Annual report pursuant to Section 13 and 15(d)

Cover Page

Cover Page - USD ($)
12 Months Ended
Dec. 31, 2021
Mar. 18, 2022
Jun. 30, 2021
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2021    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 001-40873    
Entity Registrant Name Orion Office REIT Inc.    
Entity Incorporation, State or Country Code MD    
Entity Tax Identification Number 87-1656425    
Entity Address, Address Line One 2325 E. Camelback Road, Suite 850    
Entity Address, City or Town Phoenix    
Entity Address, State or Province AZ    
Entity Address, Postal Zip Code 85016    
City Area Code (602)    
Local Phone Number 698-1002    
Title of 12(b) Security Common Stock    
Trading Symbol ONL    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding   56,625,650  
Documents Incorporated by Reference Portions of the registrant’s definitive proxy statement to be delivered to stockholders in connection with the registrant’s 2022 Annual Meeting of Stockholders (the “Proxy Statement”) are incorporated by reference into Part III of this Annual Report on Form 10-K. The registrant intends to file the Proxy Statement within 120 days after its fiscal year end. Only those portions of the Proxy Statement which are specifically incorporated by reference herein shall constitute a part of this Annual Report on Form 10-K.    
Entity Central Index Key 0001873923    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Public Float     $ 0