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		6 Months Ended
	Dec. 01, 2017 USD ($)	Oct. 27, 2017 USD ($)	May 26, 2016 USD ($)	Oct. 31, 2015 USD ($)	Jun. 30, 2018 USD ($) mortgage property	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) mortgage property	Jun. 30, 2018 USD ($) mortgage property	Jun. 30, 2018 USD ($) mortgage property	Jun. 30, 2018 USD ($) mortgage property	Jun. 30, 2017 USD ($)	Jun. 22, 2018 USD ($)	Apr. 18, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 22, 2017	Oct. 05, 2015 USD ($)	Aug. 31, 2013 USD ($)
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property					98		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								$ 253,000			$ 414,000
Interest rate swap					$ 1,115,000		$ 1,115,000	1,115,000	$ 1,115,000	$ 1,115,000				$ 504,000
Fair value of mortgage notes payable					435,100,000		435,100,000	435,100,000	435,100,000	435,100,000
Maximum borrowing capacity														75,000,000.0			$ 25,000,000.0
Extension fee on initial maturity (as percent)		0.25%
Debt instrument fees incurred		$ 900,000
Line of credit outstanding					$ 32,808,000		$ 32,808,000	$ 32,808,000	$ 32,808,000	$ 32,808,000				20,715,000
Weighted average interest rate on debt outstanding (as percent)					4.63%		4.63%	4.63%	4.63%	4.63%
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					$ 108,400,000		$ 108,400,000	$ 108,400,000	$ 108,400,000	$ 108,400,000
Weighted average interest rate (as percent)					3.81%		3.81%	3.81%	3.81%	3.81%
Letters of credit, outstanding					$ 1,000,000		$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000
Maximum additional amount that can be drawn under Line of Credit					$ 46,100,000		$ 46,100,000	$ 46,100,000	$ 46,100,000	$ 46,100,000
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%	1.75%
Variable rate mortgage loans
Debt Instrument [Line Items]
Number of properties collateralized in mortgage notes payable \| property					18		18	18	18	18
Carrying value					$ 61,590,000		$ 61,590,000	$ 61,590,000	$ 61,590,000	$ 61,590,000			$ 13,000,000.0	69,302,000
Mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage					45		45	45	45	45
Number of properties collateralized in mortgage notes payable \| property					66		66	66	66	66
Net book value of collateralized mortgage properties					$ 639,400,000		$ 639,400,000	$ 639,400,000	$ 639,400,000	$ 639,400,000
Recourse amount of mortgage notes payable					10,200,000		10,200,000	10,200,000	10,200,000	$ 10,200,000
Percentage of debt recourse (as percent)										2.30%
Carrying value					$ 439,877,000		$ 439,877,000	$ 439,877,000	$ 439,877,000	$ 439,877,000
Weighted average interest rate on debt outstanding (as percent)					4.46%		4.46%	4.46%	4.46%	4.46%
Issued and assumed mortgage notes payable
Debt Instrument [Line Items]
Number of mortgage notes payable \| mortgage					1		1	1	1	1
Number of properties collateralized in mortgage notes payable \| property					1		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	48
Payments of deferred financing costs					$ 30,000	$ 400,000		$ 200,000			$ 400,000
Stated interest rate (as percent)					5.75%		5.75%	5.75%	5.75%	5.75%
Carrying value					$ 378,287,000		$ 378,287,000	$ 378,287,000	$ 378,287,000	$ 378,287,000				$ 383,189,000
Conshohocken, Pennsylvania
Debt Instrument [Line Items]
Stated interest rate (as percent)												1.80%			1.80%
Mortgage loans on real estate, new mortgage loans			$ 11,200,000
Columbus, Ohio
Debt Instrument [Line Items]
Stated interest rate (as percent)	2.83%
Interest rate swap \| Conshohocken, Pennsylvania
Debt Instrument [Line Items]
Interest rate swap					700,000		700,000	700,000	700,000	700,000		$ 0
Interest rate swap \| Columbus, Ohio
Debt Instrument [Line Items]
Interest rate swap					$ (100,000)		$ (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%
LIBOR \| Variable rate mortgage loans
Debt Instrument [Line Items]
Spread on LIBOR (as percent)										2.25%