Orion Office REIT Inc. Annual report pursuant to Section 13 and 15(d)

Orion Office REIT, Fair Value Measures - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of properties \| property	10	1
Provisions for impairment \| $	$ 49,859,000	$ 18,671,000	$ 0
Weighted Average \| Assets Impaired During The Twelve Months Ended December 31 2021 \| Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative investment, measurement input	0.089