Real Estate - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended	3 Months Ended
Sep. 30, 2013	Jun. 30, 2013 Property	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Europe and Japan [Member]	Mar. 31, 2013 Europe and Japan [Member]
Real Estate Properties [Line Items]
Gains on acquisitions and dispositions of investments in real estate, net	$ 46,074,000	$ 56,900,000	$ 12,677,000	$ 445,954,000	$ 280,968,000	$ 43,700,000	$ 337,900,000
Number of properties contributed		1
Gains on Acquisitions and Dispositions of Investments in Real Estate				$ 446,000,000

The gain (loss) resulting from the sale of a disposal group that is not a discontinued operation. It is included in income from continuing operations before income taxes in the income statement.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228

Name:	us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration