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

Quarterly report pursuant to Section 13 or 15(d)

Mortgage Notes Payable and Credit Facility - Additional Information (Detail)

Mortgage Notes Payable and Credit Facility - Additional Information (Detail)				1 Months Ended	3 Months Ended
	Dec. 01, 2017 USD ($)	Oct. 27, 2017	Oct. 05, 2015 USD ($)	Oct. 31, 2015 USD ($)	Mar. 31, 2018 USD ($) mortgage property	Mar. 31, 2018 USD ($) mortgage property	Mar. 31, 2018 USD ($) mortgage property	Mar. 31, 2018 USD ($) mortgage property	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Aug. 31, 2013 USD ($)
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property					98	98	98	98
Number of long-term mortgages repaid					1			1
Number of properties repaid to collateralized mortgages notes payable \| mortgage					1
Number of properties collateralized \| property								2
Payments of deferred financing costs							$ 212,000		$ 17,000
Interest rate swap					$ 959,000	$ 959,000	959,000	$ 959,000		$ 504,000
Fair value of mortgage notes payable					440,500,000	440,500,000	440,500,000	440,500,000
Maximum borrowing capacity										75,000,000.0	$ 25,000,000.0
Extension fee on initial maturity (as percent)		0.25%	0.25%
Debt instrument fees incurred		0.9
Line of credit outstanding					$ 32,065,000	$ 32,065,000	$ 32,065,000	$ 32,065,000		20,715,000
Weighted average interest rate on debt outstanding (as percent)					4.59%	4.59%	4.59%	4.59%
Term Loan Facility
Debt Instrument [Line Items]
Term of debt		5 years
Extension fee on initial maturity (as percent)				0.05%
Revolving credit facility
Debt Instrument [Line Items]
Term of debt		4 years
Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 85,000,000.0	$ 85,000,000.0
Line of credit outstanding					$ 107,700,000	$ 107,700,000	$ 107,700,000	$ 107,700,000
Weighted average interest rate (as percent)					3.60%	3.60%	3.60%	3.60%
Letters of credit, outstanding					$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000
Maximum additional amount that can be drawn under Line of Credit					$ 46,300,000	$ 46,300,000	$ 46,300,000	$ 46,300,000
Line of credit \| Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 25,000,000.0
Term of debt				5 years
Letter of credit
Debt Instrument [Line Items]
Weighted average interest rate on debt outstanding (as percent)					1.75%	1.75%	1.75%	1.75%
Mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage					45	45	45	45
Number of properties collateralized in mortgage notes payable \| property					66	66	66	66
Net book value of collateralized mortgage properties					$ 648,400,000	$ 648,400,000	$ 648,400,000	$ 648,400,000
Recourse amount of mortgage notes payable					11,700,000	$ 11,700,000	11,700,000	11,700,000
Percentage of debt recourse (as percent)						2.70%
Carrying value					$ 442,779,000	$ 442,779,000	$ 442,779,000	$ 442,779,000
Weighted average interest rate on debt outstanding (as percent)					4.40%	4.40%	4.40%	4.40%
Issued and assumed mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage					1	1	1	1
Number of properties collateralized in mortgage notes payable \| property					1	1	1	1
Fixed rate mortgage loans
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property					48	48	48	48
Payments of deferred financing costs							$ 200,000		$ 0
Stated interest rate (as percent)					5.75%	5.75%	5.75%	5.75%
Carrying value					$ 380,691,000	$ 380,691,000	$ 380,691,000	$ 380,691,000		$ 383,189,000
Columbus, Ohio
Debt Instrument [Line Items]
Stated interest rate (as percent)	2.83%
Interest rate swap \| Columbus, Ohio
Debt Instrument [Line Items]
Interest rate swap					$ (100,000)	$ (100,000)	$ (100,000)	$ (100,000)
Debt assumed	$ 9,400,000
LIBOR
Debt Instrument [Line Items]
Spread on LIBOR (as percent)		2.75%