fair value		0	0
Convertible senior notes, net, fair value		0	0
Investment in Manager
Consolidated balance sheet at fair value disclosure (assets)
Investments In affiliates		734	1,755
Investment in Manager | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in Manager | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in Manager | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		4,419	7,721
Investment in AS Ajax E
Consolidated balance sheet at fair value disclosure (assets)
Investments In affiliates		894	931
Investment in AS Ajax E | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in AS Ajax E | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		968	1,012
Investment in AS Ajax E | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in GAFS
Consolidated balance sheet at fair value disclosure (assets)
Investments In affiliates		2,747	3,023
Investment in GAFS | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in GAFS | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Investment in GAFS | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		3,320	3,320
Gaea | Carrying value
Consolidated balance sheet at fair value disclosure (assets)
Investments In affiliates		19,998	19,995
Gaea | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Gaea | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Gaea | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		19,998	19,995
Legacy entities | Carrying value
Consolidated balance sheet at fair value disclosure (assets)
Investments In affiliates		651	760
Legacy entities | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Legacy entities | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		0	0
Legacy entities | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Fair Value Adjustment		651	760
Beneficial interests
Consolidated balance sheet at fair value disclosure (assets)
Investment in beneficial interests		64,703	57,954
Beneficial interests | Level 1 Quoted prices in active markets
Consolidated balance sheet at fair value disclosure (assets)
Investments, Fair Value Disclosure		0	0
Beneficial interests | Level 2 Observable inputs other than Level 1 prices
Consolidated balance sheet at fair value disclosure (assets)
Investments, Fair Value Disclosure		64,703	57,954
Beneficial interests | Level 3 Unobservable inputs
Consolidated balance sheet at fair value disclosure (assets)
Investments, Fair Value Disclosure		$ 0	$ 0

[1] As of March 31, 2020, balances for Mortgage loans, net includes $316.5 million and Secured borrowings, net of deferred costs includes $271.6 million from the 50% and 63% owned joint ventures, respectively. As of December 31, 2019, balances for Mortgage loans, net include $341.8 million and Secured borrowings, net of deferred costs includes $284.8 million from a 50% and 63% owned joint ventures, all of which the Company consolidates under U.S. Generally Accepted Accounting Principles ("U.S. GAAP").

[2] Mortgage loans net include $888.2 million and $908.6 million of loans at March 31, 2020 and December 31, 2019, respectively, transferred to securitization trusts that are variable interest entities (“VIEs”); these loans can only be used to settle obligations of the VIEs. Secured borrowings consist of notes issued by VIEs that can only be settled with the assets and cash flows of the VIEs. The creditors do not have recourse to the primary beneficiary (Great Ajax Corp.). See Note 9 — Debt. Mortgage loans, net include $16.1 million and $2.0 million of allowance for loan credit losses at March 31, 2020 and December 31, 2019, respectively.

[3] As of March 31, 2020 and December 31, 2019 Investments at fair value include amortized cost basis of $274.5 million and $230.4 million, respectively, and unrealized losses of $27.2 million and unrealized gains of $1.3 million, respectively.

[4] Investments in beneficial interests includes allowance for credit losses of $7.2 million at March 31, 2020. No allowance for credit losses were recorded as of December 31, 2019.

[5] Secured borrowings and Convertible senior notes are presented net of deferred issuance costs.