Earnings per share of QTS Realty Trust, Inc. (Computation of Basic and Diluted Net Income per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings per Share [Abstract]
Net income	$ 10,209	$ 8,120	$ 7,535	$ 21,148	$ 18,329	$ 28,683
Income attributable to noncontrolling interests	(317)		(52)		(427)	(1,642)
Preferred stock dividends	(7,045)		(7,045)		(14,090)	(14,090)
Earnings attributable to participating securities	(5,552)		(1,880)		(7,148)	(3,814)
Net income (loss) available to common stockholders after allocation of participating securities	$ (2,705)		$ (1,442)		$ (3,336)	$ 9,137
Weighted average shares outstanding - basic	59,773		54,713		58,900	53,338
Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis						416
Weighted average shares outstanding - diluted	59,773		54,713		58,900	53,754
Basic net income (loss) per share	$ (0.05)		$ (0.03)		$ (0.06)	$ 0.17
Diluted net income (loss) per share	$ (0.05)		$ (0.03)		$ (0.06)	$ 0.17