Name:	abr_CurrentInterestCoverageRatioCovenantCompliance
Namespace Prefix:	abr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the overcollateralization ratio maintained during the period under covenant compliance. Overcollateralization ratio is calculated by dividing the total principal balance of all collateral in the CDO by the total principal balance of the bonds associated with the applicable ratio.

No definition available.

Name:	abr_CurrentOvercollateralizationRatioCovenantCompliance
Namespace Prefix:	abr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the amount payable on default of senior debt under debt instrument.

No definition available.

Name:	abr_DebtInstrumentCovenantsAmountPayableOnDefaultOfSeniorDebt
Namespace Prefix:	abr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the interest coverage ratio required to be maintained under covenant compliance. Interest coverage ratio is calculated by dividing interest income by interest expense for the classes senior to those retained by the entity.

No definition available.

Name:	abr_InterestCoverageRatioCovenantCompliance
Namespace Prefix:	abr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the overcollateralization ratio required to be maintained under covenant compliance. Overcollateralization ratio is calculated by dividing the total principal balance of all collateral in the CDO by the total principal balance of the bonds associated with the applicable ratio.

No definition available.

Name:	abr_OvercollateralizationRatioCovenantCompliance
Namespace Prefix:	abr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

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

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

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

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

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