Name:	abr_AllowanceForLoanLossChargeOffs
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Represents the number of loans with unpaid principal balance.

No definition available.

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Represents the weighted average accrual rate of interest of impaired financing receivables.

No definition available.

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Reflects the percentage derived from recoveries to the average loans and investments outstanding.

No definition available.

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Represents the number of loans for which the value of the collateral securing the loan was less than the carrying value of the loan for which the entity has not recorded a provision for loan loss.

No definition available.

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The amount of proceeds related to previously written-off loans and investments.

No definition available.

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The cash inflow associated with the full satisfaction of a preferred equity investment.

No definition available.

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Represents the gross amount charged against earnings during the period as credit losses (bad debt expense) based on review of the loan and lease portfolio and application of the methodology for estimating credit losses.

No definition available.

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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.

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Number of mortgage loans 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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of decrease in 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, from sale.

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The cash inflow from proceeds from sale of receivables arising from the mortgage note on real estate; includes collections on mortgage notes receivable that are not classified as operating cash flows.

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Amount of expense related to estimated loss from loan and lease transactions.

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Name:	abr_NumberOfLoansUnpaidPrincipalBalanceAxis=abr_SixLoansCollateralizedByLandDevelopmentProjectMember
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Name:	srt_MortgageLoansOnRealEstateLoanTypeAxis=abr_MezzanineLoanMember
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