CyrusOne (CONE) 10-K 27 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Jan. 30, 2015	Jun. 30, 2014
Entity Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	CONE
Entity Registrant Name	CyrusOne Inc.
Entity Central Index Key	1553023
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$915.50
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		38,639,498
CyrusOne LP [Member]
Entity Information [Line Items]
Entity Registrant Name	CyrusOne LP
Entity Central Index Key	1575810
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment in real estate:
Land	$89.70	$89.30
Buildings and improvements	812.6	783.7
Equipment	349.1	190.2
Construction in progress	127	57.3
Subtotal	1,378.40	1,120.50
Accumulated depreciation	-327	-236.7
Net investment in real estate	1,051.40	883.8
Cash and cash equivalents	36.5	148.8
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively	60.9	41.2
Goodwill	276.2	276.2
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively	68.9	85.9
Due from affiliates	0.8	0.6
Other assets	91.8	70.3
Total assets	1,586.50	1,506.80
Liabilities and equity
Accounts payable and accrued expenses	69.9	66.8
Deferred revenue	65.7	55.9
Due to affiliates	7.3	8.5
Capital lease obligations	13.4	16.7
Long-term debt	659.8	525
Other financing arrangements	53.4	56.3
Total liabilities	869.5	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 38,651,517 and 21,991,669 shares issued and outstanding at December 31, 2014 and December 31, 2013, respectively	0.4	0.2
Additional paid in capital	516.5	340.7
Accumulated deficit	-55.9	-18.9
Accumulated other comprehensive loss	-0.3	0
Total shareholders’ equity	460.7	322
Noncontrolling interest	256.3	455.6
Total equity	717	777.6
Total liabilities and equity	1,586.50	1,506.80
Successor [Member]
Investment in real estate:
Land	89.7	89.3
Buildings and improvements	812.6	783.7
Equipment	349.1	190.2
Construction in progress	127	57.3
Subtotal	1,378.40	1,120.50
Accumulated depreciation	-327	-236.7
Net investment in real estate	1,051.40	883.8
Cash and cash equivalents	36.5	148.8
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively	60.9	41.2
Goodwill	276.2	276.2
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively	68.9	85.9
Due from affiliates	0.8	0.6
Other assets	91.8	70.3
Total assets	1,586.50	1,506.80
Liabilities and equity
Accounts payable and accrued expenses	69.9	66.8
Deferred revenue	65.7	55.9
Due to affiliates	7.3	8.5
Capital lease obligations	13.4	16.7
Long-term debt	659.8	525
Other financing arrangements	53.4	56.3
Total liabilities	869.5	729.2
Equity
Total shareholders’ equity	460.7	322
Noncontrolling interest	256.3	455.6
Total equity	717	777.6
Total liabilities and equity	1,586.50	1,506.80
CyrusOne LP [Member] | Successor [Member]
Investment in real estate:
Land	89.7	89.3
Buildings and improvements	812.6	783.7
Equipment	349.1	190.2
Construction in progress	127	57.3
Subtotal	1,378.40	1,120.50
Accumulated depreciation	-327	-236.7
Net investment in real estate	1,051.40	883.8
Cash and cash equivalents	36.5	148.8
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively	60.9	41.2
Goodwill	276.2	276.2
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively	68.9	85.9
Due from affiliates	0.8	0.6
Other assets	91.8	70.3
Total assets	1,586.50	1,506.80
Liabilities and equity
Accounts payable and accrued expenses	69.9	66.8
Deferred revenue	65.7	55.9
Due to affiliates	7.3	8.5
Capital lease obligations	13.4	16.7
Long-term debt	659.8	525
Other financing arrangements	53.4	56.3
Total liabilities	869.5	729.2
Commitment and contingencies
Equity
Partnership capital	717	777.6
Total liabilities and equity	$1,586.50	$1,506.80

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Allowance for doubtful accounts receivable	$1	$0.50
Accumulated amortization of intangible assets	72.1	55.1
Successor [Member]
Allowance for doubtful accounts receivable	1	0.5
Accumulated amortization of intangible assets	72.1	55.1
Preferred stock par value (in dollars per share)	$0.01	$0.01
Preferred stock authorized (in shares)	100,000,000	100,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$0.01	$0.01
Common stock shares authorized (in shares)	500,000,000	500,000,000
Common stock issued (in shares)	38,651,517	21,991,669
Common stock outstanding (in shares)	38,651,517	21,991,669
Successor [Member] | CyrusOne LP [Member]
Allowance for doubtful accounts receivable	1	0.5
Accumulated amortization of intangible assets	$72.10	$55.10

Consolidated_and_Combined_Stat

Consolidated and Combined Statements of Operations (USD $)	1 Months Ended	11 Months Ended	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2012
Revenue	$15,100,000		$330,900,000
Costs and expenses:
Restructuring charges				0
Operating income (loss)	-17,300,000		40,000,000
Income tax (expense) benefit	-400,000	-1,900,000	-1,400,000	5,100,000
Net loss	-20,200,000		-14,500,000
Net loss attributed to common shareholders	0		-7,800,000
Basic weighted average common shares outstanding (in shares)			29.2
Diluted weighted average common shares outstanding (in shares)			29.2
Loss per share - basic and diluted (in dollars per share)	$0		($0.25)
Successor [Member]
Revenue		248,400,000	330,900,000
Costs and expenses:
Property operating expenses		88,400,000	124,500,000
Sales and marketing		9,900,000	12,800,000
General and administrative		26,500,000	34,600,000
Depreciation and amortization		89,900,000	118,000,000
Restructuring charges		700,000	0
Transaction costs		1,300,000	1,000,000
Transaction-related compensation		0	0
Management fees charged by CBI		0	0
Loss on sale of receivables to an affiliate		0	0
Asset impairments		2,800,000	0
Total costs and expenses		219,500,000	290,900,000
Operating income (loss)		28,900,000	40,000,000
Interest expense		41,200,000	39,500,000
Other income		-100,000	0
Loss on extinguishment of debt		1,300,000	13,600,000
Net loss before income taxes		-13,500,000	-13,100,000
Income tax (expense) benefit		-1,900,000	-1,400,000
(Loss) gain on sale of real estate improvements		-200,000	0
Net loss		-15,600,000	-14,500,000
Noncontrolling interest in net loss		-10,300,000	-6,700,000
Net loss attributed to common shareholders		-5,300,000	-7,800,000
Basic weighted average common shares outstanding (in shares)		20.9	29.2
Diluted weighted average common shares outstanding (in shares)		20.9	29.2
Loss per share - basic and diluted (in dollars per share)		($0.28)	($0.30)
Predecessor [Member]
Revenue	15,100,000			220,800,000
Costs and expenses:
Property operating expenses	4,800,000			76,000,000
Sales and marketing	700,000			9,700,000
General and administrative	1,500,000			20,700,000
Depreciation and amortization	5,300,000			73,400,000
Restructuring charges	0			0
Transaction costs	100,000			5,700,000
Transaction-related compensation	20,000,000			0
Management fees charged by CBI	0			2,500,000
Loss on sale of receivables to an affiliate	0			3,200,000
Asset impairments	0			13,300,000
Total costs and expenses	32,400,000			204,500,000
Operating income (loss)	-17,300,000			16,300,000
Interest expense	2,500,000			41,800,000
Other income	0			0
Loss on extinguishment of debt	0			0
Net loss before income taxes	-19,800,000			-25,500,000
Income tax (expense) benefit	-400,000			5,100,000
(Loss) gain on sale of real estate improvements	0			100,000
Net loss	-20,200,000			-20,300,000
Net loss attributed to common shareholders	-20,200,000			-20,300,000
CyrusOne LP [Member] | Successor [Member]
Revenue		248,400,000	330,900,000
Costs and expenses:
Property operating expenses		88,400,000	124,500,000
Sales and marketing		9,900,000	12,800,000
General and administrative		26,500,000	34,600,000
Depreciation and amortization		89,900,000	118,000,000
Restructuring charges		700,000	0
Transaction costs		1,300,000	1,000,000
Transaction-related compensation		0	0
Management fees charged by CBI		0	0
Loss on sale of receivables to an affiliate		0	0
Asset impairments		2,800,000	0
Total costs and expenses		219,500,000	290,900,000
Operating income (loss)		28,900,000	40,000,000
Interest expense		41,200,000	39,500,000
Other income		-100,000	0
Loss on extinguishment of debt		1,300,000	13,600,000
Net loss before income taxes		-13,500,000	-13,100,000
Income tax (expense) benefit		-1,900,000	-1,400,000
(Loss) gain on sale of real estate improvements		-200,000	0
Net loss		-15,600,000	-14,500,000
CyrusOne LP [Member] | Predecessor [Member]
Revenue	15,100,000			220,800,000
Costs and expenses:
Property operating expenses	4,800,000			76,000,000
Sales and marketing	700,000			9,700,000
General and administrative	1,500,000			20,700,000
Depreciation and amortization	5,300,000			73,400,000
Restructuring charges	0			0
Transaction costs	100,000			5,700,000
Transaction-related compensation	20,000,000			0
Management fees charged by CBI	0			2,500,000
Loss on sale of receivables to an affiliate	0			3,200,000
Asset impairments	0			13,300,000
Total costs and expenses	32,400,000			204,500,000
Operating income (loss)	-17,300,000			16,300,000
Interest expense	2,500,000			41,800,000
Other income	0			0
Loss on extinguishment of debt	0			0
Net loss before income taxes	-19,800,000			-25,500,000
Income tax (expense) benefit	-400,000			5,100,000
(Loss) gain on sale of real estate improvements	0			100,000
Net loss	($20,200,000)			($20,300,000)

Consolidated_and_Combined_Stat1

Consolidated and Combined Statements of Comprehensive Income (USD $)	1 Months Ended	12 Months Ended	11 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jan. 23, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net loss	($20.20)	($14.50)
Other comprehensive loss:
Foreign currency translation adjustments		-0.3
Successor [Member]
Net loss		-14.5	-15.6
Other comprehensive loss:
Foreign currency translation adjustments		-0.3	0
Comprehensive loss		-14.8	-15.6
Comprehensive loss attributable to noncontrolling interests		-0.1	0
Comprehensive loss attributable to CyrusOne Inc.		-14.7	-15.6
Predecessor [Member]
Net loss	-20.2			-20.3
Other comprehensive loss:
Foreign currency translation adjustments	0			0
Comprehensive loss	-20.2			-20.3
Comprehensive loss attributable to noncontrolling interests	0			0
Comprehensive loss attributable to CyrusOne Inc.	-20.2			-20.3
CyrusOne LP [Member] | Successor [Member]
Net loss		-14.5	-15.6
Other comprehensive loss:
Foreign currency translation adjustments		-0.3	0
Comprehensive loss		-14.8	-15.6
CyrusOne LP [Member] | Predecessor [Member]
Net loss	-20.2			-20.3
Other comprehensive loss:
Foreign currency translation adjustments	0			0
Comprehensive loss	($20.20)			($20.30)

Consolidated_and_Combined_Stat2

Consolidated and Combined Statements of Cash Flows (USD $)	1 Months Ended	12 Months Ended			11 Months Ended
In Millions, unless otherwise specified	Jan. 23, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Cash flows from operating activities:
Net loss	($20.20)	($14.50)	($35.80)
Adjustments to reconcile net loss to net cash provided by operating activities:
Provision for bad debt write off		1	0.5	0.3
Cash flows from financing activities:
Cash and cash equivalents at beginning of period		148.8
Cash and cash equivalents at end of period		36.5	148.8		148.8
Supplemental disclosures
Capitalized interest		4.6	1.6	2.7
Successor [Member]
Cash flows from operating activities:
Net loss		-14.5			-15.6
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization		118			89.9
Loss on sale of receivables and other assets		0			0
Provision for bad debt write off		0.8			0.4
Asset impairments		0			2.8
Loss on extinguishment of debt		13.6			1.3
Noncash interest expense		3.4			4
Deferred income tax expense (benefit), including valuation allowance change		0			0.6
Stock-based compensation expense		10.3			6
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets		-37			-15.7
Increase (decrease) in accounts payable and accrued expenses		6.9			-14.6
Increase (decrease) in deferred revenues		9.8			-0.1
(Decrease) increase in payables to related parties		-0.2			18.4
Other		0			0
Net cash provided by operating activities		111.1			77.4
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate		0			-48
Capital expenditures – other		-284.2			-172.9
Proceeds from the sale of assets		0			0
Increase in restricted cash		0			0
Release of restricted cash		0			4.4
Advances to affiliates		0			0
Other		0			-0.2
Net cash used in investing activities		-284.2			-216.7
Cash flows from financing activities:
Issuance of common stock/partnership units		356			360.5
Stock issuance costs		-1.3			0
IPO costs		0			-26.6
Acquisition of operating partnership units		-355.9			0
Dividends/Distributions paid		-50.9			-31
Borrowings from revolving credit agreement		315			0
Borrowings from affiliates, net		0			0
Payments on revolving credit facility		-30			0
Payments on senior notes		-150.2			0
Repayment of related party note		0			0
Proceeds from issuance of debt		0			0
Payments on capital lease obligations		-3			-5.3
Payments on financing obligations		-0.9			-0.7
Payment to buyout capital leases		0			-9.6
Payment to buyout other financing arrangements		0			-10.2
Debt issuance costs		-5.2			-1.3
Payment of debt extinguishment costs		-12.8			0
Contributions from/(distributions to) parent, net		0			0
Net cash provided by (used in) by financing activities		60.8			275.8
Net (decrease) increase in cash and cash equivalents		-112.3			136.5
Cash and cash equivalents at beginning of period		148.8			12.3
Cash and cash equivalents at end of period		36.5	148.8		148.8
Supplemental disclosures
Cash paid for interest, net of amount capitalized		41.3			40.7
Cash paid for income taxes		0.4			0
Capitalized interest		4.6			1.6
Noncash investing and financing transactions:
Acquisition of property in accounts payable and other liabilities		26.8			35.8
Acquisition of property by assuming capital lease obligations and other financing arrangements		0			0
Contribution receivable from Parent related to transaction-related compensation		0			0
Dividend / Distribution payable		14.3			10.4
Assets transferred by parent		0			0
Divisional control contribution funded by settlement of intercompany balances due to Parent		0			0
Deferred IPO costs		0			0
Deferred IPO costs reclassified to additional paid in capital		0			9.5
Reclass of equipment to held for sale		0			0.3
Noncash additions to fixed assets through other financing arrangements		0			4
Predecessor [Member]
Cash flows from operating activities:
Net loss	-20.2			-20.3
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5.3			73.4
Loss on sale of receivables and other assets	0			3
Provision for bad debt write off	0			0.1
Asset impairments	0			13.3
Loss on extinguishment of debt	0			0
Noncash interest expense	0.1			0.3
Deferred income tax expense (benefit), including valuation allowance change	0.3			-4.5
Stock-based compensation expense	0.2			0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9.6			-24
Increase (decrease) in accounts payable and accrued expenses	20.5			-0.6
Increase (decrease) in deferred revenues	3.2			3.8
(Decrease) increase in payables to related parties	1.5			0
Other	0.7			0
Net cash provided by operating activities	2			44.5
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	0			-25.4
Capital expenditures – other	-7.7			-202.9
Proceeds from the sale of assets	0			0.2
Increase in restricted cash	0			-11.1
Release of restricted cash	1.9			4.8
Advances to affiliates	0			-18.3
Other	0			0.1
Net cash used in investing activities	-5.8			-252.6
Cash flows from financing activities:
Issuance of common stock/partnership units	0			0
Stock issuance costs	0			0
IPO costs	0			0
Acquisition of operating partnership units	0			0
Dividends/Distributions paid	0			0
Borrowings from revolving credit agreement	0			0
Borrowings from affiliates, net	0			119.8
Payments on revolving credit facility	0			0
Payments on senior notes	0			0
Repayment of related party note	0			-400
Proceeds from issuance of debt	0			525
Payments on capital lease obligations	-0.6			-9
Payments on financing obligations	0			0
Payment to buyout capital leases	0			0
Payment to buyout other financing arrangements	0			0
Debt issuance costs	0			-17.2
Payment of debt extinguishment costs	0			0
Contributions from/(distributions to) parent, net	0.2			5.4
Net cash provided by (used in) by financing activities	-0.4			224
Net (decrease) increase in cash and cash equivalents	-4.2			15.9
Cash and cash equivalents at beginning of period	16.5		16.5	0.6
Cash and cash equivalents at end of period	12.3			16.5
Supplemental disclosures
Cash paid for interest, net of amount capitalized	0.3			42.4
Cash paid for income taxes	0			0
Capitalized interest	0			2.7
Noncash investing and financing transactions:
Acquisition of property in accounts payable and other liabilities	15.7			7.7
Acquisition of property by assuming capital lease obligations and other financing arrangements	0			11.6
Contribution receivable from Parent related to transaction-related compensation	19.6			0
Dividend / Distribution payable	0			0
Other contributions from Parent	1.3			0
Assets transferred by parent	0			2
Divisional control contribution funded by settlement of intercompany balances due to Parent	0			203.5
Deferred IPO costs	1.7			0
Deferred IPO costs reclassified to additional paid in capital	0			0
Reclass of equipment to held for sale	0			0
Noncash additions to fixed assets through other financing arrangements	0			0
CyrusOne LP [Member] | Successor [Member]
Cash flows from operating activities:
Net loss		-14.5			-15.6
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization		118			89.9
Loss on sale of receivables and other assets		0			0
Provision for bad debt write off		0.8			0.4
Asset impairments		0			2.8
Loss on extinguishment of debt		13.6			1.3
Noncash interest expense		3.4			4
Deferred income tax expense (benefit), including valuation allowance change		0			0.6
Stock-based compensation expense		10.3			6
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets		-37			-15.7
Increase (decrease) in accounts payable and accrued expenses		6.9			-14.6
Increase (decrease) in deferred revenues		9.8			-0.1
(Decrease) increase in payables to related parties		-0.2			18.4
Other		0			0
Net cash provided by operating activities		111.1			77.4
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate		0			-48
Capital expenditures – other		-284.2			-172.9
Proceeds from the sale of assets		0			0
Increase in restricted cash		0			0
Release of restricted cash		0			4.4
Advances to affiliates		0			0
Other		0			-0.2
Net cash used in investing activities		-284.2			-216.7
Cash flows from financing activities:
Issuance of common stock/partnership units		0.1			333.9
Dividends/Distributions paid		-50.9			-31
Borrowings from revolving credit agreement		315			0
Borrowings from affiliates, net		0			0
Payments on revolving credit facility		-30			0
Payments on senior notes		-150.2			0
Repayment of related party note		0			0
Proceeds from issuance of debt		0			0
Payments on capital lease obligations		-3			-5.3
Payments on financing obligations		-0.9			-0.7
Payment to buyout capital leases		0			-9.6
Payment to buyout other financing arrangements		0			-10.2
Debt issuance costs		-5.2			-1.3
Payment of debt extinguishment costs		-12.8			0
Contributions from/(distributions to) parent, net		-1.3			0
Other		0			0
Net cash provided by (used in) by financing activities		60.8			275.8
Net (decrease) increase in cash and cash equivalents		-112.3			136.5
Cash and cash equivalents at beginning of period		148.8			12.3
Cash and cash equivalents at end of period		36.5	148.8		148.8
Supplemental disclosures
Cash paid for interest, net of amount capitalized		41.3			40.7
Cash paid for income taxes		0.4			0
Capitalized interest		4.6			1.6
Noncash investing and financing transactions:
Acquisition of property in accounts payable and other liabilities		26.8			35.8
Acquisition of property by assuming capital lease obligations and other financing arrangements		0			0
Contribution receivable from Parent related to transaction-related compensation		0			0
Dividend / Distribution payable		14.3			10.4
Other contributions from Parent		0			1.3
Non-cash distribution to CyrusOne Inc.		0			2.4
Assets transferred by parent		0			0
Divisional control contribution funded by settlement of intercompany balances due to Parent		0			0
Reclass of equipment to held for sale		0			0.3
Noncash additions to fixed assets through other financing arrangements		0			4
CyrusOne LP [Member] | Predecessor [Member]
Cash flows from operating activities:
Net loss	-20.2			-20.3
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5.3			73.4
Loss on sale of receivables and other assets	0			3
Provision for bad debt write off	0			0.1
Asset impairments	0			13.3
Loss on extinguishment of debt	0			0
Noncash interest expense	0.1			0.3
Deferred income tax expense (benefit), including valuation allowance change	0.3			-4.5
Stock-based compensation expense	0.2			0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9.6			-16.1
Increase (decrease) in accounts payable and accrued expenses	20.5			-1.4
Increase (decrease) in deferred revenues	3.2			3.8
(Decrease) increase in payables to related parties	1.5			0
Other	0.7			0
Net cash provided by operating activities	2			51.6
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	0			-25.4
Capital expenditures – other	-7.7			-202.9
Proceeds from the sale of assets	0			0.2
Increase in restricted cash	0			-11.1
Release of restricted cash	1.9			4.8
Advances to affiliates	0			-18.3
Other	0			0.1
Net cash used in investing activities	-5.8			-252.6
Cash flows from financing activities:
Issuance of common stock/partnership units	0			0
Dividends/Distributions paid	0			0
Borrowings from revolving credit agreement	0			0
Borrowings from affiliates, net	0			119.8
Payments on revolving credit facility	0			0
Payments on senior notes	0			0
Repayment of related party note	0			-400
Proceeds from issuance of debt	0			525
Payments on capital lease obligations	-0.6			-9
Payments on financing obligations	0			0
Payment to buyout capital leases	0			0
Payment to buyout other financing arrangements	0			0
Debt issuance costs	0			-17.2
Payment of debt extinguishment costs	0			0
Contributions from/(distributions to) parent, net	0.2			-1.7
Other	0			0
Net cash provided by (used in) by financing activities	-0.4			216.9
Net (decrease) increase in cash and cash equivalents	-4.2			15.9
Cash and cash equivalents at beginning of period	16.5		16.5	0.6
Cash and cash equivalents at end of period	12.3			16.5
Supplemental disclosures
Cash paid for interest, net of amount capitalized	0.3			42.4
Cash paid for income taxes	0			0
Capitalized interest	0			2.7
Noncash investing and financing transactions:
Acquisition of property in accounts payable and other liabilities	15.7			7.7
Acquisition of property by assuming capital lease obligations and other financing arrangements	0			11.6
Contribution receivable from Parent related to transaction-related compensation	19.6			0
Dividend / Distribution payable	0			0
Other contributions from Parent	1.7			0
Non-cash distribution to CyrusOne Inc.	0			0
Assets transferred by parent	0			2
Divisional control contribution funded by settlement of intercompany balances due to Parent	0			196.4
Reclass of equipment to held for sale	0			0
Noncash additions to fixed assets through other financing arrangements	$0			$0

Consolidated_and_Combined_Stat3

Consolidated and Combined Statements of Equity and Partnership Capital (USD $)	Total	CyrusOne LP [Member]	Total Shareholder’s Equity/ Parent’s Net Investment	Non Controlling Interest	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Predecessor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]	Successor [Member]
In Millions, except Share data, unless otherwise specified	USD ($)		USD ($)	USD ($)	USD ($)	CyrusOne LP [Member]	Common Stock Issued	Accum Deficit	Paid-In Capital	Partnership Capital	Divisional Control	Divisional Control	Accumulated Other Comprehensive Loss	Total Shareholder’s Equity/ Parent’s Net Investment	Non Controlling Interest	Partnership Units	Partnership Capital	USD ($)	CyrusOne LP [Member]	Common Stock Issued	Accum Deficit	Paid-In Capital	Partnership Capital	Divisional Control	Divisional Control	Accumulated Other Comprehensive Loss	Total Shareholder’s Equity/ Parent’s Net Investment	Non Controlling Interest	Partnership Units	Partnership Capital
						USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	CyrusOne LP [Member]	USD ($)	USD ($)	USD ($)	CyrusOne LP [Member]	CyrusOne LP [Member]		USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	CyrusOne LP [Member]	USD ($)	USD ($)	USD ($)	CyrusOne LP [Member]	CyrusOne LP [Member]
												USD ($)					USD ($)								USD ($)					USD ($)
Beginning Balance at Dec. 31, 2011					$0		$0	$0	$0	$0	$311.50	$311.50	$0	$311.50	$0		$0
Beginning Balance (in shares) at Dec. 31, 2011							0									0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					-20.3	-20.3				-20.3				-20.3			-20.3
Divisional control transfer					0					311.5	-311.5	-311.5					311.5
Issuance of common stock (100 shares at $ .01 par value)					0
Issuance of partnership units (in shares)																123,600,000
Issuance of partnership units					0
Contributions from Parent related to settlement of intercompany balances					0				7.1	196.4				203.5			196.4
Other contributions from Parent, net					0	0				5.4				5.4			5.4
Foreign currency translation adjustments					0	0
Ending Balance at Dec. 31, 2012					500.1		0	0	7.1	493	0	0	0	500.1	0		493
Ending Balance (in shares) at Dec. 31, 2012							0									123,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-20.2				-20.2	-20.2				-20.2				-20.2			-20.2
Common stock issued (in shares)							19,000,000									22,000,000
Issuance of common stock (100 shares at $ .01 par value)					337.1		0.2		336.9					337.1			337.1
Other contributions from Parent, net					1.3	1.7				1.3				1.3			1.3
Contributions from Parent–transaction compensation expense reimbursement					19.6					19.6				19.6			19.6
Partnership reverse unit split 2.8 to 1 (in shares)																-79,500,000
Noncontrolling interest effective January 24, 2013					0				-7.1	-493.7				-500.8	500.8
Common stock issued to CBI in exchange for operating partnership units (in shares)							-1,500,000									-1,500,000
Common stock issued to CBI in exchange for operating partnership units					0
Common stock issued to CBI in exchange for settlement of IPO costs paid by CBI (in shares)							400,000
Common stock issued to CBI in exchange for settlement of IPO costs paid by CBI					0				7.1					7.1	-7.1
IPO costs					-9.5				-9.5					-9.5
Foreign currency translation adjustments					0	0
Restricted shares issued (in shares)							1,100,000
Restricted shares issued					0
Stock based compensation																	6.2
Distributions to CyrusOne Inc.																	-2.4
Ending Balance at Jan. 23, 2013
Beginning Balance at Dec. 31, 2012								0					0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-35.8		-5.3	-10.3
Dividends declared / Partnership distributions			-13.6	-27.8
Ending Balance at Dec. 31, 2013	777.6																						0	0	0
Beginning Balance at Jan. 23, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss																		-15.6	-15.6		-15.6						-15.6			-15.6
Other contributions from Parent, net																			1.3
Foreign currency translation adjustments																		0	0
Noncontrolling interest allocated net loss																		10.3			10.3						10.3	-10.3
Stock based compensation																		6.2				6.2					6.2
Dividends declared / Partnership distributions																		-41.4			-13.6						-13.6	-27.8		-41.4
Ending Balance at Dec. 31, 2013	777.6																	777.6		0.2	-18.9	340.7	0	0	0	0	322	455.6		777.6
Beginning Balance (in shares) at Dec. 31, 2013																				22,000,000									64,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-14.5		-7.8	-6.7														-14.5	-14.5		-14.5						-14.5			-14.5
Common stock issued (in shares)																				16,000,000									700,000
Issuance of common stock (100 shares at $ .01 par value)																		356		0.2		355.8					356
Partnership units purchased by CyrusOne Inc. (in shares)																													16,000,000
Partnership units purchased by CyrusOne Inc.																														356
Other contributions from Parent, net																			0
IPO costs																		-1.3				-1.3					-1.3
Foreign currency translation adjustments	-0.3																	-0.3	-0.3							-0.3	-0.3			-0.3
Noncontrolling interest allocated net loss																		6.7			6.7						6.7	-6.7
Stock based compensation (in shares)																				700,000
Stock based compensation																		10.3				10.3					10.3			10.3
Partnership units sold by CBI																														-355.9
Partnership units sold by CBI (in shares)																													-16,000,000
Distributions to CyrusOne Inc.																														-1.3
Redemption of noncontrolling interest																		-355.9				-189					-189	-166.9
Dividends declared / Partnership distributions			-29.2	-25.7														-54.9			-29.2									-54.9
Ending Balance at Dec. 31, 2014	$717																	$717		$0.40	($55.90)	$516.50	$0	$0	$0	($0.30)	$460.70	$256.30		$717
Ending Balance (in shares) at Dec. 31, 2014																				38,700,000									65,300,000

Consolidated_and_Combined_Stat4

Consolidated and Combined Statements of Equity and Partnership Capital (Parenthetical) (USD $)	1 Months Ended
	Jan. 23, 2013	Dec. 31, 2012
Predecessor [Member]
Common stock issued (in shares)		100
Common stock par value (in dollars per share)		$0.01
CyrusOne LP [Member] | Predecessor [Member] | Partnership Units
Partnership reverse unit split, conversion ratio	2.8

Description_of_Business

Description of Business	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business
	CyrusOne Inc., together with CyrusOne GP, a wholly-owned subsidiary of CyrusOne Inc., through which CyrusOne Inc. holds a controlling interest in CyrusOne LP (the “operating partnership”) and the subsidiaries of the operating partnership (collectively, “CyrusOne”, “we”, “us”, “our”, and the “Company”) is an owner, operator and developer of enterprise-class, carrier-neutral multi-tenant data center properties. Our customers operate in a number of industries, including energy, oil and gas, mining, medical, technology, finance and consumer goods and services. We currently operate approximately 25 data centers located in the United States, United Kingdom and Singapore.

