Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details)					1 Months Ended	3 Months Ended										6 Months Ended	12 Months Ended
	Feb. 22, 2016 $ / shares	Jan. 06, 2016 $ / shares	Jan. 06, 2016 $ / shares	Mar. 02, 2015 $ / shares shares	Mar. 31, 2015 shares	Dec. 31, 2015 USD ($) item $ / shares shares	Sep. 30, 2015 $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Mar. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 $ / shares	Sep. 30, 2014 $ / shares	Jun. 30, 2014 $ / shares	Mar. 31, 2014 $ / shares		Dec. 31, 2013 USD ($) $ / shares	Dec. 31, 2015 USD ($) item shares	Dec. 31, 2015 USD ($) item security $ / shares shares	Dec. 31, 2014 $ / shares	Nov. 30, 2015 $ / shares shares	Aug. 14, 2015 $ / shares shares	Jun. 17, 2015 shares	Jun. 05, 2015 $ / shares shares	May. 04, 2015 shares
Partners Capital And Distributions [Line Items]
Proceeds from sale of stock | $								$ 203,400,000	$ 166,000,000
Capital contributions | $								$ 203,400,000	$ 166,000,000
Number of votes per share | item						50										50	50
Equity based compensation expense unrecognized | $						$ 14,700,000										$ 14,700,000	$ 14,700,000
Equity based compensation expense vesting period																	4 years
Equity based compensation awards intrinsic value | $						$ 60,300,000										$ 60,300,000	$ 60,300,000
Dividend paid to common stockholders | $ / shares						$ 0.32	$ 0.32	$ 0.32	$ 0.29	$ 0.29	$ 0.29	$ 0.29	$ 0.24	[1]	$ 0.29		$ 1.25	$ 1.11
Dividends payable, date payable						Oct. 06, 2015	Jul. 08, 2015	Apr. 07, 2015	Jan. 07, 2015	Oct. 07, 2014	Jul. 08, 2014	Apr. 08, 2014	Jan. 07, 2014
Dividends payable, date of record						Sep. 18, 2015	Jun. 19, 2015	Mar. 20, 2015	Dec. 19, 2014	Sep. 19, 2014	Jun. 20, 2014	Mar. 20, 2014	Dec. 20, 2013
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
Subsequent Event [Member]
Partners Capital And Distributions [Line Items]
Dividend paid to common stockholders | $ / shares		$ 0.32	$ 0.32
Dividends payable, date payable	Apr. 05, 2016	Jan. 06, 2016	Jan. 06, 2016
Dividends payable, date declared	Feb. 22, 2016
Cash dividend payable per common share | $ / shares	$ 0.36
Dividends payable, date of record	Mar. 18, 2016	Dec. 17, 2015	Dec. 17, 2015
Class O Units [Member]
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding						500,000										500,000	500,000
Common Class A [Member]
Partners Capital And Distributions [Line Items]
Stock transaction date						Nov. 30, 2015	Aug. 14, 2015	Jun. 05, 2015	Mar. 02, 2015
Sale of stock, price per share | $ / shares																						$ 37.00
Shares issued				5,000,000				5,750,000
Common Class A [Member] | Underwriters [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares																			$ 41.625	$ 41.00
Option to purchase share of common stock						326,250	360,000		1,402,500
Shares issued							261,000
Common Class A [Member] | General Atlantic REIT, Inc. [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares				$ 34.75
Shares of stock sold by stockholder					4,350,000				4,350,000
Chief Executive Officer [Member]
Partners Capital And Distributions [Line Items]
Percentage of operating partnership unit exchanged																	2.00%
Underwriters [Member] | Common Class A [Member]
Partners Capital And Distributions [Line Items]
Option to purchase share of common stock								1,050,000
Qualitytech, LP [Member]
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding | security																	3
GA QTS Interholdco, LLC [Member] | Common Class A [Member]
Partners Capital And Distributions [Line Items]
Sale of stock, price per share | $ / shares																			$ 41.625	$ 41.00
Shares of stock sold by stockholder																			2,175,000	2,400,000		1,250,000
Minimum [Member] | QTS Realty Trust, Inc. Employee Stock Purchase Plan [Member]
Partners Capital And Distributions [Line Items]
Monthly deduction from eligible employees for plan | $																$ 40
Maximum [Member] | QTS Realty Trust, Inc. Employee Stock Purchase Plan [Member]
Partners Capital And Distributions [Line Items]
Monthly deduction 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						1,750,000										1,750,000	1,750,000						4,750,000
Additional shares available for issuance under plan approved by Board of Directors					3,000,000

[1] The per common share and per unit rate is prorated. It covers the period beginning October 15, 2013 (the closing date of the IPO) through December 31, 2013 and is based on a full quarter distribution of $0.29 per common share and per unit.