XML 51 R41.htm IDEA: XBRL DOCUMENT v3.10.0.1

Fair Value Disclosures - Additional Information (Detail)	Jun. 30, 2018 store
Fair Value Disclosures [Abstract]
Number of operating stores held for sale	1

X

- Definition

Number of Operating Stores Owned Held-For-Sale

+ References

No definition available.

+ Details

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

X

- References

No definition available.

+ Details

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