Noncontrolling Interests (Operating Partnership Of Preferred Units Outstanding) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Noncontrolling Interest [Line Items]
Units Outstanding	223,300	2,136,700
Amount	$ 5,583	$ 53,418
Series J [Member]
Noncontrolling Interest [Line Items]
Issuance Date	May & June, 2004
Dividend Rate	7.50%
Units Outstanding		1,710,000
Amount		42,750
Series N [Member]
Noncontrolling Interest [Line Items]
Issuance Date	December, 2005
Earliest Potential Redemption Date	Dec. 01, 2010
Dividend Rate	7.125%
Units Outstanding	223,300	223,300
Amount	5,583	5,583
Series Q [Member]
Noncontrolling Interest [Line Items]
Issuance Date	March, 2007
Dividend Rate	6.55%
Units Outstanding		203,400
Amount		$ 5,085

The number of preferred units outstanding.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-Subparagraph (SAB TOPIC 4.F)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187171-122770

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section F

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 87-21

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Practice Bulletin (PB)

-Number 14

-Paragraph 8, 10, 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant