Segment Reporting - Income From Owned Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Owned Real Estate:
Lease revenues									$ 663,463	$ 656,956	$ 573,829
Lease termination income and other									35,696	25,145	17,767
Operating property revenues									30,767	30,515	28,925
Reimbursable tenant costs									25,438	22,832	24,862
Total revenues	$ 228,780	$ 225,247	$ 217,266	$ 270,240	$ 265,250	$ 214,666	$ 238,079	$ 220,388	941,533	938,383	908,446
Operating Expenses
Depreciation and amortization									276,510	280,315	237,123
Impairment charges									59,303	29,906	23,067
Property expenses, excluding reimbursable tenant costs									49,431	52,199	37,725
General and administrative									82,352	103,172	91,588
Reimbursable tenant costs									91,871	78,669	155,074
Stock-based compensation expense									18,015	21,626	31,075
Restructuring and other compensation									11,925	0	0
Merger, property acquisition, and other expenses									5,377	(7,764)	34,465
Total operating expenses	144,564	136,472	160,697	180,000	150,902	159,066	130,382	140,479	621,733	580,829	637,378
Other Income and Expenses
Interest expense									(183,409)	(194,326)	(178,122)
Equity in earnings of equity method investments in the Managed Programs and real estate									64,719	51,020	44,116
Other income and (expenses)									5,667	2,113	(14,230)
Gain on change in control of interests									0	0	105,947
Total other income and expenses									(113,023)	(141,193)	(42,289)
Income from continuing operations before income taxes and gain on sale of real estate									206,777	216,361	228,779
Provision for income taxes									(3,288)	(37,621)	(17,609)
Income from continuing operations before gain on sale of real estate									203,489	178,740	211,170
Income from discontinued operations, net of tax									0	0	33,318
Gain on sale of real estate, net of tax		49,100
Net Income	48,470	112,302	53,171	60,864	56,144	23,578	66,923	38,582	274,807	185,227	246,069
Net income attributable to noncontrolling interests	(766)	(1,359)	(1,510)	(3,425)	(5,095)	(1,833)	(3,575)	(2,466)	(7,060)	(12,969)	(6,385)
Net Income Attributable to W. P. Carey	$ 47,704	$ 110,943	$ 51,661	$ 57,439	$ 51,049	$ 21,745	$ 63,348	$ 36,116	267,747	172,258	239,826
Real Estate Ownership
Owned Real Estate:
Lease revenues									663,463	656,956	573,829
Lease termination income and other									35,696	25,145	17,767
Operating property revenues									30,767	30,515	28,925
Reimbursable tenant costs									25,438	22,832	24,862
Total revenues									755,364	735,448	645,383
Operating Expenses
Depreciation and amortization									272,274	276,236	233,099
Impairment charges									59,303	29,906	23,067
Property expenses, excluding reimbursable tenant costs									49,431	52,199	37,725
General and administrative									34,591	47,676	38,797
Reimbursable tenant costs									25,438	22,832	24,862
Stock-based compensation expense									5,224	7,873	12,659
Restructuring and other compensation									4,413	0	0
Merger, property acquisition, and other expenses									2,993	(9,908)	34,465
Total operating expenses									453,667	426,814	404,674
Other Income and Expenses
Interest expense									(183,409)	(194,326)	(178,122)
Equity in earnings of equity method investments in the Managed Programs and real estate									62,724	52,972	44,116
Other income and (expenses)									3,665	1,952	(14,505)
Gain on change in control of interests									0	0	105,947
Total other income and expenses									(117,020)	(139,402)	(42,564)
Income from continuing operations before income taxes and gain on sale of real estate									184,677	169,232	198,145
Provision for income taxes									3,418	(17,948)	916
Income from continuing operations before gain on sale of real estate									188,095	151,284	199,061
Income from discontinued operations, net of tax									0	0	33,318
Gain on sale of real estate, net of tax									71,318	6,487	1,581
Net Income									259,413	157,771	233,960
Net income attributable to noncontrolling interests									(7,060)	(10,961)	(5,573)
Net Income Attributable to W. P. Carey									$ 252,353	$ 146,810	$ 228,387