Consolidated and Combined Statements of Cash Flows (USD $)	11 Months Ended	1 Months Ended	12 Months Ended		11 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013 Successor [Member]	Jan. 23, 2013 Predecessor [Member]	Dec. 31, 2012 Predecessor [Member]	Dec. 31, 2011 Predecessor [Member]	Dec. 31, 2013 CyrusOne L.P. [Member] Successor [Member]	Jan. 23, 2013 CyrusOne L.P. [Member] Predecessor [Member]	Dec. 31, 2012 CyrusOne L.P. [Member] Predecessor [Member]	Dec. 31, 2011 CyrusOne L.P. [Member] Predecessor [Member]
Cash flows from operating activities:
Net (loss) income	$ (15,600,000)	$ (20,200,000)	$ (20,300,000)	$ 1,500,000	$ (15,600,000)	$ (20,200,000)	$ (20,300,000)	$ 1,500,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	89,900,000	5,300,000	73,400,000	55,500,000	89,900,000	5,300,000	73,400,000	55,500,000
Loss on sale of receivables and other assets	0	0	3,000,000	3,500,000	0	0	3,000,000	3,500,000
Provision for bad debt write off	400,000	0	100,000	0	400,000	0	100,000	0
Asset impairments	2,800,000	0	13,300,000	0	2,800,000	0	13,300,000	0
Loss on extinguishment of debt	1,300,000	0	0	1,400,000	1,300,000	0	0	1,400,000
Noncash interest expense	4,000,000	100,000	300,000	0	4,000,000	100,000	300,000	0
Deferred income tax expense (benefit), including valuation allowance change	600,000	300,000	(4,500,000)	1,600,000	600,000	300,000	(4,500,000)	1,600,000
Stock-based compensation expense	6,000,000	200,000		0	6,000,000	200,000	0	0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	(15,700,000)	(9,600,000)	(24,000,000)	(3,300,000)	(15,700,000)	(9,600,000)	(16,100,000)	(3,300,000)
(Decrease) Increase in accounts payable and accrued expenses	(14,600,000)	20,500,000	(600,000)	3,500,000	(14,600,000)	20,500,000	(1,400,000)	3,500,000
(Decrease) Increase in deferred revenues	(100,000)	3,200,000	3,800,000	2,300,000	(100,000)	3,200,000	3,800,000	2,300,000
Increase in payables to related parties	18,400,000	1,500,000	0	0	18,400,000	1,500,000	0	0
Other	0	700,000	0	0	0	700,000	0	0
Net cash provided by (used in) operating activities	77,400,000	2,000,000	44,500,000	66,000,000	77,400,000	2,000,000	51,600,000	66,000,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	(48,000,000)	0	(25,400,000)	(22,400,000)	(48,000,000)	0	(25,400,000)	(22,400,000)
Capital expenditures – other	(172,900,000)	(7,700,000)	(202,900,000)	(95,100,000)	(172,900,000)	(7,700,000)	(202,900,000)	(95,100,000)
Proceeds from the sale of assets	0	0	200,000	0	0	0	200,000	0
Increase in restricted cash	0	0	(11,100,000)	0	0	0	(11,100,000)	0
Release of restricted cash	4,400,000	1,900,000	4,800,000		4,400,000	1,900,000	4,800,000	0
Advances (to) from affiliates	0	0	(18,300,000)	11,600,000	0	0	(18,300,000)	11,600,000
Other	(200,000)	0	100,000	100,000	(200,000)	0	100,000	100,000
Net cash used in investing activities	(216,700,000)	(5,800,000)	(252,600,000)	(105,800,000)	(216,700,000)	(5,800,000)	(252,600,000)	(105,800,000)
Cash flows from financing activities:
Issuance of common stock/partnership units	360,500,000	0	0	0	333,900,000	0	0	0
IPO costs	(26,600,000)	0	0	0
Dividends/Distributions paid	(31,000,000)	0	0	0	(31,000,000)	0	0	0
Borrowings from affiliates, net	0	0	119,800,000	66,600,000	0	0	119,800,000	66,600,000
Repayment of related party note	0	0	(400,000,000)	0	0	0	(400,000,000)	0
Proceeds from issuance of debt	0	0	525,000,000	0	0	0	525,000,000	0
Payments on capital lease obligations	(5,300,000)	(600,000)	(9,000,000)	(7,000,000)	(5,300,000)	(600,000)	(9,000,000)	(7,000,000)
Payments on financing obligations	(700,000)	0	0	(16,200,000)	(700,000)	0	0	(16,200,000)
Payment to buyout capital leases	(9,600,000)	0	0	0	(9,600,000)	0	0	0
Payment to buyout other financing arrangements	(10,200,000)	0	0	0	(10,200,000)	0	0	0
Debt issuance costs	(1,300,000)	0	(17,200,000)	0	(1,300,000)	0	(17,200,000)	0
Contributions from/(distributions to) parent, net	0	200,000	5,400,000	(7,800,000)	0	200,000	(1,700,000)	(7,800,000)
Other	0	0	0	(100,000)	0	0	0	(100,000)
Net cash provided by (used in) by financing activities	275,800,000	(400,000)	224,000,000	35,500,000	275,800,000	(400,000)	216,900,000	35,500,000
Net increase (decrease) in cash and cash equivalents	136,500,000	(4,200,000)	15,900,000	(4,300,000)	136,500,000	(4,200,000)	15,900,000	(4,300,000)
Cash and cash equivalents at beginning of period	12,300,000	16,500,000	600,000	4,900,000	12,300,000	16,500,000	600,000	4,900,000
Cash and cash equivalents at end of period	148,800,000	12,300,000	16,500,000	600,000	148,800,000	12,300,000	16,500,000	600,000
Supplemental disclosures
Cash paid for interest, net of amount capitalized	40,700,000	300,000	42,400,000	33,000,000	40,700,000	300,000	42,400,000	33,000,000
Capitalized interest	1,600,000	0	2,700,000	2,600,000	1,600,000	0	2,700,000	2,600,000
Noncash investing and financing transactions:
Acquisition of property in accounts payable and other liabilities	35,800,000	15,700,000	7,700,000	7,600,000	35,800,000	15,700,000	7,700,000	7,600,000
Acquisition of property by assuming capital lease obligations and other financing arrangements	0	0	11,600,000	43,700,000	0	0	11,600,000	43,700,000
Contribution receivable from Parent related to transaction-related compensation	0	19,600,000	0	0	0	19,600,000	0	0
Dividend / Distribution payable	10,400,000	0	0	0	10,400,000	0	0	0
Other contributions from Parent		1,300,000	0		1,300,000	1,700,000	0	0
Non-cash distribution to CyrusOne Inc.					2,400,000	0	0	0
Assets transferred by parent	0	0	2,000,000	0	0	0	2,000,000	0
Divisional control contribution funded by settlement of intercompany balances due to Parent	0	0	203,500,000	0	0	0	196,400,000	0
Deferred IPO costs	0	1,700,000	0	0
Deferred IPO costs reclassified to additional paid in capital	9,500,000	0	0	0
Reclass of equipment to held for sale	300,000	0	0	0	300,000	0	0	0
Noncash additions to fixed assets through other financing arrangements	$ 4,000,000	$ 0	$ 0	$ 0	$ 4,000,000	$ 0	$ 0	$ 0