Discontinued Operations (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Discontinued Operation Additional Disclosures [Abstract]
Revenues	$ 2,000	$ 882,000	$ 222,000	$ 2,128,000
Expenses	38,000	427,000	139,000	1,090,000
(Loss) gain on sale of real estate	(121,000)	56,000	660,000	460,000
Impairment charges	0	985,000	0	8,137,000
(Loss) income from discontinued operations	(157,000)	(474,000)	743,000	(6,639,000)
Real Estate Properties Sold [Line Items]
Net Selling Price				5,600,000
Number Of Real Estate Properties Sold		three		three
(Loss) gain on sale of real estate	(121,000)	56,000	660,000	460,000
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	0	985,000	0	8,137,000
Impairment Charge Recognized		1,000,000		5,900,000
Proceeds from sale of properties			10,643,000	9,200,000
Domestic Properties Sold [Member]
Real Estate Properties Sold [Line Items]
Number Of Real Estate Properties Sold	four	four	four	four
Impairment Charge Recognized			2,300,000	5,100,000
Proceeds from sale of properties			$ 10,600,000	$ 9,200,000

Name:	us-gaap_DiscontinuedOperationAdditionalDisclosuresAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Gain (loss) after tax expense (benefit), not previously recognized and resulting from the sale of a business component, which is recognized at the date of sale. A gain (loss) reflects the amount by which the consideration received exceeds (is exceeded by) the net carrying amount (reflecting previous provisions for loss on disposal, if any) of the disposal group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 43

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 47
-Subparagraph b

+ Details

Name:	us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Provision recognizing a loss (after tax benefit) for initial, or subsequent, write-down to fair value (less cost to sell) of a disposal group that is classified as a component of the entity, which remains unsold as of the reporting date. May include the recognition of a (gain) (net of tax expense) for a subsequent increase in fair value (less cost to sell), but not in excess of the cumulative loss previously recognized through write-downs.

+ References

+ Details

Name:	us-gaap_DiscontinuedOperationProvisionForLossGainOnDisposalNetOfTax
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of operating expenses attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 47
-Subparagraph c

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

For the asset that is reclassified back to held and used from held-for-sale, the amount of impairment charge that is recognized on the reclassification date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 38

+ Details

Name:	us-gaap_ImpairmentChargeOnReclassifiedAssets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items and the cumulative effect of accounting changes before deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 13
-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 15
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 43

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 47
-Subparagraph c

+ Details

Name:	us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 16

+ Details

Name:	us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The charge against earnings attributable to the disposed group to reduce the carrying amount of real property to fair value during the period.

+ Details

Name:	wpc_DiscontinuedOperationImpairmentChargesOfRealEstate
Namespace Prefix:	wpc
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total selling price, net of selling costs, of real estate properties sold during the period.

+ Details

Name:	wpc_NetSellingPrice
Namespace Prefix:	wpc
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total number of real estate properties sold during the period.

+ Details

Name:	wpc_NumberOfRealEstatePropertiesSold
Namespace Prefix:	wpc
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	wpc_RealEstatePropertiesSoldLineItems
Namespace Prefix:	wpc
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration