Summary of Significant Accounting Policies - Revenue Recognition and Segment Information (Details) $ in Thousands	12 Months Ended
Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Straight line rent adjustments	$ (714)	$ (10,719)	$ 12,509
Straight line rent receivable	$ 16,264	1,897
Number of reportable segments \| segment	2
Affiliated Entity
Related Party Transaction [Line Items]
Straight line rent receivables, due from related parties	$ 33,902	47,057
Deferred percentage rental income	$ 3,277	$ 4,238	$ 3,695

Represents amount of deferred percentage rent revenue for the reporting period.

No definition available.

Name:	svc_DeferredPercentageRent
Namespace Prefix:	svc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of straight line rent receivables as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	svc_StraightLineRentReceivables
Namespace Prefix:	svc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Straight Line Rent Receivables, Due From Related Parties

+ References

No definition available.

+ Details

Name:	svc_StraightLineRentReceivablesDueFromRelatedParties
Namespace Prefix:	svc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8672-108599

+ Details

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

- Definition

Amount of the adjustment to rental revenues to measure escalating leasing revenues on a straight line basis.

+ References

No definition available.

+ Details

Name:	us-gaap_StraightLineRentAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: