Segment Reporting - Income From Owned Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Owned Real Estate:
Lease revenues	$ 163,213	$ 155,781
Operating property revenues	7,218	6,980
Reimbursable tenant costs	6,219	5,221
Lease termination income and other	942	760
Total revenues	201,810	219,059
Operating Expenses
Depreciation and amortization	65,957	62,430
General and administrative	18,583	18,424
Property expenses, excluding reimbursable tenant costs	9,899	10,110
Reimbursable tenant costs	11,523	30,921
Impairment charges	4,790	0
Stock-based compensation expense	8,219	6,910
Other expenses	(37)	73
Total operating expenses	120,966	134,882
Other Income and Expenses
Interest expense	(38,074)	(41,957)
Equity in earnings of equity method investments in the Managed Programs and real estate	15,325	15,774
Other gains and (losses)	(2,763)	516
Total other income and expenses	(25,512)	(25,667)
Income before income taxes and gain on sale of real estate	55,332	58,510
Benefit from income taxes	6,002	1,305
Income before gain on sale of real estate	61,334	59,815
Gain on sale of real estate, net of tax	6,732	10
Net Income	68,066	59,825
Net income attributable to noncontrolling interests	(2,792)	(2,341)
Net Income Attributable to W. P. Carey	65,274	57,484
Owned Real Estate
Owned Real Estate:
Lease revenues	163,213	155,781
Operating property revenues	7,218	6,980
Reimbursable tenant costs	6,219	5,221
Lease termination income and other	942	760
Total revenues	177,592	168,742
Operating Expenses
Depreciation and amortization	64,920	61,522
General and administrative	12,065	8,274
Property expenses, excluding reimbursable tenant costs	9,899	10,110
Reimbursable tenant costs	6,219	5,221
Impairment charges	4,790	0
Stock-based compensation expense	4,306	1,954
Other expenses	(37)	73
Total operating expenses	102,162	87,154
Other Income and Expenses
Interest expense	(38,074)	(41,957)
Equity in earnings of equity method investments in the Managed Programs and real estate	3,358	2,072
Other gains and (losses)	(2,887)	40
Total other income and expenses	(37,603)	(39,845)
Income before income taxes and gain on sale of real estate	37,827	41,743
Benefit from income taxes	3,533	(1,454)
Income before gain on sale of real estate	41,360	40,289
Gain on sale of real estate, net of tax	6,732	10
Net Income	48,092	40,299
Net income attributable to noncontrolling interests	(2,792)	(2,341)
Net Income Attributable to W. P. Carey	$ 45,300	$ 37,958