Schedule III - Real Estate Investments (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2013
Owned Properties [Member]
Dec. 31, 2013
Owned Properties [Member]
Suwanee, Georgia [Member]
Dec. 31, 2013
Owned Properties [Member]
Atlanta, Georgia (Atlanta-Metro) [Member]
Dec. 31, 2013
Owned Properties [Member]
Santa Clara, California [Member]
Dec. 31, 2013
Owned Properties [Member]
Richmond, Virginia [Member]
Dec. 31, 2013
Owned Properties [Member]
Sacramento, California [Member]
Dec. 31, 2013
Owned Properties [Member]
Dallas, Texas [Member]
Dec. 31, 2013
Owned Properties [Member]
Miami, Florida [Member]
Dec. 31, 2013
Owned Properties [Member]
Lenexa, Kansas [Member]
Dec. 31, 2013
Owned Properties [Member]
Wichita, Kansas [Member]
Dec. 31, 2013
Leased Properties [Member]
Dec. 31, 2013
Leased Properties [Member]
Jersey City, New Jersey [Member]
Dec. 31, 2013
Leased Properties [Member]
Overland Park, Kansas [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]                                  
Initial costs of land $ 19,700       $ 19,700 $ 1,395 $ 12,647    $ 2,000 $ 1,481    $ 1,777 $ 400            
Initial costs of buildings and improvements 163,600       161,615 29,802 35,473 15,838 11,200 52,753 5,808 6,955 3,100 686 1,985 1,985   
Costs capitalized subsequent to acquisition, Land 10,901       10,901 2,126 2,750    180    5,808    37            
Costs capitalized subsequent to acquisition, Buildings and improvements 564,630       542,042 96,684 261,074 70,706 97,779 88 (5,808) 20,598 198 723 22,588 21,826 762
Costs capitalized subsequent to acquisition, Construction in progress 146,904       146,904 3,270 32,456 1,249 67,155 4,273 38,501                  
Gross carrying amount, Land 30,601       30,601 3,521 15,397    2,180 1,481 5,808 1,777 437            
Gross carrying amount, Buildings and improvements 728,230       703,657 126,486 296,547 86,544 108,979 52,841    27,553 3,298 1,409 24,573 23,811 762
Gross carrying amount, Construction in progress 146,904       146,904 3,270 32,456 1,249 67,155 4,273 38,501                  
Accumulated depreciation and amortization $ (137,725) $ (102,900) $ (74,536) $ (52,923) $ (128,605) $ (34,590) $ (58,272) $ (19,102) $ (8,996) $ (1,403)    $ (5,662) $ (82) $ (498) $ (9,120) $ (8,686) $ (434)
Date of acquisition           Sep. 01, 2005 Oct. 03, 2006 Nov. 01, 2007 Mar. 20, 2010 Dec. 21, 2012 Feb. 08, 2013 Mar. 06, 2008 Jun. 03, 2011 Mar. 31, 2005   Nov. 01, 2006