Affiliates - Schedule of Net Income, Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at the Company's share	$ (1,112)	$ 461
Assets at Company share	1,537,847		$ 1,576,841
Liabilities at Company share	1,180,573		1,192,757
Thetis
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at 100%	(4,877)	1,408
Assets	7,229		12,277
Liabilities	2,379		2,265
Net income/(loss) at the Company's share	(966)	279
Assets at Company share	1,431		2,431
Liabilities at Company share	471		448
Great Ajax FS LLC
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at 100%	(3,450)	1,600
Assets	56,538		61,432
Liabilities	35,656		37,142
Net income/(loss) at the Company's share	(276)	128
Assets at Company share	4,523		4,915
Liabilities at Company share	2,852		2,971
AS Ajax E LLC
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at 100%	62	76
Assets	5,522		5,747
Liabilities	2		2
Net income/(loss) at the Company's share	10	13
Assets at Company share	911		948
Liabilities at Company share	0		0
Legacy entities
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at 100%	198	0
Assets	1,350		1,592
Liabilities	3,125		3,095
Net income/(loss) at the Company's share	79	0
Assets at Company share	540		637
Liabilities at Company share	1,259		1,247
Gaea
Schedule of Equity Method Investments [Line Items]
Net income/(loss) at 100%	15	0
Assets	83,173		83,068
Liabilities	772		768
Net income/(loss) at the Company's share	4	$ 0
Assets at Company share	19,277		19,252
Liabilities at Company share	$ 179		$ 178