Quarterly Financial Information (Summary of Selected Quarterly Information) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended						9 Months Ended	12 Months Ended			3 Months Ended				12 Months Ended
	Oct. 14, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Oct. 14, 2013	Dec. 31, 2014		Dec. 31, 2012	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 6,967	$ 59,563	$ 57,945	$ 51,338	$ 48,943	$ 40,462			$ 217,789
Operating income	1,143	11,682	9,913	6,266	7,413	6,203			35,274
Net income (loss)	445	5,848	4,006	3,921	5,328	4,002	[1]	(152)	19,103	[1]	(9,767)
Net income (loss)						3,154			15,072
Net income (loss) available to common stockholders		4,627	3,157	3,090	4,198	3,154			15,072
Net income per share-basic		$ 0.16	$ 0.11	$ 0.11	$ 0.14	$ 0.11	[2]		$ 0.52
Net income per share-diluted		$ 0.16	$ 0.11	$ 0.11	$ 0.14	$ 0.11	[2]		$ 0.51
Historical Predecessor [Member]
Effect of Fourth Quarter Events [Line Items]
Revenues								137,425			145,759	46,020	42,940	41,498
Operating income								19,783			15,515	7,048	6,024	5,568
Net income (loss)								(152)			(9,767)	2,709	(1,232)	(2,074)
Net income (loss)								(152)			(9,767)
Qualitytech, LP [Member]
Effect of Fourth Quarter Events [Line Items]
Revenues		59,563	57,945	51,338	48,943				217,789		145,759	46,020	42,940	41,498	47,429	177,887
Operating income		11,682	9,913	6,266	7,413				35,274		15,515	7,048	6,024	5,568	7,346	25,986
Net income (loss)									19,103		(9,767)					3,850
Net income (loss)		$ 5,848	$ 4,006	$ 3,921	$ 5,328				$ 19,103		$ (9,767)	$ 2,709	$ (1,232)	$ (2,074)	$ 4,447	$ 3,850

[1] (1) Includes 7,770 Class A and Class RS units, 195 “in the money” value of Class O units on an “as if” converted basis and 114 “in the money” value options to purchase shares of Class A common stock on an “as if” converted basis as of the year ended December 31, 2014. As of the year ended December 31, 2013, this amount includes 7,797 Class A and Class RS units and 24 “in the money” value of Class O units

[2] Net income per share attributable to QTS Realty Trust, Inc. for the period October 15, 2013 through December 31, 2013.