Mortgage Loans - Schedule of loan basis by year of origination (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Mortgage Loans [Line Items]
Year one	$ 3,808	$ 2,797
Year two	5,074	2,050
Year three	2,784	7,010
Year four	9,750	9,182
Year five	3,841	3,967
Year six	4,265	4,531
Prior years, range 1	93,090	95,938
Prior years range 2	616,317	633,115
Prior years range 3	222,348	230,494
Total	961,277	989,084
GAOP - 7f7 >50
Mortgage Loans [Line Items]
Year one	2,420	1,041
Year two	2,236	1,770
Year three	1,179	4,118
Year four	7,036	7,004
Year five	906	2,557
Year six	3,137	2,983
Prior years, range 1	28,016	32,170
Prior years range 2	204,831	198,950
Prior years range 3	79,787	80,203
Total	329,548	330,796
GAOP 7f7 Less Than 50
Mortgage Loans [Line Items]
Year one	0	0
Year two	133	0
Year three	0	0
Year four	294	337
Year five	0	0
Year six	146	0
Prior years, range 1	2,351	3,212
Prior years range 2	32,958	34,599
Prior years range 3	7,804	10,501
Total	43,686	48,649
GAOP - 6f6 and below
Mortgage Loans [Line Items]
Year one	1,388	1,756
Year two	2,705	280
Year three	883	2,158
Year four	1,634	1,040
Year five	2,129	597
Year six	379	942
Prior years, range 1	19,219	15,930
Prior years range 2	87,719	98,408
Prior years range 3	31,056	30,697
Total	147,112	151,808
Great Ajax II REIT - 7f7 >50
Mortgage Loans [Line Items]
Year one	0	0
Year two	0	0
Year three	722	734
Year four	730	661
Year five	721	800
Year six	460	467
Prior years, range 1	35,418	34,973
Prior years range 2	245,944	250,168
Prior years range 3	88,184	90,478
Total	372,179	378,281
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	56	140
Year five	13	13
Year six	0	0
Prior years, range 1	3,112	3,487
Prior years range 2	25,216	27,300
Prior years range 3	7,640	8,885
Total	36,037	39,825
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	72	0
Year six	143	139
Prior years, range 1	4,974	6,166
Prior years range 2	19,649	23,690
Prior years range 3	7,877	9,730
Total	$ 32,715	$ 39,725