Segment Reporting - Income From Investment Management (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Expenses
General and administrative	$ 19,729	$ 16,442	$ 41,014	$ 35,025
Reimbursable costs from affiliates	3,821	5,537	7,689	10,841
Subadvisor fees	1,650	1,855	3,852	3,887
Stock-based compensation expense	4,936	3,698	9,101	11,917
Depreciation and amortization	113,632	64,337	226,011	130,294
Total operating expenses	179,170	109,202	356,892	230,168
Other Income and Expenses
Equity in earnings of equity method investments in the Managed Programs and real estate	3,951	12,558	9,442	27,883
Other gains and (losses)	(671)	10,586	284	7,823
Total other income and expenses	(56,801)	(6,255)	(110,735)	(25,035)
Income before income taxes	69,240	85,686	135,907	147,750
Provision for income taxes	(3,119)	(6,262)	(990)	(260)
Net Income	66,121	79,424	134,917	147,490
Net income attributable to noncontrolling interests	(83)	(3,743)	(385)	(6,535)
Net Income Attributable to W. P. Carey	66,038	75,681	134,532	140,955
Investment Management
Investment Management:
Gross contract revenue	13,669	27,231	29,787	51,449
Operating Expenses
General and administrative	4,728	5,843	10,825	12,361
Reimbursable costs from affiliates	3,821	5,537	7,689	10,841
Subadvisor fees	1,650	1,855	3,852	3,887
Stock-based compensation expense	1,454	1,708	2,819	5,621
Depreciation and amortization	966	963	1,932	2,000
Total operating expenses	12,619	15,906	27,117	34,710
Other Income and Expenses
Equity in earnings of equity method investments in the Managed Programs and real estate	3,721	9,029	9,290	20,996
Other gains and (losses)	691	956	676	1,080
Total other income and expenses	4,412	9,985	9,966	22,076
Income before income taxes	5,462	21,310	12,636	38,815
Provision for income taxes	(100)	(4,945)	8,188	(2,476)
Net Income	5,362	16,365	20,824	36,339
Net income attributable to noncontrolling interests	(92)	0	(468)	0
Net Income Attributable to W. P. Carey	5,270	16,365	20,356	36,339
Investment Management | Asset management revenue
Investment Management:
Gross contract revenue	9,790	17,268	19,522	34,253
Investment Management | Reimbursable costs from affiliates
Investment Management:
Gross contract revenue	3,821	5,537	7,689	10,841
Investment Management | Structuring and other advisory revenue
Investment Management:
Gross contract revenue	$ 58	$ 4,426	$ 2,576	$ 6,355