Debt - Unsecured Term Loans and Revolving Credit Facility (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2023	Dec. 31, 2022
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 1,604,824	$ 830,406
Unamortized discount	31,472
Debt financing costs	22,371
Unsecured Term Loans:
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	1,088,311	554,014
Unsecured Revolving Credit Facility:
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 516,513	276,392
EUR \| Unsecured Term Loans: \| Term Loan Due 2026
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	4.34%
Debt outstanding	$ 529,700	0
Unamortized discount	3,500
Debt financing costs	300
EUR \| Unsecured Term Loans: \| Delayed Draw Term Loan Due 2025
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 227,771	229,319
EUR \| Unsecured Term Loans: \| EURIBOR \| Delayed Draw Term Loan Due 2025
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	0.85%
EUR \| Unsecured Revolving Credit Facility:
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 345,364	258,117
EUR \| Unsecured Revolving Credit Facility: \| EURIBOR
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	0.775%
GBP \| Unsecured Term Loans: \| Term Loan Due 2025
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 330,840	324,695
Unamortized discount	$ 1,000	1,500
Spread adjustment (as a percent)	0.0326%
GBP \| Unsecured Term Loans: \| GBP LIBOR \| Term Loan Due 2025
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	0.85%
USD \| Unsecured Revolving Credit Facility:
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 155,000	0
Spread adjustment (as a percent)	0.10%
USD \| Unsecured Revolving Credit Facility: \| SOFR
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	0.775%
JPY \| Unsecured Revolving Credit Facility:
Unsecured Term Loans and Unsecured Revolving Credit Facility
Debt outstanding	$ 16,149	$ 18,275
JPY \| Unsecured Revolving Credit Facility: \| JPY LIBOR
Unsecured Term Loans and Unsecured Revolving Credit Facility
Variable interest rate (as a percent)	0.775%

Amount of short-term and long-term debt and lease obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

+ Details

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

- References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt discount (premium).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-1A

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-4

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-3

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482949/835-30-55-8

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-3

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1D

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Spread Adjustment

+ References

No definition available.

+ Details

Name:	wpc_SpreadAdjustment
Namespace Prefix:	wpc_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=wpc_SeniorUnsecuredTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=wpc_SeniorUnsecuredCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_EUR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wpc_TermLoanDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wpc_DelayedDrawTermLoanDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=wpc_EuroInterbankOfferingRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_GBP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wpc_TermLoanDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=wpc_SterlingOvernightIndexAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_USD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_JPY
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=wpc_TokyoInterbankOfferedRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: