Minimum variable interest rate for loans receivable.

No definition available.

Name:	abr_LoansReceivableFloorInterestRate
Namespace Prefix:	abr_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of ownership of common stock or equity participation owned by related party.

+ References

No definition available.

+ Details

Name:	abr_RelatedPartyOwnershipPercentage
Namespace Prefix:	abr_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contractual principal due at origination of mortgage loan within 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
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Paragraph Column F
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column F))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

+ Details

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Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1)(e))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

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-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14(Column E)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6

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-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6

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-Topic 946
-SubTopic 830
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-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477346/946-830-45-39

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(1)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

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-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14(Column E)(Footnote 6)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6

+ Details

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

- Definition

Percentage added to reference rate used to compute variable rate on loan receivable.

+ References

No definition available.

+ Details

Name:	us-gaap_LoansReceivableBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

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-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

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-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

+ Details

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

- Details

Name:	abr_LoansReceivableMaturityAxis=abr_MaturityDateOfAugust2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=abr_BridgeLoanOneMultifamilyPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=abr_OtherRelatedPartyTransactionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_RelatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_BridgeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=abr_BridgeLoanSeveralMultifamilyPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Agreements and Transactions with Related Parties - 2018 Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2018
Agreements and Transactions with Related Parties
Interest income	$ 297,188	$ 335,737	$ 618,480	$ 663,685
Maturity date of August 2023 \| Bridge loan, one multifamily property \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Principal amount					$ 21,700
Maturity date of August 2023 \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Percentage of ownership interest of related party in the entity					75.00%
Interest income	$ 600	$ 500	$ 1,100	$ 1,000
Maturity date of August 2023 \| Bridge loan, several multifamily properties \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Base spread, percentage					4.75%
SOFR floor, percentage					0.25%