Basis of Presentation (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Prior Period Adjustment [Abstract]
Error Corrections and Prior Period Adjustments, Description	Out-of-Period Adjustment During the second quarter of 2012, we identified an error in the consolidated financial statements related to the misapplication of accounting guidance on the involuntary disposals of two parcels of land in the fourth quarter of 2010. We concluded that this adjustment, with a net impact on income from continuing operations and income attributable to W. P. Carey members of $1.8 million on our statement of operations for the second quarter of 2012, was not material to our results for the prior year period or for the period of adjustment. Accordingly, this change was recorded in the consolidated financial statements in the second quarter of 2012 as an out-of-period adjustment as follows: a reduction to Accounts payable, accrued expenses and other liabilities of $2.1 million and a reduction to Net investments in properties of $0.3 million on the consolidated balance sheet; and an increase in Gain on sale of real estate of $2.0 million, an increase in Property expenses of $0.4 million, an increase in Other real estate income of $0.2 million and an increase in Other interest income of $0.1 million on the consolidated statement of operations.
Accounts Payable[ Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	2.1
Net Investments In Properties [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(0.3)
Gain On Sale Of Real Estate [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(2.0)
Property Expenses [ Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	0.4
Other Real Estate Income [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(0.2)
Other Interest Income [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(0.1)
Net Income [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(1.8)