Segment Reporting - Income From Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues
Revenues	$ 290,530	$ 305,211	$ 599,529	$ 603,534
Operating Expenses
Depreciation and amortization	107,477	113,632	223,671	226,011
General and administrative	17,472	19,729	38,217	41,014
Reimbursable tenant costs	13,796	13,917	26,971	27,088
Property expenses, excluding reimbursable tenant costs	11,651	9,915	21,726	19,827
Stock-based compensation expense	2,918	4,936	5,579	9,101
Operating property expenses	1,388	10,874	6,611	21,468
Merger and other expenses	1,074	696	1,261	842
Impairment charges	0	0	19,420	0
Total operating expenses	158,379	179,170	351,366	356,892
Other Income and Expenses
Interest expense	(52,182)	(59,719)	(104,722)	(121,032)
Other gains and (losses)	8,847	(671)	4,424	284
Equity in earnings of equity method investments in real estate	33,983	3,951	(11,807)	9,442
(Loss) gain on sale of real estate, net	0	(362)	11,751	571
Total other income and expenses	(9,352)	(56,801)	(100,354)	(110,735)
Income before income taxes	122,799	69,240	147,809	135,907
(Provision for) benefit from income taxes	(7,595)	(3,119)	34,097	(990)
Net Income	115,204	66,121	181,906	134,917
Net income attributable to noncontrolling interests	(9,904)	(83)	(10,516)	(385)
Net Income Attributable to W. P. Carey	105,300	66,038	171,390	134,532
Real Estate
Revenues
Lease revenues	280,303	269,802	562,413	532,741
Lease termination income and other	1,917	6,304	8,426	9,574
Gross contract revenue	1,427	15,436	7,394	31,432
Revenues	283,647	291,542	578,233	573,747
Operating Expenses
Depreciation and amortization	107,477	112,666	222,684	224,079
General and administrative	17,472	15,001	32,394	30,189
Reimbursable tenant costs	13,796	13,917	26,971	27,088
Property expenses, excluding reimbursable tenant costs	11,651	9,915	21,726	19,827
Stock-based compensation expense	2,918	3,482	4,888	6,282
Operating property expenses	1,388	10,874	6,611	21,468
Merger and other expenses	935	696	803	842
Impairment charges	0	0	19,420	0
Total operating expenses	155,637	166,551	335,497	329,775
Other Income and Expenses
Interest expense	(52,182)	(59,719)	(104,722)	(121,032)
Other gains and (losses)	9,942	(1,362)	4,166	(392)
Equity in earnings of equity method investments in real estate	211	230	1,776	152
(Loss) gain on sale of real estate, net	0	(362)	11,751	571
Total other income and expenses	(42,029)	(61,213)	(87,029)	(120,701)
Income before income taxes	85,981	63,778	155,707	123,271
(Provision for) benefit from income taxes	(4,117)	(3,019)	27,683	(9,178)
Net Income	81,864	60,759	183,390	114,093
Net income attributable to noncontrolling interests	(39)	9	(651)	83
Net Income Attributable to W. P. Carey	$ 81,825	$ 60,768	$ 182,739	$ 114,176