The percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_DebtInstrumentCovenantCompliance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeStart1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of debt outstanding by type or by instrument at that time.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Adjustment to the amount at which a liability incurred or settled in a current transaction between willing parties, that is, other than in a forced or liquidation sale.

+ References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value of loans assumed in noncash investing or financing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The stated interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-29)

-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule IV)

-URI http://asc.fasb.org/extlink&oid=6882300&loc=d3e5864-122674

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 29

-Article 12

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule IV

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The highest stated interest rate within the mortgage loans included in the loan grouping.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule IV

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule IV)

-URI http://asc.fasb.org/extlink&oid=6882300&loc=d3e5864-122674

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-29.3)

-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 29

-Article 12

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The lowest stated interest rate within the mortgage loans included in the loan grouping.

+ References

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of debt for which creditor does not have general recourse to the debtor but rather has recourse only to the property used for collateral in the transaction or other specific property.

+ References

No definition available.

+ Details

Name:	us-gaap_NonRecourseDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amendment fees incurred during the period.

+ References

No definition available.

+ Details

Name:	wpc_AmendmentFees
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate carrying value of real estate assets posted as collateral for the mortgage loans.

+ References

No definition available.

+ Details

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

- Definition

The aadditional amount the term loan facility can be increased by.

+ References

No definition available.

+ Details

Name:	wpc_CreditFacilityPotentialIncreaseAmount
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The additional credit facility that can be taken on currencies other than the USD.

+ References

No definition available.

+ Details

Name:	wpc_CreditFacilityPotentialIncreaseCurrencyOtherThanUsdAmount
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of commitment fees for the unused borrowing capacity under the long-term financing arrangement that is available to the entity.

+ References

No definition available.

+ Details

Name:	wpc_DebtInstrumentUnusedBorrowingCapacityFeePercent
Namespace Prefix:	wpc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of debt refinaced during the period.

+ References

No definition available.

+ Details

Name:	wpc_DebtRefinanced
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the current carrying value of debt that was refinanced during the period.

+ References

No definition available.

+ Details

Name:	wpc_DebtRefinancedRestatedCarryingValue
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The rate of interert paid on facility.

+ References

No definition available.

+ Details

Name:	wpc_FacilityFeesInterestRate
Namespace Prefix:	wpc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum cash distrubtion allowed on an annual basis per the credit agreement

+ References

No definition available.

+ Details

Name:	wpc_MaximumCashDistributionPerCreditAgreement
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the life of the mortgage loan outstanding.

+ References

No definition available.

+ Details

Name:	wpc_MortgageLoanTerm
Namespace Prefix:	wpc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	wpc_NonRecourseDebtAbstract
Namespace Prefix:	wpc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Numbers of loans assumed

+ References

No definition available.

+ Details

Name:	wpc_NumberOfLoansAssumed
Namespace Prefix:	wpc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The additonal letter of credit that can be issued.

+ References

No definition available.

+ Details

Name:	wpc_PotentialAdditonalLetterOfCredit
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Potential increase in swing line loan.

+ References

No definition available.

