Condensed Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Investment in real estate:
Land	$ 89.7	$ 89.3
Equipment	312.5	190.2
Successor [Member]
Investment in real estate:
Land	89.7	89.3
Buildings and improvements	796.6	783.7
Equipment	312.5	190.2
Construction in progress	120.9	57.3
Subtotal	1,319.7	1,120.5
Accumulated depreciation	(303.5)	(236.7)
Net investment in real estate	1,016.2	883.8
Cash and cash equivalents	30.4	148.8
Rent and other receivables, net of allowance for doubtful accounts of $1.1 and $0.5 as of September 30, 2014, and December 31, 2013, respectively	59.1	41.2
Goodwill	276.2	276.2
Intangible assets, net of accumulated amortization of $67.8 and $55.1 as of September 30, 2014, and December 31, 2013, respectively	73.2	85.9
Due from affiliates	1.3	0.6
Other assets	81.6	70.3
Total assets	1,538.0	1,506.8
Liabilities and equity
Accounts payable and accrued expenses	100.2	66.8
Deferred revenue	66.1	55.9
Due to affiliates	7.4	8.5
Capital lease obligations	14.2	16.7
Long-term debt	555.0	525.0
Other financing arrangements	55.1	56.3
Total liabilities	798.0	729.2
Commitment and contingencies
Equity
Preferred stock, $.01 par value, 100,000,000 authorized; no shares issued or outstanding	0	0
Common stock, $.01 par value, 500,000,000 shares authorized and 38,653,771 and 21,991,669 shares issued and outstanding at September 30, 2014 and December 31, 2013, respectively	0.4	0.2
Additional paid in capital	513.7	340.7
Accumulated deficit	(40.8)	(18.9)
Total shareholders’ equity	473.3	322.0
Noncontrolling interest	266.7	455.6
Total equity	740.0	777.6
Total liabilities and equity	1,538.0	1,506.8
Successor [Member] | CyrusOne LP [Member]
Investment in real estate:
Land	89.7	89.3
Buildings and improvements	796.6	783.7
Equipment	312.5	190.2
Construction in progress	120.9	57.3
Subtotal	1,319.7	1,120.5
Accumulated depreciation	(303.5)	(236.7)
Net investment in real estate	1,016.2	883.8
Cash and cash equivalents	30.4	148.8
Rent and other receivables, net of allowance for doubtful accounts of $1.1 and $0.5 as of September 30, 2014, and December 31, 2013, respectively	59.1	41.2
Goodwill	276.2	276.2
Intangible assets, net of accumulated amortization of $67.8 and $55.1 as of September 30, 2014, and December 31, 2013, respectively	73.2	85.9
Due from affiliates	1.3	0.6
Other assets	81.6	70.3
Total assets	1,538.0	1,506.8
Liabilities and equity
Accounts payable and accrued expenses	100.2	66.8
Deferred revenue	66.1	55.9
Due to affiliates	7.4	8.5
Capital lease obligations	14.2	16.7
Long-term debt	555.0	525.0
Other financing arrangements	55.1	56.3
Total liabilities	798.0	729.2
Commitment and contingencies
Equity
Total equity	740.0	777.6
Total liabilities and equity	$ 1,538.0	$ 1,506.8