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Represents the accumulated amount of amortization of a major finite-lived intangible liability class.

+ References

No definition available.

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- Definition

Represents the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible liabilities having statutory or estimated useful lives.

+ References

No definition available.

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- Definition

Represents the sum of gross carrying value of a major finite-lived intangible liability class, less accumulated amortization.

+ References

No definition available.

+ Details

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- Definition

Represents the increase (decrease) in interest expense during the period resulting from the amortization of assumed above-market rate mortgages.

+ References

No definition available.

+ Details

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- Definition

Represents the increase (decrease) in rental revenue during the period resulting from the net amortization of acquired above-market and below-market leases.

+ References

No definition available.

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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Significant Accounting Policies (Details 2) (USD $)	3 Months Ended
Significant Accounting Policies (Details 2) (USD $)	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Investment in Commercial Real Estate Properties
Increase in rental revenue from amortization of acquired leases	$ 3,900,000	$ 2,100,000
Reduction in interest expense from amortization of above-market rate mortgages	1,300,000	1,000,000
Identified intangible assets (included in other assets):
Gross amount	725,708,000		725,861,000
Accumulated amortization	(279,714,000)		(263,107,000)
Net	445,994,000		462,754,000
Identified intangible liabilities (included in deferred revenue):
Gross amount	652,117,000		651,921,000
Accumulated amortization	(374,239,000)		(357,225,000)
Net	$ 277,878,000		$ 294,696,000
Other intangible assets \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
Other intangible assets \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
Above-market leases \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
Above-market leases \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
Below-market leases \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
Below-market leases \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
In-place leases \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
In-place leases \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
Buildings \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life	3 years
Buildings \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life	40 years