Earnings per share of QTS Realty Trust, Inc. (Antidilutive) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Class A Common 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	6,671	6,653
Class O 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	518	350
Series B Convertible 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	6,729	3,484