Earnings per share of QTS Realty Trust, Inc. - Antidilutive (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Class A Partnership Units
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	6,658	6,668	6,667	6,670
Class O units, TSR units and options to purchase common stock on an "as if" converted basis
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	1,176	557	1,126	0
Series B Convertible Perpetual Preferred Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	6,762	6,729	6,756	6,729