Formation

Formation	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Formation	Formation
	Prior to November 20, 2012, CyrusOne was not an operative legal entity or a combination of legal entities. The
	accompanying combined financial statements of CyrusOne for such periods represent the data center assets and operations
	owned by Cincinnati Bell Inc. (“CBI”) and, unless the context otherwise requires, its consolidated subsidiaries which
	historically have been maintained in various legal entities, some of which had significant unrelated business activities. The
	accompanying financial statements for such periods have been “carved out” of CBI’s consolidated financial statements and
	reflect significant assumptions and allocations. The combined financial statements do not fully reflect what the financial
	position, results of operations and cash flows would have been had these operations been a stand-alone company during the
	periods presented. As a result, historical financial information is not necessarily indicative of CyrusOne’s future results of
	operations, financial position and cash flows.
	On November 20, 2012, the operating partnership received a contribution of interests in real estate properties and the assumption of debt and other specified liabilities from CBI in exchange for the issuance of 123.7 million operating partnership units to CBI.
	On January 24, 2013, CyrusOne Inc. completed its initial public offering (“IPO”) of common stock, issuing approximately 19 million shares for $337.1 million, net of underwriting discounts. At that time the operating partnership executed a 2.8 to 1.0 reverse unit split, resulting in CBI owning 44.1 million operating partnership units. In addition, CBI exchanged approximately 1.5 million of its operating partnership units for 1.5 million shares of CyrusOne Inc. common stock, and CBI was issued 0.4 million shares of CyrusOne Inc. common stock in repayment for transaction costs paid by CBI. CyrusOne Inc. also issued approximately 1.1 million shares of restricted stock to its directors and employees. In addition, on January 24, 2013, CyrusOne Inc., together with CyrusOne GP, purchased approximately 21.9 million, or 33.9% of the operating partnership’s units for $337.1 million and through CyrusOne GP assumed the controlling interest in the operating partnership. CBI retained a noncontrolling interest in the operating partnership of 66.1%.
	On June 25, 2014, CyrusOne Inc. completed a public offering of 16 million shares of its common stock, including 2.1 million shares of common stock issued upon the exercise in full by the underwriters of their option to purchase additional shares, at a price to the public of $23.25 per share, or $371.7 million. CyrusOne Inc. used the proceeds of $355.9 million, net of underwriting discounts of $15.8 million, to acquire 16 million common units of limited partnership interests in the operating partnership from a subsidiary of CBI.
	As of December 31, 2014, the total number of outstanding partnership units was 65.3 million and CBI holds a 40.8% noncontrolling interest in the operating partnership. CBI effectively owns approximately 43.7% of CyrusOne through its interest in outstanding shares of common stock of CyrusOne Inc. and its interest in the operating partnership units of CyrusOne LP.

Basis_of_Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying financial statements for the period ended January 23, 2013 and the year ended December 31, 2012, were prepared on a combined basis using CBI’s historical basis in the assets and liabilities of its data center business and are presented as the “Predecessor” financial statements. The Predecessor financial statements include all revenues, costs, assets and liabilities directly attributable to the data center business. In addition, certain expenses reflected in the Predecessor financial statements include allocations of corporate expenses from CBI, which in the opinion of management are reasonable but do not necessarily reflect what CyrusOne’s financial position, results of operations and cash flows would have been had CyrusOne been a stand-alone company during these respective periods. As a result, the Predecessor financial information is not necessarily indicative of CyrusOne’s future results of operations, financial position and cash flows. The financial statements as of December 31, 2014 and 2013 and for the period from January 24, 2013 to December 31, 2013, and the year ended December 31, 2014, are prepared on a consolidated basis and are presented as the “Successor” financial statements.
	In addition, the accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). All material intercompany transactions and balances have been eliminated in consolidation.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies
	Use of Estimates—Preparation of the consolidated and combined financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated and combined financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Estimates are used in determining the fair value of leased real estate, the useful lives of real estate and other long-lived assets, future cash flows associated with goodwill and other long-lived asset impairment testing, deferred tax assets and liabilities and loss contingencies. Estimates were also utilized in the determination of historical allocations of shared employees’ payroll, benefits and incentives and management fees between CyrusOne and CBI. Actual results may differ from these estimates and assumptions.
	Investments in Real Estate—Investments in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. Real estate acquired from third parties has been recorded at its acquisition cost. Real estate acquired from CBI and its affiliates has been recorded at its historical cost basis. Additions and improvements which extend an asset’s useful life or increase its functionality are capitalized and depreciated over the asset’s remaining life. Maintenance and repairs are expensed as incurred.
	When we are involved in the construction of structural improvements to leased property, we are deemed the accounting owner of the leased real estate. In these instances, we bear substantially all the construction period risk, including managing or funding construction. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. At inception, the fair value of the real estate, which generally consists of a building shell and our associated obligation is recorded as construction in progress. As construction progresses the value of the asset and obligation increases by the fair value of the structural improvements. When construction is complete, the asset is placed in service and depreciation commences. Leased real estate is depreciated to the lesser of (i) its estimated fair value at the end of the term or (ii) the expected amount of the unamortized obligation at the end of the term.
	When we are not deemed the accounting owner, we further evaluate leased real estate to determine whether the lease should be classified as a capital or operating lease. One of the following four characteristics must be present to classify a lease as a capital lease: (i) the lease transfers ownership of the property to the lessee by the end of the lease term, (ii) the lease contains a bargain purchase option, (iii) the lease term is equal to 75% or more of the estimated economic life of the leased property or (iv) the net present value of the lease payments are at least 90% of the fair value of the leased property.
	Construction in progress includes direct and indirect expenditures for the construction and expansion of our data centers and is stated at its acquisition cost. Independent contractors perform substantially all of the construction and expansion efforts of our data centers. Construction in progress includes costs incurred under construction contracts including project management services, engineering and schematic design services, design development, construction services and other construction-related fees and services. Interest, property taxes and certain labor costs are also capitalized during the construction of an asset. Capitalized interest in 2014, 2013, and 2012 was $4.6 million, $1.6 million, and $2.7 million, respectively. These costs are depreciated over the estimated useful life of the related assets.
	Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to forty-eight years years for buildings, three to twenty-five years for building improvements, and three to five years years or equipment. Leasehold improvements are amortized over the shorter of the asset’s useful life or the remaining lease term, including renewal options which are reasonably assured.
	Management reviews the carrying value of long-lived assets, including intangible assets with finite lives, when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Examples of such indicators may include a significant adverse change in the extent to which or manner in which the property is being used, an accumulation of costs significantly in excess of the amount originally expected for acquisition or development, or a history of operating or cash flow losses. When such indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of an asset (or group of assets) and its eventual disposition and compare such amount to its carrying amount. We consider factors such as future operating income, leasing demand, competition and other factors. If our undiscounted net cash flows indicate that we are unable to recover the carrying value of the asset, an impairment loss is recognized. An impairment loss is measured as the amount by which the asset’s carrying value exceeds its estimated fair value.
	Impairment exists when the Company's net book value of real estate assets is greater than the estimated fair value. For the period ended December 31, 2013 and the year ended December 31, 2012, we recognized impairments of $2.8 million and $11.8 million, respectively. No such impairments were recognized in 2014.
	Cash and Cash Equivalents—Cash and cash equivalents include all non-restricted cash held in financial institutions and other non-restricted highly liquid short-term investments with original maturities at acquisition of three months or less.
	Goodwill—Goodwill represents the excess of the purchase price over the fair value of net assets acquired in connection with business acquisitions. We perform impairment testing of goodwill, at the reporting unit level, on an annual basis or more frequently if indicators of potential impairment exist.
	The fair value of our reporting unit was determined using a combination of market-based valuation multiples for comparable businesses and discounted cash flow analysis based on internal financial forecasts incorporating market participant assumptions. There were no impairments recognized for the years ended December 31, 2014 or 2013.
	Long-Lived and Intangible Assets—Intangible assets represent purchased assets that lack physical substance, but can be separately distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged, either on its own or in combination with a related contract, asset, or liability. Intangible assets with finite lives consist of trademarks, customer relationships, and a favorable leasehold interest.
	For the year ended December 31, 2012, we recognized an impairment of $1.5 million related to the impairment of customer relationships. There were no impairments recognized for the years ended December 31, 2014 or 2013.
	Rent and Other Receivables—Receivables consist principally of trade receivables from customers and are generally unsecured and due within 30 to 120 days. Unbilled receivables arise from services rendered but not yet billed. Expected credit losses associated with trade receivables are recorded as an allowance for uncollectible accounts. The allowance for uncollectible accounts is estimated based upon historic patterns of credit losses for aged receivables as well as specific provisions for certain identifiable, potentially uncollectible balances. When internal collection efforts on accounts have been exhausted, the accounts are written-off and the associated allowance for uncollectible accounts is reduced. The Company has receivables with one customer that exceeds 10% of the Company’s outstanding accounts receivable balance at December 31, 2014 and 2013. In addition, our receivables include $8.7 million of receivables as of December 31, 2014 which has not been billed to the customer. The amount will be billed and payable in 36 monthly payments starting in April 2015 through March 2018.
	As of December 31, 2014, receivables were $61.9 million, and the allowance for uncollectible accounts was $1.0 million. The December 31, 2013 receivables were $41.7 million, and the allowance for uncollectible accounts was $0.5 million.
	Deferred Costs—Deferred costs include both deferred leasing costs and deferred financing costs. Deferred costs are presented with other assets in the accompanying consolidated and combined balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized to expense over the term of the customer lease. Amortization of deferred leasing costs is presented with depreciation and amortization in the accompanying consolidated and combined statements of operations. If a lease terminates prior to the expected term of the lease, the remaining unamortized cost is written off to amortization expense.
	Deferred financing costs include costs incurred in connection with issuance of senior notes, term loans and revolving credit facilities. These financing costs are capitalized and amortized to expense over the term of the instrument and are included as a component of interest expense.
	Other Financing Arrangements—Other financing arrangements represent leases of real estate where we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our consolidated and combined balance sheet. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations.
	Revenue Recognition—Colocation rentals are generally billed monthly in advance, and some contracts have escalating payments over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased space or power, and the lessee takes possession of, or controls the physical use of the property (including all contractually committed power) at the beginning of the lease term, the rental payments by the lessee are recognized as revenue on a straight-line basis over the term of the lease. If rents escalate because the lessee gains access to and control over additional leased space or power, revenue is recognized in proportion to the additional space or power in the periods that the lessee has control over the use of the additional space or power. The excess of revenue recognized over amounts contractually due is recognized in other assets in the accompanying consolidated and combined balance sheets. As of December 31, 2014 and 2013, straight-line rents receivable was $33.7 million and $25.5 million, respectively.
	Some of our leases are structured on a full-service gross basis where the customer pays a fixed amount for both colocation rental and power. Other leases provide that the customer will be billed for power based upon their actual usage, which is separately metered, as well as an estimate of electricity used to power supporting infrastructure for the data center. In both cases, this revenue is presented on a gross basis in the accompanying consolidated and combined statement of operations. Power is generally billed one month in arrears and an estimate of this revenue is accrued in the month that the associated costs are incurred. We generally are not entitled to reimbursements for real estate taxes, insurance or other operating expenses.
	Revenue is recognized for services or products that are deemed separate units of accounting. When a customer makes an advance payment or they are contractually obligated to pay any amounts in advance, which is not deemed a separate unit of accounting, deferred revenue is recorded. This revenue is recognized ratably over the expected term of the lease, unless the pattern of service suggests otherwise. As of December 31, 2014 and 2013, deferred revenue was $65.7 million and $55.9 million, respectively.
	Certain customer contracts require specified levels of service or performance. If we fail to meet these service levels, our customers may be eligible to receive credits on their contractual billings. These credits are recognized against revenue when an event occurs that gives rise to such credits. Customer credits were immaterial for the years ended December 31, 2014 and 2013.
	A provision for uncollectible accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible. The provision for uncollectible accounts was $1.0 million in 2014, $0.5 million in 2013 and $0.3 million in 2012.
	Sales and Marketing Expense—Sales and marketing expense is comprised of compensation and benefits associated
	with sales and marketing personnel as well as advertising and marketing costs. Costs related to advertising are expensed as incurred and amounted to $2.9 million for the year ended December 31, 2014, $2.1 million for the period ended December 31, 2013, $0.1 million for the period ended January 23, 2013, and $2.9 million for the year ended December 31, 2012.
	Depreciation and Amortization Expense—Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal of the lease is reasonably assured. The residual value of leased real estate is estimated as the lesser of (i) the expected fair value of the asset at the end of the lease term or (ii) the expected amount of the unamortized liability at the end of the lease term. Estimated useful lives are periodically reviewed. Depreciation expense was $95.8 million for the year ended December 31, 2014, $70.3 million for the period ended December 31, 2013, $4.1 million for the period ended January 23, 2013, and $54.5 million for the year ended December 31, 2012.
	Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. An accelerated method of amortization is utilized to amortize our customer relationship intangible, consistent with the benefit expected to be derived from this asset. We amortize trademarks, favorable leasehold interests, deferred leasing costs and deferred sales commissions over their estimated useful lives. The estimated useful life of trademarks and customer relationships is eight to fifteen years. In addition, we have a favorable leasehold interest related to a land lease that is being amortized over the lease term of fifty-six years. Deferred leasing costs are amortized over three to five years. Amortization expense was $22.2 million for the year ended December 31, 2014, $19.6 million for the period ended December 31, 2013, $1.2 million for the period ended January 23, 2013, and $18.9 million for the year ended December 31, 2012.
	Transaction Costs—Transaction costs represent legal, accounting and professional fees incurred in connection with the formation transactions, our qualification as a real estate investment trust, or REIT, and potential business combinations. Transaction costs are expensed as incurred.
	Transaction-Related Compensation—During the period ended January 23, 2013, the Company received an allocated compensation charge from CBI of $20.0 million for the settlement of its long-term incentive plan associated with the completion of the IPO. The amount was determined by CBI and allocated to CyrusOne Inc. on January 23, 2013, and reflected as expense and contributed capital in the respective period.
	Income Taxes—CyrusOne Inc. was included in CBI’s consolidated tax returns in various jurisdictions for the Predecessor period and was included in the Successor period for Texas only until June 26, 2014 when CBI's ownership percentage in the operating partnership was reduced below 50%. In the accompanying financial statements, the Predecessor period and the Successor period (for Texas only until June 26, 2014) reflect income taxes as if the Company were a separate stand-alone company. The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Code"), commencing with our initial taxable year ending December 31, 2013. Provided we continue to meet the various qualification tests mandated under the Code, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our shareholders. If we fail to qualify as a REIT in any taxable year, our taxable income will be subject to federal income tax at regular corporate rates and any applicable alternative minimum tax.
	While CyrusOne Inc. and the operating partnership do not pay federal income taxes, we are still subject to foreign, state and local income taxes in the locations in which we conduct business. Our taxable REIT subsidiaries (each a “TRS”) are also subject to federal and state income taxes to the extent they earn taxable income.
	Deferred income taxes are recognized in certain entities. Deferred income taxes are provided for temporary differences in the bases between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards.
	The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various foreign, state and local jurisdictions.  The Company's previous tax filings are subject to normal reviews by regulatory agencies until the related statute of limitations expires.  With a few exceptions, the Company is no longer subject to U. S. federal, state or local examinations for years prior to 2011, and we have no liabilities for uncertain tax positions as of December 31, 2014 or 2013.
	Foreign Currency Translation and Transactions—The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average rates of exchange during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive (loss) income. Gains or losses from foreign currency transactions are included in determining net income.
	Comprehensive Loss—Comprehensive loss represents the change in net assets of a company from transactions and other events from non-owner sources. Comprehensive loss comprises all components of net loss and all components of other comprehensive loss. Comprehensive loss was equal to $0.3 million in 2014. Comprehensive loss was equal to our net loss in 2013 and 2012.
	Earnings Per Share—For all periods subsequent to January 23, 2013, we present earnings per share (“EPS”) data. Basic EPS includes only the weighted average number of common shares outstanding during the period. Diluted EPS includes the weighted average number of common shares and the dilutive effect of stock options, restricted stock and share unit awards and convertible subordinated notes outstanding during the period, when such instruments are dilutive.
	All outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are treated as participating in undistributed earnings with common shareholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS must be applied.
	Related Party Transactions—CBI provided us with a variety of services. Cost allocation methods which were employed to determine the costs to be recognized in the accompanying combined financial statements included the following:
	•Specific identification—Applied when amounts were specifically identifiable to our operations.
	•Reasonable allocation method—When amounts were not clearly or specifically identifiable to our operations,
	management applied a reasonable allocation method.
	Stock-Based Compensation—In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan (“LTIP”). The LTIP is administered by the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. The awards under the LTIP include the following:
	Restricted Shares - On January 24, 2013, CyrusOne Inc. issued approximately 1 million restricted shares to its employees, officers and members of the Company's board of directors in conjunction with CyrusOne's IPO. These restricted shares generally vest over three years. The per share grant date price was $19.00. In addition, from time to time, new employees and members of our board of directors have been issued restricted shares. These restricted shares are issued at a price equal to our share price on the grant date.
	Performance and Market Based Awards - On April 17, 2013, and February 7, 2014, the Company issued performance and market based awards in the form of options and/or restricted stock to certain employees and officers of the Company. Fifty percent of the restricted shares and stock options will vest annually based upon achieving certain performance criteria. The other fifty percent of the restricted shares and stock options will vest at the end of three years if certain market conditions are met. The fair value of these awards were determined using the Black-Scholes or Monte-Carlo model which use assumptions such as volatility, risk-free interest rate, and expected term of the awards. See Note 15 for additional details relating to these awards.
	Compensation expense for these awards is recognized over the vesting periods.
	Fair Value Measurements—Fair value measurements are utilized in accounting for business combinations and testing of goodwill and other long-lived assets for impairment and disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows:
	Level 1—Observable inputs for identical instruments such as quoted market prices;
	Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and
	Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data.
	Business Segments—Business segments are components of an enterprise for which separate financial information is available and regularly viewed by the chief operating decision maker to assess performance and allocate resources. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis. Furthermore, our data centers have similar economic characteristics and customers across all geographic locations, our service offerings have similar production processes, deliver services in a similar manner and use the same types of facilities and similar technologies. As a result, we have concluded that we have one reportable operating segment.

Recently_Issued_Accounting_Sta

Recently Issued Accounting Standards	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards
	In February 2013, the Financial Accounting Standards Board ("FASB") issued amendments to provide guidance on the recognition, measurement and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of obligation within the scope of this guidance is fixed at the reporting date, except for obligations addressed within existing guidance in GAAP. The amendments are effective for fiscal years and interim periods within those years, beginning after December 15, 2013. The Company adopted this guidance in the first quarter of 2014 and has properly reflected the impact in the guarantor financial statements.
	In May 2014, the FASB issued guidance that outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most of the existing revenue recognition guidance. This guidance requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services and also requires certain additional disclosures which are effective for interim and annual reporting periods in fiscal years that begin after December 15, 2016.  We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements.
	In June 2014, the FASB issued a guidance update for the presentation of stock compensation.  This guidance requires an entity to treat performance targets that can be met after the requisite service period of a share based award has ended, as a performance condition that affects vesting which is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2015.  We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements.
	In August 2014, the FASB issued guidance on determining when and how reporting entities must disclose going-concern uncertainties in their financial statements. The new standard requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date of issuance of the entity’s financial statements. This guidance is effective for annual periods ending after December 15, 2016, and interim periods thereafter; early adoption is permitted. We are currently evaluating the full impact of the new standard.
	In January 2015, the FASB issued guidance eliminating from U.S. GAAP the concept of an extraordinary item. An entity is no longer required to (1) segregate an extraordinary item from the results of ordinary operations; (2) separately present an extraordinary item on its income statement, net of tax, after income from continuing operations; and (3) disclose income taxes and earnings-per-share data applicable to an extraordinary item. This guidance does not affect the reporting and disclosure requirements for an event that is unusual in nature or that occurs infrequently.

Investment_in_Real_Estate

Investment in Real Estate	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Investment in Real Estate	Investment in Real Estate
	A schedule of our gross investment in real estate follows:
		December 31, 2014						December 31, 2013
	(amounts in millions)	Land		Building and		Equipment		Land		Building and		Equipment
				Improvements						Improvements
	West Seventh St., Cincinnati, OH (7th Street)	$	0.9	$	110.6	$	12.7	$	0.9	$	107.6	$	11
	Parkway Dr., Mason, OH (Mason)	—		20.2		0.9		—		20.2		0.6
	Industrial Rd., Florence, KY (Florence)	2.2		41.4		3		2.2		41.4		2.4
	Goldcoast Dr., Cincinnati, OH (Goldcoast)	0.6		6.7		0.1		0.6		6.7		0.1
	Knightsbridge Dr., Hamilton, OH (Hamilton)	—		49.2		3.7		—		49.2		3.6
	E. Monroe St., South Bend, IN (Monroe St.)	—		2.5		0.1		—		2.5		—
	Springer St., Lombard, IL (Lombard)	0.7		4.7		5.7		0.7		4.6		0.2
	Crescent Circle, South Bend, IN (Blackthorn)	—		3.3		0.1		—		3.3		0.2
	Kingsview Dr., Lebanon, OH (Lebanon)	4		77		5.5		4		71.7		2.2
	McAuley Place, Blue Ash, OH (Blue Ash)	—		0.6		0.1		—		0.6		—
	Westway Park Blvd., Houston, TX (Houston West 1)	1.4		84.4		43.8		1.4		84.4		39.4
	Westway Park Blvd., Houston, TX (Houston West 2)	2		22.5		45.1		2		22.4		15.8
	Westway Park Blvd., Houston, TX (Houston West 3)	18.4		—		—		18.3		—		—
	Southwest Fwy., Houston, TX (Galleria)	—		68.6		15		—		68.4		13.3
	E. Ben White Blvd., Austin, TX (Austin 1)	—		22.5		1.2		—		22.5		1.2
	S. State Highway 121 Business, Lewisville, TX (Lewisville)	—		76.7		22.8		—		77		20.3
	Marsh Lane, Carrollton, TX (Marsh Ln)	—		0.1		0.5		—		0.1		0.5
	Midway Rd., Carrollton, TX (Midway)	—		2		0.4		—		2		0.4
	W. Frankford Rd., Carrollton, TX (Carrollton)	16.1		51.6		85.3		16.1		42.6		34.8
	Bryan St., Dallas, TX (Bryan St)	—		0.1		0.2		—		0.1		0.1
	North Freeway, Houston, TX (Greenspoint)	—		1.3		—		—		1.3		0.4
	South Ellis Street, Chandler, AZ (Phoenix 1)	14.8		56.4		43.9		15		55.7		11.7
	South Ellis Street, Chandler, AZ (Phoenix 2)	—		13.2		21.8		—		—		—
	Westover Hills Blvd., San Antonio, TX (San Antonio 1)	4.6		32.1		32.4		4.6		32.1		29.5
	Westover Hills Blvd., San Antonio, TX (San Antonio 2)	7		—		—		6.7		—		—
	Metropolis Dr., Austin, TX (Austin 2)	2		23.2		4		2		23.1		1.7
	Kestral Way (London)	—		32.7		0.7		—		34.8		0.7
	Jurong East (Singapore)	—		9		0.1		—		9.4		0.1
	Ridgetop Circle, Sterling, VA (Northern VA)	7		—		—		6.9		—		—
	Metropolis Dr., Austin, TX (Austin 3)	8		—		—		7.9		—		—
	Total	$	89.7	$	812.6	$	349.1	$	89.3	$	783.7	$	190.2
	Construction in progress was $127.0 million and $57.3 million as of December 31, 2014 and December 31, 2013, respectively. We have sustained high amounts of construction in progress as we continue to build data center facilities.
	During 2014, we continued to invest in the development of real estate. Our development has included the completion of additional square footage and power primarily in our Phoenix 1, Phoenix 2, Carrollton, and Houston West 2 data centers.

Goodwill_Intangible_and_Other_

Goodwill, Intangible and Other Long-Lived Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Intangible and Other Long-Lived Assets	Goodwill, Intangible and Other Long-Lived Assets
	Goodwill and intangible assets were recognized in connection with the acquisition of Cyrus Networks as well as prior acquisitions. The carrying amount of goodwill was $276.2 million as of December 31, 2014 and 2013.
	Summarized below are the carrying values for the major classes of intangible assets:
	(amounts in millions)			31-Dec-14							31-Dec-13
		Weighted-		Gross		Accumulated			Total		Gross		Accumulated			Total
		Average Life		Carrying		Amortization					Carrying		Amortization
		(in years)		Amount							Amount
	Customer relationships	15		$	129.7	$	(69.5	)	$	60.2	$	129.7	$	(53.1	)	$	76.6
	Trademark	15		7.4		(2.3		)	5.1		7.4		(1.8		)	5.6
	Favorable leasehold interest	56		3.9		(0.3		)	3.6		3.9		(0.2		)	3.7
	Total			$	141	$	(72.1	)	$	68.9	$	141	$	(55.1	)	$	85.9
	There were no intangible asset impairments for the years ended December 31, 2014 or 2013.
	Amortization expense for acquired intangible assets subject to amortization was $17.0 million, $15.9 million, $1.0 million and $16.4 million for the year ended December 31, 2014, and the periods ended December 31, 2013 and January 23, 2013, and the year ended December 31, 2012, respectively.
	The following table presents estimated amortization expense for each of the next five years and thereafter, commencing January 1, 2015:
	(amounts in millions)
	2015	$	14.6
	2016	11.6
	2017	9.5
	2018	7.6
	2019	5.9
	Thereafter	19.7
	Total	$	68.9

Debt_and_Other_Financing_Arran

Debt and Other Financing Arrangements	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt and Other Financing Arrangements	Debt and Other Financing Arrangements
	Debt and other financing arrangements presented in the accompanying consolidated and combined financial statements consist of the following:
	(amounts in millions)	December 31,			December 31,
		2014			2013
	Revolving facility	$	135		$	—
	Term loan	150			—
	6 3/8% senior notes due 2022	374.8			525
	Long-term debt	659.8			525
	Capital lease obligations	13.4			16.7
	Other financing arrangements	53.4			56.3
	Total	$	726.6		$	598
	Revolving credit agreement—On October 9, 2014, CyrusOne LP entered into a new credit agreement which provides for a $450 million senior unsecured revolving credit facility to replace CyrusOne LP's $225 million secured credit facility, and a $150 million senior unsecured term loan. The revolving facility is scheduled to mature in October 2018 and includes a one-year extension option, which if exercised by CyrusOne LP would extend the maturity date to October 2019. The term loan is scheduled to mature in October 2019. The revolving facility currently bears interest at a rate per annum equal to LIBOR plus 1.70% and the term loan currently bears interest at a rate per annum equal to LIBOR plus 1.65%. The credit agreement governing the revolving credit facility and the term loan contains an accordion feature that allows CyrusOne LP to increase the aggregate commitment by up to $300 million.
	As of December 31, 2014 there were borrowings of $135 million under the revolving facility and $150 million under the term loan. There were no borrowings under the previous credit agreement as of December 31, 2013.
	We pay commitment fees for the unused amount of borrowings on the revolving facility and term loan and letter of credit fees on any outstanding letters of credit. The commitment fees are equal to 0.25% per annum of the actual daily amount by which the aggregate revolving commitments exceed the sum of outstanding revolving loans and letter of credit obligations. Commitment fees related to the credit agreement were $1.1 million for the years ended December 31, 2014 and 2013.
	Capital lease obligations—We use leasing as a source of financing for certain of our data center facilities and related equipment. We currently operate four data center facilities recognized as capital leases. We have options to extend the initial lease term on all these leases and options to purchase the facility for one of these leases. Interest expense on capital lease obligations was $5.9 million, $6.3 million, $0.3 million and $7.4 million for the year ended December 31, 2014, and the periods ended December 31, 2013, and January 23, 2013, and year ended December 31, 2012, respectively.
	6.375% Senior Notes due 2022—On November 20, 2012, CyrusOne LP and CyrusOne Finance Corp. (the “Issuers”) issued $525 million of 6.375% senior notes due 2022 (“6.375% senior notes”). The 6.375% senior notes are senior unsecured obligations of the Issuers, which rank equally in right of payment with all existing and future unsecured senior debt of the Issuers. The 6.375% senior notes are effectively subordinated to all existing and future secured indebtedness of the Issuers to the extent of the value of the assets securing such indebtedness. The 6.375% senior notes are fully and unconditionally and jointly and severally guaranteed by CyrusOne Inc., CyrusOne GP, and each of CyrusOne LP’s existing and future domestic 100% owned subsidiaries, subject to certain exceptions. Each such guarantee is a senior unsecured obligation of the applicable guarantor, ranking equally with all existing and future unsecured senior debt of such guarantor and effectively subordinated to all existing and future secured indebtedness of such guarantor to the extent of the value of the assets securing that indebtedness. The 6.375% senior notes are structurally subordinated to all liabilities (including trade payables) of each subsidiary of the Issuer that does not guarantee the senior notes. The 6.375% senior notes bear interest at a rate of 6.375% per annum, payable semi-annually on May 15 and November 15 of each year, beginning on May 15, 2013.
	The indenture governing the 6.375% senior notes contains affirmative and negative covenants customarily found in indebtedness of this type, including a number of covenants that, among other things, restrict, subject to certain exceptions, the Company’s ability to: incur secured or unsecured indebtedness; pay dividends or distributions on its equity interests, or redeem or repurchase equity interests of the Company; make certain investments or other restricted payments; enter into transactions with affiliates; enter into agreements limiting the ability of the operating partnership’s subsidiaries to pay dividends or make certain transfers and other payments to the operating partnership or to other subsidiaries; sell assets; and merge, consolidate or transfer all or substantially all of the operating partnership’s assets. Notwithstanding the foregoing, our indenture restricts CyrusOne LP from making distributions to its stockholders and limited partners, or redeeming or otherwise repurchasing shares of its capital stock or partnership units, after the occurrence and during the continuance of an event of default, except in limited circumstances including as necessary to enable CyrusOne Inc. to maintain its qualification as a REIT and to minimize the payment of income tax. The Company and its subsidiaries are also required to maintain total unencumbered assets of at least 150% of their unsecured debt on a consolidated basis, provided that for the purposes of such calculation their revolving credit facility shall be treated as unsecured indebtedness, in each case subject to certain qualifications set forth in the indenture.
	The 6.375% senior notes will mature on November 15, 2022. However, prior to November 15, 2017, the Issuers may, at their option, redeem some or all of the 6.375% senior notes at a redemption price equal to 100% of the principal amount of the 6.375% senior notes, together with accrued and unpaid interest, if any, plus a “make-whole” premium. On or after November 15, 2017, the Issuers may, at our option, redeem some or all of the 6.375% senior notes at any time at declining redemption prices equal to (i) 103.188% beginning on November 15, 2017, (ii) 102.125% beginning on November 15, 2018, (iii) 101.063% beginning on November 15, 2019 and (iv) 100.000% beginning on November 15, 2020 and thereafter, plus, in each case, accrued and unpaid interest, if any, to the applicable redemption date. In addition, before November 15, 2015, and subject to certain conditions, the Issuers may, at their option, redeem up to 35% of the aggregate principal amount of the 6.375% senior notes with the net proceeds of certain equity offerings at 106.375% of the principal amount thereof, plus accrued and unpaid interest, if any, to the date of redemption; provided that (i) at least 65% of the aggregate principal amount of the 6.375% senior notes remains outstanding and (ii) the redemption occurs within 90 days of the closing of any such equity offering.
	In November and December of 2014, we repurchased our 6.375% senior notes with an aggregate face value of $150.2 million for a purchase price of $163 million, including accrued interest. This resulted in a loss on extinguishment of debt of $12.8 million. As of December 31, 2014, the outstanding balance on our 6.375% senior notes was $374.8 million.
	Other financing arrangements—Other financing arrangements represent leases of real estate in which we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our balance sheet. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations.
	The following table summarizes our annual minimum payments associated with our other financing arrangements for the five years subsequent to December 31, 2014, and thereafter:
	(amounts in millions)
	2015	$	5.6
	2016	5.7
	2017	5.8
	2018	5.9
	2019	6
	Thereafter	21.1
	Total financing arrangements	$	50.1
	The following table summarizes annual principal maturities of our revolving facility and term loan, 6 3/8% senior notes due 2022 and capital leases for the five years subsequent to December 31, 2014, and thereafter:
	(amounts in millions)	Revolving Facility/Term Loan		6.375% Senior Notes			Capital Leases		Total
	2015	$	—	$	—		$	2.3	$	2.3
	2016	—		—			2.5		2.5
	2017	—		—			1.2		1.2
	2018	135		—			1.4		136.4
	2019	150		—			1.5		151.5
	Thereafter	—		374.8			4.5		379.3
	Total debt	$	285	$	374.8		$	13.4	$	673.2
	The payment of interest on capital leases over the next five years and thereafter will be $1.2 million, $1.0 million, $0.8 million, $0.7 million, $0.5 million and $0.8 million, respectively.
	Deferred financing costs—Deferred financing costs are costs incurred in connection with obtaining long-term financing. Deferred financing costs were incurred in connection with the issuance of the revolving facility and term loan and 6.375% senior notes due 2022. As of December 31, 2014, and 2013, deferred financing costs totaled $15.5 million and $14.1 million, respectively. Deferred financing costs related to the senior notes are amortized using the effective interest method over the term of the related indebtedness. Deferred financing costs related to the revolving facility and term loan are amortized using the straight-line method. Amortization of deferred financing costs, included in interest expense in the consolidated and combined statements of operations, totaled $3.4 million, $4.0 million and $0.1 million for the year ended December 31, 2014, and the periods ended December 31, 2013, and January 23, 2013, respectively, and $0.3 million in 2012. The amortization of deferred financing costs for the year ended December 31, 2014 included $0.8 million related to the extinguishment of debt and the correction of expense recorded in prior periods.
	Debt Covenants —The credit agreement governing the revolving facility and the term loan requires us to maintain certain financial covenants including the following, in each case on a consolidated basis:
	•	A minimum fixed charge ratio;
	•	Maximum total and secured leverage ratios;
	•	A minimum tangible net worth ratio;
	•	A maximum secured recourse indebtedness ratio;
	•	A minimum unencumbered debt yield ratio; and
	•	A maximum ratio of unsecured indebtedness to unencumbered asset value.
	Notwithstanding these limitations, we will be permitted, subject to the terms and conditions of the credit agreement, to distribute to our shareholders cash dividends in an amount not to exceed 95% of our Funds From Operations ("FFO"), as defined in the credit agreement) for any period. Similarly, our indenture permits dividends and distributions necessary for us to maintain our status as a REIT.
	The Company’s most restrictive covenants are generally included in its credit agreement. In order to continue to have access to amounts available to it under the credit agreement, the Company must remain in compliance with all covenants.
	The indenture governing the 6.375% senior notes contains affirmative and negative covenants customarily found in indebtedness of this type, including a number of covenants that, among other things, restrict, subject to certain exceptions, the Company’s ability to: incur secured or unsecured indebtedness; pay dividends or distributions on its equity interests, or redeem or repurchase equity interests of the Company; make certain investments or other restricted payments; enter into transactions with affiliates; enter into agreements limiting the ability of the operating partnership’s subsidiaries to pay dividends or make certain transfers and other payments to the operating partnership or to other subsidiaries; sell assets; and merge, consolidate or transfer all or substantially all of the operating partnership’s assets. Notwithstanding the foregoing, the covenants contained in the indenture do not restrict the Company’s ability to pay dividends or distributions to shareholders to the extent (i) no default or event of default exists or is continuing under the indenture and (ii) the Company believes in good faith that we qualify as a REIT under the Code and the payment of such dividend or distribution is necessary either to maintain its status as a REIT or to enable it to avoid payment of any tax that could be avoided by reason of such dividend or distribution. The Company and its subsidiaries are also required to maintain total unencumbered assets of at least 150% of their unsecured debt on a consolidated basis.
	As of December 31, 2014 and 2013, we believe we were in compliance with all covenants.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The fair value of cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued expenses approximate their carrying value because of the short-term nature of these instruments.
	The carrying value and fair value of other financial instruments are as follows:
		31-Dec-14				31-Dec-13
	(amounts in millions)	Carrying Value		Fair Value		Carrying Value		Fair Value
	6.375% senior notes due 2022	$	374.8	$	402	$	525	$	539.4
	Revolving facility and term loan	285		285		—		—
	Other financing arrangements	53.4		63.1		56.3		63.8
	The fair value of our senior notes as of December 31, 2014 and 2013 was based on the quoted market price for these notes, which is considered Level 1 of the fair value hierarchy. The fair value of the revolving facility and term loan was based on par value as of December 31, 2014. The fair value of other financing arrangements at December 31, 2014 and December 31, 2013, was calculated using a discounted cash flow model that incorporates current borrowing rates for obligations of similar duration. These fair value measurements are considered Level 2 of the fair value hierarchy.
	Non-recurring fair value measurements
	Certain long-lived assets, intangibles and goodwill are required to be measured at fair value on a non-recurring basis subsequent to their initial measurement. These non-recurring fair value measurements generally occur when evidence of impairment has occurred. There were no impairment charges for the year ended December 31, 2014.
	The measured fair value used in the 2013 related impairment charges is summarized below:
	(amounts in millions)	December 31,		Quoted prices		Significant		Significant		2013 Impairment
		2013		in active		Other		Unobservable		Loss
				markets for		Observable		Inputs
				Identical Assets		Inputs		(Level 3)
				(Level 1)		(Level 2)
	Equipment	$	0.3	$	—	$	0.3	$	—	$	(2.8	)
	Total Impairment									$	(2.8	)
	In the fourth quarter of 2013, we agreed to an offer to purchase equipment which had a net book value of $3.1 million for $0.3 million, resulting in a loss of $2.8 million.

