Stock-Based Compensation and Equity - Earnings Per Share (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share Reconciliation
Net income attributable to W. P. Carey	$ 105,300	$ 66,038	$ 171,390	$ 134,532
Net income attributable to nonvested participating RSUs	0	(17)	0	(35)
Net income — basic and diluted	$ 105,300	$ 66,021	$ 171,390	$ 134,497
Weighted-average shares outstanding – basic (shares)	173,401,749	171,304,112	173,325,493	169,280,360
Effect of dilutive securities (shares)	71,006	186,513	189,401	240,148
Weighted-average shares outstanding – diluted (shares)	173,472,755	171,490,625	173,514,894	169,520,508
Anti-dilutive shares (shares)	0	0		0