Segment Reporting - Income From Investment Management (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Expenses
General and administrative	$ 20,745	$ 21,285
Reimbursable costs from affiliates	4,030	3,868
Subadvisor fees	1,277	2,202
Depreciation and amortization	116,194	112,379
Stock-based compensation expense	2,661	4,165
Merger and other expenses	187	146
Total operating expenses	192,987	177,722
Other Income and Expenses
Equity in (losses) earnings of equity method investments in the Managed Programs and real estate	(45,790)	5,491
Other gains and (losses)	(4,423)	955
Total other income and expenses	(91,002)	(53,934)
Income before income taxes	25,010	66,667
Benefit from (provision for) income taxes	41,692	2,129
Net Income	66,702	68,796
Net income attributable to noncontrolling interests	(612)	(302)
Net Income Attributable to W. P. Carey	66,090	68,494
Investment Management
Investment Management:
Gross contract revenue	14,413	16,118
Operating Expenses
General and administrative	5,823	6,097
Reimbursable costs from affiliates	4,030	3,868
Subadvisor fees	1,277	2,202
Depreciation and amortization	987	966
Stock-based compensation expense	691	1,365
Merger and other expenses	319	0
Total operating expenses	13,127	14,498
Other Income and Expenses
Equity in (losses) earnings of equity method investments in the Managed Programs and real estate	(47,355)	5,569
Other gains and (losses)	1,353	(15)
Total other income and expenses	(46,002)	5,554
Income before income taxes	(44,716)	7,174
Benefit from (provision for) income taxes	9,892	8,288
Net Income	(34,824)	15,462
Net income attributable to noncontrolling interests	0	(376)
Net Income Attributable to W. P. Carey	(34,824)	15,086
Investment Management | Asset management revenue
Investment Management:
Gross contract revenue	9,889	9,732
Investment Management | Reimbursable costs from affiliates
Investment Management:
Gross contract revenue	4,030	3,868
Investment Management | Structuring and other advisory revenue
Investment Management:
Gross contract revenue	$ 494	$ 2,518