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

Mortgage Notes Payable and Credit Facility - Company's Mortgage Notes Payable and Line of Credit Additional Information (Detail)

Mortgage Notes Payable and Credit Facility - Company's Mortgage Notes Payable and Line of Credit Additional Information (Detail)	3 Months Ended
	Mar. 31, 2021 mortgage property
Debt Instrument [Line Items]
Weighted average interest rate on debt outstanding (as percent)	4.22%
Encumbered properties	117
LIBOR
Debt Instrument [Line Items]
Variable rate at period end (as percent)	0.11%
Fixed rate mortgage loans
Debt Instrument [Line Items]
Stated interest rate (as percent)	4.90%
Encumbered properties	61
Fixed rate mortgage loans \| Minimum
Debt Instrument [Line Items]
Stated interest rate (as percent)	2.80%
Fixed rate mortgage loans \| Maximum
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.63%
Mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage	53
Maturity date of mortgage notes payable, start date	Nov. 01, 2021
Maturity date of mortgage notes payable, end date	Aug. 01, 2037
Weighted average interest rate on debt outstanding (as percent)	3.52%
Encumbered properties	68
Variable rate mortgage loans
Debt Instrument [Line Items]
Encumbered properties	7
Variable rate mortgage loans \| Minimum \| LIBOR
Debt Instrument [Line Items]
Spread on LIBOR (as percent)	2.35%
Variable rate mortgage loans \| Maximum \| LIBOR
Debt Instrument [Line Items]
Spread on LIBOR (as percent)	2.75%
Variable rate revolving credit facility \| Revolving credit facility
Debt Instrument [Line Items]
Encumbered properties	49
Variable rate revolving credit facility \| LIBOR \| Revolving credit facility
Debt Instrument [Line Items]
Spread on LIBOR (as percent)	1.90%