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						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 6,907	$ 10,209	$ 8,120	$ 6,588	$ 7,535	$ 21,148	$ 25,236	$ 35,271
(Income) loss attributable to noncontrolling interests	18			49			(408)	(1,593)
Preferred stock dividends	(7,045)			(7,045)			(21,135)	(21,135)
Earnings attributable to participating securities	(4,372)			(2,184)			(11,521)	(5,999)
Net income (loss) available to common stockholders after allocation of participating securities	$ (4,492)			$ (2,592)			$ (7,828)	$ 6,544
Weighted average shares outstanding - basic (in shares)	61,036			54,928			59,615	53,874
Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis (in shares)	0			0			0	463
Weighted average shares outstanding - diluted (in shares)	61,036			54,928			59,615	54,337
Basic net income (loss) per share (in dollars per share)	$ (0.07)			$ (0.05)			$ (0.13)	$ 0.12
Diluted net income (loss) per share (in dollars per share)	$ (0.07)			$ (0.05)			$ (0.13)	$ 0.12