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, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per Share [Abstract]
Net income (loss)	$ (3,606)	$ 6,588	$ 7,535	$ 21,148	$ 6,402	$ (6,892)	$ (6,433)	$ (252)	$ 31,665	$ (7,175)	$ 1,457
Loss (Income) attributable to noncontrolling interests									(374)	2,715	(175)
Preferred stock dividends									(28,180)	(16,666)
Earnings attributable to participating securities									(7,828)	(947)	(593)
Net income (loss) available to common stockholders after allocation of participating securities									$ (4,717)	$ (22,073)	$ 689
Weighted average shares outstanding - basic									54,836,801	50,432,590	48,380,964
Effect of Class A partnership units											6,696,000
Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis											779,000
Weighted average shares outstanding - diluted									54,836,801	50,432,590	55,855,683
Basic net income (loss) per share	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01
Diluted net income (loss) per share	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01