Represents the amount related to loan servicing fee expense as related party expense.

No definition available.

Name:	ajx_RelatedPartyLoanServicingFeeExpense
Namespace Prefix:	ajx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount related to management fee expense as related party expense.

+ References

No definition available.

+ Details

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Namespace Prefix:	ajx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123605549&loc=d3e21493-158490

+ Details

Name:	us-gaap_GainLossOnSaleOfMortgageLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
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+ Details

Name:	us-gaap_RelatedPartyTransactionAmountsOfTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=ajx_ThetisAssetManagementLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=ajx_ManagementFeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=ajx_IncomefrominvestmentsinaffiliateMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=ajx_GregoryFundingLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=ajx_LoanServicingFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ajx_GaeaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=ajx_LegacyEntitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ajx_GreatAjaxFinancialServicesLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ajx_AjaxMortgageLoanTrust2021CMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Related Party Transactions - Schedule Statement of Income of Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Related Party Transaction [Line Items]
Related party expense – management fee	$ 2,270	$ 2,143	$ 4,543	$ 3,942
Related party expense – loan servicing fees	1,699	1,936	3,532	3,950
Loss on sale of mortgage loans			0	(705)
Net interest income after the impact of changes in the net present value of expected cash flows
Related Party Transaction [Line Items]
Amount of transaction	8,844	7,831	14,796	9,850
Thetis Asset Management LLC
Related Party Transaction [Line Items]
Related party expense – management fee		2,100		3,900
Thetis Asset Management LLC \| Management fee
Related Party Transaction [Line Items]
Related party expense – management fee	2,267	2,143	4,537	3,942
Thetis Asset Management LLC \| Income/(loss) from investments in affiliates
Related Party Transaction [Line Items]
Amount of transaction	283	527	451	(439)
Servicer \| Related party expense – loan servicing fees
Related Party Transaction [Line Items]
Related party expense – loan servicing fees	1,699	1,936	3,532	3,950
Gaea \| Income/(loss) from investments in affiliates
Related Party Transaction [Line Items]
Amount of transaction	42	56	60	60
Gaea \| Loss on sale of mortgage loans
Related Party Transaction [Line Items]
Loss on sale of mortgage loans			0	(705)
AS Ajax E LLC \| Income/(loss) from investments in affiliates
Related Party Transaction [Line Items]
Amount of transaction	7	6	16	16
Investment in Loan pool LLCs \| Income/(loss) from investments in affiliates
Related Party Transaction [Line Items]
Amount of transaction	(14)	(23)	(21)	56
Servicer \| Income/(loss) from investments in affiliates
Related Party Transaction [Line Items]
Amount of transaction	7	72	(55)	(204)
2021-C \| Other income
Related Party Transaction [Line Items]
Amount of transaction	$ 122	$ 0	$ 122	$ 0