v3.26.1
Cover Page - shares
9 Months Ended
Sep. 30, 2025
May 18, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2025  
Document Transition Report false  
Entity File Number 001-34364  
Entity Registrant Name OFFICE PROPERTIES INCOME TRUST  
Entity Incorporation, State or Country Code MD  
Entity Tax Identification Number 26-4273474  
Entity Address, Address Line One Two Newton Place,  
Entity Address, Address Line Two 255 Washington Street,  
Entity Address, Address Line Three Suite 300,  
Entity Address, City or Town Newton,  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02458-1634  
City Area Code 617  
Local Phone Number 219-1440  
Entity Current Reporting Status No  
Entity Interactive Data Current No  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   73,941,128
Entity Central Index Key 0001456772  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3