Noncontrolling_Interests_Opera

Noncontrolling Interests - Operating Partnership	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Noncontrolling Interest - Operating Partnership	Noncontrolling Interest - Operating Partnership
	The noncontrolling interest represents the limited partnership interest in the operating partnership held by CBI.
	The following table shows the ownership interests as of December 31, 2014 and 2013, and the portion of net loss and distributions for the year ended December 31, 2014, and the period ended December 31, 2013:
		31-Dec-14						31-Dec-13
	(amounts in millions, except unit amount)	The Company			CBI			The Company			CBI
	Operating partnership units	38.7			26.6			22			42.6
	Ownership %	59.2		%	40.8		%	34.1		%	65.9		%
	Portion of net loss	$	(7.8	)	$	(6.7	)	$	(5.3	)	$	(10.3	)
	Distributions	$	(29.2	)	$	(25.7	)	$	(13.6	)	$	(27.8	)
	CyrusOne LP issued 123.7 million operating partnership units to CBI on November 20, 2012 and CBI assumed certain of the Predecessor’s intercompany payables and other liabilities of $203.5 million. Subsequent to December 31, 2012, CyrusOne LP executed a 2.8 to 1.0 reverse unit split, resulting in CBI owning 44.1 million operating partnership units. On January 24, 2013, CBI exchanged 1.5 million operating partnership units for common shares of CyrusOne Inc.
	As stock is issued by CyrusOne Inc., CBI's ownership percentage will change. CyrusOne Inc. has issued shares in conjunction with the LTIP discussed in Note 15. Furthermore, on June 25, 2014, CyrusOne Inc. completed a public offering of 16 million shares of its common stock, including 2.1 million shares of common stock issued upon the exercise in full by the underwriters of their option to purchase additional shares, at a price to the public of $23.25 per share, or $371.7 million. CyrusOne Inc. used the proceeds of $355.9 million, net of underwriting discounts of $15.8 million, to acquire 16 million common units of limited partnership interests in the operating partnership from a subsidiary of CBI. As a result, the Company's noncontrolling interest decreased by $166.9 million and CBI's ownership decreased to 40.8% as of December 31, 2014. In addition, the Company's additional paid in capital decreased by $189 million which represents the difference between the proceeds and the noncontrolling interest redeemed by CBI.

Dividends

Dividends	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Dividends	Dividends
	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2014 and 2013 as presented in the table below:
	Record date	Payment date	Cash dividend per share or operating partnership unit
	March 29, 2013	April 15, 2013	$0.16
	June 28, 2013	July 15, 2013	$0.16
	September 27, 2013	October 15, 2013	$0.16
	December 27, 2013	January 10, 2014	$0.16
	March 28, 2014	April 15, 2014	$0.21
	June 27, 2014	July 15, 2014	$0.21
	September 26, 2014	October 15, 2014	$0.21
	December 26, 2014	January 9, 2015	$0.21
	As of December 31, 2014 and 2013 we had a dividend payable of $14.3 million and $10.4 million, respectively. On February 18, 2015, we announced a regular cash dividend of $0.315 per common share payable to shareholders of record as of March 27, 2015. In addition, holders of operating partnership units will also receive a distribution of $0.315 per unit. The dividend and distribution will be paid on April 15, 2015.

Customer_Leases

Customer Leases	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Customer Leases	Customer Leases
	Customer lease arrangements customarily contain provisions that allow either for renewal or continuation on a month-to-month arrangement. Certain leases contain early termination rights. At lease inception, early termination is generally not deemed reasonably assured due to the significant economic penalty incurred by the lessee to exercise its termination right and to relocate its equipment.
	The future minimum lease payments to be received under non-cancelable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below:
	(amounts in millions)
	2015	$	240.8
	2016	176.2
	2017	126.8
	2018	87
	2019	47.3

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans
	Currently, our employees participate in health care plans sponsored by CyrusOne, which provide medical, dental, vision and prescription benefits. We incurred $2.1 million of expenses related to these plans for the year ended December 31, 2014. For the periods ended December 31, 2013 and January 23, 2013, we incurred $1.6 million and $0.1 million, respectively, of expenses related to these plans. Effective with the completion of the IPO on January 24, 2013, we no longer receive an allocated charge from CBI or participate in CBI's sponsored health care plans.
	CyrusOne offers a retirement savings plan to its employees. CyrusOne's matching contribution to its retirement savings plan was $0.8 million for the year ended December 31, 2014, less than $0.5 million for the period ended December 31, 2013, and less than $0.1 million for the period ended January 23, 2013.
	Prior to the IPO, some of our shared employees and retirees participated in CBI’s pension and other benefit plans. CBI managed these plans on a combined basis for all its affiliates and funded all plan contributions. Our employees were also eligible to participate in one of two sponsored defined contribution plans. One of these plans was sponsored by CyrusOne and the other by CBI. Employee contributions to these plans were matched by the sponsoring employer. Our direct and allocated contributions to these plans were $0.4 million for the year ended December 31, 2012.
	In addition, prior to the IPO, some of our shared employees participated in CBI's sponsored health care plans. We were unable to estimate our share of CBI’s liability for claims incurred but not reported or reported but not paid. Our allocated costs of these plans for the year ended December 31, 2012 were $0.1 million.

Loss_per_Share

Loss per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Loss per Share	Loss Per Share
	Basic loss per share is calculated using the weighted average number of shares of common stock outstanding during the period. In addition, net loss applicable to participating securities and the related participating securities are excluded from the computation of basic loss per share.
	Diluted loss per share is calculated using the weighted average number of shares of common stock outstanding during the period, including restricted stock outstanding. If there is net income during the period, the dilutive impact of common stock equivalents outstanding would also be reflected.
	The following table reflects a reconciliation of the shares used in the basic and diluted net loss per share computation for the period ended December 31, 2014:
		Year Ended						Period Ended
		31-Dec-14						31-Dec-13
	(dollars and shares in millions, except per share amounts)	Basic			Diluted			Basic			Diluted
	Numerator:
	Net loss attributed to common shareholders	$	(7.8	)	$	(7.8	)	$	(5.3	)	$	(5.3	)
	Less: Restricted stock dividends	(0.8		)	(0.8		)	(0.6		)	(0.6		)
	Net loss available to shareholders	$	(8.6	)	$	(8.6	)	$	(5.9	)	$	(5.9	)
	Denominator:
	Weighted average common outstanding-basic	29.2			29.2			20.9			20.9
	Performance-based restricted stock(1)(2)				—						—
	Convertible securities(1)(2)				—						—
	Weighted average shares outstanding-diluted				29.2						20.9
	EPS:
	Net loss per share-basic	$	(0.30	)				$	(0.28	)
	Effect of dilutive shares										—
	Net loss per share-diluted				$	(0.30	)				$	(0.28	)
	(1) We have excluded 0.8 million shares of restricted stock, and 34.3 million of operating partnership units which are securities convertible into common stock effective January 2014, from our diluted earnings per share as of December 31, 2014. These amounts were deemed anti-dilutive.
	(2) We have excluded 0.2 million shares of restricted stock, and 42.6 million of operating partnership units which are securities convertible into common stock in January 2014, from our diluted earnings per share as of December 31, 2013. These amounts were deemed anti-dilutive.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans
	In conjunction with the CyrusOne Inc. IPO, the board of directors of CyrusOne Inc. adopted the LTIP. The LTIP is administered by the board of directors. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. CyrusOne Inc. has reserved a total of 4 million shares of CyrusOne Inc. common stock for issuance pursuant to the LTIP, which may be adjusted for changes in capitalization and certain corporate transactions. To the extent that an award, if forfeitable, expires, terminates or lapses, or an award is otherwise settled in cash without the delivery of shares of common stock to the participant, then any unpaid shares subject to the award will be available for future grant or issuance under the LTIP. The payment of dividend equivalents in cash in conjunction with any outstanding awards will not be counted against the shares available for issuance under the LTIP. The related stock compensation expense incurred by CyrusOne Inc. will be allocated to the operating partnership. Shares available under the LTIP at December 31, 2014, were approximately 2 million.
	Restricted Stock
	Restricted stock awards vest over specified periods of time as long as the employee remains employed with the Company. The following table sets forth the number of unvested shares of restricted stock and the weighted average fair value of these shares at the date of grant:
		Shares of Restricted Stock			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	1,024,064			19.01
	Vested	—			—
	Forfeited	(119,712	)		19
	Unvested balance at December 31, 2013	904,352			19.01
	Granted	46,313			20.73
	Vested	(47,845	)		19.17
	Forfeited	(25,948	)		19
	Unvested balance at December 31, 2014	876,872			$	19.09
	During the years ended December 31, 2014 and 2013, we issued 46,313 and 1,024,064 shares of restricted stock, which had an aggregate value of $1.0 million and $19.5 million, respectively, on the grant dates. This amount will be amortized to expense over the respective vesting periods, which are typically three years. Also during the year ended December 31, 2014, 47,845 shares of restricted stock vested at a value of $0.9 million on the respective vesting date.
	As of December 31, 2014, total unearned compensation on restricted stock was $6.0 million and the weighted average vesting period was 1.1 years.
	Performance and Market Based Awards
	In 2014 and 2013, the Company approved grants of performance and market based restricted stock under the LTIP. The performance based restricted stock will vest annually based upon achieving certain predetermined EBITDA thresholds over a three-year cumulative performance period. The performance based awards will vest based on the following scale:
	- Below 90% of EBITDA target =/font>0%
	- At 90% of EBITDA target =/font>50%
	- At 100% of EBITDA target =/font>100%
	- At or above 115% of EBITDA target =/font>200%
	The market based restricted stock vest at the end of three years if the total stockholder return during the three-year measurement period following the grant date meets or exceeds the return of the MSCI US REIT Index (the "Index") over the same period. The market based awards will vest based on the following scale:
	- If CyrusOne's total stockholder return is less than the return of the Index =/font>0%
	- If CyrusOne's total stockholder return is equal to or greater than the return of the Index =/font>100%, up to 200% if CyrusOne's total stockholder return exceeds the return of the Index by 2%
	- If CyrusOne's total stockholder return exceeds the return of the Index, but is negative, any calculated vesting amount will be reduced by 50%
	These awards are expensed based on the grant date fair value based on the performance that is probable to be achieved or based on the performance that is expected to be achieved. The forfeiture rate for these awards was approximately 2.2% and 11.6% during the years ended December 31, 2014 and 2013, respectively.
	The following table sets forth the number of unvested shares of performance and market based awards and the weighted average fair value of these shares at the date of grant:
		Shares of Restricted Stock			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	250,565			23.58
	Vested	—			—
	Forfeited	(28,248	)		23.58
	Unvested balance at December 31, 2013	222,317			23.58
	Granted	672,158			20.65
	Vested	(18,484	)		23.55
	Forfeited	(13,221	)		21.26
	Unvested balance at December 31, 2014	862,770			$	21.33
	During the years ended December 31, 2014 and 2013, we issued 672,158 and 250,565 shares of restricted stock, which had an aggregate value of $13.9 million and $5.9 million, respectively, on the grant dates. This amount will be amortized to expense over the respective vesting periods, which are typically three years. Also during the year ended December 31, 2014, 18,484 shares of restricted stock vested at a value of $0.4 million on the respective vesting date.
	As of December 31, 2014, total unearned compensation on these performance and market based restricted stock was $4.7 million and the weighted average vesting period was 1.8 years.
	Stock Options
	The Company awarded stock options to various executives in 2013. These awards are expensed based on the grant date fair value based on the performance that is probable to be achieved or based on the performance that is expected to be achieved. The fair value of each stock option is estimated using the Black-Scholes option-pricing model. Significant assumptions used in the Black-Scholes model were the following:
	Number of options granted	190,432
	Exercise price	$	23.58
	Expected term (in years)	6
	Expected volatility	35		%
	Expected annual dividend	3.4		%
	Risk-free rate	0.92		%
	Fair value at date of grant	$	1.4	million
	As of December 31, 2014, we have unrecognized compensation expense of approximately $0.2 million. This expense will be recognized over the remaining vesting period, or approximately 1.2 years. The exercise price for these options is $23.58.
	The following table sets forth the number of unvested options as of December 31, 2014 and 2013 and the weighted average fair value of these options at the grant date:
		Shares of Restricted Options			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	190,432			7.46
	Vested	—			—
	Forfeited	(21,469	)		7.46
	Unvested balance at December 31, 2013	168,963			7.46
	Granted	—			—
	Vested	—			—
	Forfeited	(2,091	)		7.46
	Unvested balance at December 31, 2014	166,872			$	7.46
	The following tables set forth the number of exercisable options as of December 31, 2014 and the weighted average fair value and exercise price of these options at the grant date:
		Shares of Restricted Options			Weighted Average Fair Value at Date of Grant
	Options Exercisable at December 31, 2013	—			$	—
Vested	13,915			7.46
Exercised	—			—
Options Exercisable at December 31, 2014	13,915			$	7.46
	Exercisable Options			Fair Value at Date of Grant			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
As of December 31, 2014	13,915			$	0.1	million	$	23.58	8.3 years
The following table sets forth compensation expense for the year ended December 31, 2014 and the period ended December 31, 2013:
	Year Ended				Period Ended
	31-Dec-14				31-Dec-13
Restricted Stock	$	6.4			$	5.3
Performance and market based awards	3.7				0.8
Stock options	0.2				0.1
Total compensation expense	$	10.3			$	6.2

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	Prior to November 20, 2012, CyrusOne Inc., CyrusOne GP, CyrusOne LP and its subsidiaries were operated by CBI during the periods presented. The consolidated and combined financial statements have been prepared from the records maintained by CBI and may not necessarily be indicative of the conditions that would have existed or the results of operations that would have occurred if the business had been operated as an unaffiliated company. The consolidated and combined financial statements reflect the following transactions with CBI and its affiliated entities, including Cincinnati Bell Telephone (“CBT”) and Cincinnati Bell Technology Solutions (“CBTS”):
	Revenues—The Company records revenues from CBI under contractual service arrangements. These services include leasing of data center space, power and cooling in certain of our data center facilities network interface services and office space.
	Operating Expenses—The Company records expenses from CBI incurred in relation to network support, services calls, monitoring and management, storage and backup, IT systems support, and connectivity services.
	The following related party transactions are based on agreements and arrangements that were in place during the respective periods. Revenues and expenses for the periods presented were as follows:
		Successor				Predecessor
	(amounts in millions)	31-Dec-14		January 24, 2013 to December 31, 2013		January 1, 2013 to January 23, 2013		31-Dec-12
	Revenue:
	Data center colocation agreement provided to CBT and CBTS	$	6.4	$	5.6	$	0.3	$	5.4
	229 West 7th Street lease provided to CBT	2		1.7		—		—
	Goldcoast Drive/Parkway (Mason) lease	0.4		0.3		—		0.3
	Transition services provided to CBTS (network interfaces)	0.4		0.6		0.1		0.5
	Data center leases provided to CBTS	13.6		13.1		—		14.3
	Total revenue	$	22.8	$	21.3	$	0.4	$	20.5
	Operating costs and expenses:
	Transition services agreement by CBTS	$	0.8	$	1.3	$	—	$	1.5
	Charges for services provided by CBT (connectivity)	1		1		0.1		0.7
	209 West 7th Street rent provided by CBT	0.2		0.1		—		0.1
	Management fees with CBI	—		0.1		—		2.5
	Allocated employee benefit plans by CBI	—		—		0.2		3.5
	Allocated centralized insurance costs by CBI	—		—		0.1		0.4
	Selling and marketing services provided by CBT & CBTS	—		—		—		0.3
	Interest expense on note with CBI	—		—		—		7
	Loss on sale of receivables	—		—		—		3.2
	Total operating costs and expenses	$	2	$	2.5	$	0.4	$	19.2
	As of December 31, 2014 and 2013, the amounts receivable and payable to CBI were as follows:
		Successor		Successor
		As of		As of
	(amounts in millions)	December 31, 2014		December 31, 2013
	Accounts receivable from CBI	$	0.8	$	0.6
	Accounts payable	$	1.7	$	1.7
	Dividends payable	5.6		6.8
	Accounts payable to CBI	$	7.3	$	8.5
	The dividends payable as of December 31, 2014 reflect the balance due to CBI related to the dividend declared on November 4, 2014, of $0.21 per common share equivalent payable on their limited partnership units.
	Other Related Party Transactions
	Prior to joining CyrusOne in March 2013, our internal counsel was principal in the Law Offices of Thomas W. Bosse, PLLC, (“Bosselaw”).  In 2013, amounts paid to Bosselaw for services rendered prior to his employment were $1.6 million, which included a bonus payment under CyrusOne’s Data Center Plan as a result of the successful completion of the initial public offering.
	In the ordinary course of its business, CyrusOne periodically pays brokerage commissions to real estate brokerage firms in connection with property transactions and tenant leases.  In 2013, CyrusOne paid $1.5 million to one such firm, Jones Lang LaSalle.  One of our former directors is a principal with Jones Lang LaSalle.
	The spouse of one of our directors is a partner with Skadden, Arps, Slate, Meagher & Flom LLP ("Skadden"). For the years ended December 31, 2014 and December 31, 2013, CyrusOne paid Skadden $1.1 million and $0.2 million, respectively, for services rendered.
	Our director, Lynn A. Wentworth, is a member of the board of directors of CBI, and serves as the chair of its audit committee.

Restructuring_Charges

Restructuring Charges	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges
	For the years ended December 31, 2014 and 2012, we incurred no restructuring charges. For the period ended December 31, 2013, we incurred restructuring charges of $0.7 million that were a result of moving certain administrative functions to the corporate office. All restructuring charges have been settled by December 31, 2014.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	CyrusOne Inc., elected to be taxed as a REIT under the Code, as amended, commencing with our taxable year ended December 31, 2013. To remain qualified as a REIT, we are required to distribute at least 90% of our taxable income to our stockholders and meet various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we qualify for taxation as a REIT, we are generally not subject to corporate level federal income tax on the taxable income distributed currently to our shareholders. It is our policy and intent, subject to change, to distribute 100% of our taxable income and therefore no provision is required in the accompanying financial statements for federal income taxes with regards to activities of the CyrusOne Inc. and its subsidiary pass-through entities.
	We have elected to designate two subsidiaries as TRSs. A TRS may perform services for our tenants that would otherwise be considered impermissible for REITs. The income generated from these services is taxed at regular federal and state corporate rates. Income tax expense for the year ended December 31, 2014 and the periods ended December 31, 2013 and January 23, 2013 was $1.4 million, $1.9 million and $0.4 million, respectively. For the year ended December 31, 2012, we recognized income tax benefit of $5.1 million.
	In conjunction with the Company’s tax sharing arrangement with CBI, CBI may be required to file Texas margin tax returns on a consolidated, combined or unitary basis with the Company for any given year.   If such return is prepared by CBI on a combined or consolidated basis to include the Company, the related Texas margin tax of the Company will be paid by CBI. The Company will then reimburse CBI for its portion of the related Texas margin tax.  As of December 31, 2014, our total Texas margin tax payable was $1.7 million.
	For certain entities we calculate deferred tax assets and liabilities for temporary differences in the basis between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards. Deferred tax assets (net of valuation allowance) and liabilities were accrued, as necessary, for the periods ended December 31, 2014, and December 31, 2013. Historically, we have recorded a full valuation allowance on our foreign net deferred tax assets related to our foreign generated net operating losses due to the uncertainty of their realization. In 2013 and 2014, management determined it was necessary to record a full valuation allowance on all of our domestic and foreign net deferred tax assets due to the uncertainty of their realization. Accordingly, at December 31, 2014 and at December 31, 2013, the net domestic and foreign deferred tax assets were zero.
	In 2014 and 2013, we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the year ended December 31, 2014 and the period ended December 31, 2013:
		Year Ended		Period Ended
		31-Dec-14		31-Dec-13
	Common Stock dividend per share:
	Ordinary income	$	0.45	$	0.23
	Capital gains	—		—
	Return of capital	0.34		0.25
	Total dividend	$	0.79	$	0.48
	Common stock dividends are characterized for federal income tax purposes as ordinary income, qualified dividend, capital gains, non-taxable return of capital or a combination of the four. Common stock dividends that exceed our current and accumulated earnings and profits (calculated for tax purposes) constitute a return of capital rather than a dividend and generally reduce the stockholder's basis in the common stock. To the extent that a dividend exceeds both current and accumulated earnings and profits and the stockholder's basis in the common stock, it will generally be treated as a gain from the sale or exchange of that stockholder's common stock. At the beginning of each year, we notify our stockholders of the taxability of the common stock dividends paid during the preceding year.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Operating Leases
	We lease certain data center facilities and equipment from third parties. Operating lease expense was $6.7 million, $6.5 million, $0.2 million and $5.9 million for the year ended December 31, 2014, and the periods ended December 31, 2013 and January 23, 2013, and the year ended December 31, 2012, respectively. Certain of these leases provide for renewal options with fixed rent escalations beyond the initial lease term.
	At December 31, 2014, future minimum lease payments required under operating leases having initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(amounts in millions)
	2015	$	4.6
	2016	1.4
	2017	0.9
	2018	0.2
	2019	—
	Thereafter	0.9
	Total	$	8
	Performance Guarantees
	Customer contracts generally require specified levels of performance related to uninterrupted service and cooling temperatures. If these performance standards are not met, we could be obligated to issue billing credits to the customer. Management assesses the probability that a performance standard will not be achieved. As of December 31, 2014 and 2013, no accruals for performance guarantees were required.
	Indemnifications
	During the normal course of business, CyrusOne has made certain indemnities, commitments and guarantees under which it may be required to make payments in relation to certain transactions. These include (i) intellectual property indemnities to customers in connection with the use, sale, and/or license of products and services, (ii) indemnities to vendors and service providers pertaining to claims based on negligence or willful misconduct and (iii) indemnities involving the representations and warranties in certain contracts. The majority of these indemnities, commitments and guarantees do not provide for any limitation on the maximum potential for future payments that we could be obligated to make.
	Purchase Commitments
	CyrusOne has non-cancelable purchase commitments related to certain services and contracts related to construction of data center facilities and equipment. These agreements range from one to two years and provide for payments for early termination or require minimum payments for the remaining term. As of December 31, 2014, the minimum commitments for these arrangements were $19.9 million.
	Contingencies
	CyrusOne is involved in legal, tax and regulatory proceedings arising from the conduct of its business activities. Liabilities are established for loss contingencies when losses associated with such claims are deemed to be probable, and the loss can be reasonably estimated. Based on information currently available and consultation with legal counsel, we believe that the outcome of all claims will not, individually or in the aggregate, have a material effect on our financial statements.

