Investments in Partially Owned Entities (Parentheticals) (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Oct. 31, 2008	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Toys R Us [Member]
Gain Loss Related To Litigation Settlement				$ 10,200
Equity Method Investment Income Tax Expense		(1,132)	(45,418)	(13,185)
Lexington Realty Trust [Member]
Gain on Stock Issuance		9,760	13,710
Prior Period Non Cash Impairment Charges	107,882
Impairment loss				19,121
LNR [Member]
Equity Method Investment Income Tax Expense		(12,380)
Tax Adjustments, Settlements, and Unusual Provisions		8,977
Net gains from asset sales		6,020
India real estate ventures [Member]
Impairment loss		13,794
Other equity method investments [Member]
Prior Period Non Cash Impairment Charges			11,481	17,820
Other equity method investments [Member] | Verde Realty Operating Partnership [Member]
Impairment loss				14,515
Other equity method investments [Member] | Downtown Crossing [Member]
Lease termination payment				$ 7,650