Goodwill and Other Intangibles (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Related Party Transaction [Line Items]
Number of segments | segment			2
Intangible assets	$ 127,835		$ 127,835		$ 150,359
Managed REITs [Member] | Management And Advisory Contracts [Member]
Related Party Transaction [Line Items]
Intangible assets	150,400	$ 385,600	150,400	$ 385,600
Intangible assets, accumulated amortization	(22,500)	(62,300)	$ (22,500)	(62,300)
Estimated useful life			5 years
Amortization expense	7,500	$ 24,300	$ 22,500	$ 62,300
Estimated amortization expense for remainder of fiscal year	7,600		7,600
Estimated amortization expense, 2016	30,100		30,100
Estimated amortization expense, 2017	30,100		30,100
Estimated amortization expense, 2018	30,100		30,100
Estimated amortization expense, 2019	$ 30,100		$ 30,100