Summary of Significant Accounting Policies - Deferred Financing Costs, Net of Accumulated Amortization (Detail) (QualityTech, LP [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
QualityTech, LP [Member]
Deferred Costs And Other Assets [Line Items]
Deferred financing costs	$ 9,159	$ 10,165
Accumulated amortization	(1,231)	(3,309)
Deferred financing costs, net	$ 7,928	$ 6,856