Represents the period over which the average market closing price is measured.

No definition available.

Name:	exr_AverageClosingMarketPriceMeasurementPeriod
Namespace Prefix:	exr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The average closing market price of the entity's common stock.

+ References

No definition available.

+ Details

Name:	exr_CommonStockAverageClosingMarketPrice
Namespace Prefix:	exr_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Note Receivable, Reduction Of Noncontrolling Interests

+ References

No definition available.

+ Details

Name:	exr_NoteReceivableReductionOfNoncontrollingInterests
Namespace Prefix:	exr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the stated interest rate of notes receivable.

+ References

No definition available.

+ Details

Name:	exr_NotesReceivableStatedInterestRate
Namespace Prefix:	exr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Joint Ventures

+ References

No definition available.

+ Details

Name:	exr_NumberOfJointVenturesOperating
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Joint Ventures With Property Under Development

+ References

No definition available.

+ Details

Name:	exr_NumberOfJointVenturesWithPropertyUnderDevelopment
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount the entity would have paid in cash to redeem the operating partnership units.

+ References

No definition available.

+ Details

Name:	exr_OperatingPartnershipUnitsRedemptionAmount
Namespace Prefix:	exr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of consolidated joint ventures as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	exr_RealEstateConsolidatedJointVenturesNumber
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Shareholders' Equity, Units Conversion Ratio

+ References

No definition available.

+ Details

Name:	exr_ShareholdersEquityUnitsConversionRatio
Namespace Prefix:	exr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Total Number Of Stores In Consolidated Joint Ventures

+ References

No definition available.

+ Details

Name:	exr_TotalNumberOfStoresInConsolidatedJointVentures
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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

No definition available.

+ Details

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of preferred units outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-5

+ Details

Name:	us-gaap_PreferredUnitsOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_StatementEquityComponentsAxis=exr_CommonOperatingPartnershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=exr_CommonOperatingPartnershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=exr_NonControllingInterestOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
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Noncontrolling Interests In Operating Partnership and Other Noncontrolling Interests - Additional Information (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2024	Mar. 31, 2026 USD ($) store joint_venture $ / shares shares	Dec. 31, 2025 USD ($)
Noncontrolling Interest [Line Items]
Note receivable interest rate	10.00%
Period used as a denomination to determine the average closing price of common stock		10 days
Ten day average closing stock price (in dollars per share) \| $ / shares		$ 131.31
Preferred units outstanding (in shares) \| shares		9,421,211
Consideration to be paid on redemption of common OP units \| $		$ 1,237,099
Number of consolidated joint ventures \| joint_venture		12
Total number of stores in consolidated joint venture \| store		16
Number of joint ventures operating store \| joint_venture		12
Number of joint ventures with property under development \| store		4
Operating Partnership
Noncontrolling Interest [Line Items]
Loan receivable, reduction of noncontrolling interests \| $		$ 50,000	$ 50,000
Common Stock
Noncontrolling Interest [Line Items]
Unit conversion ratio		1
Operating Partnership
Noncontrolling Interest [Line Items]
Ownership interest held		95.60%
Ownership interest held by joint venture partner		4.40%
Other noncontrolling interests \| Maximum
Noncontrolling Interest [Line Items]
Ownership interest held by joint venture partner		25.00%