Orion Office REIT Inc. Quarterly report pursuant to Section 13 or 15(d)

Realty Income Office Assets, Mortgages Payable - Narrative (Details) - Realty Income Office Assets $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) debtInstrument	Sep. 30, 2020 USD ($) debtInstrument
Debt Instrument [Line Items]
Payments of mortgage notes payable				$ 26,851	$ 9,203
Loss on extinguishment of debt, net		$ 3,499	$ 0	3,499	0
Mortgages
Debt Instrument [Line Items]
Payments of mortgage notes payable				$ 26,800	$ 9,200
Debt instrument, number repaid \| debtInstrument				2	1
Amount of debt redeemed early	$ 12,500
Loss on extinguishment of debt, net	3,500
Prepayment penalty	4,000
Writeoff of unamortized premium	$ 500
Mortgages \| Mortgages Paid In Full Member
Debt Instrument [Line Items]
Payments of mortgage notes payable				$ 26,500	$ 8,500