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Equity Method Investment, Number Of Store Acquired

No definition available.

Name:	exr_EquityMethodInvestmentNumberOfStoreAcquired
Namespace Prefix:	exr_
Data Type:	xbrli:integerItemType
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Period Type:	duration

Equity Method Investments, Number Of Investments Purchased

No definition available.

Name:	exr_EquityMethodInvestmentsNumberOfInvestmentsPurchased
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Equity Method Investments, Number Of Investments Sold

No definition available.

Name:	exr_EquityMethodInvestmentsNumberOfInvestmentsSold
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Equity Method Investments, Number Of Stores Acquired

No definition available.

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Equity Method Investments, Number Of Stores Sold

No definition available.

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

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_EquityMethodInvestmentAggregateCost
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of gain (loss) on sale or disposal of an equity method investment.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(7)(c))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(9)(a))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Name:	us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The cash outflow associated with the purchase of real estate held-for-investment and real estate joint ventures.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireRealEstateAndRealEstateJointVentures
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromSaleOfEquityMethodInvestments
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of revenue derived from managing real estate properties.

No definition available.

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

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.

No definition available.