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

Real Estate and Intangible Assets - Carrying Value of Intangible Assets and Accumulated Amortization (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Below market leases and deferred revenue, gross	$ (25,576)	$ (21,606)
Below market leases and deferred revenue, accumulated amortization	10,022	8,959
Lease Intangibles
Finite-Lived Intangible Assets [Line Items]
Lease Intangibles	188,528	169,734
Intangibles, accumulated amortization	(73,318)	(64,181)
In-place leases
Finite-Lived Intangible Assets [Line Items]
Lease Intangibles	78,975	71,482
Intangibles, accumulated amortization	(32,140)	(28,182)
Leasing costs
Finite-Lived Intangible Assets [Line Items]
Lease Intangibles	53,706	48,000
Intangibles, accumulated amortization	(21,889)	(18,599)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Lease Intangibles	55,847	50,252
Intangibles, accumulated amortization	(19,289)	(17,400)
Above market leases and below market leases and deferred revenue
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets (liabilities), gross	(13,059)	(11,127)
Finite-lived intangible assets (liabilities), accumulated amortization	2,296	1,663
Above market leases
Finite-Lived Intangible Assets [Line Items]
Lease Intangibles	12,517	10,479
Intangibles, accumulated amortization	$ (7,726)	$ (7,296)