Guarantors

Guarantors	12 Months Ended
	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Guarantors	Guarantors
	CyrusOne Inc.
	CyrusOne LP and CyrusOne Finance Corp., as “LP Co-issuer” and “Finance Co-issuer,” respectively (together, the “Issuers”), had $374.8 million aggregate principal amount of senior notes outstanding at December 31, 2014 and $525 million as of December 31, 2013. The senior notes are fully and unconditionally and jointly and severally guaranteed on a senior basis by CyrusOne Inc. (“Parent Guarantor”), CyrusOne GP (“General Partner”), and CyrusOne LP’s 100% owned subsidiaries, CyrusOne LLC, CyrusOne TRS Inc. and CyrusOne Foreign Holdings LLC (such subsidiaries, together the “Guarantors”). None of the subsidiaries organized outside of the United States (collectively, the “Non-Guarantors”) guarantee the senior notes. Subject to the provisions of the indenture governing the senior notes, in certain circumstances, a Guarantor may be released from its guarantee obligation, including:
	•	upon the sale or other disposition (including by way of consolidation or merger) of such Guarantor or of all of the capital stock of such Guarantor such that such Guarantor is no longer a restricted subsidiary under the indenture,
	•	upon the sale or disposition of all or substantially all of the assets of the Guarantor,
	•	upon the LP Co-issuer designating such Guarantor as an unrestricted subsidiary under the terms of the indenture,
	•	if such Guarantor is no longer a guarantor or other obligor of any other indebtedness of the LP Co-issuer or the Parent Guarantor, and
	•	upon the defeasance or discharge of the senior notes in accordance with the terms of the indenture.
	The following provides information regarding the entity structure of each guarantor of the senior notes:
	CyrusOne Inc. – CyrusOne Inc. was formed on July 31, 2012. As of January 23, 2013, CyrusOne Inc. was a wholly-owned subsidiary of CBI. Effective January 24, 2013, CyrusOne Inc. completed its IPO of common stock for net proceeds of $337.1 million, and together with the General Partner, purchased a 33.9% ownership interest in CyrusOne LP. CyrusOne Inc. also represents a guarantor or Parent Guarantor and became a separate registrant with the SEC upon completion of its IPO.
	CyrusOne GP – CyrusOne GP was formed on July 31, 2012, and was a 100% owned subsidiary of CyrusOne Inc. as of January 23, 2013. Effective upon completion of CyrusOne Inc.’s IPO, this entity became the general partner and 1% owner of CyrusOne LP and has no other assets or operations. Prior to the IPO, this entity did not incur any obligations or record any transactions.
	Issuers – The Issuers include CyrusOne LP and CyrusOne Finance Corp. CyrusOne Finance Corp., a 100% owned subsidiary of CyrusOne LP, was formed for the sole purpose of acting as co-issuer of the senior notes and has no other assets or operations. CyrusOne LP, in addition to being the co-issuer of the senior notes, is also the 100% owner, either directly or indirectly, of the Guarantors and Non-Guarantors.
	Guarantors – The guarantors include CyrusOne LLC, CyrusOne TRS Inc., and CyrusOne Foreign Holdings LLC. CyrusOne LLC accounts for all of the domestic operations of CyrusOne LP, including the businesses that composed the Predecessor operations. CyrusOne LLC, together with CyrusOne Foreign Holdings LLC, directly or indirectly owns 100% of the Non-Guarantors. As of December 31, 2014, CyrusOne TRS Inc. had not incurred any obligations or recorded any material transactions for the period ended December 31, 2014, and January 23, 2013.
	As of December 31, 2014, the Non-Guarantors consist of 100% owned subsidiaries, which conduct operations in the United Kingdom and Singapore.
	The following schedules present the financial information for the year ended December 31, 2014, periods ended December 31, 2013 and January 23, 2013, and the year ended December 31, 2012, for the Parent Guarantor, General Partner, LP Co-issuer, Finance Co-issuer, Guarantors, and Non-Guarantors. The financial statements for the period ended January 23, 2013, present the financial information prior to the effective date of the IPO, and the financial statements for the period ended December 31, 2013, present the financial information after the effective date of the IPO. The consolidating schedules are provided in accordance with the reporting requirements for guarantor subsidiaries.
	(1) - During 2014, the Company revised its Guarantor Condensed Consolidated Balance Sheets, Condensed Consolidating Statements of Income, and Condensed Consolidating Statement of Cash Flows to correct an immaterial error in the prior periods. Previously, the Investment in Subsidiaries and Equity Loss related to Investment in Subsidiaries reported by the Parent Guarantors included amounts related to noncontrolling interests. Those noncontrolling interest amounts are now reported in the Eliminations/Consolidations column. The impact of those changes was to (a) reduce the investments in subsidiaries and total equity for the Parent Guarantor by $455.6 million as of December 31, 2013; (b) reduce the equity loss related to investment in subsidiaries and noncontrolling interest in net loss for the Parent Guarantor by $10.3 million for the period ended December 31, 2013; (c) reduce the net loss and the equity loss related to investment in subsidiaries for the Parent Guarantor by $10.3 million in the statement of cash flows for the period ended December 31, 2013; and (d) reduce the dividends paid by the Parent Guarantor by $20.4 million in the statement of cash flows for the period ended December 31, 2013. These errors had no effect on the consolidated financials of either CyrusOne Inc. or CyrusOne LP and is not material to the consolidated financial statements taken as a whole.
	Consolidating Balance Sheets
			As of December 31, 2014
	(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
			Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
	Land		$	—		$	—		$	—		$	—		$	89.7		$	—		$	—		$	89.7
	Buildings and improvements		—			—			—			—			770.9			41.7			—			812.6
	Equipment		—			—			—			—			348.3			0.8			—			349.1
	Construction in progress		—			—			—			—			124.8			—			2.2			127
	Subtotal		—			—			—			—			1,333.70			42.5			2.2			1,378.40
	Accumulated depreciation		—			—			—			—			(319.7		)	(7.3		)	—			(327.0		)
	Net investment in real estate		—			—			—			—			1,014.00			35.2			2.2			1,051.40
	Cash and cash equivalents		—			—			—			—			33.5			3			—			36.5
	Investment in subsidiaries		458.5			7.1			734.3			—			3.6			—			(1,203.5		)	—
	Rent and other receivables		—			—			—			—			57.9			3			—			60.9
	Intercompany receivable		—			—			642.9			—			—			—			(642.9		)	—
	Goodwill		—			—			—			—			276.2			—			—			276.2
	Intangible assets, net		—			—			—			—			68.9			—			—			68.9
	Due from affiliates		—			—			—			—			0.8			—			—			0.8
	Other assets		—			—			15.5			—			73.1			3.2			—			91.8
	Total assets		$	458.5		$	7.1		$	1,392.70		$	—		$	1,528.00		$	44.4		$	(1,844.2	)	$	1,586.50
	Accounts payable and accrued expenses		$	—		$	—		$	12.5		$	—		$	56.9		$	0.5		$	—		$	69.9
	Deferred revenue		—			—			—			—			65.1			0.6			—			65.7
	Intercompany payable		—			—			—			—			642.9			—			(642.9		)	—
	Due to affiliates		—			—			5.6			—			1.7			—			—			7.3
	Capital lease obligations		—			—			—			—			6.2			7.2			—			13.4
	Long-term debt		—			—			659.8			—			—			—			—			659.8
	Other financing arrangements		—			—			—			—			20.9			32.5			—			53.4
	Total liabilities		—			—			677.9			—			793.7			40.8			(642.9		)	869.5
	Total shareholders' equity		458.5			7.1			714.8			—			734.3			3.6			(1,457.6		)	460.7
	Noncontrolling interest		—			—			—			—			—			—			256.3			256.3
	Total equity		458.5			7.1			714.8			—			734.3			3.6			(1,201.3		)	717
	Total liabilities and equity		$	458.5		$	7.1		$	1,392.70		$	—		$	1,528.00		$	44.4		$	(1,844.2	)	$	1,586.50
			As of December 31, 2013
	(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
			Guarantor(1)			Partner			Co-issuer			Co-issuer						Guarantors
	Land		$	—		$	—		$	—		$	—		$	89.3		$	—		$	—		$	89.3
	Buildings and improvements		—			—			—			—			739.6			44.1			—			783.7
	Equipment		—			—			—			—			189.4			0.8			—			190.2
	Construction in progress		—			—			—			—			57.3			—			—			57.3
	Subtotal		—			—			—			—			1,075.60			44.9			—			1,120.50
	Accumulated depreciation		—			—			—			—			(232.0		)	(4.7		)	—			(236.7		)
	Net investment in real estate		—			—			—			—			843.6			40.2			—			883.8
	Cash and cash equivalents		—			—			—			—			146.8			2			—			148.8
	Investment in subsidiaries		322			7.8			795			—			2.1			—			(1,126.9		)	—
	Rent and other receivables		—			—			—			—			40.3			0.9			—			41.2
	Intercompany receivable		—			—			508.1			—			0.2			—			(508.3		)	—
	Goodwill		—			—			—			—			276.2			—			—			276.2
	Intangible assets, net		—			—			—			—			85.9			—			—			85.9
Due from affiliates		—			—			—			—			0.6			—			—			0.6
Other assets		—			—			14.1			—			53			3.2			—			70.3
Total assets		$	322		$	7.8		$	1,317.20		$	—		$	1,448.70		$	46.3		$	(1,635.2	)	$	1,506.80
Accounts payable and accrued expenses		$	—		$	—		$	7.8		$	—		$	58.6		$	0.4		$	—		$	66.8
Deferred revenue		—			—			—			—			55.1			0.8			—			55.9
Intercompany payable		—			—			—			—			508.1			0.2			(508.3		)	—
Due to affiliates		—			—			6.8			—			1.7			—			—			8.5
Capital lease obligations		—			—			—			—			8.6			8.1			—			16.7
Long-term debt		—			—			525			—			—			—			—			525
Other financing arrangements		—			—			—			—			21.6			34.7			—			56.3
Total liabilities		—			—			539.6			—			653.7			44.2			(508.3		)	729.2
Total shareholders' equity		322			7.8			777.6			—			795			2.1			(1,582.5		)	322
Noncontrolling interest		—			—			—			—			—			—			455.6			455.6
Total equity		322			7.8			777.6			—			795			2.1			(1,126.9		)	777.6
Total liabilities and equity		$	322		$	7.8		$	1,317.20		$	—		$	1,448.70		$	46.3		$	(1,635.2	)	$	1,506.80
Consolidating Statements of Operations
	Year Ended December 31, 2014
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	—		$	—		$	325.1		$	5.8		$	—		$	330.9
Costs and expenses:
Property operating expenses		—			—			—			—			121.9			2.6			—			124.5
Sales and marketing		—			—			—			—			12.6			0.2			—			12.8
General and administrative		—			—			—			—			34.2			0.4			—			34.6
Depreciation and amortization		—			—			—			—			115			3			—			118
Transaction costs		—			—			—			—			1			—			—			1
Total costs and expenses		—			—			—			—			284.7			6.2			—			290.9
Operating income (loss)		—			—			—			—			40.4			(0.4		)	—			40
Interest expense		—			—			38.2			—			—			3.5			(2.2		)	39.5
Loss on extinguishment of debt		—			—			13.6			—			—			—			—			13.6
(Loss) income before income taxes		—			—			(51.8		)	—			40.4			(3.9		)	2.2			(13.1		)
Income tax expense		—			—			—			—			(1.4		)	—			—			(1.4		)
Equity (loss) earnings related to investment in subsidiaries		(10.0		)	(0.2		)	35.1			—			(3.9		)	—			(21.0		)	—
Net loss		(10.0		)	(0.2		)	(16.7		)	—			35.1			(3.9		)	(18.8		)	(14.5		)
Noncontrolling interest in net loss		—			—			—			—			—			—			(6.7		)	(6.7		)
Net (loss) income attributed to common shareholders		$	(10.0	)	$	(0.2	)	$	(16.7	)	$	—		$	35.1		$	(3.9	)	$	(12.1	)	$	(7.8	)
	Period Ended December 31, 2013
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor(1)			Partner			Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	—		$	—		$	244.3		$	4.1		$	—		$	248.4
Costs and expenses:
Property operating expenses		—			—			—			—			85.9			2.5			—			88.4
Sales and marketing		—			—			—			—			9.7			0.2			—			9.9
General and administrative		—			—			—			—			26.3			0.2			—			26.5
Depreciation and amortization		—			—			—			—			87.1			2.8			—			89.9
Restructuring charges		—			—			—			—			0.7			—			—			0.7
Transaction costs		—			—			—			—			1.3			—			—			1.3
Asset impairment		—			—			—			—			2.8			—			—			2.8
Total costs and expenses		—			—			—			—			213.8			5.7			—			219.5
Operating income (loss)		—			—			—			—			30.5			(1.6		)	—			28.9
Interest expense		—			—			36.5			—			1.8			2.9			—			41.2
Other income		—			—			—			—			(0.1		)	—			—			(0.1		)
Loss on extinguishment of debt		—			—			—			—			1.3			—			—			1.3
(Loss) income before income taxes		—			—			(36.5		)	—			27.5			(4.5		)	—			(13.5		)
Income tax expense		—			—			—			—			(1.9		)	—			—			(1.9		)
Equity (loss) earnings related to investment in subsidiaries		(5.3		)	(0.2		)	20.9			—			(4.5		)	—			(10.9		)	—
Loss on sale of real estate improvements		—			—			—			—			(0.2		)	—			—			(0.2		)
Net loss		(5.3		)	(0.2		)	(15.6		)	—			20.9			(4.5		)	(10.9		)	(15.6		)
Noncontrolling interest in net loss		—			—			—			—			—			—			(10.3		)	(10.3		)
Net (loss) income attributed to common shareholders		$	(5.3	)	$	(0.2	)	$	(15.6	)	$	—		$	20.9		$	(4.5	)	$	(0.6	)	$	(5.3	)
		Period Ended January 23, 2013
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	—		$	—		$	14.9		$	0.2		$	—		$	15.1
Costs and expenses:
Property operating expenses		—			—			—			—			4.8			—			—			4.8
Sales and marketing		—			—			—			—			0.7			—			—			0.7
General and administrative		—			—			—			—			1.4			0.1			—			1.5
Transaction-related compensation		—			—			—			—			20			—			—			20
Depreciation and amortization		—			—			—			—			5.2			0.1			—			5.3
Transaction costs		—			—			—			—			0.1			—			—			0.1
Total costs and expenses		—			—			—			—			32.2			0.2			—			32.4
Operating loss		—			—			—			—			(17.3		)	—			—			(17.3		)
Interest expense		—			—			2.3			—			0.1			0.1			—			2.5
Loss before income taxes		—			—			(2.3		)	—			(17.4		)	(0.1		)	—			(19.8		)
Income tax expense		—			—			—			—			(0.4		)	—			—			(0.4		)
Equity loss related to investment in subsidiaries		—			—			(17.9		)	—			(0.1		)	—			18			—
Net loss		$	—		$	—		$	(20.2	)	$	—		$	(17.9	)	$	(0.1	)	$	18		$	(20.2	)
		Year Ended December 31, 2012
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	—		$	—		$	219.4		$	1.4		$	—		$	220.8
Costs and expenses:
Property operating expenses		—			—			—			—			74.1			1.9			—			76
Sales and marketing		—			—			—			—			9.5			0.2			—			9.7
General and administrative		—			—			—			—			20.6			0.1			—			20.7
Depreciation and amortization		—			—			—			—			71.9			1.5			—			73.4
Transaction costs		—			—			5.7			—			—			—			—			5.7
Management fees charged by CBI		—			—			—			—			2.5			—			—			2.5
Loss on sale of receivables to an affiliate		—			—			—			—			3.2			—			—			3.2
Asset impairment		—			—			—			—			13.3			—			—			13.3
Total costs and expenses		—			—			5.7			—			195.1			3.7			—			204.5
Operating (loss) income		—			—			(5.7		)	—			24.3			(2.3		)	—			16.3
Interest expense		—			—			4.2			—			35			2.6			—			41.8
Loss before income taxes		—			—			(9.9		)	—			(10.7		)	(4.9		)	—			(25.5		)
Income tax benefit		—			—			—			—			5.1			—			—			5.1
Equity loss related to investment in subsidiaries		—			—			(10.4		)	—			(4.9		)	—			15.3			—
Gain on sale of real estate improvements		—			—			—			—			0.1			—			—			0.1
Net loss		$	—		$	—		$	(20.3	)	$	—		$	(10.4	)	$	(4.9	)	$	15.3		$	(20.3	)
Consolidating Statements of Cash Flows
		Year Ended December 31, 2014
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(10.0	)	(0.2		)	$	(16.7	)	$	—		35.1			$	(3.9	)	$	(18.8	)	$	(14.5	)
Equity earnings (loss) related to investment in subsidiaries		10			0.2			(35.1		)	—			3.9			—			21			—
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities:
Depreciation and amortization		—			—			—			—			115			3			—			118
Stock-based compensation expense		—			—			—			—			10.3			—			—			10.3
Noncash interest expense		—			—			3.4			—			—			—			—			3.4
Provision for bad debt write off		—			—			—			—			0.8			—			—			0.8
Loss on extinguishment of debt		—			—			13.6			—			—			—			—			13.6
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		—			—			0.4			—			(35.3		)	(2.1		)	—			(37.0		)
Accounts payable and accrued expenses		—			—			4.7			—			2.1			0.1			—			6.9
Payables to related parties		—			—			—			—			(0.2		)	—			—			(0.2		)
Deferred revenue		—			—			—			—			10			(0.2		)	—			9.8
Net cash (used in) provided by operating activities		—			—			(29.7		)	—			141.7			(3.1		)	2.2			111.1
Cash flows from investing activities:
Capital expenditures - other		—			—			—			—			(283.9		)	(0.3		)	—			(284.2		)
Return of investment		25.2			—			97.3			—			(45.4		)	—			(77.1		)	—
Intercompany receipts		—			—			180.2			—			—			—			(180.2		)	—
Intercompany distributions		—			—			(315.0		)	—			—			—			315			—
Net cash provided by (used in) investing activities		25.2			—			(37.5		)	—			(329.3		)	(0.3		)	57.7			(284.2		)
Cash flows from financing activities:
Issuance of common stock		356			—			—			—			—			—			—			356
Stock issuance costs		(1.3		)	—			—			—			—			—			—			(1.3		)
Acquisition of operating partnership units		(355.9		)	—			—			—			—			—			—			(355.9		)
Dividends paid		(24.0		)	—			(50.9		)	—			(50.9		)	—			74.9			(50.9		)
Intercompany borrowings		—			—			—			—			315			—			(315.0		)	—
Intercompany payments		—			—			—			—			(180.2		)	—			180.2			—
Borrowings from revolving credit agreement		—			—			315			—			—			—			—			315
Payments on revolving credit facility		—			—			(30.0		)	—			—			—			—			(30.0		)
Payments on senior notes		—			—			(150.2		)	—			—			—			—			(150.2		)
Payments on capital lease obligations		—			—			—			—			(2.4		)	(0.6		)	—			(3.0		)
Payments on financing obligations		—			—			—			—			(0.7		)	(0.2		)	—			(0.9		)
Payment of debt extinguishment costs		—			—			(12.8		)	—			—			—			—			(12.8		)
Contributions from/(distributions to) parent, net		—			—			1.3			—			(6.5		)	5.2			—			—
Debt issuance costs		—			—			(5.2		)	—			—			—			—			(5.2		)
Net cash (used in) provided by financing activities		(25.2		)	—			67.2			—			74.3			4.4			(59.9		)	60.8
Net (decrease) increase in cash and cash equivalents		—			—			—			—			(113.3		)	1			—			(112.3		)
Cash and cash equivalents at beginning of period		—			—			—			—			146.8			2			—			148.8
Cash and cash equivalents at end of period		$	—		$	—		$	—		$	—		$	33.5		$	3		$	—		$	36.5
		Period Ended December 31, 2013
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor(1)			Partner			Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(5.3	)	(0.2		)	$	(15.6	)	$	—		20.9			$	(4.5	)	$	(10.9	)	$	(15.6	)
Equity earnings (loss) related to investment in subsidiaries		5.3			0.2			(20.9		)	—			4.5			—			10.9			—
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities:
Depreciation and amortization		—			—			—			—			87.1			2.8			—			89.9
Stock-based compensation expense		—			—			—			—			6			—			—			6
Noncash interest expense		—			—			4			—			—			—			—			4
Provision for bad debt write off		—			—			—			—			0.4			—			—			0.4
Loss on extinguishment of debt		—			—			—			—			1.3			—			—			1.3
Asset impairments		—			—			—			—			2.8			—			—			2.8
Deferred income tax expense		—			—			—			—			0.6			—			—			0.6
Other, net		(7.1		)	—			(13.4		)	—			(16.2		)	—			36.7			—
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		9.4			—			—			—			(9.9		)	(3.0		)	(12.2		)	(15.7		)
Accounts payable and accrued expenses		(2.3		)	—			4.8			—			0.2			0.3			(17.6		)	(14.6		)
Payables to related parties		—			—			6.8			—			18.4			—			(6.8		)	18.4
Deferred revenue		—			—			—			—			(0.3		)	0.2			—			(0.1		)
Net cash provided by (used in) operating activities		—			—			(34.3		)	—			115.8			(4.2		)	0.1			77.4
Cash flows from investing activities:
Capital expenditures - acquisitions of real estate		—			—			—			—			(48.0		)	—			—			(48.0		)
Capital expenditures - other		—			—			—			—			(172.9		)	—			—			(172.9		)
Investment in subsidiaries		(337.1		)	—			(337.1		)	—			—			—			674.2			—
Release of restricted cash		—			—			—			—			4.4			—			—			4.4
Return of investment		10.6			—			66.5			—			—			—			(77.1		)	—
Other, net		—			—			—			—			(0.2		)	—			—			(0.2		)
Net cash (used in) provided by investing activities		(326.5		)	—			(270.6		)	—			(216.7		)	—			597.1			(216.7		)
Cash flows from financing activities:
Issuance of common stock/partnership units		360.5			—			337.1			—			—			—			(337.1		)	360.5
IPO costs		(23.4		)	—			—			—			(3.2		)	—			—			(26.6		)
Dividends paid		(10.6		)	—			(31.0		)	—			(31.0		)	—			41.6			(31.0		)
Payments on capital leases		—			—			—			—			(4.4		)	(0.9		)	—			(5.3		)
Other financing arrangements		—			—			—			—			(0.5		)	(0.2		)	—			(0.7		)
Payments to buyout capital leases		—			—			—			—			(9.6		)	—			—			(9.6		)
Payment to buyout other financing arrangement		—			—			—			—			(10.2		)	—			—			(10.2		)
Contributions from parent guarantor		—			—			—			—			295.4			6.3			(301.7		)	—
Debt issuance costs		—			—			(1.3		)	—			—			—			—			(1.3		)
Net cash provided by (used in) financing activities		326.5			—			304.8			—			236.5			5.2			(597.2		)	275.8
Net (decrease) increase in cash and cash equivalents		—			—			(0.1		)	—			135.6			1			—			136.5
Cash and cash equivalents at beginning of period		—			—			0.1			—			11.2			1			—			12.3
Cash and cash equivalents at end of period		$	—		$	—		$	—		$	—		$	146.8		$	2		$	—		$	148.8
		Period Ended January 23, 2013
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	—		—			$	(20.2	)	—			$	(17.9	)	(0.1		)	$	18		$	(20.2	)
Equity loss related to investment in subsidiaries		—			—			17.9			—			0.1			—			(18.0		)	—
Adjustments to reconcile net (loss) income to net cash provided by operating activities		—			—			0.2			—			5.6			0.1			—			5.9
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		—			—			—			—			(9.6		)	—			—			(9.6		)
Accounts payable and accrued expenses		—			—			2.1			—			18.4			—			—			20.5
Payables to related parties		—			—			—			—			1.5			—			—			1.5
Other changes in assets and liabilities		—			—			—			—			3.8			0.1			—			3.9
Net cash provided by operating activities		—			—			—			—			1.9			0.1			—			2
Cash flows from investing activities:
Capital expenditures - other		—			—			—			—			(7.7		)	—			—			(7.7		)
Release of restricted cash		—			—			—			—			1.9			—			—			1.9
Intercompany advances, net		—			—			0.1			—			(0.1		)	—			—			—
Net cash provided by (used in) investing activities		—			—			0.1			—			(5.9		)	—			—			(5.8		)
Cash flows from financing activities:
Payments on capital lease obligations		—			—			—			—			(0.6		)	—			—			(0.6		)
Contributions from parent, net		—			—			—			—			0.2			—			—			0.2
Net cash used in financing activities		—			—			—			—			(0.4		)	—			—			(0.4		)
Net increase (decrease) in cash and cash equivalents		—			—			0.1			—			(4.4		)	0.1			—			(4.2		)
Cash and cash equivalents at beginning of period		—			—			—			—			15.6			0.9			—			16.5
Cash and cash equivalents at end of period		$	—		$	—		$	0.1		$	—		$	11.2		$	1		$	—		$	12.3
		Year Ended December 31, 2012
(amounts in millions)		Parent			General			LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Guarantor			Partner			Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	—		$	—		$	(20.3	)	$	—		$	(10.4	)	$	(4.9	)	$	15.3		$	(20.3	)
Equity loss related to investment in subsidiaries		—			—			10.4			—			4.9			—			(15.3		)	—
Adjustments to reconcile net (loss) income to net cash provided by operating activities		—			—			0.2			—			83.9			1.5			—			85.6
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		(7.9		)	—			—			—			(15.5		)	(0.6		)	—			(24.0		)
Accounts payable and accrued expenses		0.8			—			4.4			—			(5.5		)	(0.3		)	—			(0.6		)
Increase in deferred revenues		—			—			—			—			3.3			0.5			—			3.8
Net cash ( used in) provided by operating activities		(7.1		)	—			(5.3		)	—			60.7			(3.8		)	—			44.5
Cash flows from investing activities:
Capital expenditures - acquisitions of real estate		—			—			—			—			(25.1		)	(0.3		)	—			(25.4		)
Capital expenditures - other		—			—			—			—			(202.9		)	—			—			(202.9		)
Proceeds from sale of assets		—			—			—			—			0.2			—			—			0.2
Increase in restricted cash		—			—			—			—			(11.1		)	—			—			(11.1		)
Release of restricted cash		—			—			—			—			4.8			—			—			4.8
Advances to affiliate		—			—			—			—			(18.3		)	—			—			(18.3		)
Intercompany advances, net		—			—			(508.2		)	—			508.1			0.1			—			—
Other, net		—			—			—			—			0.1			—			—			0.1
Net cash (used in) provided by investing activities		—			—			(508.2		)	—			255.8			(0.2		)	—			(252.6		)
Cash flows from financing activities:
Borrowings from affiliates, net		—			—			—			—			119.8			—			—			119.8
Repayment of related party note		—			—			—			—			(400.0		)	—			—			(400.0		)
Proceeds from issuance of debt		—			—			525			—			—			—			—			525
Payment on capital lease obligations		—			—			—			—			(8.4		)	(0.6		)	—			(9.0		)
Debt issuance costs		—			—			(17.2		)	—			—			—			—			(17.2		)
Contributions from (distribution to) parent, net		7.1			—			5.7			—			(12.7		)	5.3			—			5.4
Net cash provided by (used in) financing activities		7.1			—			513.5			—			(301.3		)	4.7			—			224
Net increase in cash and cash equivalents		—			—			—			—			15.2			0.7			—			15.9
Cash and cash equivalents at beginning of period		—			—			—			—			0.4			0.2			—			0.6
Cash and cash equivalents at end of period		$	—		$	—		$	—		$	—		$	15.6		$	0.9		$	—		$	16.5
CyrusOne L.P. [Member]
Condensed Financial Statements, Captions [Line Items]
Guarantors	CyrusOne LP
	CyrusOne LP and CyrusOne Finance Corp., as “LP Co-issuer” and “Finance Co-issuer,” respectively (together, the “Issuers”), had $374.8 million aggregate principal amount of senior notes outstanding at December 31, 2014 and $525.0 million as of December 31, 2013. The senior notes are fully and unconditionally and jointly and severally guaranteed on a senior basis by CyrusOne Inc. (“Parent Guarantor”), CyrusOne GP (“General Partner”), and CyrusOne LP’s 100% owned subsidiaries, CyrusOne LLC, CyrusOne TRS Inc. and CyrusOne Foreign Holdings LLC (such subsidiaries, together the “Guarantors”). None of the subsidiaries organized outside of the United States (collectively, the “Non-Guarantors”) guarantee the senior notes. Subject to the provisions of the indenture governing the senior notes, in certain circumstances, a Guarantor may be released from its guarantee obligation, including:
	•	upon the sale or other disposition (including by way of consolidation or merger) of such Guarantor or of all of the capital stock of such Guarantor such that such Guarantor is no longer a restricted subsidiary under the indenture,
	•	upon the sale or disposition of all or substantially all of the assets of the Guarantor,
	•	upon the LP Co-issuer designating such Guarantor as an unrestricted subsidiary under the terms of the indenture,
	•	if such Guarantor is no longer a guarantor or other obligor of any other indebtedness of the LP Co-issuer or the Parent Guarantor, and
	•	upon the defeasance or discharge of the senior notes in accordance with the terms of the indenture.
	The following provides information regarding the entity structure of each guarantor of the senior notes:
	CyrusOne Inc.—CyrusOne Inc. was formed on July 31, 2012. As of January 23, 2013, CyrusOne Inc. was a 100% owned subsidiary of CBI. Effective January 24, 2013, CyrusOne Inc. completed its IPO of common stock for net proceeds of $337.1 million, and together with the General Partner, purchased a 33.9% ownership interest in CyrusOne LP. CyrusOne Inc. also represents a guarantor or Parent Guarantor. In addition, CyrusOne Inc. became a separate registrant with the SEC upon completion of its IPO.
	CyrusOne GP—CyrusOne GP was formed on July 31, 2012, and was a 100% owned subsidiary of CyrusOne Inc. as of January 23, 2013. Effective upon completion of CyrusOne Inc.’s IPO, this entity became the general partner and 1% owner of CyrusOne LP and has no other assets or operations. Prior to the IPO, this entity did not incur any obligations or record any transactions.
	Issuers—The Issuers include CyrusOne LP and CyrusOne Finance Corp. CyrusOne Finance Corp., a 100% owned subsidiary of CyrusOne LP, was formed for the sole purpose of acting as co-issuer of the senior notes and has no other assets or operations. CyrusOne LP, in addition to being the co-issuer of the senior notes, is also the 100% owner, either directly or indirectly, of the Guarantors and Non-Guarantors.
	Guarantors—The guarantors include CyrusOne LLC, CyrusOne TRS Inc., and CyrusOne Foreign Holdings LLC. CyrusOne LLC accounts for all of the domestic operations of CyrusOne LP, including the businesses that composed the Predecessor operations. CyrusOne LLC, together with CyrusOne Foreign Holdings LLC, directly or indirectly owns 100% of the Non-Guarantors. As of December 31, 2013, CyrusOne TRS Inc. had not incurred any obligations or recorded any material transactions for the period ended December 31, 2013 and January 23, 2013.
	As of December 31, 2013, the Non-Guarantors consist of 100% owned subsidiaries, which conduct operations in the United Kingdom and Singapore.
	The following schedules present the financial information for the periods ended December 31, 2014, and January 23, 2013, and the years ended December 31, 2012 and December 31, 2011, for the LP Co-issuer, Finance Co-issuer, Guarantors, and Non-Guarantors. The financial statements for the period ended January 23, 2013, present the financial information prior to the effective date of the IPO, and the financial statements for the period ended December 31, 2013, present the financial information after the effective date of the IPO. The consolidating schedules are provided in accordance with the reporting requirements for guarantor subsidiaries.
	Consolidating Balance Sheets
			As of December 31, 2014
	(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
			Co-issuer			Co-issuer						Guarantors
	Land		$	—		$	—		$	89.7		$	—		$	—		$	89.7
	Buildings and improvements		—			—			770.9			41.7			—			812.6
	Equipment		—			—			348.3			0.8			—			349.1
	Construction in progress		—			—			124.8			—			2.2			127
	Subtotal		—			—			1,333.70			42.5			2.2			1,378.40
	Accumulated depreciation		—			—			(319.7		)	(7.3		)	—			(327.0		)
	Net investment in real estate		—			—			1,014.00			35.2			2.2			1,051.40
	Cash and cash equivalents		—			—			33.5			3			—			36.5
	Investment in subsidiaries		734.3			—			3.6			—			(737.9		)	—
	Rent and other receivables		—			—			57.9			3			—			60.9
	Intercompany receivable		642.9			—			—			—			(642.9		)	—
	Goodwill		—			—			276.2			—			—			276.2
	Intangible assets, net		—			—			68.9			—			—			68.9
	Due from affiliates		—			—			0.8			—			—			0.8
	Other assets		15.5			—			73.1			3.2			—			91.8
	Total assets		$	1,392.70		$	—		$	1,528.00		$	44.4		$	(1,378.6	)	$	1,586.50
	Accounts payable and accrued expenses		$	12.5		$	—		$	56.9		$	0.5		$	—		$	69.9
	Deferred revenue		—			—			65.1			0.6			—			65.7
	Intercompany payable		—			—			642.9			—			(642.9		)	—
	Due to affiliates		5.6			—			1.7			—			—			7.3
	Capital lease obligations		—			—			6.2			7.2			—			13.4
	Long-term debt		659.8			—			—			—			—			659.8
	Other financing arrangements		—			—			20.9			32.5			—			53.4
	Total liabilities		677.9			—			793.7			40.8			(642.9		)	869.5
	Total partnership capital		714.8			—			734.3			3.6			(735.7		)	717
	Total liabilities and parent’s net investment		$	1,392.70		$	—		$	1,528.00		$	44.4		$	(1,378.6	)	$	1,586.50
			As of December 31, 2013
	(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
			Co-issuer			Co-issuer						Guarantors
	Land		$	—		$	—		$	89.3		$	—		$	—		$	89.3
	Buildings and improvements		—			—			739.6			44.1			—			783.7
	Equipment		—			—			189.4			0.8			—			190.2
	Construction in progress		—			—			57.3			—			—			57.3
	Subtotal		—			—			1,075.60			44.9			—			1,120.50
	Accumulated depreciation		—			—			(232.0		)	(4.7		)	—			(236.7		)
	Net investment in real estate		—			—			843.6			40.2			—			883.8
	Cash and cash equivalents		—			—			146.8			2			—			148.8
	Investment in subsidiaries		795			—			2.1			—			(797.1		)	—
	Rent and other receivables		—			—			40.3			0.9			—			41.2
	Intercompany receivable		508.1			—			0.2			—			(508.3		)	—
	Goodwill		—			—			276.2			—			—			276.2
	Intangible assets, net		—			—			85.9			—			—			85.9
	Due from affiliates		—			—			0.6			—			—			0.6
	Other assets		14.1			—			53			3.2			—			70.3
	Total assets		$	1,317.20		$	—		$	1,448.70		$	46.3		$	(1,305.4	)	$	1,506.80
	Accounts payable and accrued expenses		$	7.8		$	—		$	58.6		$	0.4		$	—		$	66.8
Deferred revenue		—			—			55.1			0.8			—			55.9
Intercompany payable		—			—			508.1			0.2			(508.3		)	—
Due to affiliates		6.8			—			1.7			—			—			8.5
Capital lease obligations		—			—			8.6			8.1			—			16.7
Long-term debt		525			—			—			—			—			525
Other financing arrangements		—			—			21.6			34.7			—			56.3
Total liabilities		539.6			—			653.7			44.2			(508.3		)	729.2
Partnership capital		777.6			—			795			2.1			(797.1		)	777.6
Total liabilities and partnership capital		$	1,317.20		$	—		$	1,448.70		$	46.3		$	(1,305.4	)	$	1,506.80
Consolidating Statements of Operations
	Year Ended December 31, 2014
(amounts in millions)		LP			Finance Co-issuer			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer									Guarantors
Revenue		$	—		$	—		$	325.1		$	5.8		$	—		$	330.9
Costs and expenses:
Property operating expenses		—			—			121.9			2.6			—			124.5
Sales and marketing		—			—			12.6			0.2			—			12.8
General and administrative		—			—			34.2			0.4			—			34.6
Depreciation and amortization		—			—			115			3			—			118
Transaction costs		—			—			1			—			—			1
Total costs and expenses		—			—			284.7			6.2			—			290.9
Operating income (loss)		—			—			40.4			(0.4		)	—			40
Interest expense (income)		38.2			—			—			3.5			(2.2		)	39.5
Loss on extinguishment of debt		13.6			—			—			—			—			13.6
(Loss) income before income taxes		(51.8		)	—			40.4			(3.9		)	2.2			(13.1		)
Income tax expense		—			—			(1.4		)	—			—			(1.4		)
Equity earnings (loss) related to investment in subsidiaries		35.1			—			(3.9		)	—			(31.2		)	—
Net (loss) income		$	(16.7	)	$	—		$	35.1		$	(3.9	)	$	(29.0	)	$	(14.5	)
	Period Ended December 31, 2013
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	244.3		$	4.1		$	—		$	248.4
Costs and expenses:
Property operating expenses		—			—			85.9			2.5			—			88.4
Sales and marketing		—			—			9.7			0.2			—			9.9
General and administrative		—			—			26.3			0.2			—			26.5
Depreciation and amortization		—			—			87.1			2.8			—			89.9
Restructuring charges		—			—			1.3			—			—			1.3
Transaction costs		—			—			0.7			—			—			0.7
Asset impairment		—			—			2.8			—			—			2.8
Total costs and expenses		—			—			213.8			5.7			—			219.5
Operating income (loss)		—			—			30.5			(1.6		)	—			28.9
Interest expense		36.5			—			1.8			2.9			—			41.2
Other income		—			—			(0.1		)	—			—			(0.1		)
Loss on extinguishment of debt		—			—			1.3			—			—			1.3
(Loss) income before income taxes		(36.5		)	—			27.5			(4.5		)	—			(13.5		)
Income tax expense		—			—			(1.9		)	—			—			(1.9		)
Equity earnings (loss) related to investment in subsidiaries		20.9			—			(4.5		)	—			(16.4		)	—
(Loss) income from continuing operations		(15.6		)	—			21.1			(4.5		)	(16.4		)	(15.4		)
Loss on sale of real estate improvements		—			—			(0.2		)	—			—			(0.2		)
Net (loss) income		$	(15.6	)	$	—		$	20.9		$	(4.5	)	$	(16.4	)	$	(15.6	)
		Period Ended January 23, 2013
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	14.9		$	0.2		$	—		$	15.1
Costs and expenses:
Property operating expenses		—			—			4.8			—			—			4.8
Sales and marketing		—			—			0.7			—			—			0.7
General and administrative		—			—			1.4			0.1			—			1.5
Transaction-related compensation		—			—			20			—			—			20
Depreciation and amortization		—			—			5.2			0.1			—			5.3
Transaction costs		—			—			0.1			—			—			0.1
Total costs and expenses		—			—			32.2			0.2			—			32.4
Operating loss		—			—			(17.3		)	—			—			(17.3		)
Interest expense		2.3			—			0.1			0.1			—			2.5
Loss before income taxes		(2.3		)	—			(17.4		)	(0.1		)	—			(19.8		)
Income tax expense		—			—			(0.4		)	—			—			(0.4		)
Equity loss related to investment in subsidiaries		(17.9		)	—			(0.1		)	—			18			—
Net loss		$	(20.2	)	$	—		$	(17.9	)	$	(0.1	)	$	18		$	(20.2	)
		Year Ended December 31, 2012
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Revenue		$	—		$	—		$	219.4		$	1.4		$	—		$	220.8
Costs and expenses:
Property operating expenses		—			—			74.1			1.9			—			76
Sales and marketing		—			—			9.5			0.2			—			9.7
General and administrative		—			—			20.6			0.1			—			20.7
Depreciation and amortization		—			—			71.9			1.5			—			73.4
Transaction costs		5.7			—			—			—			—			5.7
Management fees charged by CBI		—			—			2.5			—			—			2.5
Loss on sale of receivables to an affiliate		—			—			3.2			—			—			3.2
Asset impairments		—			—			13.3			—			—			13.3
Total costs and expenses		5.7			—			195.1			3.7			—			204.5
Operating (loss) income		(5.7		)	—			24.3			(2.3		)	—			16.3
Interest expense		4.2			—			35			2.6			—			41.8
Loss before income taxes		(9.9		)	—			(10.7		)	(4.9		)	—			(25.5		)
Income tax benefit		—			—			5.1			—			—			5.1
Equity loss related to investment in subsidiaries		(10.4		)	—			(4.9		)	—			15.3			—
Loss from continuing operations		(20.3		)	—			(10.5		)	(4.9		)	15.3			(20.4		)
Gain on sale of real estate improvements		—			—			0.1			—			—			0.1
Net loss		$	(20.3	)	$	—		$	(10.4	)	$	(4.9	)	$	15.3		$	(20.3	)
Consolidating Statements of Cash Flows
		Year Ended December 31, 2014
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(16.7	)	$	—		35.1			$	(3.9	)	$	(29.0	)	$	(14.5	)
Equity earnings (loss) related to investment in subsidiaries		(35.1		)	—			3.9			—			31.2			—
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities:
Depreciation and amortization		—			—			115			3			—			118
Stock-based compensation expense		—			—			10.3			—			—			10.3
Noncash interest expense		3.4			—			—			—			—			3.4
Provision for bad debt write off		—			—			0.8			—			—			0.8
Loss on extinguishment of debt		13.6			—			—			—			—			13.6
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		0.4			—			(35.3		)	(2.1		)	—			(37.0		)
Accounts payable and accrued expenses		4.7			—			2.1			0.1			—			6.9
Payables to related parties		—			—			(0.2		)	—			—			(0.2		)
Deferred revenue		—			—			10			(0.2		)	—			9.8
Net cash (used in) provided by operating activities		(29.7		)	—			141.7			(3.1		)	2.2			111.1
Cash flows from investing activities:
Capital expenditures - other		—			—			(283.9		)	(0.3		)	—			(284.2		)
Return of investment		97.3			—			(45.4		)	—			(51.9		)	—
Intercompany receipts		180.2			—			—			—			(180.2		)	—
Intercompany distributions		(315.0		)	—			—			—			315			—
Net cash provided by (used in) investing activities		(37.5		)	—			(329.3		)	(0.3		)	82.9			(284.2		)
Cash flows from financing activities:
Issuance of partnership units		0.1			—			—			—			—			0.1
Dividends paid		(50.9		)	—			(50.9		)	—			50.9			(50.9		)
Intercompany borrowings		—			—			315			—			(315.0		)	—
Intercompany payments		—			—			(180.2		)	—			180.2			—
Borrowings from revolving credit agreement		315			—			—			—			—			315
Payments on revolving credit facility		(30.0		)	—			—			—			—			(30.0		)
Payments on senior notes		(150.2		)	—			—			—			—			(150.2		)
Payments on capital leases		—			—			(2.4		)	(0.6		)	—			(3.0		)
Other financing arrangements		—			—			(0.7		)	(0.2		)	—			(0.9		)
Debt extinguishment costs		(12.8		)	—			—			—			—			(12.8		)
Contributions (distributions) from parent guarantor		1.2			—			(6.5		)	5.2			(1.2		)	(1.3		)
Debt issuance costs		(5.2		)	—			—			—			—			(5.2		)
Net cash provided by (used in) financing activities		67.2			—			74.3			4.4			(85.1		)	60.8
Net (decrease) increase in cash and cash equivalents		—			—			(113.3		)	1			—			(112.3		)
Cash and cash equivalents at beginning of period		—			—			146.8			2			—			148.8
Cash and cash equivalents at end of period		$	—		$	—		$	33.5		$	3		$	—		$	36.5
		Period Ended December 31, 2013
(amounts in millions)		LP (1)			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(15.6	)	$	—		$	20.9		$	(4.5	)	$	(16.4	)	$	(15.6	)
Equity earnings (loss) related to investment in subsidiaries		(20.9		)	—			4.5			—			16.4			—
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization		—			—			87.1			2.8			—			89.9
Stock-based compensation expense		—			—			6			—			—			6
Noncash interest expense		4			—			—			—			—			4
Provision for bad debt write off		—			—			0.4			—			—			0.4
Loss on extinguishment of debt		—			—			1.3			—			—			1.3
Asset impairments		—			—			2.8			—			—			2.8
Deferred income tax expense		—			—			0.6			—			—			0.6
Other, net		(13.4		)	—			(16.2		)	—			29.6			—
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		—			—			(9.9		)	(3.0		)	(2.8		)	(15.7		)
Accounts payable and accrued expenses		4.8			—			0.2			0.3			(19.9		)	(14.6		)
Payables to related parties		6.8			—			18.4			—			(6.8		)	18.4
Deferred revenue		—			—			(0.3		)	0.2			—			(0.1		)
Net cash provided by (used in) operating activities		(34.3		)	—			115.8			(4.2		)	0.1			77.4
Cash flows from investing activities:
Capital expenditures - acquisitions of real estate		—			—			(48.0		)	—			—			(48.0		)
Capital expenditures - other		—			—			(172.9		)	—			—			(172.9		)
Investment in subsidiaries		(337.1		)	—			—			—			337.1			—
Return of investment		66.5			—			—			—			(66.5		)	—
Release of restricted cash		—			—			4.4			—			—			4.4
Intercompany advances, net		—			—			—			—			—			—
Other, net		—			—			(0.2		)	—			—			(0.2		)
Net cash provided by (used in) investing activities		(270.6		)	—			(216.7		)	—			270.6			(216.7		)
Cash flows from financing activities:
Issuance of partnership units		337.1			—			(3.2		)	—			—			333.9
Distributions paid		(31.0		)	—			(31.0		)	—			31			(31.0		)
Payments on capital leases		—			—			(4.4		)	(0.9		)	—			(5.3		)
Other financing arrangements		—			—			(0.5		)	(0.2		)	—			(0.7		)
Payments to buyout capital leases		—			—			(9.6		)	—			—			(9.6		)
Payment to buyout other financing arrangement		—			—			(10.2		)	—			—			(10.2		)
Contribution from parent, net		—			—			295.4			6.3			(301.7		)	—
Debt issuance costs		(1.3		)	—			—			—			—			(1.3		)
Net cash provided by (used in) financing activities		304.8			—			236.5			5.2			(270.7		)	275.8
Net increase (decrease) in cash and cash equivalents		(0.1		)	—			135.6			1			—			136.5
Cash and cash equivalents at beginning of period		0.1			—			11.2			1			—			12.3
Cash and cash equivalents at end of period		$	—		$	—		$	146.8		$	2		$	—		$	148.8
		Period Ended January 23, 2013
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(20.2	)	$	—		$	(17.9	)	$	(0.1	)	$	18		$	(20.2	)
Equity loss related to investment in subsidiaries		17.9			—			0.1			—			(18.0		)	—
Adjustments to reconcile net (loss) income to net cash provided by operating activities		0.2			—			5.6			0.1			—			5.9
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		—			—			(9.6		)	—			—			(9.6		)
Accounts payable and accrued expenses		2.1			—			18.4			—			—			20.5
Payables to related parties		—			—			1.5			—			—			1.5
Other changes in assets and liabilities		—			—			3.8			0.1			—			3.9
Net cash provided by operating activities		—			—			1.9			0.1			—			2
Cash flows from investing activities:
Capital expenditures - other		—			—			(7.7		)	—			—			(7.7		)
Release of restricted cash		—			—			1.9			—			—			1.9
Intercompany advances, net		0.1			—			(0.1		)	—			—			—
Net cash provided by (used in) investing activities		0.1			—			(5.9		)	—			—			(5.8		)
Cash flows from financing activities:																	—
Payments on capital lease obligations		—			—			(0.6		)	—			—			(0.6		)
Contributions from parent, net		—			—			0.2			—			—			0.2
Net cash used in financing activities		—			—			(0.4		)	—			—			(0.4		)
Net increase (decrease) in cash and cash equivalents		0.1			—			(4.4		)	0.1			—			(4.2		)
Cash and cash equivalents at beginning of period		—			—			15.6			0.9			—			16.5
Cash and cash equivalents at end of period		$	0.1		$	—		$	11.2		$	1		$	—		$	12.3
		Year Ended December 31, 2012
(amounts in millions)		LP			Finance			Guarantors			Non-			Eliminations/Consolidations			Total
		Co-issuer			Co-issuer						Guarantors
Net (loss) income		$	(20.3	)	$	—		$	(10.4	)	$	(4.9	)	$	15.3		$	(20.3	)
Equity loss related to investment in subsidiaries		10.4			—			4.9			—			(15.3		)	—
Adjustments to reconcile net (loss) income to net cash provided by operating activities		0.2			—			83.9			1.5			—			85.6
Changes in operating assets and liabilities, net of effects of acquisitions:
Rent receivables and other assets		—			—			(15.5		)	(0.6		)	—			(16.1		)
Accounts payable and accrued expenses		4.4			—			(5.5		)	(0.3		)	—			(1.4		)
Payables to related parties		—			—			3.3			0.5			—			3.8
Net cash (used in) provided by operating activities		(5.3		)	—			60.7			(3.8		)	—			51.6
Cash flows from investing activities:
Capital expenditures - acquisitions of real estate		—			—			(25.1		)	(0.3		)	—			(25.4		)
Capital expenditures - other		—			—			(202.9		)	—			—			(202.9		)
Proceeds from sale of assets		—			—			0.2			—			—			0.2
Increase in restricted cash		—			—			(11.1		)	—			—			(11.1		)
Release of restricted cash		—			—			4.8			—			—			4.8
Advances to affiliate		—			—			(18.3		)	—			—			(18.3		)
Intercompany advances, net		(508.2		)	—			508.1			0.1			—			—
Other, net		—			—			0.1			—			—			0.1
Net cash (used in) provided by investing activities		(508.2		)	—			255.8			(0.2		)	—			(252.6		)
Cash flows from financing activities:
Borrowings from affiliates, net		—			—			119.8			—			—			119.8
Repayment of related party note		—			—			(400.0		)	—			—			(400.0		)
Proceeds from issuance of debt		525			—			—			—			—			525
Payment on capital lease obligations		—			—			(8.4		)	(0.6		)	—			(9.0		)
Debt issuance costs		(17.2		)	—			—			—			—			(17.2		)
Contributions from (distributions to) parent, net		5.7			—			(12.7		)	5.3			—			(1.7		)
Net cash provided by (used in) financing activities		513.5			—			(301.3		)	4.7			—			216.9
Net increase in cash and cash equivalents		—			—			15.2			0.7			—			15.9
Cash and cash equivalents at beginning of period		—			—			0.4			0.2			—			0.6
Cash and cash equivalents at end of period		$	—		$	—		$	15.6		$	0.9		$	—		$	16.5

