Earnings per Share (Summary of Basic and Diluted Earnings per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended						9 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
Earnings per Share [Abstract]
Net income (loss) available to common stockholders		$ 4,627	$ 3,157	$ 3,090	$ 4,198	$ 3,154			$ 15,072
Weighted average shares outstanding-basic						28,972,774			29,054,576
Net income per share-basic		$ 0.16	$ 0.11	$ 0.11	$ 0.14	$ 0.11	[1]		$ 0.52
Net income	$ 445	$ 5,848	$ 4,006	$ 3,921	$ 5,328	$ 4,002	[2]	$ (152)	$ 19,103	[2]	$ (9,767)
Weighted average shares outstanding-diluted						36,794,215	[3]		37,133,584	[3]
Net income per share-diluted		$ 0.16	$ 0.11	$ 0.11	$ 0.14	$ 0.11	[1]		$ 0.51

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

[2] (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

[3] 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 on as “as if” converted basis.