Noncontrolling Interests - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Consolidated joint ventures and funds	$ 685,176us-gaap_MinorityInterestInJointVentures	$ 685,888us-gaap_MinorityInterestInJointVentures
Operating partnerships	$ 994,799	$ 958,203

Carrying amount of the equity interests owned by noncontrolling shareholders, partners, or other equity holders in joint ventures included in the entity's consolidated financial statements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4568740-111683

Name:	us-gaap_MinorityInterestInJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant