Consolidation of Variable Interest Entities - Schedule of Accrual Status of Residential Mortgage Loans of Consolidated VIE (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	$ 29,375	$ 29,697
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	203,456	7,442
Variable Interest Entity, Primary Beneficiary \| Business Purpose Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	3,750	$ 7,442
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	3,908
Difference	(158)
Variable Interest Entity, Primary Beneficiary \| Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	199,706
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	233,322
Difference	(33,616)
Less than 90 Days Past Due \| Accrual Status \| Variable Interest Entity, Primary Beneficiary \| Business Purpose Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	151
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	151
Less than 90 Days Past Due \| Accrual Status \| Variable Interest Entity, Primary Beneficiary \| Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	198,876
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	232,353
Difference	(33,477)
90 Days or More Past Due \| Non-accrual Status \| Variable Interest Entity, Primary Beneficiary \| Business Purpose Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	3,599
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	3,757
Difference	(158)
90 Days or More Past Due \| Non-accrual Status \| Variable Interest Entity, Primary Beneficiary \| Residential Mortgage Loans
Variable Interest Entity [Line Items]
Loans Receivable, Fair Value Disclosure	830
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	969
Difference	$ (139)

The excess of the fair value amount over unpaid principal balance of loans.

No definition available.

Name:	aaic_AggregateDifferenceOfFairValueLoansOverUnpaidPrincipalBalance
Namespace Prefix:	aaic_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI https://asc.fasb.org/subtopic&trid=2196772

+ Details

Name:	us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G))
-URI https://asc.fasb.org/extlink&oid=120402547&loc=d3e617274-123014

+ Details

Name:	us-gaap_MortgageLoansOnRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

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

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=aaic_BusinessPurposeResidentialMortgageLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_PerformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_NonperformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: