Mortgage Loans - Schedule of loan basis by year of origination (Details) - Mortgage loans held-for-investment, net - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Mortgage Loans [Line Items]
Year one	$ 0	$ 0
Year two	0	3,610
Year three	519	4,149
Year four	0	2,100
Year five	728	8,385
Year six	829	2,601
Prior years, range 1	47,866	89,438
Prior years range 2	290,755	556,092
Prior years range 3	98,001	198,176
Total	438,698	864,551
GAOP - 7f7 >50
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	2,473
Year three	0	2,597
Year four	0	1,370
Year five	0	6,598
Year six	0	658
Prior years, range 1	3,456	30,891
Prior years range 2	4,430	190,106
Prior years range 3	1,739	79,110
Total	9,625	313,803
GAOP 7f7 Less Than 50
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	546
Year three	109	137
Year four	0	0
Year five	0	215
Year six	0	0
Prior years, range 1	0	2,356
Prior years range 2	870	27,368
Prior years range 3	217	6,530
Total	1,196	37,152
GAOP - 6f6 and below
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	591
Year three	410	1,415
Year four	0	0
Year five	0	737
Year six	0	1,134
Prior years, range 1	1,519	13,343
Prior years range 2	5,561	55,452
Prior years range 3	267	14,642
Total	7,757	87,314
Great Ajax II REIT - 7f7 >50
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	730
Year five	728	764
Year six	758	795
Prior years, range 1	35,156	34,864
Prior years range 2	240,791	243,034
Prior years range 3	83,366	84,634
Total	360,799	364,821
Great Ajax II REIT 7f7 Less Than 50
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	71
Year six	71	14
Prior years, range 1	2,665	2,658
Prior years range 2	22,312	22,360
Prior years range 3	6,472	6,508
Total	31,520	31,611
Great Ajax II REIT - 6f6 and below
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Year six	0	0
Prior years, range 1	5,070	5,326
Prior years range 2	16,791	17,772
Prior years range 3	5,940	6,752
Total	$ 27,801	$ 29,850