Cover - shares	3 Months Ended
	Mar. 31, 2022	May 04, 2022
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-36844
Entity Registrant Name	GREAT AJAX CORP.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	46-5211870
Entity Address, Address Line One	13190 SW 68th Parkway
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Tigard
Entity Address, State or Province	OR
Entity Address, Postal Zip Code	97223
City Area Code	503
Local Phone Number	505-5670
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		23,183,898
Entity Central Index Key	0001614806
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Common stock, par value $0.01 per share
Entity Information [Line Items]
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	AJX
Security Exchange Name	NYSE
7.25% Convertible Senior Notes due 2024
Entity Information [Line Items]
Title of 12(b) Security	7.25% Convertible Senior Notes due 2024
Trading Symbol	AJXA
Security Exchange Name	NYSE