+ Details

Name:	wpc_PotentialIncreaseInSwingLineLoan
Namespace Prefix:	wpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	wpc_RevolvingLineOfCreditAbstract
Namespace Prefix:	wpc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Debt (Narratives) (Details) (USD $)	12 Months Ended
Debt (Narratives) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revolving Line Of Credit
Senior credit facility	$ 625,000,000	$ 450,000,000
Credit facility, expiration date	Dec. 31, 2014
Letters of credit outstanding amount	5,400,000
Amendement fees	7,000,000
Debt instrument, covenant compliance	We were in compliance with all of these covenants at December 31, 2012.
Maximum cash distributions	50,000,000
Non Recourse Debt
Amount of debt acquired	23,800,000	29,000,000	35,000,000
Collateral mortgage loan, carrying value	2,000,000,000
Debt instrument maturity date, range start	Jan. 01, 2013
Debt instrument maturity date, range end	Dec. 31, 2026
Mortgage loans on real estate, interest rate	4.20%	5.10%	5.50%
Debt refinanced	21,200,000	10,500,000
Debt refinanced, restated carrying value		11,900,000
Mortgage loan term	11.5	10.4	10
Variable rate basis			Libor
Variable rate spread			2.50%
Carey Storage Ventures
Non Recourse Debt
Mortgage loans on real estate, interest rate		6.70%	6.30%
Mortgage loan term		8.2	8.5
Fair value of mortgage loans assumed			17,100,000
Carey Storage Ventures \| Investors
Non Recourse Debt
Amount of debt acquired		2,800,000	8,200,000
CPA 14
Non Recourse Debt
Amount of debt acquired		88,700,000
Fair value market adjustment		1,100,000
Mortgage loans on real estate, interest rate		5.80%
Mortgage loan term		8.3
Fair value of mortgage loans assumed		87,600,000
WPC/CPA 15 Merger
Non Recourse Debt
Fair value market adjustment	14,800,000
Maximum
Revolving Line Of Credit
Credit facililty potential increase	125,000,000
Potential increase in swing line loan	35,000,000
Potential increase in credit facility demonitated in currency other than USD	150,000,000
Additional potential letter of credit	50,000,000
Revolving Credit Facility
Revolving Line Of Credit
Senior credit facility	450,000,000
Interest rate on debt	2.00%
Line of credit facility, available	625,000,000
Term Loan Facility
Revolving Line Of Credit
Senior credit facility	175,000,000
Letter of Credit
Revolving Line Of Credit
Letters of credit outstanding amount	253,000,000
Investment Grade \| Maximum
Revolving Line Of Credit
Facility interest rate	0.40%
Investment Grade \| Maximum \| Euro Currency
Revolving Line Of Credit
Interest rate on debt	2.00%
Investment Grade \| Maximum \| Base Rate Loans
Revolving Line Of Credit
Interest rate on debt	1.00%
Investment Grade \| Minimum
Revolving Line Of Credit
Facility interest rate	0.20%
Investment Grade \| Minimum \| Euro Currency
Revolving Line Of Credit
Interest rate on debt	1.10%
Investment Grade \| Minimum \| Base Rate Loans
Revolving Line Of Credit
Interest rate on debt	0.10%
Not Investment Grade \| Maximum
Revolving Line Of Credit
Dent instrument unused borrowing capacity fee %	0.40%
Not Investment Grade \| Maximum \| Euro Currency
Revolving Line Of Credit
Interest rate on debt	2.50%
Not Investment Grade \| Maximum \| Base Rate Loans
Revolving Line Of Credit
Interest rate on debt	1.50%
Not Investment Grade \| Minimum
Revolving Line Of Credit
Dent instrument unused borrowing capacity fee %	0.30%
Not Investment Grade \| Minimum \| Euro Currency
Revolving Line Of Credit
Interest rate on debt	1.75%
Not Investment Grade \| Minimum \| Base Rate Loans
Revolving Line Of Credit
Interest rate on debt	0.75%
Fixed Interest Rate Loans
Non Recourse Debt
Mortgage loan on real estate, minimum interest rate	2.70%
Mortgage loan on real estate, maximum interest rate	10.00%
Fixed Interest Rate Loans \| Carey Storage Ventures
Non Recourse Debt
Amount of debt acquired		4,600,000
Fixed Interest Rate Loans \| WPC/CPA 15 Merger
Non Recourse Debt
Amount of debt acquired	1,100,000,000
Mortgage loans on real estate, interest rate	5.08%
Numbers of loans assumed	58
Variable Interest Rate Loans
Non Recourse Debt
Mortgage loan on real estate, minimum interest rate	1.20%
Mortgage loan on real estate, maximum interest rate	7.60%
Variable Interest Rate Loans \| WPC/CPA 15 Merger
Non Recourse Debt
Amount of debt acquired	$ 295,200,000
Mortgage loans on real estate, interest rate	5.03%
Numbers of loans assumed	9