Segment Reporting - Income From Investment Management (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investment Management:
Revenues	$ 1,741,358	$ 1,479,086	$ 1,331,524
Operating Expenses
Reimbursable costs from affiliates	368	2,518	4,035
Impairment charges — Investment Management goodwill	0	29,334	0
Merger and other expenses	4,954	19,387	(4,546)
Total operating expenses	1,018,007	866,983	726,656
Other Income and Expenses
Other gains and (losses)	(36,184)	96,038	(12,885)
Non-operating income	21,442	30,309	13,860
Gain on change in control of interests	0	33,931	0
Earnings from equity method investments in the Managed Programs	19,575	29,509	(10,829)
Total other income and expenses	28,965	14,103	(166,260)
Income before income taxes	752,316	626,206	438,608
Provision for income taxes	(44,052)	(27,724)	(28,486)
Net Income Attributable to W. P. Carey	708,334	599,139	409,988
Investment Management
Investment Management:
Operating property revenues	3,219	10,985	19,398
Operating Expenses
Impairment charges — Investment Management goodwill		29,334
Investment Management | Operating Segments
Investment Management:
Revenues	3,219	10,985	19,398
Operating Expenses
Reimbursable costs from affiliates	368	2,518	4,035
Impairment charges — Investment Management goodwill	0	29,334	0
Merger and other expenses	0	3	51
Total operating expenses	368	31,855	4,086
Other Income and Expenses
Other gains and (losses)	243	(1,111)	791
Non-operating income	13	20	82
Gain on change in control of interests	0	22,526	0
Earnings from equity method investments in the Managed Programs	0	13,288	8,820
Total other income and expenses	256	34,723	9,693
Income before income taxes	3,107	13,853	25,005
Provision for income taxes	390	(6,317)	217
Net Income Attributable to W. P. Carey	3,497	7,536	25,222
Investment Management | Asset management revenue
Investment Management:
Operating property revenues	2,184	8,467	15,363
Investment Management | Asset management revenue | Operating Segments
Investment Management:
Operating property revenues	2,184	8,467	15,363
Investment Management | Other advisory income and reimbursements | Operating Segments
Investment Management:
Operating property revenues	667	0	0
Investment Management | Reimbursable costs from affiliates
Investment Management:
Operating property revenues	368	2,518	4,035
Investment Management | Reimbursable costs from affiliates | Operating Segments
Investment Management:
Operating property revenues	$ 368	$ 2,518	$ 4,035