Minimum variable interest rate for loans receivable.

No definition available.

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

- Definition

Represents the fixed interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

+ References

No definition available.

+ Details

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Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the cash outflow during the reporting period in respect of payments for loans and investments funded and purchased by the reporting entity.

+ References

No definition available.

+ Details

Name:	abr_PaymentForLoansAndInvestmentsFundedOriginatedAndPurchased
Namespace Prefix:	abr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of equity participation interest.

+ References

No definition available.

+ Details

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Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum amount the entity agreed to fund under the related party commitment.

+ References

No definition available.

+ Details

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Namespace Prefix:	abr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The upsized amount the entity agreed to fund under the related party commitment.

+ References

No definition available.

+ Details

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

- 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

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-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

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

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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
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-SubTopic 10
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+ Details

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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

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
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
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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

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

- Details

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Period Type:

- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=abr_OtherRelatedPartyTransactionsMember
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Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_SingleFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	abr_LoansReceivableMaturityAxis=abr_MaturityDateDecember2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_AcquisitionFinancingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	abr_LoansReceivableMaturityAxis=abr_MaturityDateOfMay2025Member
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Period Type:

- Details

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Period Type:

- Details

Name:	abr_LoansReceivableMaturityAxis=abr_MaturesInApril2023Member
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Period Type:

- Details

Name:	abr_LoansReceivableMaturityAxis=abr_MaturityDateApril2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_MultifamilyMember
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Data Type:	na
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Name:	abr_LoansReceivableMaturityAxis=abr_MaturityDateJuly2023Member
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Agreements and Transactions with Related Parties - 2020 Activity (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($) property	Nov. 30, 2023 USD ($)	Apr. 30, 2023 USD ($)	Dec. 31, 2021 USD ($)
Agreements and Transactions with Related Parties
Loans and investments funded, originated and purchased			$ 615,518	$ 867,804
Interest income	$ 297,188	$ 335,737	618,480	663,685
Related Party
Agreements and Transactions with Related Parties
Amount invested									$ 4,200
Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Equity participation interest (as a percentage)						18.90%
Bridge loans \| Other Related Party Transactions \| Immediate Family Member of Management or Principal Owner
Agreements and Transactions with Related Parties
Equity participation interest (as a percentage)						21.80%
Single-Family Rental \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Loan committed			38,900
Loans and investments funded, originated and purchased						$ 3,500
Loan committed upsized							$ 39,900	$ 38,900
Single-Family Rental \| Preferred equity investments \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Loans and investments funded, originated and purchased						$ 4,600
Single-Family Rental \| Mezzanine Loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Interest income	100	100	200	100
Maturity Date December 2023 \| Other Related Party Transactions \| Immediate Family Member of Management or Principal Owner \| Preferred equity interest financing agreement
Agreements and Transactions with Related Parties
Interest income	1,100		2,100
Maturity Date December 2023 \| Bridge loans \| Other Related Party Transactions \| Immediate Family Member of Management or Principal Owner
Agreements and Transactions with Related Parties
Base spread, percentage						3.75%
SOFR floor, percentage						0.75%
Interest income		600		1,200
Maturity Date December 2023 \| Preferred equity investments \| Other Related Party Transactions \| Immediate Family Member of Management or Principal Owner
Agreements and Transactions with Related Parties
Fixed rate of interest						12.00%
Maturity Date December 2023 \| Single-Family Rental \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Loan committed						$ 32,500
Maturity date of May 2025 \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Loan committed			10,600
Equity participation interest (as a percentage)					2.25%
Base spread, percentage					4.63%
SOFR floor, percentage					0.25%
Interest income	300		400
Principal amount					$ 67,100
Maturity date of May 2025 \| Single-Family Rental \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Loan committed						$ 30,500
Matures in May 2023 \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Base spread, percentage						4.25%
SOFR floor, percentage						1.00%
Amount invested	35,200		35,200
Matures in April 2023 \| Bridge loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Interest income	1,100	$ 800	2,300	$ 1,500
Matures in April 2023 \| Preferred equity investments \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Fixed rate of interest						12.00%
Maturity Date April 2030 \| Bridge loan, two multifamily properties \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Principal amount						$ 14,800
Percentage of ownership interest of related party in the entity						50.00%
Maturity Date April 2030 \| Mezzanine Loans \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Fixed rate of interest						9.00%
Maturity Date April 2030 \| Multifamily \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Number of real estate properties \| property						2
Maturity Date April 2030 \| Multifamily \| Preferred equity investments \| Other Related Party Transactions \| Related Party
Agreements and Transactions with Related Parties
Equity investment						$ 3,400
Maturity Date July 2023 \| Bridge loans \| Related Party
Agreements and Transactions with Related Parties
Principal amount	35,000		35,000
Maturity Date June 2027 \| Preferred equity investments \| Related Party
Agreements and Transactions with Related Parties
Equity investment	$ 10,000		$ 10,000