Intangible Assets (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Intangible assets
Total Cost	$ 194,483	$ 222,160
Accumulated Amortization	(116,082)	(124,698)
Intangible assets, net	78,401	97,462
Below market leases acquired	25,556	29,233
Customer Relationships [Member]
Intangible assets
Total Cost	80,242	95,385
Accumulated Amortization	(46,041)	(52,113)
Intangible assets, net	34,201	43,272
Leases, Acquired-in-Place [Member]
Intangible assets
Total Cost	97,523	108,456
Accumulated Amortization	(61,390)	(63,010)
Intangible assets, net	36,133	45,446
Above market tenant leases acquired [Member]
Intangible assets
Total Cost	16,718	18,319
Accumulated Amortization	(8,651)	(9,575)
Intangible assets, net	8,067	8,744
Below market ground lease acquired [Member]
Intangible assets
Total Cost	66,402	67,198
Accumulated Amortization	$ (40,846)	$ (37,965)

The accumulated amount of amortization of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph a(1)

+ Details

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- Definition

Sum of the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible assets having statutory or estimated useful lives. The aggregate gross carrying amount (including any previously recognized impairment charges) of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph a(1)

+ Details

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- Definition

The aggregate sum of gross carrying value of a major finite-lived intangible asset class, less accumulated amortization and any impairment charges. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph a(1)

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- Definition

This element represents a liability associated with the acquisition of an off-market lease when the terms of the lease are unfavorable to the market terms for the lease at the date of acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 37

+ Details

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