Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details)				1 Months Ended		3 Months Ended					6 Months Ended
	Aug. 06, 2015 $ / shares	Jul. 08, 2015	Jul. 08, 2015 $ / shares	Jun. 30, 2015 USD ($) item shares	Mar. 31, 2015 shares	Jun. 30, 2015 USD ($) item $ / shares shares	Mar. 31, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($) $ / shares	Mar. 31, 2014 USD ($) $ / shares	Dec. 31, 2013 USD ($)	Jun. 30, 2015 USD ($) item security shares	Jun. 05, 2015 $ / shares shares	May. 03, 2015 shares	Mar. 02, 2015 $ / shares shares
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding | security											3
Stock transaction date							Mar. 02, 2015
Number of units issued														5,000,000
Proceeds from sale of stock | $							$ 166,400,000
Capital contributions | $							166,400,000
Number of votes per share | item				50		50					50
Equity based compensation expense unrecognized | $				$ 16,800,000		$ 16,800,000					$ 16,800,000
Equity based compensation expense vesting period											4 years
Equity based compensation awards intrinsic value | $				$ 44,100,000		44,100,000					$ 44,100,000
Aggregate distribution made to stockholders and partners | $						$ 13,400,000	$ 10,700,000	$ 10,700,000	$ 9,000,000
Dividend paid to common stockholders | $ / shares						$ 0.32	$ 0.29	$ 0.29	$ 0.24
Partnership distribution per unit | $ / shares						$ 0.32	$ 0.29	$ 0.29	$ 0.24
Dividends payable, date payable						Apr. 07, 2015	Jan. 07, 2015	Apr. 08, 2014	Jan. 07, 2014
Net proceeds from issuance of shares | $										$ 279,000,000
QTS Realty Trust, Inc. Employee Stock Purchase Plan [Member]
Partners Capital And Distributions [Line Items]
Shares reserved for purchase under plan				250,000		250,000					250,000
Underwriters [Member]
Partners Capital And Distributions [Line Items]
Shares issued				1,050,000
General Atlantic REIT, Inc. [Member]
Partners Capital And Distributions [Line Items]
Shares sold							4,350,000
Sale of stock, price per share | $ / shares														$ 34.75
Class O LTIP Holders [Member]
Partners Capital And Distributions [Line Items]
Aggregate distribution made to stockholders and partners | $								$ 200,000
Class O Units [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding				600,000		600,000					600,000
Class RS Units [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding				100,000		100,000					100,000
Common Class A [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares												$ 37.00
Shares issued				5,750,000
Net proceeds from issuance of shares | $				$ 203,700,000
Chief Executive Officer [Member]
Partners Capital And Distributions [Line Items]
Percentage of operating partnership unit exchanged											2.00%
Underwriters [Member] | General Atlantic REIT, Inc. [Member]
Partners Capital And Distributions [Line Items]
Option to purchase share of common stock							1,402,500
Qualitytech, LP [Member]
Partners Capital And Distributions [Line Items]
Dividends payable, date of record											Jun. 19, 2015
Qualitytech, LP [Member] | Subsequent Event [Member]
Partners Capital And Distributions [Line Items]
Dividend paid to common stockholders | $ / shares			$ 0.32
Dividends payable, date payable	Oct. 06, 2015	Jul. 08, 2015
Dividends payable, date declared	Aug. 06, 2015
Cash dividend payable per common share | $ / shares	$ 0.32
Dividends payable, date of record	Sep. 18, 2015
GA QTS Interholdco, LLC [Member] | Common Class A [Member]
Partners Capital And Distributions [Line Items]
Shares of stock sold by stockholder												1,250,000
Minimum [Member] | QTS Realty Trust, Inc. Employee Stock Purchase Plan [Member]
Partners Capital And Distributions [Line Items]
Monthly diduction from eligible employees for plan | $				40
Maximum [Member] | QTS Realty Trust, Inc. Employee Stock Purchase Plan [Member]
Partners Capital And Distributions [Line Items]
Monthly diduction from eligible employees for plan | $				$ 2,000
Restricted Class A Common Stock [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding				400,000		400,000					400,000
Options to purchase Class A common stock [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding				400,000		400,000					400,000
2013 Equity Incentive Plan [Member]
Partners Capital And Distributions [Line Items]
Authorized shares to be issued under the plan				4,750,000		4,750,000					4,750,000		1,750,000
Additional shares available for issuance under plan approved by Board of Directors					3,000,000