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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings per Share [Abstract]
Net income available to common stockholders - basic	$ 4,040	$ 5,100	$ 8,917	$ 10,989
Effect of net income attributable to noncontrolling interests and income allocated to participating securities	356	707	814	1,677
Net income available to common stockholders	$ 4,396	$ 5,807	$ 9,731	$ 12,666
Weighted average shares outstanding-basic	47,666,086	47,783,093	47,561,507	44,537,769
Effect of Class A and Class RS partnership units	6,783,000	6,794,000	6,783,000	6,797,000
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	1,009,000	998,000	991,000	939,000
Weighted average shares outstanding-diluted	55,458,429	55,574,545	55,336,062	52,274,198
Basic net income per share	$ 0.08	$ 0.11	$ 0.18	$ 0.25
Diluted net income per share	$ 0.08	$ 0.10	$ 0.17	$ 0.24