Equity Investment in Real Estate and the Managed REITs (Narratives) (Details) (USD $)	12 Months Ended					12 Months Ended								0 Months Ended	12 Months Ended															0 Months Ended				12 Months Ended				12 Months Ended										1 Months Ended	3 Months Ended			1 Months Ended				3 Months Ended	12 Months Ended		1 Months Ended				1 Months Ended					1 Months Ended
	Dec. 31, 2013 property	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2014 property	Dec. 31, 2007 Propco property	Dec. 31, 2013 Combined Equity Investments	Dec. 31, 2012 Combined Equity Investments	Dec. 31, 2011 Combined Equity Investments	Dec. 31, 2013 Real Estate Investments	Dec. 31, 2012 Real Estate Investments	Dec. 31, 2011 Real Estate Investments	Dec. 31, 2012 CPA: 15	Sep. 28, 2012 CPA: 15 property	May 02, 2011 CPA 14/16 Merger	Dec. 31, 2013 CPA: 16 - Global property	Dec. 31, 2012 CPA: 16 - Global	Dec. 31, 2011 CPA: 16 - Global	Dec. 31, 2011 CPA: 16 - Global CPA 14/16 Merger	Dec. 31, 2011 CPA: 16 - Global CPA 14/16 Merger Combined Equity Investments	Dec. 31, 2011 CPA: 16 - Global CPA 14/16 Merger Real Estate Investments	Dec. 31, 2013 CPA:16 - Global operating partnership	Dec. 31, 2012 CPA:16 - Global operating partnership	Dec. 31, 2011 CPA:16 - Global operating partnership	Dec. 31, 2013 CPA: 17 - Global	Dec. 31, 2012 CPA: 17 - Global	Dec. 31, 2011 CPA: 17 - Global	Dec. 31, 2013 CPA:17 - Global operating partnership	Dec. 31, 2012 CPA:17 - Global operating partnership	Dec. 31, 2011 CPA:17 - Global operating partnership	Dec. 14, 2012 CPA:18 - Global	Sep. 13, 2012 CPA:18 - Global	Dec. 31, 2013 CPA:18 - Global	Dec. 31, 2012 CPA:18 - Global	Dec. 31, 2013 CPA:18 - Global operating partnership	Jul. 03, 2013 CPA:18 - Global operating partnership	Dec. 31, 2013 CWI	Dec. 31, 2012 CWI	Dec. 31, 2013 Managed REITs	Dec. 31, 2012 Managed REITs	Dec. 31, 2011 Managed REITs	Dec. 31, 2012 Managed REITs CPA: 15	Dec. 31, 2011 CPA 14 CPA 14/16 Merger	Dec. 31, 2013 Managed Reits [Member]	Dec. 31, 2012 Managed Reits [Member]	Dec. 31, 2011 Managed Reits [Member]	Dec. 31, 2013 Managed Reits [Member] CPA:16 - Global operating partnership	Dec. 31, 2012 Managed Reits [Member] CPA:16 - Global operating partnership	Jun. 30, 2013 U.S. Airways Group, Inc.	Jun. 30, 2013 U.S. Airways Group, Inc.	Dec. 31, 2013 U.S. Airways Group, Inc. Real Estate Investments	Dec. 31, 2012 U.S. Airways Group, Inc. Real Estate Investments	Dec. 31, 2012 Wanbishi Archives Co. Ltd.	Dec. 31, 2012 Wanbishi Archives Co. Ltd. Real Estate Investments	Dec. 31, 2013 Wanbishi Archives Co. Ltd. Real Estate Investments	Dec. 31, 2012 Wanbishi Archives Co. Ltd. CPA: 17 - Global	Jun. 30, 2012 Medica France, S.A.	Dec. 31, 2012 Medica France, S.A. Combined Equity Investments	Dec. 31, 2011 Symphony IRI Group Inc Combined Equity Investments	Oct. 31, 2013 The Talaria Company (Hinckley) property	Dec. 31, 2013 The Talaria Company (Hinckley) Real Estate Investments	Dec. 31, 2012 The Talaria Company (Hinckley) Real Estate Investments	Oct. 31, 2013 The Talaria Company (Hinckley) CPA: 16 - Global	Oct. 31, 2013 Hellweg 2 Propco	Dec. 31, 2010 Hellweg 2 Propco	Nov. 30, 2010 Hellweg 2 Propco	Dec. 31, 2007 Hellweg 2 Propco	Dec. 31, 2007 Hellweg 2 CPA: 16 - Global	Oct. 31, 2013 Hellweg 2 CPA: 17 - Global	Dec. 31, 2007 Hellweg 2 CPA 14	Dec. 31, 2007 Hellweg 2 CPA: 15
Investments in REITs
Asset management fees receivable, shares																								197,231								3,781				43,850
Distributions received from equity investment									$ 25,900,000	$ 20,000,000	$ 15,300,000				$ 25,300,000	$ 24,300,000	$ 12,400,000				$ 15,200,000	$ 15,400,000	$ 6,200,000	$ 3,000,000	$ 1,600,000	$ 600,000	$ 16,900,000	$ 14,600,000	$ 9,400,000																														$ 4,200,000
Percentage of total assets (more than 20%)																	20.00%
Gain or loss on sale of investment properties	39,711,000	(2,773,000)	(3,391,000)																																			7,700,000	35,400,000	45,400,000		78,800,000															34,000,000
Gain from difference in market value and cost																		28,700,000
