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. 17, 2019 USD ($) ft² property	Dec. 16, 2019 USD ($) ft²	Nov. 14, 2019 USD ($) ft²	Sep. 26, 2019 USD ($) ft² property	Jul. 30, 2019 USD ($) ft²	Jun. 18, 2019 USD ($) ft²	Apr. 30, 2019 USD ($) ft²	Apr. 05, 2019 USD ($) ft² property	Feb. 28, 2019 USD ($) ft²	Feb. 08, 2019 USD ($) ft²	Dec. 27, 2018 USD ($) ft²	Oct. 30, 2018 USD ($) ft² property shares	Sep. 20, 2018 USD ($) ft²	Mar. 09, 2018 USD ($) ft²	Dec. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($) ft²
Business Acquisition [Line Items]
Aggregate Purchase Price															$ 130,313	$ 63,245
Acquisition Expenses															1,200	$ 900
New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Fixed Rate Debt Issued															$ 69,650
Stated interest rate (as a percent)															3.90%
Series of Property Acquisitions
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²															2,562,483	591,037
Lease Term															12 years 9 months 18 days	11 years 1 month 6 days
Aggregate Purchase Price															$ 130,313	$ 63,245
Acquisition Expenses															1,231	905
Aggregate Annualized GAAP Rent															10,009	5,984
Aggregate Mortgage Debt Issued or Assumed															37,410	$ 11,663
Six Property Portfolio
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²	509,211
Lease Term	10 years 15 days
Aggregate Purchase Price	$ 37,600
Aggregate Annualized GAAP Rent	$ 2,700
Number of properties in portfolio \| property	6
Six Property Portfolio \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Fixed Rate Debt Issued															$ 19,500
Stated interest rate (as a percent)															3.75%
Moorestown, New Jersey
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²										26,050
Lease Term										15 years 23 days
Aggregate Purchase Price										$ 2,700
Aggregate Annualized GAAP Rent										$ 200
Indianapolis, Indiana
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²			231,509						34,800
Lease Term			13 years 5 months 16 days						10 years 1 day
Aggregate Purchase Price			$ 8,200						$ 3,600
Aggregate Annualized GAAP Rent			$ 600						$ 300
Ocala, Florida
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²								383,000
Lease Term								20 years 26 days
Aggregate Purchase Price								$ 19,200
Aggregate Annualized GAAP Rent								$ 1,500
Number of properties in portfolio \| property								2
Columbus, Ohio
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²							54,430						157,810
Lease Term							7 years						15 years 11 days
Aggregate Purchase Price							$ 3,200						$ 8,500
Aggregate Annualized GAAP Rent							$ 200						800
Columbus, Ohio \| Interest rate swaps
Business Acquisition [Line Items]
Aggregate Mortgage Debt Issued or Assumed													$ 4,700
Stated interest rate (as a percent)													3.22%
Columbus, Ohio \| LIBOR \| Interest rate swaps
Business Acquisition [Line Items]
Derivative, basis spread on variable rate													5.32%
Tifton, Georgia
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²						676,031
Lease Term						8 years 5 months 13 days
Aggregate Purchase Price						$ 17,900
Aggregate Annualized GAAP Rent						$ 1,600
Tifton, Georgia \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Fixed Rate Debt Issued															$ 8,900
Denton, Texas
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²					78,452
Lease Term					11 years 11 months 1 day
Aggregate Purchase Price					$ 6,600
Aggregate Annualized GAAP Rent					$ 500
Temple, Texas
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²				211,000
Lease Term				20 years
Aggregate Purchase Price				$ 14,100
Aggregate Annualized GAAP Rent				$ 1,200
Number of properties in portfolio \| property				2
Jackson, Tennessee
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²		241,000
Lease Term		9 years 8 months 16 days
Aggregate Purchase Price		$ 9,100
Aggregate Annualized GAAP Rent		$ 700
Jackson, Tennessee \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Fixed Rate Debt Issued															$ 4,800
Stated interest rate (as a percent)															3.97%
Carrollton, Georgia
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²	117,000
Lease Term	12 years 15 days
Aggregate Purchase Price	$ 8,100
Aggregate Annualized GAAP Rent	$ 600
Carrollton, Georgia \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Fixed Rate Debt Issued															$ 4,200
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
Detroit, Michigan
Business Acquisition [Line Items]
Aggregate Square Footage \| ft²												218,703
Lease Term												10 years 6 months
Aggregate Purchase Price												$ 21,700
Aggregate Annualized GAAP Rent												$ 1,700
Number of properties in portfolio \| property												2
Number of units issued in acquisition (in shares) \| shares												742,937
Detroit, Michigan \| New fixed rate mortgage notes payable
Business Acquisition [Line Items]
Aggregate Mortgage Debt Issued or Assumed												$ 6,900
Stated interest rate (as a percent)												4.63%
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