Summary of Significant Accounting Policies - Real Estate Assets (Details)	12 Months Ended
Dec. 31, 2024 store
Property, Plant and Equipment [Line Items]
Number of properties whereby leases cannot be classified as ground or building leases	3
Number of properties whereby leases have been assumed at rates lower than the current market rates	9
Buildings, improvements and other intangibles \| Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Buildings, improvements and other intangibles \| Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	39 years

Represents the number of properties to which purchase price amounts are allocated, which cannot be classified as ground or building leases and represented as Intangible lease rights.

No definition available.

+ Details

Name:	exr_NumberOfLeasedPropertiesThatCannotBeClassifiedAsGroundOrBuildingLeases
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of properties related to ground leases, where the leases were assumed by the entity at rates that were lower than the current market rates for similar leases.

+ References

No definition available.

+ Details

Name:	exr_NumberOfPropertiesRelatedToGroundLeasesAssumedByTheEntityAtRatesLowerThanCurrentMarketRates
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
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/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

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: