Significant Transactions (Details 2) (Series of Individually Immaterial Business Acquisitions [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013 Property	Dec. 31, 2012 Property
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of apartment homes	134	614
Acquisition price	$ 53,575	$ 126,873
Non-recourse property debt assumed (outstanding principal balance)	12,446	38,819
Non-recourse property debt assumed (fair value)	14,767	43,938
Total fair value allocated to real estate	$ 55,896	$ 130,547

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7488404&loc=d3e6927-128479

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