Related Person Transactions - Relationships Between Client Companies (Details)	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2020
Related Party Transaction [Line Items]
Term of registration and lock up agreement	10 years	10 years
TA
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners			4.60%
Five Star
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners			6.40%
SVC | TA
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners			8.20%
SVC | Sonesta
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners			33.90%
DHC | Five Star
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners			33.90%