Investment in Real Estate - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	8 Months Ended	0 Months Ended			1 Months Ended				8 Months Ended					0 Months Ended		12 Months Ended		12 Months Ended
	Aug. 07, 2013 acre	Sep. 30, 2013	May 03, 2013 Springer Street (Lombard) [Member]	May 03, 2013 Industrial Road (Florence) [Member]	Jun. 18, 2013 Metropolis Dr. (Austin 2) [Member]	Jun. 30, 2013 Land [Member] Houston West [Member]	Sep. 30, 2013 Land [Member] Houston West [Member] acre	Mar. 31, 2014 Successor [Member]	Dec. 31, 2013 Successor [Member]	Sep. 30, 2013 Successor [Member] Springer St., Lombard, IL (Lombard) [Member]	Sep. 30, 2013 Successor [Member] Industrial Rd., Florence, KY (Florence) [Member]	Dec. 31, 2013 Predecessor [Member]	Mar. 31, 2014 CyrusOne L.P. [Member] Successor [Member]	Dec. 31, 2013 CyrusOne L.P. [Member] Successor [Member]	Jun. 18, 2013 Land [Member] Metropolis Dr. (Austin 2) [Member]	Jun. 18, 2013 Capital Lease Obligations [Member] Metropolis Dr. (Austin 2) [Member]	Dec. 31, 2013 Metropolis Dr., Austin, TX (Austin 3) [Member] Land [Member]	Jun. 30, 2013 Metropolis Dr., Austin, TX (Austin 3) [Member] Land [Member] acre	Dec. 31, 2013 Ridgetop Circle, Sterling, VA (Northern VA) [Member] Land [Member]	Jun. 30, 2013 Ridgetop Circle, Sterling, VA (Northern VA) [Member] Land [Member] acre
Real Estate Properties [Line Items]
Cost of construction in progress								$ 99.4	$ 57.3			$ 57.3	$ 99.4	$ 57.3
Area of Land	22						33											22		14
Purchase price			5.5	10.5		18.2									2.0		7.9		6.9
Extinguishment of debt					12.2											8.9
Loss on extinguishment of debt					(1.3)
Acqusition of land for future data expansion	6.7
Property, Plant and Equipment, Useful Life		25 years
Adjusted net carrying value										$ 0.1	$ 7.9