Gladstone Commercial Corporation Quarterly report pursuant to Section 13 or 15(d)

Real Estate and Intangible Assets - Weighted Average Amortization Period for Intangible Assets Acquired and Liabilities Assumed (Detail)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	12 years 10 months 24 days	11 years 6 months
In-Place Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	11 years 6 months	10 years 2 months 12 days
Leasing Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	11 years 6 months	10 years 2 months 12 days
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	16 years 1 month 6 days	14 years 7 months 6 days
Above Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	17 years 2 months 12 days	9 years 3 months 18 days
Below Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Period for intangible assets and liabilities	13 years 6 months	9 years 10 months 24 days