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)		3 Months Ended		6 Months Ended
	Oct. 05, 2015 USD ($)	Jun. 30, 2017 USD ($) mortgage property	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) mortgage lender property	Jun. 30, 2016 USD ($)	Jun. 22, 2017 USD ($)	Dec. 31, 2016 USD ($)	Aug. 31, 2013 USD ($)
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property		90		90
Number of long-term mortgages repaid \| mortgage				3
Number of properties repaid to collateralized mortgages notes payable \| mortgage				7
Payments of deferred financing costs				$ 414,000	$ 690,000
Assumed interest rate swap fair market value				42,000	0
Fair value of mortgage notes payable		$ 428,200,000		$ 428,200,000
Maximum borrowing capacity	$ 150,000,000.0							$ 100,000,000.0
Expiration date	2019-08
Term of extended period	1 year
Optional extension period	1 year
Extension fee on initial maturity (as percent)				0.25%
Number of lenders added to agreement \| lender				3
Line of credit outstanding		$ 37,478,000		$ 37,478,000			$ 39,225,000
Weighted average interest rate on debt outstanding (as percent)		4.65%		4.65%
Term Loan Facility
Debt Instrument [Line Items]
Expiration date	2020-10
Extension fee on initial maturity (as percent)				0.05%
Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 85,000,000.0
Line of credit outstanding		$ 62,800,000		$ 62,800,000
Weighted average interest rate (as percent)		3.46%		3.46%
Letters of credit, outstanding		$ 1,000,000		$ 1,000,000
Maximum additional amount that can be drawn under Line of Credit		$ 36,100,000		$ 36,100,000
Line of credit \| Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 25,000,000.0
Letter of credit
Debt Instrument [Line Items]
Weighted average interest rate on debt outstanding (as percent)		2.25%		2.25%
Mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage		44		44
Number of properties collateralized in mortgage notes payable \| property		66		66
Net book value of collateralized mortgage properties		$ 625,600,000		$ 625,600,000
Recourse amount of mortgage notes payable		11,700,000		$ 11,700,000
Percentage of debt recourse (as percent)				2.80%
Carrying value		$ 427,490,000		$ 427,490,000
Weighted average interest rate on debt outstanding (as percent)		4.50%		4.50%
Issued and assumed mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage		2		2
Number of properties collateralized in mortgage notes payable \| property		3		3
Fixed rate mortgage loans
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property		47		47
Payments of deferred financing costs		$ 400,000	$ 300,000	$ 400,000	$ 700,000
Carrying value		$ 357,997,000		$ 357,997,000			$ 378,477,000
Weighted average interest rate on debt outstanding (as percent)		6.05%		6.05%
New fixed rate note
Debt Instrument [Line Items]
Debt assumed				$ 11,179,000
Weighted average interest rate on debt outstanding (as percent)		3.55%		3.55%
Conshohocken, Pennsylvania
Debt Instrument [Line Items]
Stated interest rate (as percent)						1.80%
Debt assumed				$ 11,200,000
Interest rate swap \| Conshohocken, Pennsylvania
Debt Instrument [Line Items]
Interest rate swap		$ 200,000		$ 200,000		$ 40,000