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
	Mar. 31, 2017	Mar. 31, 2016
Earnings per Share [Abstract]
Net income available to common stockholders - basic	$ 4,877	$ 5,889
Effect of net income attributable to noncontrolling interests	691	970
Net income available to common stockholders - diluted	$ 5,568	$ 6,859
Weighted average shares outstanding-basic	47,908,709	41,292,445
Effect of Class A and Class RS partnership units	6,783,000	6,801,000
Effect of Class O units and options to purchase Class A common stock on an "as if" converted basis	928,000	881,000
Weighted average shares outstanding-diluted	55,620,260	48,973,851
Net income per share attributable to common stockholders - basic	$ 0.10	$ 0.14
Net income per share attributable to common stockholders - diluted	$ 0.10	$ 0.14