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Quarterly Financial Information (Unaudited)
	The table below reflects the unaudited selected quarterly information for the years ended December 31, 2014 and 2013:
	(dollars in millions, except per share amounts)
					2014
					First			Second			Third			Fourth			Total
					Quarter			Quarter			Quarter			Quarter
	Revenue				$	77.5		$	81.7		$	84.8		$	86.9		$	330.9
	Operating income				11.8			7.4			9.6			11.2			40
	Net income (loss)				0.7			(3.6		)	0.2			(11.8		)	(14.5		)
	Net income (loss) attributed to common shareholders				0.2			(1.1		)	0.1			(7.0		)	(7.8		)
	Basic and diluted loss per share(a)				—			(0.06		)	—			(0.19		)	(0.25		)
		2013
		January 1, 2013 to January 23, 2013			January 24, 2013 to March 31, 2013			Second			Third			Fourth			Total
								Quarter			Quarter			Quarter
	Revenue	$	15.1		$	45		$	63.6		$	67.5		$	72.3		$	263.5
	Operating (loss) income	(17.3		)	5.8			5.6			8.5			9			11.6
	Net loss	(20.2		)	(2.8		)	(6.8		)	(2.2		)	(3.8		)	(35.8		)
	Net loss attributed to common shareholders	—			(0.9		)	(2.3		)	(0.8		)	(1.3		)	(5.3		)
	Basic and diluted loss per share	—			(0.05		)	(0.12		)	(0.05		)	(0.06		)	(0.28		)
	(a) The basic and diluted income (loss) per share for 2014 was $(0.30) compared to $(0.25) due to the impact of the 16 million shares of common stock issued during the secondary offering in June 2014.

Subsequent_Event

Subsequent Event	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event
	On February 19, 2015, CyrusOne LLC entered into an agreement with Met Center Partners to purchase Austin Met 2 for $17.3 million. The purchase was funded with proceeds from the credit agreement.

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	Schedule II.
	Valuation and Qualifying Accounts
		Beginning		Charge		Deductions/			End
	(dollars in millions)	of Period		to Expenses		(Additions)			of Period
	Allowance for Doubtful Accounts
	2014	$	0.5	$	0.8	$	0.3		$	1
	2013	0.3		0.4		0.2			0.5
	2012	—		0.1		(0.2		)	0.3
	Deferred Tax Valuation Allowance
	2014	$	3.6	$	2.1	$	—		$	5.7
	2013	1.9		1.7		—			3.6
	2012	0.3		1.6		—			1.9
	Prior to October 1, 2012, CyrusOne sold most of its receivables to an affiliated entity at a discount of 2.5% of the face value. Proceeds from the sale of these assets were settled through CBI’s centralized cash management system. Effective October 1, 2012, we terminated our participation in this program.

Real_Estate_Properties_and_Acc

Real Estate Properties and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Real Estate and Accumulated Depreciation Disclosure	Real Estate Properties and Accumulated Depreciation
	CyrusOne Inc.
		As of December 31, 2014
	(dollars in millions)	Initial Costs								Cost Capitalized Subsequent to								Gross Carrying Amount
										Acquisition
	Description	Land			Building and			Equipment		Land			Building and			Equipment		Land		Building and		Equipment		Accumulated		Acquisition
					Improvements								Improvements							Improvements				Depreciation
	West Seventh St., Cincinnati, OH (7th Street)	$	0.9		$	42.2		$	—	$	—		$	68.4		$	12.7	$	0.9	$	110.6	$	12.7	$	69.5	1999
	Parkway Dr., Mason, OH (Mason)	—			—			—		—			20.2			0.9		—		20.2		0.9		10.8		2004
	Industrial Rd., Florence, KY (Florence)	2.2			7.7			—		—			33.7			3		2.2		41.4		3		18.6		2005
	Goldcoast Dr., Cincinnati, OH (Goldcoast)	0.6			—			—		—			6.7			0.1		0.6		6.7		0.1		2.2		2007
	Knightsbridge Dr., Hamilton, OH (Hamilton)	—			9.5			—		—			39.7			3.7		—		49.2		3.7		20.3		2007
	E. Monroe St., South Bend, IN (Monroe St.)	—			—			—		—			2.5			0.1		—		2.5		0.1		1.1		2007
	Springer St., Lombard, IL (Lombard)	0.7			3.2			—		—			1.5			5.7		0.7		4.7		5.7		1.3		2008
	Crescent Circle, South Bend, IN (Blackthorn)	—			1.1			—		—			2.2			0.1		—		3.3		0.1		1.3		2008
	Kingsview Dr., Lebanon, OH (Lebanon)	4			12.3			—		—			64.7			5.5		4		77		5.5		21.4		2008
	McAuley Place, Blue Ash, OH (Blue Ash)	—			2.6			—		—			(2.0		)	0.1		—		0.6		0.1		0.2		2009
	Westway Park Blvd., Houston, TX (Houston West 1)	1.4			21.4			0.1		—			63			43.7		1.4		84.4		43.8		39.6		2010
	Westway Park Blvd., Houston, TX (Houston West 2)	2			—			—		—			22.5			45.1		2		22.5		45.1		8		2013
	Westway Park Blvd., Houston, TX (Houston West 3)	18.3			—			—		0.1			—			—		18.4		—		—		—		2013
	Southwest Fwy., Houston, TX (Galleria)	—			56			2		—			12.6			13		—		68.6		15		29.4		2010
	E. Ben White Blvd., Austin, TX (Austin 1)	—			11.9			0.2		—			10.6			1		—		22.5		1.2		8.2		2010
	S. State Highway 121 Business, Lewisville, TX (Lewisville)	—			46.2			2.2		—			30.5			20.6		—		76.7		22.8		37.5		2010
	Marsh Lane, Carrollton, TX (Marsh Ln)	—			—			—		—			0.1			0.5		—		0.1		0.5		0.3		2010
	Midway Rd., Carrollton, TX (Midway)	—			1.8			—		—			0.2			0.4		—		2		0.4		2.2		2010
	W. Frankford Rd., Carrollton, TX (Carrollton)	16.1			—			—		—			51.6			85.3		16.1		51.6		85.3		17.4		2012
	Bryan St., Dallas, TX (Bryan St)	—			0.1			—		—			—			0.2		—		0.1		0.2		0.1		2010
	North Freeway, Houston, TX (Greenspoint)	—			—			—		—			1.3			—		—		1.3		—		1.3		2010
	South Ellis Street, Chandler, AZ (Phoenix 1)	15			—			—		—			56.4			43.9		14.8		56.4		43.9		11		2011
	South Ellis Street, Chandler, AZ (Phoenix 2)	—			—			—		—			13.2			21.8		—		13.2		21.8		0.7		2014
	Westover Hills Blvd., San Antonio, TX (San Antonio 1)	4.6			3			—		—			29.1			32.4		4.6		32.1		32.4		10		2011
	Westover Hills Blvd., San Antonio, TX (San Antonio 2)	6.7			—			—		0.3			—			—		7		—		—		—		2013
	Metropolis Dr., Austin, TX (Austin 2)	2			—			—		—			23.2			4		2		23.2		4		7.2		2011
	Kestral Way (London)	—			16.5			—		—			16.2			0.7		—		32.7		0.7		4.4		2011
	Jurong East (Singapore)	—			9			—		—			—			0.1		—		9		0.1		3		2011
	Ridgetop Circle, Sterling, VA (Northern VA)	6.9			—			—		0.1			—			—		7		—		—		—		2013
	Metropolis Dr., Austin, TX (Austin 3)	7.9			—			—		0.1			—			—		8		—		—		—		2013
		$	89.3		$	244.5		$	4.5	$	0.6		$	568.1		$	344.6	$	89.7	$	812.6	$	349.1	$	327
	The aggregate cost of the total properties for federal income tax purposes was $1,725.0 million at December 31, 2014.
	Historical Cost and Accumulated Depreciation and Amortization
	The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2014, 2013 and 2012.
			Years Ended December 31,
	(amounts in millions)		2014				2013			2012
	Property
	Balance—beginning of period		$	1,120.50			$	883.6		$	660.2
	Disposals		(0.1		)		(8.5		)	(1.2		)
	Impairments		—				(4.0		)	(17.1		)
	Additions (acquisitions and improvements)		258				249.4			241.7
	Balance, end of period		$	1,378.40			$	1,120.50		$	883.6
	Accumulated Depreciation
	Balance—beginning of period		$	236.7			$	176.7		$	131.2
	Disposals		—				(9.3		)	(1.2		)
	Impairments		—				(0.9		)	(5.3		)
	Additions (depreciation and amortization expense)		90.3				70.2			52
	Balance, end of period		$	327			$	236.7		$	176.7

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying financial statements for the period ended January 23, 2013 and the year ended December 31, 2012, were prepared on a combined basis using CBI’s historical basis in the assets and liabilities of its data center business and are presented as the “Predecessor” financial statements. The Predecessor financial statements include all revenues, costs, assets and liabilities directly attributable to the data center business. In addition, certain expenses reflected in the Predecessor financial statements include allocations of corporate expenses from CBI, which in the opinion of management are reasonable but do not necessarily reflect what CyrusOne’s financial position, results of operations and cash flows would have been had CyrusOne been a stand-alone company during these respective periods. As a result, the Predecessor financial information is not necessarily indicative of CyrusOne’s future results of operations, financial position and cash flows. The financial statements as of December 31, 2014 and 2013 and for the period from January 24, 2013 to December 31, 2013, and the year ended December 31, 2014, are prepared on a consolidated basis and are presented as the “Successor” financial statements.
	In addition, the accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). All material intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates—Preparation of the consolidated and combined financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated and combined financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Estimates are used in determining the fair value of leased real estate, the useful lives of real estate and other long-lived assets, future cash flows associated with goodwill and other long-lived asset impairment testing, deferred tax assets and liabilities and loss contingencies. Estimates were also utilized in the determination of historical allocations of shared employees’ payroll, benefits and incentives and management fees between CyrusOne and CBI. Actual results may differ from these estimates and assumptions.
Investments in Real Estate	Investments in Real Estate—Investments in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. Real estate acquired from third parties has been recorded at its acquisition cost. Real estate acquired from CBI and its affiliates has been recorded at its historical cost basis. Additions and improvements which extend an asset’s useful life or increase its functionality are capitalized and depreciated over the asset’s remaining life. Maintenance and repairs are expensed as incurred.
	When we are involved in the construction of structural improvements to leased property, we are deemed the accounting owner of the leased real estate. In these instances, we bear substantially all the construction period risk, including managing or funding construction. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. At inception, the fair value of the real estate, which generally consists of a building shell and our associated obligation is recorded as construction in progress. As construction progresses the value of the asset and obligation increases by the fair value of the structural improvements. When construction is complete, the asset is placed in service and depreciation commences. Leased real estate is depreciated to the lesser of (i) its estimated fair value at the end of the term or (ii) the expected amount of the unamortized obligation at the end of the term.
	When we are not deemed the accounting owner, we further evaluate leased real estate to determine whether the lease should be classified as a capital or operating lease. One of the following four characteristics must be present to classify a lease as a capital lease: (i) the lease transfers ownership of the property to the lessee by the end of the lease term, (ii) the lease contains a bargain purchase option, (iii) the lease term is equal to 75% or more of the estimated economic life of the leased property or (iv) the net present value of the lease payments are at least 90% of the fair value of the leased property.
	Construction in progress includes direct and indirect expenditures for the construction and expansion of our data centers and is stated at its acquisition cost. Independent contractors perform substantially all of the construction and expansion efforts of our data centers. Construction in progress includes costs incurred under construction contracts including project management services, engineering and schematic design services, design development, construction services and other construction-related fees and services. Interest, property taxes and certain labor costs are also capitalized during the construction of an asset. Capitalized interest in 2014, 2013, and 2012 was $4.6 million, $1.6 million, and $2.7 million, respectively. These costs are depreciated over the estimated useful life of the related assets.
	Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to forty-eight years years for buildings, three to twenty-five years for building improvements, and three to five years years or equipment. Leasehold improvements are amortized over the shorter of the asset’s useful life or the remaining lease term, including renewal options which are reasonably assured.
	Management reviews the carrying value of long-lived assets, including intangible assets with finite lives, when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Examples of such indicators may include a significant adverse change in the extent to which or manner in which the property is being used, an accumulation of costs significantly in excess of the amount originally expected for acquisition or development, or a history of operating or cash flow losses. When such indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of an asset (or group of assets) and its eventual disposition and compare such amount to its carrying amount. We consider factors such as future operating income, leasing demand, competition and other factors. If our undiscounted net cash flows indicate that we are unable to recover the carrying value of the asset, an impairment loss is recognized. An impairment loss is measured as the amount by which the asset’s carrying value exceeds its estimated fair value.
	Impairment exists when the Company's net book value of real estate assets is greater than the estimated fair value. For the period ended December 31, 2013 and the year ended December 31, 2012, we recognized impairments of $2.8 million and $11.8 million, respectively. No such impairments were recognized in 2014.
Cash and Cash Equivalents	Cash and Cash Equivalents—Cash and cash equivalents include all non-restricted cash held in financial institutions and other non-restricted highly liquid short-term investments with original maturities at acquisition of three months or less.
Goodwill	Goodwill—Goodwill represents the excess of the purchase price over the fair value of net assets acquired in connection with business acquisitions. We perform impairment testing of goodwill, at the reporting unit level, on an annual basis or more frequently if indicators of potential impairment exist.
	The fair value of our reporting unit was determined using a combination of market-based valuation multiples for comparable businesses and discounted cash flow analysis based on internal financial forecasts incorporating market participant assumptions. There were no impairments recognized for the years ended December 31, 2014 or 2013.
Long-Lived and Intangible Assets	Long-Lived and Intangible Assets—Intangible assets represent purchased assets that lack physical substance, but can be separately distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged, either on its own or in combination with a related contract, asset, or liability. Intangible assets with finite lives consist of trademarks, customer relationships, and a favorable leasehold interest.
	For the year ended December 31, 2012, we recognized an impairment of $1.5 million related to the impairment of customer relationships. There were no impairments recognized for the years ended December 31, 2014 or 2013.
Receivables	Rent and Other Receivables—Receivables consist principally of trade receivables from customers and are generally unsecured and due within 30 to 120 days. Unbilled receivables arise from services rendered but not yet billed. Expected credit losses associated with trade receivables are recorded as an allowance for uncollectible accounts. The allowance for uncollectible accounts is estimated based upon historic patterns of credit losses for aged receivables as well as specific provisions for certain identifiable, potentially uncollectible balances. When internal collection efforts on accounts have been exhausted, the accounts are written-off and the associated allowance for uncollectible accounts is reduced. The Company has receivables with one customer that exceeds 10% of the Company’s outstanding accounts receivable balance at December 31, 2014 and 2013. In addition, our receivables include $8.7 million of receivables as of December 31, 2014 which has not been billed to the customer. The amount will be billed and payable in 36 monthly payments starting in April 2015 through March 2018.
	As of December 31, 2014, receivables were $61.9 million, and the allowance for uncollectible accounts was $1.0 million. The December 31, 2013 receivables were $41.7 million, and the allowance for uncollectible accounts was $0.5 million.
Deferred Costs	Deferred Costs—Deferred costs include both deferred leasing costs and deferred financing costs. Deferred costs are presented with other assets in the accompanying consolidated and combined balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized to expense over the term of the customer lease. Amortization of deferred leasing costs is presented with depreciation and amortization in the accompanying consolidated and combined statements of operations. If a lease terminates prior to the expected term of the lease, the remaining unamortized cost is written off to amortization expense.
	Deferred financing costs include costs incurred in connection with issuance of senior notes, term loans and revolving credit facilities. These financing costs are capitalized and amortized to expense over the term of the instrument and are included as a component of interest expense.
Other Financing Arrangements	Other Financing Arrangements—Other financing arrangements represent leases of real estate where we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our consolidated and combined balance sheet. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations.
Revenue Recognition	Revenue Recognition—Colocation rentals are generally billed monthly in advance, and some contracts have escalating payments over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased space or power, and the lessee takes possession of, or controls the physical use of the property (including all contractually committed power) at the beginning of the lease term, the rental payments by the lessee are recognized as revenue on a straight-line basis over the term of the lease. If rents escalate because the lessee gains access to and control over additional leased space or power, revenue is recognized in proportion to the additional space or power in the periods that the lessee has control over the use of the additional space or power. The excess of revenue recognized over amounts contractually due is recognized in other assets in the accompanying consolidated and combined balance sheets. As of December 31, 2014 and 2013, straight-line rents receivable was $33.7 million and $25.5 million, respectively.
	Some of our leases are structured on a full-service gross basis where the customer pays a fixed amount for both colocation rental and power. Other leases provide that the customer will be billed for power based upon their actual usage, which is separately metered, as well as an estimate of electricity used to power supporting infrastructure for the data center. In both cases, this revenue is presented on a gross basis in the accompanying consolidated and combined statement of operations. Power is generally billed one month in arrears and an estimate of this revenue is accrued in the month that the associated costs are incurred. We generally are not entitled to reimbursements for real estate taxes, insurance or other operating expenses.
	Revenue is recognized for services or products that are deemed separate units of accounting. When a customer makes an advance payment or they are contractually obligated to pay any amounts in advance, which is not deemed a separate unit of accounting, deferred revenue is recorded. This revenue is recognized ratably over the expected term of the lease, unless the pattern of service suggests otherwise. As of December 31, 2014 and 2013, deferred revenue was $65.7 million and $55.9 million, respectively.
	Certain customer contracts require specified levels of service or performance. If we fail to meet these service levels, our customers may be eligible to receive credits on their contractual billings. These credits are recognized against revenue when an event occurs that gives rise to such credits. Customer credits were immaterial for the years ended December 31, 2014 and 2013.
	A provision for uncollectible accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible. The provision for uncollectible accounts was $1.0 million in 2014, $0.5 million in 2013 and $0.3 million in 2012.
Sales and Marketing Expense	Sales and Marketing Expense—Sales and marketing expense is comprised of compensation and benefits associated
	with sales and marketing personnel as well as advertising and marketing costs. Costs related to advertising are expensed as incurred and amounted to $2.9 million for the year ended December 31, 2014, $2.1 million for the period ended December 31, 2013, $0.1 million for the period ended January 23, 2013, and $2.9 million for the year ended December 31, 2012.
Depreciation and Amortization Expense	Depreciation and Amortization Expense—Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal of the lease is reasonably assured. The residual value of leased real estate is estimated as the lesser of (i) the expected fair value of the asset at the end of the lease term or (ii) the expected amount of the unamortized liability at the end of the lease term. Estimated useful lives are periodically reviewed. Depreciation expense was $95.8 million for the year ended December 31, 2014, $70.3 million for the period ended December 31, 2013, $4.1 million for the period ended January 23, 2013, and $54.5 million for the year ended December 31, 2012.
	Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. An accelerated method of amortization is utilized to amortize our customer relationship intangible, consistent with the benefit expected to be derived from this asset. We amortize trademarks, favorable leasehold interests, deferred leasing costs and deferred sales commissions over their estimated useful lives. The estimated useful life of trademarks and customer relationships is eight to fifteen years. In addition, we have a favorable leasehold interest related to a land lease that is being amortized over the lease term of fifty-six years. Deferred leasing costs are amortized over three to five years. Amortization expense was $22.2 million for the year ended December 31, 2014, $19.6 million for the period ended December 31, 2013, $1.2 million for the period ended January 23, 2013, and $18.9 million for the year ended December 31, 2012.
Transaction Costs	Transaction Costs—Transaction costs represent legal, accounting and professional fees incurred in connection with the formation transactions, our qualification as a real estate investment trust, or REIT, and potential business combinations. Transaction costs are expensed as incurred.
Transaction-related Compensation	Transaction-Related Compensation—During the period ended January 23, 2013, the Company received an allocated compensation charge from CBI of $20.0 million for the settlement of its long-term incentive plan associated with the completion of the IPO. The amount was determined by CBI and allocated to CyrusOne Inc. on January 23, 2013, and reflected as expense and contributed capital in the respective period.
Income Taxes	Income Taxes—CyrusOne Inc. was included in CBI’s consolidated tax returns in various jurisdictions for the Predecessor period and was included in the Successor period for Texas only until June 26, 2014 when CBI's ownership percentage in the operating partnership was reduced below 50%. In the accompanying financial statements, the Predecessor period and the Successor period (for Texas only until June 26, 2014) reflect income taxes as if the Company were a separate stand-alone company. The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Code"), commencing with our initial taxable year ending December 31, 2013. Provided we continue to meet the various qualification tests mandated under the Code, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our shareholders. If we fail to qualify as a REIT in any taxable year, our taxable income will be subject to federal income tax at regular corporate rates and any applicable alternative minimum tax.
	While CyrusOne Inc. and the operating partnership do not pay federal income taxes, we are still subject to foreign, state and local income taxes in the locations in which we conduct business. Our taxable REIT subsidiaries (each a “TRS”) are also subject to federal and state income taxes to the extent they earn taxable income.
	Deferred income taxes are recognized in certain entities. Deferred income taxes are provided for temporary differences in the bases between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards.
	The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various foreign, state and local jurisdictions.  The Company's previous tax filings are subject to normal reviews by regulatory agencies until the related statute of limitations expires.  With a few exceptions, the Company is no longer subject to U. S. federal, state or local examinations for years prior to 2011, and we have no liabilities for uncertain tax positions as of December 31, 2014 or 2013.
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions—The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average rates of exchange during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive (loss) income. Gains or losses from foreign currency transactions are included in determining net income.
Comprehensive Income (Loss)	Comprehensive Loss—Comprehensive loss represents the change in net assets of a company from transactions and other events from non-owner sources. Comprehensive loss comprises all components of net loss and all components of other comprehensive loss. Comprehensive loss was equal to $0.3 million in 2014. Comprehensive loss was equal to our net loss in 2013 and 2012.
Earnings Per Share	Earnings Per Share—For all periods subsequent to January 23, 2013, we present earnings per share (“EPS”) data. Basic EPS includes only the weighted average number of common shares outstanding during the period. Diluted EPS includes the weighted average number of common shares and the dilutive effect of stock options, restricted stock and share unit awards and convertible subordinated notes outstanding during the period, when such instruments are dilutive.
	All outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are treated as participating in undistributed earnings with common shareholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS must be applied.
Related Party Transactions	Related Party Transactions—CBI provided us with a variety of services. Cost allocation methods which were employed to determine the costs to be recognized in the accompanying combined financial statements included the following:
	•Specific identification—Applied when amounts were specifically identifiable to our operations.
	•Reasonable allocation method—When amounts were not clearly or specifically identifiable to our operations,
	management applied a reasonable allocation method.
Stock-Based Compensation	Stock-Based Compensation—In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan (“LTIP”). The LTIP is administered by the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. The awards under the LTIP include the following:
	Restricted Shares - On January 24, 2013, CyrusOne Inc. issued approximately 1 million restricted shares to its employees, officers and members of the Company's board of directors in conjunction with CyrusOne's IPO. These restricted shares generally vest over three years. The per share grant date price was $19.00. In addition, from time to time, new employees and members of our board of directors have been issued restricted shares. These restricted shares are issued at a price equal to our share price on the grant date.
	Performance and Market Based Awards - On April 17, 2013, and February 7, 2014, the Company issued performance and market based awards in the form of options and/or restricted stock to certain employees and officers of the Company. Fifty percent of the restricted shares and stock options will vest annually based upon achieving certain performance criteria. The other fifty percent of the restricted shares and stock options will vest at the end of three years if certain market conditions are met. The fair value of these awards were determined using the Black-Scholes or Monte-Carlo model which use assumptions such as volatility, risk-free interest rate, and expected term of the awards. See Note 15 for additional details relating to these awards.
	Compensation expense for these awards is recognized over the vesting periods.
Fair Value Measurements	Fair Value Measurements—Fair value measurements are utilized in accounting for business combinations and testing of goodwill and other long-lived assets for impairment and disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows:
	Level 1—Observable inputs for identical instruments such as quoted market prices;
	Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and
	Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data.
Business Segments	Business Segments—Business segments are components of an enterprise for which separate financial information is available and regularly viewed by the chief operating decision maker to assess performance and allocate resources. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis. Furthermore, our data centers have similar economic characteristics and customers across all geographic locations, our service offerings have similar production processes, deliver services in a similar manner and use the same types of facilities and similar technologies. As a result, we have concluded that we have one reportable operating segment.
Recently Issued Accounting Standards	Recently Issued Accounting Standards
	In February 2013, the Financial Accounting Standards Board ("FASB") issued amendments to provide guidance on the recognition, measurement and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of obligation within the scope of this guidance is fixed at the reporting date, except for obligations addressed within existing guidance in GAAP. The amendments are effective for fiscal years and interim periods within those years, beginning after December 15, 2013. The Company adopted this guidance in the first quarter of 2014 and has properly reflected the impact in the guarantor financial statements.
	In May 2014, the FASB issued guidance that outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most of the existing revenue recognition guidance. This guidance requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services and also requires certain additional disclosures which are effective for interim and annual reporting periods in fiscal years that begin after December 15, 2016.  We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements.
	In June 2014, the FASB issued a guidance update for the presentation of stock compensation.  This guidance requires an entity to treat performance targets that can be met after the requisite service period of a share based award has ended, as a performance condition that affects vesting which is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2015.  We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements.
	In August 2014, the FASB issued guidance on determining when and how reporting entities must disclose going-concern uncertainties in their financial statements. The new standard requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date of issuance of the entity’s financial statements. This guidance is effective for annual periods ending after December 15, 2016, and interim periods thereafter; early adoption is permitted. We are currently evaluating the full impact of the new standard.
	In January 2015, the FASB issued guidance eliminating from U.S. GAAP the concept of an extraordinary item. An entity is no longer required to (1) segregate an extraordinary item from the results of ordinary operations; (2) separately present an extraordinary item on its income statement, net of tax, after income from continuing operations; and (3) disclose income taxes and earnings-per-share data applicable to an extraordinary item. This guidance does not affect the reporting and disclosure requirements for an event that is unusual in nature or that occurs infrequently.

Investment_in_Real_Estate_Tabl

Investment in Real Estate (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Schedule of Gross Investment in Real Estate	A schedule of our gross investment in real estate follows:
		December 31, 2014						December 31, 2013
	(amounts in millions)	Land		Building and		Equipment		Land		Building and		Equipment
				Improvements						Improvements
	West Seventh St., Cincinnati, OH (7th Street)	$	0.9	$	110.6	$	12.7	$	0.9	$	107.6	$	11
	Parkway Dr., Mason, OH (Mason)	—		20.2		0.9		—		20.2		0.6
	Industrial Rd., Florence, KY (Florence)	2.2		41.4		3		2.2		41.4		2.4
	Goldcoast Dr., Cincinnati, OH (Goldcoast)	0.6		6.7		0.1		0.6		6.7		0.1
	Knightsbridge Dr., Hamilton, OH (Hamilton)	—		49.2		3.7		—		49.2		3.6
	E. Monroe St., South Bend, IN (Monroe St.)	—		2.5		0.1		—		2.5		—
	Springer St., Lombard, IL (Lombard)	0.7		4.7		5.7		0.7		4.6		0.2
	Crescent Circle, South Bend, IN (Blackthorn)	—		3.3		0.1		—		3.3		0.2
	Kingsview Dr., Lebanon, OH (Lebanon)	4		77		5.5		4		71.7		2.2
	McAuley Place, Blue Ash, OH (Blue Ash)	—		0.6		0.1		—		0.6		—
	Westway Park Blvd., Houston, TX (Houston West 1)	1.4		84.4		43.8		1.4		84.4		39.4
	Westway Park Blvd., Houston, TX (Houston West 2)	2		22.5		45.1		2		22.4		15.8
	Westway Park Blvd., Houston, TX (Houston West 3)	18.4		—		—		18.3		—		—
	Southwest Fwy., Houston, TX (Galleria)	—		68.6		15		—		68.4		13.3
	E. Ben White Blvd., Austin, TX (Austin 1)	—		22.5		1.2		—		22.5		1.2
	S. State Highway 121 Business, Lewisville, TX (Lewisville)	—		76.7		22.8		—		77		20.3
	Marsh Lane, Carrollton, TX (Marsh Ln)	—		0.1		0.5		—		0.1		0.5
	Midway Rd., Carrollton, TX (Midway)	—		2		0.4		—		2		0.4
	W. Frankford Rd., Carrollton, TX (Carrollton)	16.1		51.6		85.3		16.1		42.6		34.8
	Bryan St., Dallas, TX (Bryan St)	—		0.1		0.2		—		0.1		0.1
	North Freeway, Houston, TX (Greenspoint)	—		1.3		—		—		1.3		0.4
	South Ellis Street, Chandler, AZ (Phoenix 1)	14.8		56.4		43.9		15		55.7		11.7
	South Ellis Street, Chandler, AZ (Phoenix 2)	—		13.2		21.8		—		—		—
	Westover Hills Blvd., San Antonio, TX (San Antonio 1)	4.6		32.1		32.4		4.6		32.1		29.5
	Westover Hills Blvd., San Antonio, TX (San Antonio 2)	7		—		—		6.7		—		—
	Metropolis Dr., Austin, TX (Austin 2)	2		23.2		4		2		23.1		1.7
	Kestral Way (London)	—		32.7		0.7		—		34.8		0.7
	Jurong East (Singapore)	—		9		0.1		—		9.4		0.1
	Ridgetop Circle, Sterling, VA (Northern VA)	7		—		—		6.9		—		—
	Metropolis Dr., Austin, TX (Austin 3)	8		—		—		7.9		—		—
	Total	$	89.7	$	812.6	$	349.1	$	89.3	$	783.7	$	190.2

Goodwill_Intangible_and_Other_1

Goodwill, Intangible and Other Long-Lived Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Carrying Value of Major Classes of Intangible Assets	Summarized below are the carrying values for the major classes of intangible assets:
	(amounts in millions)			31-Dec-14							31-Dec-13
		Weighted-		Gross		Accumulated			Total		Gross		Accumulated			Total
		Average Life		Carrying		Amortization					Carrying		Amortization
		(in years)		Amount							Amount
	Customer relationships	15		$	129.7	$	(69.5	)	$	60.2	$	129.7	$	(53.1	)	$	76.6
	Trademark	15		7.4		(2.3		)	5.1		7.4		(1.8		)	5.6
	Favorable leasehold interest	56		3.9		(0.3		)	3.6		3.9		(0.2		)	3.7
	Total			$	141	$	(72.1	)	$	68.9	$	141	$	(55.1	)	$	85.9
Schedule of Estimated Amortization Expense for Finite-Lived Intangible Assets	The following table presents estimated amortization expense for each of the next five years and thereafter, commencing January 1, 2015:
	(amounts in millions)
	2015	$	14.6
	2016	11.6
	2017	9.5
	2018	7.6
	2019	5.9
	Thereafter	19.7
	Total	$	68.9

Debt_and_Other_Financing_Arran1

Debt and Other Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt and other financing arrangements	Debt and other financing arrangements presented in the accompanying consolidated and combined financial statements consist of the following:
	(amounts in millions)	December 31,			December 31,
		2014			2013
	Revolving facility	$	135		$	—
	Term loan	150			—
	6 3/8% senior notes due 2022	374.8			525
	Long-term debt	659.8			525
	Capital lease obligations	13.4			16.7
	Other financing arrangements	53.4			56.3
	Total	$	726.6		$	598
Annual minimum payments associated with our other financing arrangements	The following table summarizes our annual minimum payments associated with our other financing arrangements for the five years subsequent to December 31, 2014, and thereafter:
	(amounts in millions)
	2015	$	5.6
	2016	5.7
	2017	5.8
	2018	5.9
	2019	6
	Thereafter	21.1
	Total financing arrangements	$	50.1
Schedule of annual principal maturities of our 6 3/8% Senior Notes due 2022 and capital leases	The following table summarizes annual principal maturities of our revolving facility and term loan, 6 3/8% senior notes due 2022 and capital leases for the five years subsequent to December 31, 2014, and thereafter:
	(amounts in millions)	Revolving Facility/Term Loan		6.375% Senior Notes			Capital Leases		Total
	2015	$	—	$	—		$	2.3	$	2.3
	2016	—		—			2.5		2.5
	2017	—		—			1.2		1.2
	2018	135		—			1.4		136.4
	2019	150		—			1.5		151.5
	Thereafter	—		374.8			4.5		379.3
	Total debt	$	285	$	374.8		$	13.4	$	673.2

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Carrying Value and Fair Value of Other Financial Instruments	The carrying value and fair value of other financial instruments are as follows:
		31-Dec-14				31-Dec-13
	(amounts in millions)	Carrying Value		Fair Value		Carrying Value		Fair Value
	6.375% senior notes due 2022	$	374.8	$	402	$	525	$	539.4
	Revolving facility and term loan	285		285		—		—
	Other financing arrangements	53.4		63.1		56.3		63.8
Assets Measured at Fair Value	The measured fair value used in the 2013 related impairment charges is summarized below:
	(amounts in millions)	December 31,		Quoted prices		Significant		Significant		2013 Impairment
		2013		in active		Other		Unobservable		Loss
				markets for		Observable		Inputs
				Identical Assets		Inputs		(Level 3)
				(Level 1)		(Level 2)
	Equipment	$	0.3	$	—	$	0.3	$	—	$	(2.8	)
	Total Impairment									$	(2.8	)

Noncontrolling_Interests_Opera1

Noncontrolling Interests - Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Schedule of Ownership Interests in Operating Partnership	The following table shows the ownership interests as of December 31, 2014 and 2013, and the portion of net loss and distributions for the year ended December 31, 2014, and the period ended December 31, 2013:
		31-Dec-14						31-Dec-13
	(amounts in millions, except unit amount)	The Company			CBI			The Company			CBI
	Operating partnership units	38.7			26.6			22			42.6
	Ownership %	59.2		%	40.8		%	34.1		%	65.9		%
	Portion of net loss	$	(7.8	)	$	(6.7	)	$	(5.3	)	$	(10.3	)
	Distributions	$	(29.2	)	$	(25.7	)	$	(13.6	)	$	(27.8	)

Dividends_Tables

Dividends (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Schedule of declared cash dividends on common shares and distributions on operating partnership units	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2014 and 2013 as presented in the table below:
	Record date	Payment date		Cash dividend per share or operating partnership unit
	March 29, 2013	April 15, 2013		$0.16
	June 28, 2013	July 15, 2013		$0.16
	September 27, 2013	October 15, 2013		$0.16
	December 27, 2013	January 10, 2014		$0.16
	March 28, 2014	April 15, 2014		$0.21
	June 27, 2014	July 15, 2014		$0.21
	September 26, 2014	October 15, 2014		$0.21
	December 26, 2014	January 9, 2015		$0.21
	In 2014 and 2013, we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the year ended December 31, 2014 and the period ended December 31, 2013:
		Year Ended			Period Ended
		31-Dec-14			31-Dec-13
	Common Stock dividend per share:
	Ordinary income	$	0.45		$	0.23
	Capital gains	—			—
	Return of capital	0.34			0.25
	Total dividend	$	0.79		$	0.48

Customer_Leases_Tables

Customer Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The future minimum lease payments to be received under non-cancelable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below:
	(amounts in millions)
	2015	$	240.8
	2016	176.2
	2017	126.8
	2018	87
	2019	47.3
	At December 31, 2014, future minimum lease payments required under operating leases having initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(amounts in millions)
	2015	$	4.6
	2016	1.4
	2017	0.9
	2018	0.2
	2019	—
	Thereafter	0.9
	Total	$	8

Loss_per_Share_Tables

Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) Per Share	The following table reflects a reconciliation of the shares used in the basic and diluted net loss per share computation for the period ended December 31, 2014:
		Year Ended						Period Ended
		31-Dec-14						31-Dec-13
	(dollars and shares in millions, except per share amounts)	Basic			Diluted			Basic			Diluted
	Numerator:
	Net loss attributed to common shareholders	$	(7.8	)	$	(7.8	)	$	(5.3	)	$	(5.3	)
	Less: Restricted stock dividends	(0.8		)	(0.8		)	(0.6		)	(0.6		)
	Net loss available to shareholders	$	(8.6	)	$	(8.6	)	$	(5.9	)	$	(5.9	)
	Denominator:
	Weighted average common outstanding-basic	29.2			29.2			20.9			20.9
	Performance-based restricted stock(1)(2)				—						—
	Convertible securities(1)(2)				—						—
	Weighted average shares outstanding-diluted				29.2						20.9
	EPS:
	Net loss per share-basic	$	(0.30	)				$	(0.28	)
	Effect of dilutive shares										—
	Net loss per share-diluted				$	(0.30	)				$	(0.28	)

StockBased_Compensation_Plans_

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Restricted Stock Awards Activity	Restricted stock awards vest over specified periods of time as long as the employee remains employed with the Company. The following table sets forth the number of unvested shares of restricted stock and the weighted average fair value of these shares at the date of grant:
		Shares of Restricted Stock			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	1,024,064			19.01
	Vested	—			—
	Forfeited	(119,712	)		19
	Unvested balance at December 31, 2013	904,352			19.01
	Granted	46,313			20.73
	Vested	(47,845	)		19.17
	Forfeited	(25,948	)		19
	Unvested balance at December 31, 2014	876,872			$	19.09
Schedule of Performance-Based and Market-Based Stock Activity	The following table sets forth the number of unvested shares of performance and market based awards and the weighted average fair value of these shares at the date of grant:
		Shares of Restricted Stock			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	250,565			23.58
	Vested	—			—
	Forfeited	(28,248	)		23.58
	Unvested balance at December 31, 2013	222,317			23.58
	Granted	672,158			20.65
	Vested	(18,484	)		23.55
	Forfeited	(13,221	)		21.26
	Unvested balance at December 31, 2014	862,770			$	21.33
Schedule of Option Valuation Assumptions	Significant assumptions used in the Black-Scholes model were the following:
	Number of options granted	190,432
	Exercise price	$	23.58
	Expected term (in years)	6
	Expected volatility	35		%
	Expected annual dividend	3.4		%
	Risk-free rate	0.92		%
	Fair value at date of grant	$	1.4	million
Schedule of Unvested Stock Options	The following table sets forth the number of unvested options as of December 31, 2014 and 2013 and the weighted average fair value of these options at the grant date:
		Shares of Restricted Options			Weighted Average Fair Value at Date of Grant
	Unvested balance at December 31, 2012	—			$	—
	Granted	190,432			7.46
	Vested	—			—
	Forfeited	(21,469	)		7.46
	Unvested balance at December 31, 2013	168,963			7.46
	Granted	—			—
	Vested	—			—
	Forfeited	(2,091	)		7.46
	Unvested balance at December 31, 2014	166,872			$	7.46
Schedule of Exercisable Options	The following tables set forth the number of exercisable options as of December 31, 2014 and the weighted average fair value and exercise price of these options at the grant date:
		Shares of Restricted Options			Weighted Average Fair Value at Date of Grant
	Options Exercisable at December 31, 2013	—			$	—
	Vested	13,915			7.46
	Exercised	—			—
	Options Exercisable at December 31, 2014	13,915			$	7.46
		Exercisable Options			Fair Value at Date of Grant			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
	As of December 31, 2014	13,915			$	0.1	million	$	23.58	8.3 years
Schedule of Compensation Expense	The following table sets forth compensation expense for the year ended December 31, 2014 and the period ended December 31, 2013:
		Year Ended				Period Ended
		31-Dec-14				31-Dec-13
	Restricted Stock	$	6.4			$	5.3
	Performance and market based awards	3.7				0.8
	Stock options	0.2				0.1
	Total compensation expense	$	10.3			$	6.2

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following related party transactions are based on agreements and arrangements that were in place during the respective periods. Revenues and expenses for the periods presented were as follows:
		Successor				Predecessor
	(amounts in millions)	31-Dec-14		January 24, 2013 to December 31, 2013		January 1, 2013 to January 23, 2013		31-Dec-12
	Revenue:
	Data center colocation agreement provided to CBT and CBTS	$	6.4	$	5.6	$	0.3	$	5.4
	229 West 7th Street lease provided to CBT	2		1.7		—		—
	Goldcoast Drive/Parkway (Mason) lease	0.4		0.3		—		0.3
	Transition services provided to CBTS (network interfaces)	0.4		0.6		0.1		0.5
	Data center leases provided to CBTS	13.6		13.1		—		14.3
	Total revenue	$	22.8	$	21.3	$	0.4	$	20.5
	Operating costs and expenses:
	Transition services agreement by CBTS	$	0.8	$	1.3	$	—	$	1.5
	Charges for services provided by CBT (connectivity)	1		1		0.1		0.7
	209 West 7th Street rent provided by CBT	0.2		0.1		—		0.1
	Management fees with CBI	—		0.1		—		2.5
	Allocated employee benefit plans by CBI	—		—		0.2		3.5
	Allocated centralized insurance costs by CBI	—		—		0.1		0.4
	Selling and marketing services provided by CBT & CBTS	—		—		—		0.3
	Interest expense on note with CBI	—		—		—		7
	Loss on sale of receivables	—		—		—		3.2
	Total operating costs and expenses	$	2	$	2.5	$	0.4	$	19.2
	As of December 31, 2014 and 2013, the amounts receivable and payable to CBI were as follows:
		Successor		Successor
		As of		As of
	(amounts in millions)	December 31, 2014		December 31, 2013
	Accounts receivable from CBI	$	0.8	$	0.6
	Accounts payable	$	1.7	$	1.7
	Dividends payable	5.6		6.8
	Accounts payable to CBI	$	7.3	$	8.5

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of taxability of common stock dividends per share	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2014 and 2013 as presented in the table below:
	Record date	Payment date		Cash dividend per share or operating partnership unit
	March 29, 2013	April 15, 2013		$0.16
	June 28, 2013	July 15, 2013		$0.16
	September 27, 2013	October 15, 2013		$0.16
	December 27, 2013	January 10, 2014		$0.16
	March 28, 2014	April 15, 2014		$0.21
	June 27, 2014	July 15, 2014		$0.21
	September 26, 2014	October 15, 2014		$0.21
	December 26, 2014	January 9, 2015		$0.21
	In 2014 and 2013, we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the year ended December 31, 2014 and the period ended December 31, 2013:
		Year Ended			Period Ended
		31-Dec-14			31-Dec-13
	Common Stock dividend per share:
	Ordinary income	$	0.45		$	0.23
	Capital gains	—			—
	Return of capital	0.34			0.25
	Total dividend	$	0.79		$	0.48

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The future minimum lease payments to be received under non-cancelable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below:
	(amounts in millions)
	2015	$	240.8
	2016	176.2
	2017	126.8
	2018	87
	2019	47.3
	At December 31, 2014, future minimum lease payments required under operating leases having initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(amounts in millions)
	2015	$	4.6
	2016	1.4
	2017	0.9
	2018	0.2
	2019	—
	Thereafter	0.9
	Total	$	8

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Unaudited Selected Quarterly Financial Information	The table below reflects the unaudited selected quarterly information for the years ended December 31, 2014 and 2013:
	(dollars in millions, except per share amounts)
					2014
					First			Second			Third			Fourth			Total
					Quarter			Quarter			Quarter			Quarter
	Revenue				$	77.5		$	81.7		$	84.8		$	86.9		$	330.9
	Operating income				11.8			7.4			9.6			11.2			40
	Net income (loss)				0.7			(3.6		)	0.2			(11.8		)	(14.5		)
	Net income (loss) attributed to common shareholders				0.2			(1.1		)	0.1			(7.0		)	(7.8		)
	Basic and diluted loss per share(a)				—			(0.06		)	—			(0.19		)	(0.25		)
		2013
		January 1, 2013 to January 23, 2013			January 24, 2013 to March 31, 2013			Second			Third			Fourth			Total
								Quarter			Quarter			Quarter
	Revenue	$	15.1		$	45		$	63.6		$	67.5		$	72.3		$	263.5
	Operating (loss) income	(17.3		)	5.8			5.6			8.5			9			11.6
	Net loss	(20.2		)	(2.8		)	(6.8		)	(2.2		)	(3.8		)	(35.8		)
	Net loss attributed to common shareholders	—			(0.9		)	(2.3		)	(0.8		)	(1.3		)	(5.3		)
	Basic and diluted loss per share	—			(0.05		)	(0.12		)	(0.05		)	(0.06		)	(0.28		)

Description_of_Business_Detail

Description of Business (Details)	Dec. 31, 2014
	Center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of data operating centers	25

Formation_Details

Formation (Details) (USD $)	0 Months Ended		1 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 25, 2013	Jun. 25, 2014	Jun. 30, 2014	Nov. 20, 2012	Dec. 31, 2014	Dec. 31, 2013	Jan. 23, 2013
Business Formation [Line Items]
Common stock issued (in shares)	400,000
Partners' capital units converted (in shares)	1,500,000
Proceeds from exchange of partnership units	1,500,000
Number of common shares issued to directors and employees	1,100,000
Shares purchased of Operating partnership's units		16,000,000
Ownership percentage by noncontrolling owners					40.80%	65.90%
IPO [Member]
Business Formation [Line Items]
Common stock issued (in shares)	19,000,000	16,000,000	16,000,000
Net proceeds from IPO after underwriting discounts and commissions	337.1	$355.90
Share price (in dollars per share)		$23.25
Net proceeds from IPO after underwriting discounts and commissions		371.7
Underwriting discount		15.8
Over-Allotment Option [Member]
Business Formation [Line Items]
Common stock issued (in shares)		2,100,000
CyrusOne Inc. and CyrusOne GP [Member]
Business Formation [Line Items]
Shares purchased of Operating partnership's units							21,900,000
Combined interest held on completion of transactions							33.90%
Purchase of Operating partnership's units							$337.10
Cincinnati Bell Inc. [Member]
Business Formation [Line Items]
Operating partnership units owned (in shares)	44,100,000
Remaining combined interest held							66.10%
Ownership percentage by noncontrolling owners					40.80%
General Partner [Member] | Cincinnati Bell Inc. [Member]
Business Formation [Line Items]
Ownership percentage by noncontrolling owners					43.70%
CyrusOne L.P. [Member]
Business Formation [Line Items]
Issuance of partnership units (in shares)				123,700,000
Partnership reverse unit split, conversion ratio	2.8
Operating partnership units					65,300,000

Significant_Accounting_Policie2

Significant Accounting Policies (Details) (USD $)	1 Months Ended	11 Months Ended	12 Months Ended			0 Months Ended		3 Months Ended
	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 25, 2013	Apr. 17, 2013	Mar. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Percentage of lease term			75.00%
Percentage of lease payment			90.00%
Capitalized interest			$4,600,000	$1,600,000	$2,700,000
Impairment of real estate			0	2,800,000	11,800,000
Impairment of goodwill			0	0
Impairment of long-lived and intangible assets			0	0
Unbilled receivables			8,700,000
Unbilled receivables, collection term			36 months
Receivables		41,700,000	61,900,000	41,700,000
Allowance for doubtful accounts receivable		500,000	1,000,000	500,000
Straight-line rents receivable			33,700,000	25,500,000
Deferred revenue		55,900,000	65,700,000	55,900,000
Provision for uncollectible accounts			1,000,000	500,000	300,000
Advertising expense	100,000	2,100,000	2,900,000		2,900,000
Depreciation expense	4,100,000	70,300,000	95,800,000		54,500,000
Lease term of favorable leasehold interest which being amortized			56 years
Amortization expense for intangible assets subject to amortization	1,200,000	19,600,000	22,200,000		18,900,000
Foreign currency translation adjustments			300,000
Restricted Stock
Summary Of Significant Accounting Policies [Line Items]
Other than options issued (in shares)			46,313	1,024,064		1,000,000
Award vesting period			3 years			3 years
Other than options granted, weighted average grant date fair value (in dollars per share)			$20.73	$19.01		$19
Performance Awards [Member]
Summary Of Significant Accounting Policies [Line Items]
Award vesting period							3 years
Performance Awards [Member] | Performance Criteria [Member]
Summary Of Significant Accounting Policies [Line Items]
Award vesting rights percentage							50.00%
Performance Awards [Member] | Market Conditions [Member]
Summary Of Significant Accounting Policies [Line Items]
Award vesting rights percentage							50.00%
Cincinnati Bell Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Transaction-related compensation	20,000,000
Customer Relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived and intangible assets					$1,500,000
Useful life of finite-lived intangible assets			15 years
Customer Concentration Risk [Member] | Receivables [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers that exceed 10% of total receivables			1
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Receivables due term			30 days
Deferred leasing costs amortization term			3 years
Minimum [Member] | Trademarks and Customer Relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life of finite-lived intangible assets			8 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Receivables due term			120 days
Deferred leasing costs amortization term			5 years
Maximum [Member] | Trademarks and Customer Relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life of finite-lived intangible assets			15 years
Buildings [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								9 years
Buildings [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								48 years
Building Improvements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								3 years
Building Improvements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								25 years
Equipment [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								3 years
Equipment [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life								5 years

Investment_in_Real_Estate_Sche

Investment in Real Estate - Schedule of Gross Investment in Real Estate (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Real Estate Properties [Line Items]
Land	$89.70	$89.30
Building and Improvements	812.6	783.7
Equipment	349.1	190.2
West Seventh St., Cincinnati, OH (7th Street) [Member]
Real Estate Properties [Line Items]
Land	0.9	0.9
Building and Improvements	110.6	107.6
Equipment	12.7	11
Parkway Dr., Mason, OH (Mason) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	20.2	20.2
Equipment	0.9	0.6
Industrial Rd., Florence, KY (Florence) [Member]
Real Estate Properties [Line Items]
Land	2.2	2.2
Building and Improvements	41.4	41.4
Equipment	3	2.4
Goldcoast Dr., Cincinnati, OH (Goldcoast) [Member]
Real Estate Properties [Line Items]
Land	0.6	0.6
Building and Improvements	6.7	6.7
Equipment	0.1	0.1
Knightsbridge Dr., Hamilton, OH (Hamilton) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	49.2	49.2
Equipment	3.7	3.6
E. Monroe St., South Bend, IN (Monroe St.) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	2.5	2.5
Equipment	0.1	0
Springer St., Lombard, IL (Lombard) [Member]
Real Estate Properties [Line Items]
Land	0.7	0.7
Building and Improvements	4.7	4.6
Equipment	5.7	0.2
Crescent Circle, South Bend, IN (Blackthorn) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	3.3	3.3
Equipment	0.1	0.2
Kingsview Dr., Lebanon, OH (Lebanon) [Member]
Real Estate Properties [Line Items]
Land	4	4
Building and Improvements	77	71.7
Equipment	5.5	2.2
McAuley Place, Blue Ash, OH (Blue Ash) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.6	0.6
Equipment	0.1	0
Westway Park Blvd., Houston, TX (Houston West 1) [Member]
Real Estate Properties [Line Items]
Land	1.4	1.4
Building and Improvements	84.4	84.4
Equipment	43.8	39.4
Westway Park Blvd., Houston, TX (Houston West 2) [Member]
Real Estate Properties [Line Items]
Land	2	2
Building and Improvements	22.5	22.4
Equipment	45.1	15.8
N. Sam Houston Pkwy., Houston, TX (Houston West 3) [Member]
Real Estate Properties [Line Items]
Land	18.4	18.3
Building and Improvements	0	0
Equipment	0	0
Southwest Fwy., Houston, TX (Galleria) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	68.6	68.4
Equipment	15	13.3
E. Ben White Blvd., Austin, TX (Austin 1) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	22.5	22.5
Equipment	1.2	1.2
S. State Highway 121 Business, Lewisville, TX (Lewisville) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	76.7	77
Equipment	22.8	20.3
Marsh Lane, Carrollton, TX (Marsh Ln) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.1	0.1
Equipment	0.5	0.5
Midway Rd., Carrollton, TX (Midway) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	2	2
Equipment	0.4	0.4
W. Frankford Rd., Carrollton, TX (Carrollton) [Member]
Real Estate Properties [Line Items]
Land	16.1	16.1
Building and Improvements	51.6	42.6
Equipment	85.3	34.8
Bryan St., Dallas, TX (Bryan St) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.1	0.1
Equipment	0.2	0.1
North Freeway, Houston, TX (Greenspoint) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	1.3	1.3
Equipment	0	0.4
South Ellis Street Chandler, AZ (Phoenix 1) [Member]
Real Estate Properties [Line Items]
Land	14.8	15
Building and Improvements	56.4	55.7
Equipment	43.9	11.7
South Ellis Street Chandler, AZ (Phoenix 2) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	13.2	0
Equipment	21.8	0
Westover Hills Blvd., San Antonio, TX (San Antonio 1) [Member]
Real Estate Properties [Line Items]
Land	4.6	4.6
Building and Improvements	32.1	32.1
Equipment	32.4	29.5
Westover Hills Blvd., San Antonio, TX (San Antonio 2) [Member]
Real Estate Properties [Line Items]
Land	7	6.7
Building and Improvements	0	0
Equipment	0	0
Metropolis Dr., Austin, TX (Austin 2) [Member]
Real Estate Properties [Line Items]
Land	2	2
Building and Improvements	23.2	23.1
Equipment	4	1.7
Kestral Way (London) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	32.7	34.8
Equipment	0.7	0.7
Jurong East (Singapore) [Member]
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	9	9.4
Equipment	0.1	0.1
Ridgetop Circle, Sterling, VA (Northern VA) [Member]
Real Estate Properties [Line Items]
Land	7	6.9
Building and Improvements	0	0
Equipment	0	0
Metropolis Dr., Austin, TX (Austin 3) [Member]
Real Estate Properties [Line Items]
Land	8	7.9
Building and Improvements	0	0
Equipment	$0	$0

Investment_in_Real_Estate_Addi

Investment in Real Estate - Additional Information (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Real Estate [Abstract]
Cost of construction in progress	$127	$57.30

Goodwill_Intangible_and_Other_2

Goodwill, Intangible and Other Long-Lived Assets - Narrative (Details) (USD $)	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill		$276,200,000	$276,200,000	$276,200,000
Impairment of long-lived and intangible assets			0	0
Amortization expense for intangible assets subject to amortization	$1,000,000	$15,900,000	$17,000,000		$16,400,000

Goodwill_Intangible_and_Other_3

Goodwill, Intangible and Other Long-Lived Assets - Carrying Value of Major Classes of Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$141	$141
Accumulated Amortization	-72.1	-55.1
Total	68.9	85.9
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	15 years
Gross Carrying Amount	129.7	129.7
Accumulated Amortization	-69.5	-53.1
Total	60.2	76.6
Trademark [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	15 years
Gross Carrying Amount	7.4	7.4
Accumulated Amortization	-2.3	-1.8
Total	5.1	5.6
Favorable Leasehold Interests [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	56 years
Gross Carrying Amount	3.9	3.9
Accumulated Amortization	-0.3	-0.2
Total	$3.60	$3.70

Goodwill_Intangible_and_Other_4

Goodwill, Intangible and Other Long-Lived Assets - Estimated Amortization Expense For Finite-Lived Intangible Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$14.60
2016	11.6
2017	9.5
2018	7.6
2019	5.9
Thereafter	19.7
Total	$68.90	$85.90

Debt_and_Other_Financing_Arran2

Debt and Other Financing Arrangements - Debt and Capital Lease Obligations (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Revolving credit agreement	$135,000,000	$0
Capital lease obligations	13,400,000	16,700,000
Long-term debt	659,800,000	525,000,000
Other financing arrangements	53,400,000	56,300,000
Total	726,600,000	598,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt	150,000,000	0
6.375% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$374,800,000	$525,000,000
Stated interest rate	6.38%	6.38%

Debt_and_Other_Financing_Arran3

Debt and Other Financing Arrangements - Narrative (Details) (USD $)	1 Months Ended	11 Months Ended	12 Months Ended		0 Months Ended	2 Months Ended	0 Months Ended
	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2012	Oct. 09, 2014	Dec. 31, 2014	Nov. 20, 2012	Oct. 08, 2014
Debt Instrument [Line Items]
Outstanding borrowings on revolving credit agreement		$0	$135,000,000			$135,000,000
Long-term debt		525,000,000	659,800,000			659,800,000
Interest expense on capital lease obligations	300,000	6,300,000	5,900,000	7,400,000
Total unencumbered assets			150.00%
Extinguishment of debt			800,000
Deferred financing costs		14,100,000	15,500,000			15,500,000
Amortization of deferred financing costs	100,000	4,000,000	3,400,000	300,000
6.375% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt		525,000,000	374,800,000			374,800,000
Stated interest rate		6.38%	6.38%			6.38%
Term Loan [Member]
Debt Instrument [Line Items]
Face amount of debt					150,000,000
Long-term debt			150,000,000			150,000,000
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					1.65%
6.375% Senior Notes | 6.375% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt			374,800,000			374,800,000
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
6.375% Senior Notes | 6.375% Senior Notes Due 2022 [Member] | Cyrus One Lp And Cyrus One Finance Corp [Member]
Debt Instrument [Line Items]
Long-term debt							525,000,000
Subsidiary ownership percentage threshold to act as guarantor							100.00%
Stated interest rate							6.38%
Total unencumbered assets							150.00%
Percentage of redemption price							100.00%
Percentage of senior notes declining redemption 1							103.19%
Percentage of senior notes declining redemption 2							102.13%
Percentage of senior notes declining redemption 3							101.06%
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							106.38%
Percentage of Redemption of the least aggregate principal							65.00%
Term of redemption occurs							90 days
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit agreement amount					450,000,000			225,000,000
Term of extension option					1 year
Optional additional borrowing capacity					300,000,000
Outstanding borrowings on revolving credit agreement		0	135,000,000			135,000,000
Commitment fee percent			0.25%
Commitment fee amount			$1,100,000
Maximum percentage of dividends allowed to be distributed			95.00%			95.00%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					1.70%

Debt_and_Other_Financing_Arran4

Debt and Other Financing Arrangements - Capital Lease Obligations (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Capital Leased Assets [Line Items]
2015	$5.60
2016	5.7
2017	5.8
2018	5.9
2019	6
Thereafter	21.1
Total financing arrangements	50.1
Interest on Capital Leases [Member]
Capital Leased Assets [Line Items]
2015	1.2
2016	1
2017	0.8
2018	0.7
2019	0.5
Thereafter	$0.80

Debt_and_Other_Financing_Arran5

Debt and Other Financing Arrangements - Maturities of Debt (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]
2015	$2.30
2016	2.5
2017	1.2
2018	136.4
2019	151.5
Thereafter	379.3
Long-term Debt	673.2
Revolving Facility/Term Loan
Debt Instrument [Line Items]
2015	0
2016	0
2017	0
2018	135
2019	150
Thereafter	0
Long-term Debt	285
6.375% Senior Notes
Debt Instrument [Line Items]
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	374.8
Long-term Debt	374.8
Capital Leases
Debt Instrument [Line Items]
2015	2.3
2016	2.5
2017	1.2
2018	1.4
2019	1.5
Thereafter	4.5
Long-term Debt	$13.40

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$659.80	$525
Other financing arrangements	53.4	56.3
Equipment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset impairments	-2.8
Book value of assets	3.1
Equipment purchased	0.3
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset impairments		-2.8
Fair Value, Measurements, Nonrecurring [Member] | Equipment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-lived intangible assets		0.3
Asset impairments		-2.8
Quoted prices in active markets for Identical Assets (Level 1) | Fair Value, Measurements, Nonrecurring [Member] | Equipment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-lived intangible assets		0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring [Member] | Equipment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-lived intangible assets		0.3
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring [Member] | Equipment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-lived intangible assets		0
6.375% Senior Notes Due 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	374.8	525
Stated interest rate	6.38%	6.38%
Revolving Facility/Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	285	0
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other financing arrangements	63.1	63.8
Fair Value | 6.375% Senior Notes Due 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	402	539.4
Fair Value | Revolving Facility/Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$285	$0

Noncontrolling_Interests_Opera2

Noncontrolling Interests - Operating Partnership (Details) (USD $)	0 Months Ended	1 Months Ended	2 Months Ended	3 Months Ended							12 Months Ended		0 Months Ended	11 Months Ended	0 Months Ended	1 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 25, 2013	Jan. 23, 2013	Mar. 31, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Nov. 20, 2012	Dec. 31, 2013	Jun. 25, 2014	Jun. 30, 2014	Sep. 30, 2014
Noncontrolling Interest [Line Items]
Net loss		($20.20)	($2.80)	($11.80)	$0.20	($3.60)	$0.70	($3.80)	($2.20)	($6.80)	($14.50)	($35.80)
Partners' capital units converted (in shares)	1,500,000
Common stock issued (in shares)	400,000
Ownership percentage by noncontrolling owners				40.80%				65.90%			40.80%	65.90%		65.90%
CyrusOne LP [Member]
Noncontrolling Interest [Line Items]
Issuance of partnership units (in shares)													123,700,000
Predecessor's intercompany payables and other liabilities assumed by previous parent company												203.5
Partnership reverse unit split, conversion ratio	2.8
Cincinnati Bell Inc. [Member]
Noncontrolling Interest [Line Items]
Operating partnership units owned (in shares)	44,100,000
Ownership percentage by noncontrolling owners				40.80%							40.80%
Successor [Member]
Noncontrolling Interest [Line Items]
Net loss											-14.5			-15.6
Dividends declared / Partnership distributions											-54.9			-41.4
Successor [Member] | CyrusOne LP [Member]
Noncontrolling Interest [Line Items]
Net loss											-14.5			-15.6
IPO [Member]
Noncontrolling Interest [Line Items]
Common stock issued (in shares)	19,000,000														16,000,000	16,000,000
Share price (in dollars per share)															$23.25
Net proceeds from IPO after underwriting discounts and commissions															371.7
Net proceeds from IPO after underwriting discounts and commissions	337.1														355.9
Underwriting discount															15.8
Over-Allotment Option [Member]
Noncontrolling Interest [Line Items]
Common stock issued (in shares)															2,100,000
Parent [Member]
Noncontrolling Interest [Line Items]
Operating partnership units				38,700,000				22,000,000			38,700,000	22,000,000		22,000,000
Ownership %				59.20%				34.10%			59.20%	34.10%		34.10%
Net loss											-7.8	-5.3
Dividends declared / Partnership distributions											-29.2	-13.6
Parent [Member] | Successor [Member]
Noncontrolling Interest [Line Items]
Net loss											-14.5			-15.6
Dividends declared / Partnership distributions														-13.6
Non Controlling Interest
Noncontrolling Interest [Line Items]
Operating partnership units				26,600,000				42,600,000			26,600,000	42,600,000		42,600,000
Net loss											-6.7	-10.3
Dividends declared / Partnership distributions											-25.7	-27.8
Acquisition of partnership units																	166.9
Non Controlling Interest | Successor [Member]
Noncontrolling Interest [Line Items]
Dividends declared / Partnership distributions														-27.8
Paid-In Capital
Noncontrolling Interest [Line Items]
Acquisition of partnership units																	$189

Dividends_Details

Dividends (Details) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

11 Months Ended

In Millions, except Per Share data, unless otherwise specified

Oct. 15, 2014

Jul. 15, 2014

Apr. 15, 2014

Oct. 15, 2013

Jul. 15, 2013

Apr. 15, 2013

Jan. 10, 2013

Dec. 31, 2014

Dec. 31, 2013

Feb. 18, 2015

Jan. 09, 2015

Dec. 31, 2013

Schedule Of Stockholders Equity [Line Items]

Cash dividend per share or operating partnership unit (in dollars per share)

$0.21

$0.21

$0.21

$0.16

$0.16

$0.16

$0.16

$0.79

$0.48

Subsequent Event [Member]

Schedule Of Stockholders Equity [Line Items]

Cash dividend per share or operating partnership unit (in dollars per share)

$0.21

Dividends declared per share (in dollars per share)

$0.32

Subsequent Event [Member] | CyrusOne L.P. [Member]

Schedule Of Stockholders Equity [Line Items]

Dividends declared per share (in dollars per share)

$0.32

Successor [Member]

Schedule Of Stockholders Equity [Line Items]

Dividend / Distribution payable

$14.30

$10.40

Dividends declared per share (in dollars per share)

$0.84

$0.64

Customer_Leases_Details

Customer Leases (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Leases [Abstract]
2015	$240.80
2016	176.2
2017	126.8
2018	87
2019	$47.30

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	1 Months Ended	11 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2012
CyrusOne Health Care Plan [Member]
Defined Contribution Plan [Line Items]
Plan expense	$0.10	$1.60	$2.10
Retirement Savings Plan [Member]
Defined Contribution Plan [Line Items]
Employer contribution (less than $0.5 million for the period ended December 31, 2013, and less than $0.1 million for the period ended January 23, 2013)	0.1	0.5	0.8
CBI Pension and Other Benefit Plans [Member]
Defined Contribution Plan [Line Items]
Employer contribution (less than $0.5 million for the period ended December 31, 2013, and less than $0.1 million for the period ended January 23, 2013)				0.4
CBI Sponsored Health Care Plans [Member]
Defined Contribution Plan [Line Items]
Plan expense				$0.10

Loss_per_Share_Computation_of_

Loss per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) (USD $)	1 Months Ended	2 Months Ended	3 Months Ended							12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Jan. 23, 2013	Mar. 31, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss attributed to common shareholders	$0	($0.90)	($7)	$0.10	($1.10)	$0.20	($1.30)	($0.80)	($2.30)	($7.80)	($5.30)
Less: Restricted stock dividends										-0.8	-0.6
Less: Restricted stock dividends										-0.8	-0.6
Net loss available to stockholders, Basic										-8.6	-5.9
Net loss available to stockholders, Diluted										($8.60)	($5.90)
Denominator:
Weighted average common outstanding - basic (in shares)										29.2	20.9
Performance-based restricted stock (in shares)										0	0
Convertible securities (in shares)										0	0
Weighted average shares outstanding- diluted (in shares)										29.2	20.9
Loss per share - basic and diluted (in dollars per share)	$0	($0.05)	($0.19)	$0	($0.06)	$0	($0.06)	($0.05)	($0.12)	($0.25)	($0.28)
EPS:
Net loss per share- basic (in dollars per share)										($0.30)	($0.28)
Effect of dilutive shares (in dollars per share)											$0
Loss per share - diluted (in dollars per share)										($0.30)	($0.28)
Restricted Stock
EPS:
Anti-dilutive securities excluded from diluted earning per share (in shares)										0.8	0.2
Operating Partnership Units [Member]
EPS:
Anti-dilutive securities excluded from diluted earning per share (in shares)										34.3	42.6

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans - Narrative (Details) (USD $)	0 Months Ended	12 Months Ended		0 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 25, 2013	Dec. 31, 2014	Dec. 31, 2013	Apr. 17, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, options		$0.20
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)	1,000,000	46,313	1,024,064
Other than options grant date value		19.5	1
Award vesting period	3 years	3 years
Other than options vested (in shares)		47,845	0
Other than options vest date value		0.9
Unrecognized compensation expense, other than options		6
Unrecognized compensation expense, period for recognition		1 year 1 month 6 days
Performance and market based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)		672,158	250,565
Other than options grant date value		5.9	13.9
Award vesting period		3 years
Other than options vested (in shares)		18,484	0
Other than options vest date value		0.4
Unrecognized compensation expense, other than options		$4.70
Unrecognized compensation expense, period for recognition		1 year 9 months 18 days
Forfeiture rate		2.20%	11.60%
Performance based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
Performance period		3 years
Performance based restricted stock | Below 90% of EBITDA Target [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		0.00%
Performance based restricted stock | At 90% of EBITDA Target [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		50.00%
Performance based restricted stock | At 100% of EBITDA Target [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		100.00%
Performance based restricted stock | At or above 115% of EBITDA Target [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		200.00%
Market based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Measurement Period		3 years
Market based restricted stock | If CyrusOne's total stockholder return is less than the return of the Index [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		0.00%
Market based restricted stock | If CyrusOne's total stockholder return is equal to or greater than the return of the Index [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		100.00%
Market based restricted stock | if CyrusOne's total stockholder return exceeds the return of the Index by 2% [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		200.00%
Market based restricted stock | If CyrusOne's total stockholder return exceeds the return of the Index, but is negative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		-50.00%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, period for recognition		1 year 2 months 12 days
Exercise price (in dollars per share)			$23.58
2012 LTIP Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)		4,000,000
Shares available for grant (in shares)		2,000,000

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans - Other Than Options (Details) (USD $)	0 Months Ended	12 Months Ended
	Jan. 25, 2013	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock
Shares
Unvested balance (in shares)		904,352	0
Granted (in shares)	1,000,000	46,313	1,024,064
Vested (in shares)		-47,845	0
Forfeited (in shares)		-25,948	-119,712
Unvested balance (in shares)		876,872	904,352
Weighted Average Fair Value at Date of Grant
Unvested balance (in dollars per share)		$19.01	$0
Granted (in dollars per share)	$19	$20.73	$19.01
Vested (in dollars per share)		$19.17	$0
Forfeited (in dollars per share)		$19	$19
Unvested balance (in dollars per share)		$19.09	$19.01
Performance and market based awards
Shares
Unvested balance (in shares)		222,317	0
Granted (in shares)		672,158	250,565
Vested (in shares)		-18,484	0
Forfeited (in shares)		-13,221	-28,248
Unvested balance (in shares)		862,770	222,317
Weighted Average Fair Value at Date of Grant
Unvested balance (in dollars per share)		$23.58	$0
Granted (in dollars per share)		$20.65	$23.58
Vested (in dollars per share)		$23.55	$0
Forfeited (in dollars per share)		$21.26	$23.58
Unvested balance (in dollars per share)		$21.33	$23.58

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans - Option Valuation Assumptions (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)	0	190,432
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)		190,432
Exercise price (in dollars per share)		23.58
Expected term (in years)		6 years
Expected volatility		35.00%
Expected annual dividend		3.40%
Risk-free rate		0.92%
Fair value at date of grant		1.4

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans - Options (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Shares of Restricted Options
Unvested balance (in shares)	168,963	0
Exercisable (in shares)	0
Granted (in shares)	0	190,432
Vested (in shares)	-13,915
Forfeited (in shares)	-2,091	-21,469
Exercised (in shares)	0
Exercisable (in shares)	13,915	0
Unvested balance (in shares)	166,872	168,963
Weighted Average Fair Value at Date of Grant
Unvested balance (in dollars per share)	$7.46	$0
Granted (in dollars per share)	$0	$7.46
Vested (in dollars per share)	$7.46
Exercised (in dollars per share)	$0
Forfeited (in dollars per share)	$7.46	$7.46
Exercisable (in dollars per share)	$7.46	$0
Unvested balance (in dollars per share)	$7.46	$7.46
Options, Additional Disclosures
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Fair Value	$0.10
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$7.46	$0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	8 years 3 months 18 days

StockBased_Compensation_Plans_5

Stock-Based Compensation Plans - Compensation Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$10.30	$6.20
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	6.4	5.3
Performance and market based awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	3.7	0.8
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$0.20	$0.10

