Gladstone Commercial Corporation Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Details) $ in Thousands		1 Months Ended	9 Months Ended
	Oct. 26, 2021 USD ($) property	Nov. 01, 2021 USD ($) shares	Sep. 30, 2021 USD ($) property shares	Sep. 30, 2020 USD ($)
Subsequent Event [Line Items]
Encumbered properties \| property			124
Repayments on mortgage notes			$ 14,336	$ 31,667
Fixed rate mortgage loans
Subsequent Event [Line Items]
Encumbered properties \| property			61
Repayments on mortgage notes			$ 4,470
Stated interest rate			4.90%
Subsequent Event \| Fixed rate mortgage loans
Subsequent Event [Line Items]
Encumbered properties \| property	1
Repayments on mortgage notes	$ 3,200
Stated interest rate	4.92%
Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Consideration received		$ 8,000
Redeemable preferred stock, shares issued (in shares) \| shares		378,495
Series F Preferred Stock \| Preferred Stock
Subsequent Event [Line Items]
Consideration received			$ 4,900
Redeemable preferred stock, shares issued (in shares) \| shares			217,422
Series F Preferred Stock \| Preferred Stock \| Subsequent Event
Subsequent Event [Line Items]
Consideration received		$ 800
Redeemable preferred stock, shares issued (in shares) \| shares		33,572