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

Real Estate and Intangible Assets - Carrying Value of Intangible Assets, Liabilities and Accumulated Amortization (Detail)

Real Estate and Intangible Assets - Carrying Value of Intangible Assets, Liabilities and Accumulated Amortization (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 181,345	$ 163,034
Finite-lived intangible assets, accumulated amortization	(63,084)	(53,696)
Finite-lived intangible assets, gross	9,591	8,314
Finite-lived intangible assets, accumulated amortization	(6,307)	(6,384)
Below market leases, gross	16,946	15,939
Below market leases, accumulated amortization	(7,932)	(7,345)
In-Place Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	65,642	59,233
Finite-lived intangible assets, accumulated amortization	(21,198)	(17,379)
Leasing Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	42,936	38,305
Finite-lived intangible assets, accumulated amortization	(13,803)	(11,411)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	46,230	41,243
Finite-lived intangible assets, accumulated amortization	(13,844)	(11,177)
Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	154,808	138,781
Finite-lived intangible assets, accumulated amortization	(48,845)	(39,967)
Above and Below Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	26,537	24,253
Finite-lived intangible assets, accumulated amortization	$ (14,239)	$ (13,729)