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, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings per Share [Abstract]
Net income (loss)	$ 7,535	$ 21,148	$ (6,433)	$ (252)	$ 28,683	$ (6,685)
Loss (Income) attributable to noncontrolling interests	(52)		1,002		(1,642)	1,031
Preferred stock dividends	(7,045)		(2,248)		(14,090)	(2,576)
Earnings attributable to participating securities	(1,880)		(227)		(3,814)	(485)
Net income (loss) available to common stockholders after allocation of participating securities	$ (1,442)		$ (7,906)		$ 9,137	$ (8,715)
Weighted average shares outstanding - basic	54,713		50,542		53,338	50,366
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					416
Weighted average shares outstanding - diluted	54,713		50,542		53,754	50,366
Basic net income (loss) per share	$ (0.03)		$ (0.16)		$ 0.17	$ (0.17)
Diluted net income (loss) per share	$ (0.03)		$ (0.16)		$ 0.17	$ (0.17)