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

Annual report pursuant to Section 13 and 15(d)

Real Estate and Intangible Assets - Summary of Properties Acquired (Detail)

Real Estate and Intangible Assets - Summary of Properties Acquired (Detail) $ in Thousands									12 Months Ended
	Dec. 27, 2018 USD ($) ft²	Oct. 30, 2018 USD ($) ft² property shares	Sep. 20, 2018 USD ($) ft²	Mar. 09, 2018 USD ($) ft²	Dec. 01, 2017 USD ($) ft²	Jul. 31, 2017 USD ($) ft² property	Jul. 07, 2017 USD ($) ft²	Jun. 22, 2017 USD ($) ft²	Dec. 31, 2018 USD ($) ft²	Dec. 31, 2017 USD ($) ft²	Dec. 31, 2016 USD ($)	Jul. 25, 2014 ft²
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²												81,371
Aggregate Purchase Price									$ 63,245	$ 132,157
Change in unrealized (loss) gain related to interest rate hedging instruments, net									$ (183)	$ 35	$ 0
New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Stated interest rate (as a percent)									4.76%
Series of Property Acquisitions
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²									591,037	871,038
Lease Term									11 years 1 month 6 days	10 years 1 month 6 days
Aggregate Purchase Price									$ 63,245	$ 132,157
Acquisition Expenses									905	1,348
Aggregate Annualized GAAP Rent									5,984	15,507
Aggregate Mortgage Debt Issued or Assumed									11,663	54,887
Vance, Alabama
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²				127,444
Lease Term				9 years 9 months 18 days
Aggregate Purchase Price				$ 14,300
Aggregate Annualized GAAP Rent				$ 1,100
Columbus, Ohio
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²			157,810		102,559
Lease Term			15 years 11 days		6 years 10 months 24 days
Aggregate Purchase Price			$ 8,500		$ 17,300
Aggregate Annualized GAAP Rent			800		$ 1,700
Aggregate Mortgage Debt Issued or Assumed			$ 4,700
Stated interest rate (as a percent)			3.22%
Detroit, Michigan
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²		218,703
Lease Term		10 years 5 months 19 days
Aggregate Purchase Price		$ 21,700
Aggregate Annualized GAAP Rent		1,700
Aggregate Mortgage Debt Issued or Assumed		$ 6,900
Number of units issued in acquisition (in shares) \| shares		742,937
Number of properties in portfolio \| property		2
Lake Mary, Florida
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²	87,080
Lease Term	11 years
Aggregate Purchase Price	$ 18,700
Aggregate Annualized GAAP Rent	$ 2,400
Conshohocken, Pennsylvania
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²								60,016
Lease Term								8 years 6 months
Aggregate Purchase Price								$ 15,700
Aggregate Annualized GAAP Rent								1,700
Aggregate Mortgage Debt Issued or Assumed								$ 11,200
Stated interest rate (as a percent)								1.80%
Philadelphia, Pennsylvania
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²							300,000
Lease Term							15 years 4 months 24 days
Aggregate Purchase Price							$ 27,100
Aggregate Annualized GAAP Rent							2,300
Aggregate Mortgage Debt Issued or Assumed							$ 14,900
Stated interest rate (as a percent)							3.75%
Maitland, Florida
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²						306,435
Lease Term						8 years 7 months 6 days
Aggregate Purchase Price						$ 51,600
Aggregate Annualized GAAP Rent						6,800
Aggregate Mortgage Debt Issued or Assumed						$ 28,800
Stated interest rate (as a percent)						3.89%
Number of properties in portfolio \| property						3
Salt Lake City, Utah
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²					102,028
Lease Term					10 years 1 month 6 days
Aggregate Purchase Price					$ 20,500
Aggregate Annualized GAAP Rent					$ 3,000
Interest rate swaps
Business Acquisition [Line Items]
Liabilities assumed									0	42
Change in unrealized (loss) gain related to interest rate hedging instruments, net									$ (260)	$ 274	$ 0
Interest rate swaps \| Detroit, Michigan \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Stated interest rate (as a percent)									4.625%
Interest rate swaps \| Asset Acquisitions
Business Acquisition [Line Items]
Change in unrealized (loss) gain related to interest rate hedging instruments, net									$ 500
Interest rate swap two \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Stated interest rate (as a percent)									5.32%
LIBOR \| Interest rate swaps \| Columbus, Ohio
Business Acquisition [Line Items]
Derivative, basis spread on variable rate			5.32%
LIBOR \| Interest rate swaps \| Conshohocken, Pennsylvania
Business Acquisition [Line Items]
Derivative, basis spread on variable rate								3.55%