Acquisitions and Dispositions (Summary of Preliminary Allocation of Fair Value of Amounts Recognized) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Real estate assets	$ 403,616
Lease-related intangible assets	56,536
Other assets	4,372
Total acquired assets	464,524
Secured debt	283,241
Other liabilities	8,359
Total assumed liabilities	291,600
Fair value of acquired net assets	172,924
Premier Portfolio [Member]
Real estate assets	153,656	249,960
Lease-related intangible assets	25,445	31,091
Other assets	2,571	1,801
Total acquired assets	181,672	282,852
Secured debt	125,003	158,238
Other liabilities	4,284	4,075
Total assumed liabilities	129,287	162,313
Fair value of acquired net assets	52,385	120,539
Other 2011 Acquisitions [Member]
Real estate assets	161,825
Lease-related intangible assets	22,879
Other assets	338
Total acquired assets	185,042
Secured debt	20,138
Other liabilities	1,588
Total assumed liabilities	21,726
Fair value of acquired net assets	$ 163,316

This element represents the amount of value allocated by a lesser (acquirer) to lease agreements which exist at acquisition of a leased property. Such amount includes the value assigned to tenant relationships and the market adjustment for above-market leases, but excludes the market adjustment for below market leases (which are classified as other liabilities).

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- Definition

The amount of acquisition cost of a business combination allocated to assets acquired.

+ References

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The total purchase price of the acquired entity. This includes cash paid to equity interest holders of the acquired entity, fair value of debt and equity securities issued to equity holders of the acquired entity, and transaction costs paid to third parties to consummate the acquisition.

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- Definition

The amount of acquisition cost of a business combination allocated to other current liabilities of the acquired entity. Does not include amounts allocated to the current portion of long-term debt, accounts payable and accrued expenses.

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- Definition

The amount of acquisition cost of a business combination allocated to liabilities assumed.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-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.

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 98-1

-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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The amount of acquisition cost of a business combination allocated to the noncurrent portion of the long-term debt assumed from the acquired entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-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.

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 98-1

-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.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-Subparagraph g

-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

The amount of acquisition cost of a business combination allocated to noncurrent assets of the acquired entity, except for property plant and equipment, intangible assets, and goodwill.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-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.

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 98-1

-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.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-Subparagraph f

-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

The amount of acquisition cost of a business combination allocated to land and building to be used in the normal course of business, not including assets that are held-for-sale.

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