Earnings per share of QTS Realty Trust, Inc. (Computation of Basic and Diluted Net Income per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings per Share [Abstract]
Net income available to common stockholders - basic	$ (14,142)	$ 6,507	$ 4,040	$ 4,877	$ 4,806	$ 5,730	$ 5,100	$ 5,889	$ 1,282	$ 21,525	$ 20,326
Effect of net income attributable to noncontrolling interests and income allocated to participating securities									(593)	3,160	3,803
Net income available to common stockholders									$ 689	$ 24,685	$ 24,129
Weighted average shares outstanding - basic									48,380,964	46,205,937	37,568,109
Effect of Class A and Class RS partnership units									6,696,000	6,783,000	7,029,000
Effect of Class O units and options to purchase Class A common stock and restricted Class A common stock on an "as if" converted basis									779,000	973,000	756,000
Weighted average shares outstanding-diluted									55,855,683	53,962,234	45,353,170
Basic net income per share	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ 0.10	$ 0.12	$ 0.11	$ 0.14	$ 0.01	$ 0.47	$ 0.54
Diluted net income per share	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ 0.10	$ 0.12	$ 0.10	$ 0.14	$ 0.01	$ 0.46	$ 0.53