Gladstone Commercial Corporation Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Monthly Distributions Declared by Company's Board of Directors (Detail)

Subsequent Events - Monthly Distributions Declared by Company's Board of Directors (Detail) - $ / shares													1 Months Ended
	Apr. 05, 2021	Mar. 31, 2021	Mar. 24, 2021	Mar. 18, 2021	Mar. 05, 2021	Feb. 26, 2021	Feb. 24, 2021	Feb. 17, 2021	Feb. 05, 2021	Jan. 29, 2021	Jan. 27, 2021	Jan. 22, 2021	Mar. 31, 2021	Feb. 28, 2021	Jan. 31, 2021	Jan. 12, 2021
Subsequent Event \| Series D Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)																$ 0.4374999
Subsequent Event \| Series E Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)																0.414063
Subsequent Event \| Series F Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)																0.375
Subsequent Event \| Senior Common Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)																0.2625
Subsequent Event \| Common Stock and Non-controlling OP Units
Dividends Payable [Line Items]
Distributions (in dollars per share)																$ 0.37545
Subsequent Event \| Dividend Declared for Month of January
Dividends Payable [Line Items]
Record date												Jan. 22, 2021
Payment date										Jan. 29, 2021
Subsequent Event \| Dividend Declared for Month of January \| Series D Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)										$ 0.1458333
Subsequent Event \| Dividend Declared for Month of January \| Series E Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)										0.138021
Subsequent Event \| Dividend Declared for Month of January \| Series F Preferred Stock
Dividends Payable [Line Items]
Payment date									Feb. 05, 2021
Month in which distribution is payable to holders of record											January 27, 2021
Distributions (in dollars per share)									$ 0.125
Subsequent Event \| Dividend Declared for Month of January \| Senior Common Stock
Dividends Payable [Line Items]
Payment date									Feb. 05, 2021
Month in which distribution is payable to holders of record															January
Distributions (in dollars per share)									$ 0.0875
Subsequent Event \| Dividend Declared for Month of January \| Common Stock and Non-controlling OP Units
Dividends Payable [Line Items]
Distributions (in dollars per share)										$ 0.12515
Scenario, Forecast \| Dividend Declared for Month of February
Dividends Payable [Line Items]
Record date								Feb. 17, 2021
Payment date						Feb. 26, 2021
Scenario, Forecast \| Dividend Declared for Month of February \| Series D Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)						$ 0.1458333
Scenario, Forecast \| Dividend Declared for Month of February \| Series E Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)						0.138021
Scenario, Forecast \| Dividend Declared for Month of February \| Series F Preferred Stock
Dividends Payable [Line Items]
Payment date					Mar. 05, 2021
Month in which distribution is payable to holders of record							February 24, 2021
Distributions (in dollars per share)					$ 0.125
Scenario, Forecast \| Dividend Declared for Month of February \| Senior Common Stock
Dividends Payable [Line Items]
Payment date					Mar. 05, 2021
Month in which distribution is payable to holders of record														February
Distributions (in dollars per share)					$ 0.0875
Scenario, Forecast \| Dividend Declared for Month of February \| Common Stock and Non-controlling OP Units
Dividends Payable [Line Items]
Distributions (in dollars per share)						$ 0.12515
Scenario, Forecast \| Dividend Declared for Month of March
Dividends Payable [Line Items]
Record date				Mar. 18, 2021
Payment date		Mar. 31, 2021
Scenario, Forecast \| Dividend Declared for Month of March \| Series D Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)		$ 0.1458333											$ 0.1458333
Scenario, Forecast \| Dividend Declared for Month of March \| Series E Preferred Stock
Dividends Payable [Line Items]
Distributions (in dollars per share)		0.138021											$ 0.138021
Scenario, Forecast \| Dividend Declared for Month of March \| Series F Preferred Stock
Dividends Payable [Line Items]
Payment date	Apr. 05, 2021
Month in which distribution is payable to holders of record			March 24, 2021
Distributions (in dollars per share)	$ 0.125
Scenario, Forecast \| Dividend Declared for Month of March \| Senior Common Stock
Dividends Payable [Line Items]
Payment date	Apr. 05, 2021
Month in which distribution is payable to holders of record													March
Distributions (in dollars per share)	$ 0.0875
Scenario, Forecast \| Dividend Declared for Month of March \| Common Stock and Non-controlling OP Units
Dividends Payable [Line Items]
Distributions (in dollars per share)		$ 0.12515											$ 0.12515