Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Data
Revenues	$ 228,780	$ 225,247	$ 217,266	$ 270,240	$ 265,250	$ 214,666	$ 238,079	$ 220,388	$ 941,533	$ 938,383	$ 908,446
Expenses	144,564	136,472	160,697	180,000	150,902	159,066	130,382	140,479	621,733	580,829	637,378
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
Earnings per share attributable to W. P. Carey:
Basic (usd per share)	$ 0.44	$ 1.03	$ 0.48	$ 0.54	$ 0.48	$ 0.20	$ 0.60	$ 0.34	$ 2.50	$ 1.62	$ 2.42
Diluted (usd per share)	0.44	1.03	0.48	0.54	0.48	0.20	0.59	0.34	2.49	1.61	2.39
Distributions declared per share (usd per share)	$ 0.99	$ 0.985	$ 0.98	$ 0.9742	$ 0.9646	$ 0.955	$ 0.954	$ 0.9525	$ 3.9292	$ 3.8261	$ 3.685