Summary of Significant Accounting Policies (Narratives) (Details) (USD $)	3 Months Ended								12 Months Ended				12 Months Ended						3 Months Ended									12 Months Ended							0 Months Ended	1 Months Ended	5 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Internal-use software development costs Minimum	Dec. 31, 2013 Internal-use software development costs Maximum	Dec. 31, 2013 Building and building improvements	Dec. 31, 2013 Furniture and fixtures	Dec. 31, 2012 CPA: 15	Sep. 28, 2012 CPA: 15	Dec. 31, 2013 Accounting for deferred foreign income taxes Net Income (Loss) Attributable to Parent	Dec. 31, 2013 Accounting for deferred foreign income taxes Provision for income taxes	Dec. 31, 2013 Accounting for deferred foreign income taxes Other Assets	Dec. 31, 2013 Accounting for deferred foreign income taxes Income taxes, net	Dec. 31, 2013 Accounting for deferred foreign income taxes Assets	Dec. 31, 2013 Accounting for deferred foreign income taxes Goodwill	Dec. 31, 2013 Accounting for deferred foreign income taxes Real Estate Investment Property, Net	Dec. 31, 2013 Accounting for deferred foreign income taxes CPA: 15 property	Dec. 31, 2013 Accounting for deferred foreign income taxes Unidentified Acquisitions, 2000-2013 property	Dec. 31, 2012 Income from continuing operations investment	Dec. 31, 2012 Gain on sale of real estate	Dec. 31, 2011 Net investments in direct financing lease	Dec. 31, 2011 Operating lease	Dec. 31, 2011 Lease revenue	Dec. 31, 2011 Impairment	Dec. 31, 2011 Depreciation	Jul. 25, 2013 CPA:18 - Global	Nov. 30, 2012 CPA:18 - Global	Dec. 31, 2013 CPA:18 - Global
Basis of Consolidation
Common stock maximum offering amount																																				$ 1,000,000,000
Amount From Dividend Reinvestment Plan																																				400,000,000
Ownership interest percentage																																			8.50%		100.00%
Depreciation
Fixed asset useful life													3 years	5 years	40 years	7 years
Revenue recognition
Real estate tax expense									37,300,000	18,700,000	6,400,000
Foreign currency gains (losses)
Foreign Currency Transaction Gain (Loss), Realized									(200,000)	(600,000)	400,000
Out-of-Period Adjustment
Deferred Tax Assets, Gross	61,185,000				43,237,000				61,185,000	43,237,000
Deferred Tax Liabilities, Gross	78,710,000				45,432,000				78,710,000	45,432,000
Assets	4,678,950,000				4,609,042,000				4,678,950,000	4,609,042,000
Goodwill	350,208,000				329,132,000				350,208,000	329,132,000	63,607,000	63,607,000					268,683,000	268,683,000
Investments in real estate	2,353,391,000				2,298,123,000				2,353,391,000	2,298,123,000							1,762,872,000
Net income attributable to W. P. Carey	23,022,000	18,506,000	43,167,000	14,181,000	15,477,000	2,588,000	31,777,000	12,290,000	98,876,000	62,132,000	139,079,000
Out of period adjustment, number of properties																										95	7
Out of period adjustment											$ 200,000								$ 2,300,000	$ 2,000,000	$ 2,300,000	$ (37,500,000)	$ 32,400,000	$ 31,400,000	$ 1,000,000			$ (2,500,000)	$ (2,000,000)	$ (17,600,000)	$ 17,900,000	$ (900,000)	$ (1,600,000)	$ 2,200,000
Out of period adjustment, number of investments																												2