INVESTMENT IN HOTEL PROPERTIES - Total revenue and net income for hotel properties acquired (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
2017 Acquisitions
Business Acquisition [Line Items]
Revenues	$ 53,443
Net income	5,914
2016 Acquisitions
Business Acquisition [Line Items]
Revenues	47,842	$ 28,560
Net income	$ 8,736	$ 6,992

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.

+ Details

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

- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

+ Details

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

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=inn_BusinessAcquisitions2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=inn_BusinessAcquisitions2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: