Affiliates - Schedule of Net Income, Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Net income at Company share	$ 1,332	$ 762	$ 707
Assets at Company share	1,576,841	1,602,871
Liabilities at Company share	1,192,757	1,268,592
GA-E 2014-12
Schedule of Equity Method Investments [Line Items]
Net income at 100%	0	0	426
Net income at Company share	0	0	173
Great Ajax FS LLC
Schedule of Equity Method Investments [Line Items]
Net income at 100%	2,233	1,257	0
Assets	61,432	74,164
Liabilities	37,142	52,184
Net income at Company share	179	90	0
Assets at Company share	4,915	5,933
Liabilities at Company share	$ 2,971	4,175
Thetis
Schedule of Equity Method Investments [Line Items]
Ownership percentage	19.80%
Net income at 100%	$ 4,685	2,202	2,136
Assets	12,277	8,604
Liabilities	2,265	2,136
Net income at Company share	928	436	423
Assets at Company share	2,431	1,704
Liabilities at Company share	$ 448	$ 423
AS Ajax E LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage	16.50%	16.50%
Net income at 100%	$ 299	$ 324	319
Assets	5,747	6,424
Liabilities	2	13
Net income at Company share	49	53	53
Assets at Company share	948	1,060
Liabilities at Company share	$ 0	2
Gaea
Schedule of Equity Method Investments [Line Items]
Ownership percentage	23.20%
Net income at 100%	$ (20)	0	0
Assets	83,068	0
Liabilities	768	0
Net income at Company share	(5)	0	0
Assets at Company share	19,252	0
Liabilities at Company share	178	0
Legacy entities
Schedule of Equity Method Investments [Line Items]
Net income at 100%	(9)	0	0
Assets	1,592	0
Liabilities	3,095	0
Net income at Company share	(4)	0	$ 0
Assets at Company share	637	0
Liabilities at Company share	$ 1,247	0
Unconsolidated Affiliates
Schedule of Equity Method Investments [Line Items]
Ownership percentage	100.00%
Great Ajax FS LLC | Income from investments in affiliates
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Amounts of Transaction	$ 179	90
Thetis | Income from investments in affiliates
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Amounts of Transaction	$ 928	$ 436