Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details)				1 Months Ended		3 Months Ended							9 Months Ended
	Oct. 06, 2015	Oct. 06, 2015 $ / shares	Aug. 15, 2014 $ / shares shares	Jun. 30, 2015 USD ($) shares	Mar. 31, 2015 shares	Sep. 30, 2015 USD ($) item $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Mar. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares	Jun. 30, 2014 USD ($) $ / shares	Mar. 31, 2014 USD ($) $ / shares	Dec. 31, 2013 USD ($)	Sep. 30, 2015 USD ($) 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 | $								$ 166,000,000
Capital contributions | $								166,000,000
Number of votes per share | item						50							50
Equity based compensation expense unrecognized | $						$ 16,700,000							$ 16,700,000
Equity based compensation expense vesting period													4 years
Equity based compensation awards intrinsic value | $						58,400,000							$ 58,400,000
Aggregate distribution made to stockholders and partners | $						$ 15,300,000	$ 13,400,000	$ 10,700,000	$ 10,700,000	$ 10,700,000	$ 9,000,000
Dividend paid to common stockholders | $ / shares						$ 0.32	$ 0.32	$ 0.29	$ 0.29	$ 0.29	$ 0.24
Partnership distribution per unit | $ / shares						$ 0.32	$ 0.32	$ 0.29		$ 0.29	$ 0.24
Dividends payable, date payable						Jul. 08, 2015	Apr. 07, 2015	Jan. 07, 2015	Jul. 08, 2014	Apr. 08, 2014	Jan. 07, 2014
Dividends payable, date of record						Jun. 19, 2015				Jun. 20, 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
Underwriters [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares			$ 41.00
Option to purchase common stock shares			360,000
Shares issued			261,000	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						500,000							500,000
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 | $				$ 203,400,000
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													Sep. 18, 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
GA QTS Interholdco, LLC [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares			$ 41.00
Shares issued			2,400,000
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
Options to purchase Class A common stock [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding						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		1,750,000
Additional shares available for issuance under plan approved by Board of Directors					3,000,000