Condensed Consolidated Statement of Equity (USD $) In Millions, unless otherwise specified	Total USD ($)	CyrusOne L.P. [Member]	Predecessor [Member] USD ($)	Predecessor [Member] CyrusOne L.P. [Member] USD ($)	Predecessor [Member] Common Stock Issued USD ($)	Predecessor [Member] Additional Paid In Capital USD ($)	Predecessor [Member] Accumulated Deficit USD ($)	Predecessor [Member] Partnership Interest [Member] USD ($)	Predecessor [Member] Total Shareholder’s Equity/ Parent’s Net Investment USD ($)	Predecessor [Member] Non- controlling Interest USD ($)	Predecessor [Member] Partnership Units CyrusOne L.P. [Member]	Predecessor [Member] Partnership Capital CyrusOne L.P. [Member] USD ($)	Successor [Member] USD ($)	Successor [Member] CyrusOne L.P. [Member] USD ($)	Successor [Member] Common Stock Issued USD ($)	Successor [Member] Additional Paid In Capital USD ($)	Successor [Member] Accumulated Deficit USD ($)	Successor [Member] Partnership Interest [Member] USD ($)	Successor [Member] Total Shareholder’s Equity/ Parent’s Net Investment USD ($)	Successor [Member] Non- controlling Interest USD ($)	Successor [Member] Partnership Units CyrusOne L.P. [Member]	Successor [Member] Partnership Capital CyrusOne L.P. [Member] USD ($)
Beginning Balance at Dec. 31, 2012			$ 500.1		$ 0	$ 7.1	$ 0	$ 493.0	$ 500.1	$ 0
Beginning Balance (in shares) at Dec. 31, 2012					0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			(20.2)	(20.2)				(20.2)	(20.2)
Partnership reverse unit split, conversion ratio											2.8
Common stock issued, shares					19.0
Other Contribution From Parent			1.3					1.3	1.3
Contributions From Parent			19.6					19.6	19.6
Noncontrolling Interest, Increase from Business Combination			0			(7.1)		(493.7)	(500.8)	500.8
Stock Issued During Period, Value, New Issues			337.1		0.2	336.9			337.1
Stock Issued During Period Share To Parent Entity In Exchange Of Equity Interest In Third Entity					1.5
Stock Issued During Period Value To Parent Entity In Exchange Of Equity Interest In Third Entity			0
Stock Issued During Period Share In Settlement Of Issuing Cost With Parent Entity					0.4
Stock Issued During Period Value In Settlement Of Issuing Cost With Parent Entity			0			7.1			7.1	(7.1)
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			9.5			9.5			9.5
Stock Issued During Period, Shares, Restricted Stock Award, Gross					1.0
Stock Issued During Period, Value, Restricted Stock Award, Gross			0
Ending Balance at Jan. 23, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest													(2.8)	(2.8)			(2.8)		(2.8)
Noncontrolling interest allocated net (income) loss	0												1.9				1.9		1.9	(1.9)
Stock based compensation													1.2			1.2			1.2
Dividends and distributions, $0.21 per share													(10.3)				(3.0)		(3.0)	(7.3)
Ending Balance at Mar. 31, 2013													816.5		0.2	335.7	(3.9)	0	332.0	484.5
Ending Balance (in shares) at Mar. 31, 2013															21.9
Beginning Balance at Dec. 31, 2013			777.6		0.2	340.7	(18.9)	0	322.0	455.6		777.6	777.6	777.6
Beginning Balance (in shares) at Dec. 31, 2013					22.0						64.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest													0.7	0.7			0.7		0.7	0		0.7
Common stock issued, shares															0.7						0.7
Noncontrolling interest allocated net (income) loss													(0.5)				(0.5)		(0.5)	0.5
Stock based compensation													2.2			2.2			2.2			2.2
Dividends and distributions, $0.21 per share													(13.7)				(4.8)		(4.8)	(8.9)		13.7
Ending Balance at Mar. 31, 2014													$ 766.8	$ 766.8	$ 0.2	$ 342.9	$ (23.5)	$ 0	$ 319.6	$ 447.2		$ 766.8
Ending Balance (in shares) at Mar. 31, 2014															22.7						65.3