Agreements and Transactions with Related Parties (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Due from affiliates
Deferred acquisition fees receivable	$ 26,913wpc_Deferredacquisitionfeesreceivable	$ 19,684wpc_Deferredacquisitionfeesreceivable
Organization and offering costs	2,120	2,700
Accounts receivable	2,680	3,716
Current acquisition fees receivable	2,463wpc_CurrentAcquisitionFeesReceivable	4,149wpc_CurrentAcquisitionFeesReceivable
Reimbursable costs	301	334
Asset management fee receivable	0wpc_AssetManagementFeesReceivable	1,451wpc_AssetManagementFeesReceivable
Due from affiliates	$ 34,477us-gaap_DueFromAffiliates	$ 32,034us-gaap_DueFromAffiliates

For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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-Publisher SEC

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

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-Paragraph 1

-Subparagraph (SX 210.4-08.(k)(1))

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

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-Publisher SEC

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-Publisher SEC

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-Publisher FASB

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- Definition

Unpaid revenue in the period for (1) performance (incentive) fees based on the investment results achieved for management of certain institutional accounts and hedge funds, (2) schedule-based fees earned for management of mutual funds and closed-end funds, based either on average daily net assets or on a combination of the average daily net assets and gross income, and (3) other investment management and advisory fees.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The current amount of fees due from affiliates for structuring and negotiating investments on their behalf.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The deferred amount of fees due from affiliates for structuring and negotiating investments on their behalf.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Includes offering costs of open-end investment companies, and closed-end funds with a continuous offering period that is still due from affiliates.

+ References

No definition available.

+ Details

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Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of reimbursable costs due from affiliates as of the balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant