Debt and Other Financing Arrangements - Narrative (Details)				1 Months Ended	2 Months Ended	11 Months Ended	12 Months Ended
	Jul. 01, 2015 USD ($)	Jun. 22, 2015 USD ($)	Nov. 20, 2012 USD ($)	Jan. 23, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) data_center purchase_option	Dec. 31, 2014 USD ($)	Oct. 09, 2014 USD ($)	Oct. 08, 2014 USD ($)
Debt Instrument [Line Items]
Long-term debt					$ 644,300,000		$ 996,500,000	$ 644,300,000
Interest expense on capital lease obligations				$ 300,000		$ 6,300,000	$ 7,800,000	5,900,000
Total unencumbered assets							150.00%
Lease financing arrangements					53,400,000		$ 150,000,000	53,400,000
Deferred financing costs					$ 15,500,000		17,600,000	15,500,000
Amortization of deferred financing costs				$ 100,000		4,000,000	$ 3,400,000	3,400,000
Additional amortization due to extinguishment of debt								$ 800,000
Number of data centers under capital lease | data_center							4
Option to purchase leased assets | purchase_option							1
2016							$ 17,800,000
2017							16,800,000
2018							14,800,000
2019							15,100,000
2020							26,000,000
Thereafter							$ 127,000,000
6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Stated interest rate					6.375%		6.375%	6.375%
Term Loan
Debt Instrument [Line Items]
Face amount of debt		$ 300,000,000							$ 150,000,000
Remaining borrowing capacity		$ 250,000,000
Long-term debt					$ 150,000,000			$ 150,000,000
Term Loan | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.65%
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Long-term debt					374,800,000		$ 477,600,000	374,800,000
Stated interest rate							6.375%
Premium on debt	$ 3,800,000
Number of days to register	180 days
Repurchased face amount					150,200,000			150,200,000
Repurchase amount					163,000,000			163,000,000
Loss on repurchase of notes					12,800,000
Proceeds from Issuance of Private Placement	$ 100,000,000
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium | Cyrus One Lp And Cyrus One Finance Corp
Debt Instrument [Line Items]
Long-term debt			$ 525,000,000
Stated interest rate			6.375%				6.375%
Percentage of redemption price			100.00%
Percentage of senior notes declining redemption 1			103.188%
Percentage of senior notes declining redemption 2			102.125%
Percentage of senior notes declining redemption 3			101.063%
Percentage of senior notes declining redemption 4			100.00%
Percentage of Redemption of the aggregate principal			35.00%
Percentage of equity offering on principal amount			106.375%
Percentage of Redemption of the least aggregate principal			65.00%
Term of redemption occurs			90 days
Notes Payable
Debt Instrument [Line Items]
Long-term debt					0			0
Periodic payment							$ 9,000
Revolving credit facility
Debt Instrument [Line Items]
Credit agreement amount									$ 450,000,000	$ 225,000,000
Increase (decrease) in credit facility		$ 350,000,000
Term of extension option		1 year
Outstanding borrowings on revolving credit agreement		$ 650,000,000			$ 135,000,000	$ 0	$ 235,000,000	135,000,000
Commitment fee percent							0.25%
Commitment fee amount							$ 900,000	$ 1,100,000
Maximum percentage of dividends allowed to be distributed							95.00%
Revolving credit facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.70%
Revolving credit facility | First Amendment to Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount		$ 600,000,000
Optional additional borrowing capacity		300,000,000
Revolving credit facility | Second Amendment to Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount		950,000,000
Optional additional borrowing capacity		$ 600,000,000
Interest on Capital Leases
Debt Instrument [Line Items]
2016							$ 1,000,000
2017							800,000
2018							700,000
2019							500,000
2020							400,000
Thereafter							$ 400,000