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

Subsequent Events - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014 sqft	Dec. 31, 2013	Dec. 31, 2012	Feb. 09, 2015 Property sqft	Jul. 25, 2014 sqft
Subsequent Event [Line Items]
Previously occupied space	61,306us-gaap_AreaOfRealEstateProperty				81,371us-gaap_AreaOfRealEstateProperty
Lease commission to be paid	$ 1,159,000us-gaap_PaymentsForLeaseCommissions	$ 1,041,000us-gaap_PaymentsForLeaseCommissions	$ 1,738,000us-gaap_PaymentsForLeaseCommissions
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of properties expanded				2
Number of properties occupied by tenant				2
Renew the lease for additional periods				5 years
Extended lease period				2020-07
Previously occupied space				174,426
Reduced space by tenant				94,200
Annualized straight line rent escalations				900,000
Lease commission to be paid				200,000
Amount to be paid for tenant Improvements				100,000
Subsequent Event [Member] \| Previously Reported [Member]
Subsequent Event [Line Items]
Annualized straight line rent escalations				$ 1,300,000
Subsequent Event [Member] \| Lease One [Member]
Subsequent Event [Line Items]
Period for lease expiration				2015-07
Subsequent Event [Member] \| Lease Two [Member]
Subsequent Event [Line Items]
Period for lease expiration				2015-07