Equity Investment in Real Estate and the Managed REITs (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Combined Equity Investments
Equity Method Investment Summarized Financial Information Income Statement
Revenues	$ 64,294	$ 117,278	$ 108,242
Expenses	(27,801)	(50,907)	(64,453)
(Loss) income from continuing operations	36,493	66,371	43,789
Net (loss) income attributable to the Managed Programs or jointly owned investments	36,493	15,762	79,591
Managed Programs
Equity Method Investment Summarized Financial Information Income Statement
Revenues	825,405	796,637	860,983
Expenses	(838,100)	(701,830)	(759,435)
(Loss) income from continuing operations	(12,695)	94,807	101,548
Net (loss) income attributable to the Managed Programs or jointly owned investments	$ (12,695)	$ 104,342	$ 128,455