Acquisitions (Details) - NY2 Secaucus NJ $ in Millions	34 Months Ended
	Dec. 31, 2015 ft² item	Feb. 28, 2013 USD ($)
Acquisitions
Book value of acquired land and vacant building | $		$ 23.4
Number of computer rooms developed | item	6
Net rentable space leased to an affiliate (in square feet) | ft²	101,742
Percentage of site that is occupied	68.50%