Segment Reporting - Income From Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Revenues	$ 319,724	$ 290,530	$ 630,890	$ 599,529
Operating Expenses
Depreciation and amortization	114,348	107,477	224,670	223,671
General and administrative	20,464	17,472	42,547	38,217
Reimbursable tenant costs	15,092	13,796	30,850	26,971
Property expenses, excluding reimbursable tenant costs	11,815	11,651	22,698	21,726
Stock-based compensation expense	9,048	2,918	14,429	5,579
Merger and other expenses	(2,599)	1,074	(3,075)	1,261
Operating property expenses	2,049	1,388	3,960	6,611
Impairment charges	0	0	0	19,420
Total operating expenses	171,185	158,379	338,088	351,366
Other Income and Expenses
Interest expense	(49,252)	(52,182)	(100,892)	(104,722)
Gain on sale of real estate, net	19,840	0	29,212	11,751
Other gains and (losses)	7,545	4,259	(33,643)	(5,556)
Non-operating income	3,065	4,588	9,421	9,980
(Losses) earnings from equity method investments	(156)	33,983	(9,889)	(11,807)
Total other income and expenses	(18,958)	(9,352)	(105,791)	(100,354)
Income before income taxes	129,581	122,799	187,011	147,809
(Provision for) benefit from income taxes	(9,298)	(7,595)	(15,087)	34,097
Net Income	120,283	115,204	171,924	181,906
Net income attributable to noncontrolling interests	(38)	(9,904)	(45)	(10,516)
Net Income Attributable to W. P. Carey	120,245	105,300	171,879	171,390
Real Estate
Revenues
Lease revenues	305,310	280,303	607,075	562,413
Lease termination income and other	6,235	1,917	8,462	8,426
Operating property revenues	3,245	1,427	5,424	7,394
Revenues	314,790	283,647	620,961	578,233
Operating Expenses
Depreciation and amortization	114,348	107,477	224,670	222,684
General and administrative	20,464	17,472	42,547	32,394
Reimbursable tenant costs	15,092	13,796	30,850	26,971
Property expenses, excluding reimbursable tenant costs	11,815	11,651	22,698	21,726
Stock-based compensation expense	9,048	2,918	14,429	4,888
Merger and other expenses	(2,599)	935	(3,090)	803
Operating property expenses	2,049	1,388	3,960	6,611
Impairment charges	0	0	0	19,420
Total operating expenses	170,217	155,637	336,064	335,497
Other Income and Expenses
Interest expense	(49,252)	(52,182)	(100,892)	(104,722)
Gain on sale of real estate, net	19,840	0	29,212	11,751
Other gains and (losses)	7,472	5,437	(34,717)	(5,536)
Non-operating income	3,065	4,505	9,337	9,702
(Losses) earnings from equity method investments	(1,854)	211	(12,973)	1,776
Total other income and expenses	(20,729)	(42,029)	(110,033)	(87,029)
Income before income taxes	123,844	85,981	174,864	155,707
(Provision for) benefit from income taxes	(9,119)	(4,117)	(15,545)	27,683
Net Income	114,725	81,864	159,319	183,390
Net income attributable to noncontrolling interests	(38)	(39)	(45)	(651)
Net Income Attributable to W. P. Carey	$ 114,687	$ 81,825	$ 159,274	$ 182,739