Other-than-temporary impairment charges																																						25,600,000	25,000,000	57,700,000			15,383,000	9,910,000	0	15,400,000	9,900,000
Mortgage debt tenants in common									171,000,000
Pro rata share mortgage debt on tenancy in common									43,900,000
Income from equity method investments	52,731,000	62,392,000	51,228,000															5,000,000	(2,400,000)	(500,000)																		(4,700,000)	(4,200,000)	(7,800,000)	(200,000)	7,400,000	7,057,000	8,867,000	19,912,000												15,100,000	400,000					(8,400,000)
Impairment charges	5,294,000	0	(1,365,000)			0	0	8,602,000																																																		8,600,000
Aggregate unamortized basis difference on equity investments									8,900,000																													9,700,000
Other Transactions
Related Party shares owned																															1,000
Common stock, per share value	$ 0.001	$ 0.001																													$ 0.001
Payments to purchase common stock																															9,000
Capital distributions																														200,000
Shares exchanged																														22,222
Equity method investment, ownership percentage					75.00%										18.533%	18.33%					0.015%	0.015%		1.91%	1.29%		0.009%	0.015%				0.127%	100.00%	0.015%	0.015%	0.538%	0.40%													75.00%		3.00%		3.00%	97.00%				30.00%	0.00%		70.00%		95.00%	70.00%	25.00%	27.00%		33.00%	40.00%
Real estate transfer tax																																																															22,100,000
Distributions received from equity investment									25,900,000	20,000,000	15,300,000				25,300,000	24,300,000	12,400,000				15,200,000	15,400,000	6,200,000	3,000,000	1,600,000	600,000	16,900,000	14,600,000	9,400,000																														4,200,000
Increase in ownership interest in equity investments																																																																				5.00%
Income from equity method investments	52,731,000	62,392,000	51,228,000															5,000,000	(2,400,000)	(500,000)																		(4,700,000)	(4,200,000)	(7,800,000)	(200,000)	7,400,000	7,057,000	8,867,000	19,912,000												15,100,000	400,000					(8,400,000)
Equity investments in real estate	530,020,000	565,626,000							185,036,000	212,481,000		166,247,000	166,247,000		282,520,000	296,301,000					813,000	17,140,000		57,753,000	38,977,000		0	0				320,000	0	209,000	200,000	3,369,000	727,000													0	7,995,000		(736,000)	395,000						0	7,702,000
Percentage of Available Cash distribution to advisor														10.00%																				10.00%
Merger and acquisition expenses	9,230,000	31,639,000	33,000															13,600,000																							3,100,000
Loss on the extinguishment of debt																		2,800,000
Number of real estate properties	418				37								305		467
Acquisition and Disposition of Unconsolidated Real Estate Investment
Payments to acquire equity method investments	1,945,000	726,000	2,297,000																																																	52,100,000	1,500,000
Interest rate on debt													5.60%																																							2.00%
Debt maturity term																																																				5 years
Repayments of secured debt	391,764,000	54,964,000	25,327,000																																													2,900,000
Number of properties sold				6																																																							5
Non-recourse debt	1,492,410,000	1,715,397,000										1,350,755,000	1,350,755,000	117,100,000																																		17,100,000	17,100,000										25,700,000
Proceeds from mortgage financing	115,567,000	23,750,000	45,491,000																																													13,900,000				31,600,000	900,000
Value of investments sold																																																											41,400,000
Proceeds from the sales of real estate investment																																																28,400,000
Gain (Loss) on Sale of Equity Investments	$ 52,472,000	$ 87,921,000	$ 85,632,000																																														$ 19,500,000							$ 15,100,000			$ 500,000