Real Estate Assets and Construction in Progress (Summary of Properties Owned or Leased by the Company) (Details) $ in Thousands		Jun. 30, 2015 USD ($) property	Dec. 31, 2014 USD ($)
Real Estate Properties [Line Items]
Land		$ 52,430	$ 48,577
Buildings and improvements		1,073,120	914,286
Construction in progress		320,885	214,719
Total cost		1,446,435	1,177,582
Owned Properties [Member]
Real Estate Properties [Line Items]
Land		51,300	48,577
Buildings and improvements		965,280	886,116
Construction in progress		307,315	213,772
Total cost		1,323,895	1,148,465
Owned Properties [Member] | Suwanee, Georgia (Atlanta-Suwanee) [Member]
Real Estate Properties [Line Items]
Land		3,521	3,521
Buildings and improvements		143,672	138,991
Construction in progress		13,699	6,345
Total cost		160,892	148,857
Owned Properties [Member] | Atlanta, Georgia (Atlanta-Metro) [Member]
Real Estate Properties [Line Items]
Land		15,396	15,397
Buildings and improvements		374,600	356,122
Construction in progress		36,183	22,693
Total cost		$ 426,179	$ 394,212
Owned Properties [Member] | Santa Clara, California [Member]
Real Estate Properties [Line Items]
Land	[1]
Buildings and improvements	[1]	$ 92,614	$ 90,332
Construction in progress	[1]	916	650
Total cost	[1]	93,530	90,982
Owned Properties [Member] | Richmond, Virginia [Member]
Real Estate Properties [Line Items]
Land		2,180	2,180
Buildings and improvements		166,030	127,080
Construction in progress		107,770	71,794
Total cost		275,980	201,054
Owned Properties [Member] | Sacramento, California [Member]
Real Estate Properties [Line Items]
Land		1,481	1,481
Buildings and improvements		60,179	60,094
Construction in progress		524	278
Total cost		62,184	61,853
Owned Properties [Member] | Princeton New Jersey [Member]
Real Estate Properties [Line Items]
Land		20,700	17,976
Buildings and improvements		32,572	35,951
Construction in progress		272	90
Total cost		53,544	54,017
Owned Properties [Member] | Dallas, Texas [Member]
Real Estate Properties [Line Items]
Land		5,808	5,808
Buildings and improvements		61,863	44,053
Construction in progress		111,247	89,982
Total cost		$ 178,918	$ 139,843
Owned Properties [Member] | Chicago, Illinois [Member]
Real Estate Properties [Line Items]
Land
Buildings and improvements
Construction in progress		$ 35,491	$ 21,786
Total cost		35,491	21,786
Owned Properties [Member] | Miami, Florida [Member]
Real Estate Properties [Line Items]
Land		1,777	1,777
Buildings and improvements		28,875	28,786
Construction in progress		1,192	129
Total cost		31,844	30,692
Owned Properties [Member] | Lenexa, Kansas [Member]
Real Estate Properties [Line Items]
Land		437	437
Buildings and improvements		3,466	3,298
Construction in progress		21	25
Total cost		$ 3,924	$ 3,760
Owned Properties [Member] | Wichita, Kansas [Member]
Real Estate Properties [Line Items]
Land
Buildings and improvements		$ 1,409	$ 1,409
Construction in progress
Total cost		$ 1,409	$ 1,409
Leased Properties [Member]
Real Estate Properties [Line Items]
Land		1,130
Buildings and improvements		107,840	$ 28,170
Construction in progress		13,570	947
Total cost		$ 122,540	$ 29,117
Leased Properties [Member] | Jersey City, New Jersey [Member]
Real Estate Properties [Line Items]
Land
Buildings and improvements		$ 27,611	$ 27,318
Construction in progress		1,404	920
Total cost		$ 29,015	$ 28,238
Leased Properties [Member] | Overland Park, Kansas [Member]
Real Estate Properties [Line Items]
Land	[2]
Buildings and improvements	[2]	$ 857	$ 852
Construction in progress	[2]	39	27
Total cost	[2]	896	$ 879
Leased Properties [Member] | Carpathia Properties [Member]
Real Estate Properties [Line Items]
Land	[3]	1,130
Buildings and improvements	[3]	79,372
Construction in progress	[3]	12,127
Total cost	[3]	$ 92,629
Number of facilities leased | property		13

[1] Owned facility subject to long-term ground sublease.

[2] This does not include the portion of the business that is used for QTS office space or other real estate not used by customers.

[3] Includes 13 facilities. All facilities are leased, including those subject to capital leases.