Reportable Segments - Additional Information (Details)	Sep. 30, 2018 Property Customer	Sep. 30, 2017 Customer
Segment Reporting Information [Line Items]
Number of customer contributed 10% or more of total revenue \| Customer	0	0
Denver \| Non-same store
Segment Reporting Information [Line Items]
Number of properties acquired \| Property	2

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.

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