Discontinued Operations (Narratives) (Details) (USD $)	12 Months Ended				12 Months Ended				12 Months Ended			3 Months Ended	12 Months Ended		3 Months Ended				12 Months Ended
	Dec. 31, 2013 property	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2014 property	Dec. 31, 2013 Hotel	Dec. 31, 2012 Hotel	Dec. 31, 2013 Assets held-for-sale property	Jan. 31, 2014 Assets held-for-sale property	Dec. 31, 2012 Domestic Properties Thirteen property	Dec. 31, 2011 Domestic Properties Thirteen	Dec. 31, 2012 Merger Property [Member]	Dec. 31, 2013 Self-storage property	Dec. 31, 2013 Self-storage officer property	Dec. 31, 2012 Be Aerospace	Sep. 30, 2011 Career Education Institute	Dec. 31, 2010 Career Education Institute	Dec. 31, 2013 Officers Self-storage	Dec. 31, 2013 Third Party Self-storage	Dec. 31, 2013 Real Estate Ownership	Dec. 31, 2012 Real Estate Ownership	Dec. 31, 2011 Real Estate Ownership	Dec. 31, 2013 Domestic property	Dec. 31, 2012 Domestic	Dec. 31, 2011 Domestic property	Dec. 31, 2013 Domestic Real Estate Ownership	Dec. 31, 2012 Domestic Real Estate Ownership	Dec. 31, 2011 Domestic Real Estate Ownership
Discontinued Operation Additional Disclosures
Properties sold				6				6	13			19	19									7		7
Proceeds from the sale of properties					$ 3,700,000				$ 44,800,000		$ 1,400,000		$ 112,300,000	$ 25,300,000								$ 22,700,000		$ 12,500,000
Gain (Loss) on Sale of Equity Investments	52,472,000	87,921,000	85,632,000									39,600,000							51,704,000	84,043,000	82,937,000				48,405,000	77,441,000	76,764,000
Gain (loss) on the sale of real estate	39,711,000	(2,773,000)	(3,391,000)		(200,000)				(1,400,000)					(500,000)								600,000		(3,400,000)
Impairment recognized on asset to be disposed					1,100,000	10,500,000	3,400,000		12,500,000	11,800,000						5,600,000						3,900,000	200,000	100,000
Payment of mortgage obligation													45,100,000									5,700,000
Gain (loss) on extinguishment of debt, net of tax	(2,415,000)	0	0										(2,500,000)									100,000
Number of officers													2
Ownership interest of jointed owned investment												38.30%	38.30%				1.70%	60.00%
Number of real estate properties	418											20	20
Net income attributable to noncontrolling interest												24,400,000
Loss on extinguishment of debt attributable to noncontrolling interest, net of tax													(1,500,000)
Distribution to noncontrolling interest holders	72,059,000	7,314,000	7,258,000										40,800,000
Non-recourse mortgage															6,300,000
Net investments in properties	2,353,391,000	2,298,123,000													5,300,000
Goodwill allocation adjustment	13,118,000	3,158,000																	13,118,000	3,158,000
Number of properties held for sale							9
Assets held for sale							117,500,000
Intangible assets and goodwill, disposed											3,200,000
Gain on deconsolidation of a subsidiary	$ 0	$ 0	$ 1,008,000												$ 1,000,000