Segment Information (Details 3) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Net real estate property:
United States	$ 15,598,457	$ 4,857,510
Canada	397,585	422,009
Net real estate property	$ 15,996,042	$ 5,279,519

Amount of long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets, located in foreign countries in total in which the entity holds assets.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 38

-Subparagraph b(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 41

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Name:	us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInForeignCountries
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant