Provision charged for the period based on estimated losses to be realized from rent transactions.

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock, less than ten percent in the investee accounted for under the cost method of accounting.

+ References

No definition available.

+ Details

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Namespace Prefix:	are_
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Balance Type:	na
Period Type:	instant

- Definition

Represents the maximum period within which sale of property is expected to be completed.

+ References

No definition available.

+ Details

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Namespace Prefix:	are_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of annual taxable income which must be distributed to stockholders in order to comply with requirements of the federal tax law for treatment as a real estate investment trust.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The "more likely than not" threshold is based on a cumulative probability model under which the largest amount of tax benefit recognized is the amount with a likelihood greater than this percentage of being realized upon ultimate settlement with the taxing authority having full knowledge of all relevant information.

+ References

No definition available.

+ Details

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Namespace Prefix:	are_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of leases containing effective annual rent escalations.

+ References

No definition available.

+ Details

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Namespace Prefix:	are_
Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Represents the percentage of leases that provided for the recapture of certain capital expenditures.

+ References

No definition available.

+ Details

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

- Definition

The entity generally distributes this percentage or more of its taxable income.

+ References

No definition available.

+ Details

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Namespace Prefix:	are_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of leases which are triple net leases.

+ References

No definition available.

+ Details

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

- Definition

The sum of domestic current and deferred income tax expense or benefit attributable to continuing operations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32672-109319

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Income Tax Expense (or Benefit)

-URI http://asc.fasb.org/extlink&oid=6515339

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 1

-Article 4

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Data Type:	xbrli:monetaryItemType
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- Definition

Interest generated from day to day operating activities of the business. This element represents a revenue generating activity and is therefore gross (before any related cost of revenue items).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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Period Type:	duration

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Data Type:	xbrli:stringItemType
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- Definition

The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 48

-Paragraph 21

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Basis of presentation (Details 2) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
Basis of presentation (Details 2) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Maximum expected period of sale of property (in years)			1 year
Cost method investment ownership percentage	10.00%		10.00%		10.00%
Minimum percentage of taxable income to be distributed			100.00%
The Company generally distributes this percentage or more of its taxable income			100.00%
Provision for federal income taxes			$ 0
The "more likely than not" probability threshold (as a percent)			50.00%
Unrecognized tax benefits	0		0
Interest income included in other income	1,200,000	1,000,000	3,500,000	2,500,000
Allowance for estimated losses			$ 0		$ 0
Percentage of leases which are triple net leases	94.00%		94.00%
Percentage of leases containing effective annual rent escalations	95.00%		95.00%
Percentage of leases providing for recapture of certain capital expenditures	92.00%		92.00%