Represents the amount of impairment loss from real estate owned.

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

Represents the liability for mortgage notes payable by the reporting entity in connection with the acquisition of real property which is held-for-sale.

+ References

No definition available.

+ Details

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- Definition

Represents the liability for mortgage notes payable by the reporting entity in connection with the acquisition of real property.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the number of properties reclassified as real estate held for sale.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Represents the number of real estate properties sold within the portfolio.

+ References

No definition available.

+ Details

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Namespace Prefix:	abr_
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Balance Type:	na
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- Details

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- Definition

Represents the number of properties classified as real estate owned by the entity, as of the balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of weighted average daily rate of properties classified as real estate owned.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Represents the weighted average occupancy rate of properties classified as real estate owned.

+ References

No definition available.

+ Details

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Namespace Prefix:	abr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of weighted average revenue per available room of properties classified as real estate owned.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

The value of notes retired (or transferred to another entity) in noncash investing or financing transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

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-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 4

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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- Definition

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

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- Definition

Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

+ References

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(3))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 7

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Real Estate Owned and Held-For-Sale (Details) (USD $)	9 Months Ended																				3 Months Ended				9 Months Ended		3 Months Ended
Real Estate Owned and Held-For-Sale (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Multifamily Portfolio	Dec. 31, 2013 Multifamily Portfolio	Sep. 30, 2014 Hotel Portfolio	Dec. 31, 2013 Hotel Portfolio	Sep. 30, 2014 Land	Dec. 31, 2013 Land	Sep. 30, 2014 Land Multifamily Portfolio	Dec. 31, 2013 Land Multifamily Portfolio	Sep. 30, 2014 Land Hotel Portfolio	Dec. 31, 2013 Land Hotel Portfolio	Sep. 30, 2014 Building and intangible assets	Dec. 31, 2013 Building and intangible assets	Sep. 30, 2014 Building and intangible assets Multifamily Portfolio	Dec. 31, 2013 Building and intangible assets Multifamily Portfolio	Sep. 30, 2014 Building and intangible assets Hotel Portfolio	Dec. 31, 2013 Building and intangible assets Hotel Portfolio	Sep. 30, 2014 Real Estate owned	Dec. 31, 2013 Real Estate owned	Sep. 30, 2014 Real Estate owned Multifamily Portfolio item	Jun. 30, 2014 Real Estate owned Multifamily Portfolio	Mar. 31, 2014 Real Estate owned Multifamily Portfolio	Dec. 31, 2013 Real Estate owned Multifamily Portfolio	Sep. 30, 2014 Real Estate owned Hotel Portfolio item	Sep. 30, 2013 Real Estate owned Hotel Portfolio	Sep. 30, 2014 Real Estate held for sale Multifamily Portfolio item	Dec. 31, 2014 Real Estate held for sale Multifamily Portfolio Subsequent event item	Sep. 30, 2014 First mortgage Multifamily Portfolio	Jun. 30, 2014 First mortgage Multifamily Portfolio
Real Estate owned
Real estate owned, gross							$ 16,432,495	$ 22,276,230	$ 5,538,844	$ 11,382,579	$ 10,893,651	$ 10,893,651	$ 94,250,878	$ 107,748,075	$ 31,129,305	$ 46,115,430	$ 63,121,573	$ 61,632,645
Less: accumulated depreciation and amortization	(19,945,236)	(18,306,128)	(7,077,163)	(8,598,915)	(12,868,073)	(9,707,213)
Real estate owned, net	90,738,137	111,718,177	29,590,986	48,899,094	61,147,151	62,819,083																11,400,000
Number of properties																					3				5
Number of properties sold																												1
Proceeds from sale of properties																					3,100,000
Gain on sale of property																					(200,000)							500,000
Reduction of mortgage note payable																					3,400,000
Weighted average occupancy rate of properties (as a percent)																					86.00%			85.00%	57.00%	56.00%
Impairment loss on real estate owned	250,000																						300,000
Amount of weighted average daily rate of properties																									79	80
Amount of weighted average daily rate of properties																									44	45
First lien mortgage - real estate owned	25,022,701	42,745,650																			25,000,000			42,700,000						11,000,000
Depreciation in connection with reclassification of property from real estate held-for-sale to real estate owned, net																						300,000
Restricted cash due to escrow requirement	143,848,917	54,962,316																	1,500,000	900,000
Real Estate Held-For-Sale
Number of properties reclassified as real estate held-for-sale																											3
Carrying value of real estate properties classified as held-for-sale																											26,400,000	11,000,000	23,800,000
Mortgage notes payable-held-for-sale	$ 23,791,205	$ 11,005,354