Useful life of finite-lived intangible asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-5

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow from the acquisition of a piece of land, anything permanently fixed to it, including buildings, structures on it and so forth; includes real estate intended to generate income for the owner; excludes real estate acquired for use by the owner.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 905
-SubTopic 360
-Name Accounting Standards Codification
-Section 25
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478704/905-360-25-4

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482338/360-10-05-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 30
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482222/360-10-30-2

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482338/360-10-05-3

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482338/360-10-05-3

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482338/360-10-05-3

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 350
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482558/350-40-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

+ Details

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

- Details

Name:	us-gaap_RealEstatePropertiesAxis=wpc_RealEstateSubjectToOperatingLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_LeasesAcquiredInPlaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_AboveMarketLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=wpc_BelowMarketRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=wpc_BelowMarketGroundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_UseRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=wpc_RightOfUseLiabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Land, Buildings and Improvements, and Assets Held for Sale - Aggregate Purchase Price Allocation (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Property, Plant, and Equipment
Payment to acquire real estate	$ 1,210,921	$ 542,216
Operating Lease
Property, Plant, and Equipment
Payment to acquire real estate	1,303,224
Operating Lease \| In-place lease
Property, Plant, and Equipment
Payment to acquire real estate	$ 210,068
Finite lived intangible assets useful life (in years)	16 years 3 months 18 days
Operating Lease \| Above-market rent
Property, Plant, and Equipment
Payment to acquire real estate	$ 114
Finite lived intangible assets useful life (in years)	12 years 1 month 6 days
Operating Lease \| Below-market rent
Property, Plant, and Equipment
Payment to acquire real estate	$ 2,017
Finite lived intangible assets useful life (in years)	12 years 4 months 24 days
Operating Lease \| Below Market Ground
Property, Plant, and Equipment
Payment to acquire real estate	$ 7,653
Finite lived intangible assets useful life (in years)	39 years 8 months 12 days
Land \| Operating Lease
Property, Plant, and Equipment
Payment to acquire real estate	$ 421,871
Land \| Operating Lease \| Land lease right-of-use assets
Property, Plant, and Equipment
Payment to acquire real estate	335
Land \| Operating Lease \| Land lease right-of-use liabilities
Property, Plant, and Equipment
Payment to acquire real estate	335
Buildings and improvements \| Operating Lease
Property, Plant, and Equipment
Payment to acquire real estate	$ 665,535