Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details)								1 Months Ended	3 Months Ended	4 Months Ended
	May 09, 2019 shares	Apr. 04, 2019 $ / shares	Jun. 25, 2018	Jun. 22, 2018	Apr. 16, 2018 $ / shares	Mar. 15, 2018	May 04, 2017 USD ($) item	Mar. 31, 2019 USD ($) item shares	Mar. 31, 2019 USD ($) item $ / shares shares	Oct. 31, 2018 $ / shares	Mar. 31, 2017 USD ($)
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding | item									4
Equity based compensation expense unrecognized | $								$ 30,600,000	$ 30,600,000
Equity based compensation expense vesting period									1 year 1 month 6 days
Equity based compensation awards intrinsic value | $								$ 20,500,000	$ 20,500,000
Preferred stock dividends per share cash paid | $ / shares					$ 0.14844
Partnership distribution per unit | $ / shares		$ 0.44
Preferred Stock, Dividend Rate, Percentage						7.125%
Net proceeds from stock offering | $									$ 158,663,000
QTS Realty Trust, Inc. Employee Stock Purchase Plan
Partners Capital And Distributions [Line Items]
Shares reserved for purchase under plan								250,000	250,000
2017 Plan
Partners Capital And Distributions [Line Items]
Minimum period of service							30 days
Minimum hours per week of service | item							30
Purchase period per year | item							4
Class B Common Stock
Partners Capital And Distributions [Line Items]
Number of votes per share | item								50	50
Class A Common Stock | At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued | $											$ 300,000,000
Class A Common Stock | 2017 Plan
Partners Capital And Distributions [Line Items]
Discount rate of purchase price of common stock							10.00%
Series A Redeemable Perpetual Preferred
Partners Capital And Distributions [Line Items]
Dividend paid to common stockholders | $ / shares									$ 0.45
Series A Redeemable Perpetual Preferred | Preferred stock
Partners Capital And Distributions [Line Items]
Shares issued									4,280,000
Series B Convertible preferred stock [Member]
Partners Capital And Distributions [Line Items]
Dividend paid to common stockholders | $ / shares									$ 1.63
Preferred stock dividends per share cash paid | $ / shares										$ 1.9861111
Preferred Stock, Dividend Rate, Percentage			6.50%	6.50%
Chief Executive Officer | Class B Common Stock
Partners Capital And Distributions [Line Items]
Percentage of operating partnership unit exchanged									2.00%
Minimum | 2017 Plan
Partners Capital And Distributions [Line Items]
Minimum percentage of combined voting power							5.00%
Deductions per paycheck for purchase of shares | $							$ 20
Holding period after purchase of share							1 year
Maximum | 2017 Plan
Partners Capital And Distributions [Line Items]
Deductions per paycheck for purchase of shares | $							$ 1,000
Restricted Class A Common Stock
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding								600,000	600,000
Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Options outstanding								86,089	86,089
Performance-Based FFO Units | Minimum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award								0.00%
Performance-Based FFO Units | Maximum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award								200.00%
Performance-Based Relative TSR Units
Partners Capital And Distributions [Line Items]
Vesting period								3 years
Options outstanding								86,089	86,089
Performance-Based Relative TSR Units | Minimum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award								0.00%
Performance-Based Relative TSR Units | Maximum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award								200.00%
Options to purchase Class A common stock
Partners Capital And Distributions [Line Items]
Options outstanding								600,000	600,000
2013 Equity Incentive Plan | Class A Common Stock
Partners Capital And Distributions [Line Items]
Authorized shares to be issued under the plan								1,750,000	1,750,000
Additional shares available for issuance under plan approved by stockholders	1,110,000
Qualitytech, LP
Partners Capital And Distributions [Line Items]
Net proceeds from stock offering | $									$ 158,663,000
First portion | Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Vesting period								2 years
Vesting percentage								67.00%
Second portion | Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Vesting period								3 years
Vesting percentage								33.00%