Related_Party_Transactions_Sch

Related Party Transactions - Schedule of Related Party Transactions (Details) (USD $)	12 Months Ended		11 Months Ended	1 Months Ended	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Jan. 23, 2013	Dec. 31, 2012
Receivable and payable to CBI:
Due from affiliates	$0.60	$0.80	$0.60
Cincinnati Bell Inc. [Member]
Receivable and payable to CBI:
Cash dividend payable (in dollars per share)		$0.21
Bosselaw [Member]
Operating costs and expenses:
Expenses to related party	1.6
Receivable and payable to CBI:
Expenses to related party	1.6
Jones Lang LaSalle [Member]
Operating costs and expenses:
Expenses to related party	1.5
Receivable and payable to CBI:
Expenses to related party	1.5
Skadden [Member]
Operating costs and expenses:
Expenses to related party	0.2	1.1
Receivable and payable to CBI:
Expenses to related party	0.2	1.1
Successor [Member]
Revenue:
Total revenue		22.8	21.3
Operating costs and expenses:
Expenses to related party		2	2.5
Receivable and payable to CBI:
Due from affiliates	0.6	0.8	0.6
Accounts payable	1.7	1.7	1.7
Dividends payable	6.8	5.6	6.8
Accounts payable to CBI	8.5	7.3	8.5
Expenses to related party		2	2.5
Successor [Member] | Data center colocation agreement provided to CBT and CBTS
Revenue:
Total revenue		6.4	5.6
Successor [Member] | 229 West 7th Street lease provided to CBT
Revenue:
Total revenue		2	1.7
Successor [Member] | Goldcoast Drive lease provided to CBT [Member]
Revenue:
Total revenue		0.4	0.3
Successor [Member] | Transition services provided to CBTS (network interfaces)
Revenue:
Total revenue		0.4	0.6
Operating costs and expenses:
Expenses to related party		0.8	1.3
Receivable and payable to CBI:
Expenses to related party		0.8	1.3
Successor [Member] | Data center leases provided to CBTS
Revenue:
Total revenue		13.6	13.1
Successor [Member] | Charges for services provided by CBT (connectivity)
Operating costs and expenses:
Expenses to related party		1	1
Receivable and payable to CBI:
Expenses to related party		1	1
Successor [Member] | 209 West 7th Street rent provided by CBT [Member]
Operating costs and expenses:
Expenses to related party		0.2	0.1
Receivable and payable to CBI:
Expenses to related party		0.2	0.1
Successor [Member] | Management fees with CBI [Member]
Operating costs and expenses:
Expenses to related party		0	0.1
Receivable and payable to CBI:
Expenses to related party		0	0.1
Successor [Member] | Allocated employee benefit plans by CBI
Operating costs and expenses:
Expenses to related party		0	0
Receivable and payable to CBI:
Expenses to related party		0	0
Successor [Member] | Allocated centralized insurance costs by CBI
Operating costs and expenses:
Expenses to related party		0	0
Receivable and payable to CBI:
Expenses to related party		0	0
Successor [Member] | Selling and marketing services provided by CBT & CBTS [Member]
Operating costs and expenses:
Expenses to related party		0	0
Receivable and payable to CBI:
Expenses to related party		0	0
Successor [Member] | Interest Expense on Note with CBI [Member]
Operating costs and expenses:
Expenses to related party		0	0
Receivable and payable to CBI:
Expenses to related party		0	0
Successor [Member] | Loss on Sale of Receivables [Member]
Operating costs and expenses:
Expenses to related party		0	0
Receivable and payable to CBI:
Expenses to related party		0	0
Predecessor [Member]
Revenue:
Total revenue				0.4	20.5
Operating costs and expenses:
Expenses to related party				0.4	19.2
Receivable and payable to CBI:
Expenses to related party				0.4	19.2
Predecessor [Member] | Data center colocation agreement provided to CBT and CBTS
Revenue:
Total revenue				0.3	5.4
Predecessor [Member] | 229 West 7th Street lease provided to CBT
Revenue:
Total revenue				0	0
Predecessor [Member] | Goldcoast Drive lease provided to CBT [Member]
Revenue:
Total revenue				0	0.3
Predecessor [Member] | Transition services provided to CBTS (network interfaces)
Revenue:
Total revenue				0.1	0.5
Operating costs and expenses:
Expenses to related party				0	1.5
Receivable and payable to CBI:
Expenses to related party				0	1.5
Predecessor [Member] | Data center leases provided to CBTS
Revenue:
Total revenue				0	14.3
Predecessor [Member] | Charges for services provided by CBT (connectivity)
Operating costs and expenses:
Expenses to related party				0.1	0.7
Receivable and payable to CBI:
Expenses to related party				0.1	0.7
Predecessor [Member] | 209 West 7th Street rent provided by CBT [Member]
Operating costs and expenses:
Expenses to related party				0	0.1
Receivable and payable to CBI:
Expenses to related party				0	0.1
Predecessor [Member] | Management fees with CBI [Member]
Operating costs and expenses:
Expenses to related party				0	2.5
Receivable and payable to CBI:
Expenses to related party				0	2.5
Predecessor [Member] | Allocated employee benefit plans by CBI
Operating costs and expenses:
Expenses to related party				0.2	3.5
Receivable and payable to CBI:
Expenses to related party				0.2	3.5
Predecessor [Member] | Allocated centralized insurance costs by CBI
Operating costs and expenses:
Expenses to related party				0.1	0.4
Receivable and payable to CBI:
Expenses to related party				0.1	0.4
Predecessor [Member] | Selling and marketing services provided by CBT & CBTS [Member]
Operating costs and expenses:
Expenses to related party				0	0.3
Receivable and payable to CBI:
Expenses to related party				0	0.3
Predecessor [Member] | Interest Expense on Note with CBI [Member]
Operating costs and expenses:
Expenses to related party				0	7
Receivable and payable to CBI:
Expenses to related party				0	7
Predecessor [Member] | Loss on Sale of Receivables [Member]
Operating costs and expenses:
Expenses to related party				0	3.2
Receivable and payable to CBI:
Expenses to related party				$0	$3.20

Restructuring_Charges_Details

Restructuring Charges (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Restructuring and Related Activities [Abstract]
Restructuring charges	$700,000	$0

Income_Taxes_Details

Income Taxes (Details) (USD $)	0 Months Ended							1 Months Ended	11 Months Ended	12 Months Ended
	Oct. 15, 2014	Jul. 15, 2014	Apr. 15, 2014	Oct. 15, 2013	Jul. 15, 2013	Apr. 15, 2013	Jan. 10, 2013	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
										Subsidiary
Income Taxes [Line Items]
Number of REIT subsidiaries										2
Income tax expense (benefit)								$400,000	$1,900,000	$1,400,000		($5,100,000)
Texas margin tax payable										1,700,000
Total deferred tax assets									$0	$0	$0
Common Stock:
Dividends, Common Stock, Per Share, Tax, Ordinary Income										$0.45	$0.23
Dividends, Common Stock, Per Share, Tax, Capital Gains										$0	$0
Dividends, Common Stock, Per Share, Tax, Return on Capital										$0.34	$0.25
Dividends, Common Stock, Per Share, Tax, Total Dividend	$0.21	$0.21	$0.21	$0.16	$0.16	$0.16	$0.16			$0.79	$0.48
Minimum [Member]
Income Taxes [Line Items]
Percentage of distributed taxable income to qualify as a REIT										90.00%
Maximum [Member]
Income Taxes [Line Items]
Percentage of distributed taxable income to qualify as a REIT										100.00%

Commitments_and_Contingencies_1

Commitments and Contingencies - Operating Leases (Details) (USD $)	1 Months Ended	11 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jan. 23, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
2015			$4.60
2016			1.4
2017			0.9
2018			0.2
2019			0
Thereafter			0.9
Total			8
Operating lease expense	$0.20	$6.50	$6.70	$5.90

Commitments_and_Contingencies_2

Commitments and Contingencies - Performance Guarantees (Details) (Performance Guarantee [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
Performance Guarantee [Member]
Loss Contingencies [Line Items]
Loss contingency accrual	$0	$0

Commitments_and_Contingencies_3

Commitments and Contingencies - Purchase Commitments (Details) (Certain Services [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
Minimum commitments	19.9
Minimum [Member]
Long-term Purchase Commitment [Line Items]
Term of non-cancelable purchase commitments	1 year
Maximum [Member]
Long-term Purchase Commitment [Line Items]
Term of non-cancelable purchase commitments	2 years

Guarantors_Details

Guarantors (Details) (USD $)	1 Months Ended	2 Months Ended	3 Months Ended							11 Months Ended	12 Months Ended			0 Months Ended
	Jan. 23, 2013	Mar. 31, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 25, 2014	Jan. 25, 2013	Dec. 31, 2011
Condensed Consolidating Balance Sheets
Land			$89,700,000				$89,300,000			$89,300,000	$89,700,000	$89,300,000
Buildings and improvements			812,600,000				783,700,000			783,700,000	812,600,000	783,700,000
Equipment			349,100,000				190,200,000			190,200,000	349,100,000	190,200,000
Construction in progress			127,000,000				57,300,000			57,300,000	127,000,000	57,300,000
Subtotal			1,378,400,000				1,120,500,000			1,120,500,000	1,378,400,000	1,120,500,000
Accumulated depreciation			-327,000,000				-236,700,000			-236,700,000	-327,000,000	-236,700,000
Net investment in real estate			1,051,400,000				883,800,000			883,800,000	1,051,400,000	883,800,000
Cash and cash equivalents			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			60,900,000				41,200,000			41,200,000	60,900,000	41,200,000
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			91,800,000				70,300,000			70,300,000	91,800,000	70,300,000
Total assets			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Accounts payable and accrued expenses			69,900,000				66,800,000			66,800,000	69,900,000	66,800,000
Deferred revenue			65,700,000				55,900,000			55,900,000	65,700,000	55,900,000
Due to affiliates			7,300,000				8,500,000			8,500,000	7,300,000	8,500,000
Capital lease obligations			13,400,000				16,700,000			16,700,000	13,400,000	16,700,000
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			53,400,000				56,300,000			56,300,000	53,400,000	56,300,000
Total liabilities			869,500,000				729,200,000			729,200,000	869,500,000	729,200,000
Total shareholders’ equity			460,700,000				322,000,000			322,000,000	460,700,000	322,000,000
Noncontrolling interest			256,300,000				455,600,000			455,600,000	256,300,000	455,600,000
Total equity			717,000,000				777,600,000			777,600,000	717,000,000	777,600,000
Total liabilities and equity			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Condensed Consolidating Statements of Operations
Revenue	15,100,000	45,000,000	86,900,000	84,800,000	81,700,000	77,500,000	72,300,000	67,500,000	63,600,000		330,900,000	263,500,000
Costs and expenses:
Restructuring charges												700,000	0
Operating income (loss)	-17,300,000	5,800,000	11,200,000	9,600,000	7,400,000	11,800,000	9,000,000	8,500,000	5,600,000		40,000,000	11,600,000
Income tax (expense) benefit	-400,000									-1,900,000	-1,400,000		5,100,000
Net loss	-20,200,000	-2,800,000	-11,800,000	200,000	-3,600,000	700,000	-3,800,000	-2,200,000	-6,800,000		-14,500,000	-35,800,000
Net loss attributed to common shareholders	0	-900,000	-7,000,000	100,000	-1,100,000	200,000	-1,300,000	-800,000	-2,300,000		-7,800,000	-5,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000	-2,800,000	-11,800,000	200,000	-3,600,000	700,000	-3,800,000	-2,200,000	-6,800,000		-14,500,000	-35,800,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Provision for bad debt write off											1,000,000	500,000	300,000
Cash flows from financing activities:
Cash and cash equivalents at beginning of period						148,800,000					148,800,000
Cash and cash equivalents at end of period			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions	33.90%
CyrusOne GP [Member]
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions								1.00%
Ownership percentage of non-guarantors/subsidiaries	100.00%		100.00%								100.00%
LP Co-Issuer and Finance Co-Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of non-guarantors/subsidiaries			100.00%								100.00%
Non-Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of non-guarantors/subsidiaries								100.00%
Eliminations/Consolidations [Member]
Condensed Consolidating Balance Sheets
Noncontrolling interest							455,600,000			455,600,000		455,600,000
Costs and expenses:
Noncontrolling interest in net loss												10,300,000
Cash flows from financing activities:
Dividends/Distributions paid												-20,400,000
CyrusOne L.P. [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions	33.90%
Ownership percentage of non-guarantors/subsidiaries	100.00%
CyrusOne L.P. [Member] | CyrusOne LP [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of non-guarantors/subsidiaries			100.00%								100.00%
CyrusOne L.P. [Member] | CyrusOne GP [Member]
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions								1.00%
Ownership percentage of non-guarantors/subsidiaries	100.00%
CyrusOne L.P. [Member] | LP Co-Issuer and Finance Co-Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of non-guarantors/subsidiaries			100.00%								100.00%
CyrusOne L.P. [Member] | Non-Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of non-guarantors/subsidiaries								100.00%
Successor [Member]
Condensed Consolidating Balance Sheets
Land			89,700,000				89,300,000			89,300,000	89,700,000	89,300,000
Buildings and improvements			812,600,000				783,700,000			783,700,000	812,600,000	783,700,000
Equipment			349,100,000				190,200,000			190,200,000	349,100,000	190,200,000
Construction in progress			127,000,000				57,300,000			57,300,000	127,000,000	57,300,000
Subtotal			1,378,400,000				1,120,500,000			1,120,500,000	1,378,400,000	1,120,500,000
Accumulated depreciation			-327,000,000				-236,700,000			-236,700,000	-327,000,000	-236,700,000
Net investment in real estate			1,051,400,000				883,800,000			883,800,000	1,051,400,000	883,800,000
Cash and cash equivalents			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			60,900,000				41,200,000			41,200,000	60,900,000	41,200,000
Intercompany receivable			0				0			0	0	0
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			91,800,000				70,300,000			70,300,000	91,800,000	70,300,000
Total assets			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Accounts payable and accrued expenses			69,900,000				66,800,000			66,800,000	69,900,000	66,800,000
Deferred revenue			65,700,000				55,900,000			55,900,000	65,700,000	55,900,000
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			7,300,000				8,500,000			8,500,000	7,300,000	8,500,000
Capital lease obligations			13,400,000				16,700,000			16,700,000	13,400,000	16,700,000
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			53,400,000				56,300,000			56,300,000	53,400,000	56,300,000
Total liabilities			869,500,000				729,200,000			729,200,000	869,500,000	729,200,000
Total shareholders’ equity			460,700,000				322,000,000			322,000,000	460,700,000	322,000,000
Noncontrolling interest			256,300,000				455,600,000			455,600,000	256,300,000	455,600,000
Total equity			717,000,000				777,600,000			777,600,000	717,000,000	777,600,000
Total liabilities and equity			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Condensed Consolidating Statements of Operations
Revenue										248,400,000	330,900,000
Costs and expenses:
Property operating expenses										88,400,000	124,500,000
Sales and marketing										9,900,000	12,800,000
General and administrative										26,500,000	34,600,000
Transaction-related compensation										0	0
Depreciation and amortization										89,900,000	118,000,000
Restructuring charges										700,000	0
Transaction costs										1,300,000	1,000,000
Management fees charged by CBI										0	0
Loss on sale of receivables to an affiliate										0	0
Asset impairments										2,800,000	0
Total costs and expenses										219,500,000	290,900,000
Operating income (loss)										28,900,000	40,000,000
Interest expense										41,200,000	39,500,000
Loss on extinguishment of debt										1,300,000	13,600,000
Other income										-100,000	0
Net loss before income taxes										-13,500,000	-13,100,000
Income tax (expense) benefit										-1,900,000	-1,400,000
Equity loss related to investment in subsidiaries										0	0
(Loss) gain on sale of real estate improvements										-200,000	0
Net loss										-15,600,000	-14,500,000
Noncontrolling interest in net loss										-10,300,000	-6,700,000
Net loss attributed to common shareholders										-5,300,000	-7,800,000
Condensed Consolidating Statements of Cash Flows
Net loss										-15,600,000	-14,500,000
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										89,900,000	118,000,000
Stock-based compensation expense										6,000,000	10,300,000
Noncash interest expense										4,000,000	3,400,000
Provision for bad debt write off										400,000	800,000
Loss on extinguishment of debt										1,300,000	13,600,000
Asset impairments										2,800,000	0
Deferred income tax expense (benefit), including valuation allowance change										600,000	0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-15,700,000	-37,000,000
Increase (decrease) in accounts payable and accrued expenses										-14,600,000	6,900,000
(Decrease) increase in payables to related parties										18,400,000	-200,000
Increase (decrease) in deferred revenues										-100,000	9,800,000
Net cash provided by operating activities										77,400,000	111,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										-48,000,000	0
Capital expenditures – other										-172,900,000	-284,200,000
Proceeds from the sale of assets										0	0
Increase in restricted cash										0	0
Investment in subsidiaries										0
Release of restricted cash										4,400,000	0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										-200,000	0
Net cash used in investing activities										-216,700,000	-284,200,000
Cash flows from financing activities:
Issuance of common stock/partnership units										360,500,000	356,000,000
IPO costs										-26,600,000	0
Stock issuance costs										0	-1,300,000
Acquisition of operating partnership units										0	-355,900,000
Dividends/Distributions paid										-31,000,000	-50,900,000
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement										0	315,000,000
Payments on revolving credit facility										0	-30,000,000
Payments on senior notes										0	-150,200,000
Borrowings from affiliates, net										0	0
Repayment of related party note										0	0
Proceeds from issuance of debt										0	0
Payments on capital lease obligations										-5,300,000	-3,000,000
Payments on financing obligations										-700,000	-900,000
Payments to buyout capital leases										-9,600,000
Payment to buyout other financing arrangements										-10,200,000	0
Payment of debt extinguishment costs										0	-12,800,000
Contributions from/(distributions to) parent, net										0	0
Debt issuance costs										-1,300,000	-5,200,000
Net cash provided by (used in) by financing activities										275,800,000	60,800,000
Net (decrease) increase in cash and cash equivalents										136,500,000	-112,300,000
Cash and cash equivalents at beginning of period		12,300,000				148,800,000				12,300,000	148,800,000
Cash and cash equivalents at end of period			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Successor [Member] | Parent Company [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			458,500,000				322,000,000			322,000,000	458,500,000	322,000,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			458,500,000				322,000,000			322,000,000	458,500,000	322,000,000
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			0				0			0	0	0
Total shareholders’ equity			458,500,000				322,000,000			322,000,000	458,500,000	322,000,000
Noncontrolling interest			0				0			0	0	0
Total equity			458,500,000				322,000,000			322,000,000	458,500,000	322,000,000
Total liabilities and equity			458,500,000				322,000,000			322,000,000	458,500,000	322,000,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	0
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	0
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										-5,300,000	-10,000,000
(Loss) gain on sale of real estate improvements										0
Net loss										-5,300,000	-10,000,000
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										-5,300,000	-10,000,000
Condensed Consolidating Statements of Cash Flows
Net loss										-5,300,000	-10,000,000
Equity earnings (loss) related to investment in subsidiaries										5,300,000	10,000,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										-7,100,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										9,400,000	0
Increase (decrease) in accounts payable and accrued expenses										-2,300,000	0
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										0	0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										-337,100,000
Release of restricted cash										0
Return of investment										10,600,000	25,200,000
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										-326,500,000	25,200,000
Cash flows from financing activities:
Issuance of common stock/partnership units										360,500,000	356,000,000
IPO costs										-23,400,000
Stock issuance costs											-1,300,000
Acquisition of operating partnership units											-355,900,000
Dividends/Distributions paid										-10,600,000	-24,000,000
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0	0
Payments on financing obligations										0	0
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										0	0
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										326,500,000	-25,200,000
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | CyrusOne LP [Member]
Condensed Consolidating Balance Sheets
Land			89,700,000				89,300,000			89,300,000	89,700,000	89,300,000
Buildings and improvements			812,600,000				783,700,000			783,700,000	812,600,000	783,700,000
Equipment			349,100,000				190,200,000			190,200,000	349,100,000	190,200,000
Construction in progress			127,000,000				57,300,000			57,300,000	127,000,000	57,300,000
Subtotal			1,378,400,000				1,120,500,000			1,120,500,000	1,378,400,000	1,120,500,000
Accumulated depreciation			-327,000,000				-236,700,000			-236,700,000	-327,000,000	-236,700,000
Net investment in real estate			1,051,400,000				883,800,000			883,800,000	1,051,400,000	883,800,000
Cash and cash equivalents			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			60,900,000				41,200,000			41,200,000	60,900,000	41,200,000
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			91,800,000				70,300,000			70,300,000	91,800,000	70,300,000
Total assets			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Accounts payable and accrued expenses			69,900,000				66,800,000			66,800,000	69,900,000	66,800,000
Deferred revenue			65,700,000				55,900,000			55,900,000	65,700,000	55,900,000
Due to affiliates			7,300,000				8,500,000			8,500,000	7,300,000	8,500,000
Capital lease obligations			13,400,000				16,700,000			16,700,000	13,400,000	16,700,000
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			53,400,000				56,300,000			56,300,000	53,400,000	56,300,000
Total liabilities			869,500,000				729,200,000			729,200,000	869,500,000	729,200,000
Condensed Consolidating Statements of Operations
Revenue										248,400,000	330,900,000
Costs and expenses:
Property operating expenses										88,400,000	124,500,000
Sales and marketing										9,900,000	12,800,000
General and administrative										26,500,000	34,600,000
Transaction-related compensation										0	0
Depreciation and amortization										89,900,000	118,000,000
Restructuring charges										700,000	0
Transaction costs										1,300,000	1,000,000
Management fees charged by CBI										0	0
Loss on sale of receivables to an affiliate										0	0
Asset impairments										2,800,000	0
Total costs and expenses										219,500,000	290,900,000
Operating income (loss)										28,900,000	40,000,000
Interest expense										41,200,000	39,500,000
Loss on extinguishment of debt										1,300,000	13,600,000
Other income										-100,000	0
Net loss before income taxes										-13,500,000	-13,100,000
Income tax (expense) benefit										-1,900,000	-1,400,000
(Loss) gain on sale of real estate improvements										-200,000	0
Net loss										-15,600,000	-14,500,000
Condensed Consolidating Statements of Cash Flows
Net loss										-15,600,000	-14,500,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										89,900,000	118,000,000
Stock-based compensation expense										6,000,000	10,300,000
Noncash interest expense										4,000,000	3,400,000
Provision for bad debt write off										400,000	800,000
Loss on extinguishment of debt										1,300,000	13,600,000
Asset impairments										2,800,000	0
Deferred income tax expense (benefit), including valuation allowance change										600,000	0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-15,700,000	-37,000,000
Increase (decrease) in accounts payable and accrued expenses										-14,600,000	6,900,000
(Decrease) increase in payables to related parties										18,400,000	-200,000
Increase (decrease) in deferred revenues										-100,000	9,800,000
Net cash provided by operating activities										77,400,000	111,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										-48,000,000	0
Capital expenditures – other										-172,900,000	-284,200,000
Proceeds from the sale of assets										0	0
Increase in restricted cash										0	0
Release of restricted cash										4,400,000	0
Other										-200,000	0
Net cash used in investing activities										-216,700,000	-284,200,000
Cash flows from financing activities:
Issuance of common stock/partnership units										333,900,000	100,000
Dividends/Distributions paid										-31,000,000	-50,900,000
Borrowings from revolving credit agreement										0	315,000,000
Payments on revolving credit facility										0	-30,000,000
Payments on senior notes										0	-150,200,000
Borrowings from affiliates, net										0	0
Repayment of related party note										0	0
Proceeds from issuance of debt										0	0
Payments on capital lease obligations										-5,300,000	-3,000,000
Payments on financing obligations										-700,000	-900,000
Payment to buyout other financing arrangements										-10,200,000	0
Payment of debt extinguishment costs										0	-12,800,000
Contributions from/(distributions to) parent, net										0	-1,300,000
Debt issuance costs										-1,300,000	-5,200,000
Net cash provided by (used in) by financing activities										275,800,000	60,800,000
Net (decrease) increase in cash and cash equivalents										136,500,000	-112,300,000
Cash and cash equivalents at beginning of period		12,300,000				148,800,000				12,300,000	148,800,000
Cash and cash equivalents at end of period			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Successor [Member] | LP Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			734,300,000				795,000,000			795,000,000	734,300,000	795,000,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			642,900,000				508,100,000			508,100,000	642,900,000	508,100,000
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			15,500,000				14,100,000			14,100,000	15,500,000	14,100,000
Total assets			1,392,700,000				1,317,200,000			1,317,200,000	1,392,700,000	1,317,200,000
Accounts payable and accrued expenses			12,500,000				7,800,000			7,800,000	12,500,000	7,800,000
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			5,600,000				6,800,000			6,800,000	5,600,000	6,800,000
Capital lease obligations			0				0			0	0	0
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			0				0			0	0	0
Total liabilities			677,900,000				539,600,000			539,600,000	677,900,000	539,600,000
Total shareholders’ equity			714,800,000				777,600,000			777,600,000	714,800,000	777,600,000
Noncontrolling interest			0				0			0	0	0
Total equity			714,800,000				777,600,000			777,600,000	714,800,000	777,600,000
Total liabilities and equity			1,392,700,000				1,317,200,000			1,317,200,000	1,392,700,000	1,317,200,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										36,500,000	38,200,000
Loss on extinguishment of debt										0	13,600,000
Other income										0
Net loss before income taxes										-36,500,000	-51,800,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										20,900,000	35,100,000
(Loss) gain on sale of real estate improvements										0
Net loss										-15,600,000	-16,700,000
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										-15,600,000	-16,700,000
Condensed Consolidating Statements of Cash Flows
Net loss										-15,600,000	-16,700,000
Equity earnings (loss) related to investment in subsidiaries										-20,900,000	-35,100,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										4,000,000	3,400,000
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	13,600,000
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										-13,400,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										0	400,000
Increase (decrease) in accounts payable and accrued expenses										4,800,000	4,700,000
(Decrease) increase in payables to related parties										6,800,000	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										-34,300,000	-29,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										-337,100,000
Release of restricted cash										0
Return of investment										66,500,000	97,300,000
Intercompany receipts											180,200,000
Intercompany distributions											-315,000,000
Other										0
Net cash used in investing activities										-270,600,000	-37,500,000
Cash flows from financing activities:
Issuance of common stock/partnership units										337,100,000	0
IPO costs										0
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										-31,000,000	-50,900,000
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											315,000,000
Payments on revolving credit facility											-30,000,000
Payments on senior notes											-150,200,000
Payments on capital lease obligations										0	0
Payments on financing obligations										0	0
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											-12,800,000
Contributions from/(distributions to) parent, net										0	1,300,000
Debt issuance costs										-1,300,000	-5,200,000
Net cash provided by (used in) by financing activities										304,800,000	67,200,000
Net (decrease) increase in cash and cash equivalents										-100,000	0
Cash and cash equivalents at beginning of period		100,000				0				100,000	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			0				0			0	0	0
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			0				0			0	0	0
Total shareholders’ equity			0				0			0	0	0
Noncontrolling interest			0				0			0	0	0
Total equity			0				0			0	0	0
Total liabilities and equity			0				0			0	0	0
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	0
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	0
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										0	0
(Loss) gain on sale of real estate improvements										0
Net loss										0	0
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										0	0
Condensed Consolidating Statements of Cash Flows
Net loss										0	0
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										0	0
Increase (decrease) in accounts payable and accrued expenses										0	0
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										0	0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										0
Release of restricted cash										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										0	0
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
IPO costs										0
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										0	0
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0	0
Payments on financing obligations										0	0
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										0	0
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										0	0
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | Guarantors [Member]
Condensed Consolidating Balance Sheets
Land			89,700,000				89,300,000			89,300,000	89,700,000	89,300,000
Buildings and improvements			770,900,000				739,600,000			739,600,000	770,900,000	739,600,000
Equipment			348,300,000				189,400,000			189,400,000	348,300,000	189,400,000
Construction in progress			124,800,000				57,300,000			57,300,000	124,800,000	57,300,000
Subtotal			1,333,700,000				1,075,600,000			1,075,600,000	1,333,700,000	1,075,600,000
Accumulated depreciation			-319,700,000				-232,000,000			-232,000,000	-319,700,000	-232,000,000
Net investment in real estate			1,014,000,000				843,600,000			843,600,000	1,014,000,000	843,600,000
Cash and cash equivalents			33,500,000				146,800,000			146,800,000	33,500,000	146,800,000
Investment in subsidiary			3,600,000				2,100,000			2,100,000	3,600,000	2,100,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			57,900,000				40,300,000			40,300,000	57,900,000	40,300,000
Intercompany receivable			0				200,000			200,000	0	200,000
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			73,100,000				53,000,000			53,000,000	73,100,000	53,000,000
Total assets			1,528,000,000				1,448,700,000			1,448,700,000	1,528,000,000	1,448,700,000
Accounts payable and accrued expenses			56,900,000				58,600,000			58,600,000	56,900,000	58,600,000
Deferred revenue			65,100,000				55,100,000			55,100,000	65,100,000	55,100,000
Intercompany and loan payable			642,900,000				508,100,000			508,100,000	642,900,000	508,100,000
Due to affiliates			1,700,000				1,700,000			1,700,000	1,700,000	1,700,000
Capital lease obligations			6,200,000				8,600,000			8,600,000	6,200,000	8,600,000
Long-term debt			0				0			0	0	0
Other financing arrangements			20,900,000				21,600,000			21,600,000	20,900,000	21,600,000
Total liabilities			793,700,000				653,700,000			653,700,000	793,700,000	653,700,000
Total shareholders’ equity			734,300,000				795,000,000			795,000,000	734,300,000	795,000,000
Noncontrolling interest			0				0			0	0	0
Total equity			734,300,000				795,000,000			795,000,000	734,300,000	795,000,000
Total liabilities and equity			1,528,000,000				1,448,700,000			1,448,700,000	1,528,000,000	1,448,700,000
Condensed Consolidating Statements of Operations
Revenue										244,300,000	325,100,000
Costs and expenses:
Property operating expenses										85,900,000	121,900,000
Sales and marketing										9,700,000	12,600,000
General and administrative										26,300,000	34,200,000
Depreciation and amortization										87,100,000	115,000,000
Restructuring charges										700,000
Transaction costs										1,300,000	1,000,000
Asset impairments										2,800,000
Total costs and expenses										213,800,000	284,700,000
Operating income (loss)										30,500,000	40,400,000
Interest expense										1,800,000	0
Loss on extinguishment of debt										1,300,000	0
Other income										-100,000
Net loss before income taxes										27,500,000	40,400,000
Income tax (expense) benefit										-1,900,000	-1,400,000
Equity loss related to investment in subsidiaries										-4,500,000	-3,900,000
(Loss) gain on sale of real estate improvements										-200,000
Net loss										20,900,000	35,100,000
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										20,900,000	35,100,000
Condensed Consolidating Statements of Cash Flows
Net loss										20,900,000	35,100,000
Equity earnings (loss) related to investment in subsidiaries										4,500,000	3,900,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										87,100,000	115,000,000
Stock-based compensation expense										6,000,000	10,300,000
Noncash interest expense										0	0
Provision for bad debt write off										400,000	800,000
Loss on extinguishment of debt										1,300,000	0
Asset impairments										2,800,000
Deferred income tax expense (benefit), including valuation allowance change										600,000
Other, net										-16,200,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-9,900,000	-35,300,000
Increase (decrease) in accounts payable and accrued expenses										200,000	2,100,000
(Decrease) increase in payables to related parties										18,400,000	-200,000
Increase (decrease) in deferred revenues										-300,000	10,000,000
Net cash provided by operating activities										115,800,000	141,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										-48,000,000
Capital expenditures – other										-172,900,000	-283,900,000
Investment in subsidiaries										0
Release of restricted cash										4,400,000
Return of investment										0	-45,400,000
Intercompany receipts											0
Intercompany distributions											0
Other										-200,000
Net cash used in investing activities										-216,700,000	-329,300,000
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
IPO costs										-3,200,000
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										-31,000,000	-50,900,000
Intercompany borrowings											315,000,000
Intercompany payments											-180,200,000
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										-4,400,000	-2,400,000
Payments on financing obligations										-500,000	-700,000
Payments to buyout capital leases										-9,600,000
Payment to buyout other financing arrangements										-10,200,000
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										295,400,000	-6,500,000
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										236,500,000	74,300,000
Net (decrease) increase in cash and cash equivalents										135,600,000	-113,300,000
Cash and cash equivalents at beginning of period		11,200,000				146,800,000				11,200,000	146,800,000
Cash and cash equivalents at end of period			33,500,000				146,800,000			146,800,000	33,500,000	146,800,000
Successor [Member] | Non-Guarantor [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			41,700,000				44,100,000			44,100,000	41,700,000	44,100,000
Equipment			800,000				800,000			800,000	800,000	800,000
Construction in progress			0				0			0	0	0
Subtotal			42,500,000				44,900,000			44,900,000	42,500,000	44,900,000
Accumulated depreciation			-7,300,000				-4,700,000			-4,700,000	-7,300,000	-4,700,000
Net investment in real estate			35,200,000				40,200,000			40,200,000	35,200,000	40,200,000
Cash and cash equivalents			3,000,000				2,000,000			2,000,000	3,000,000	2,000,000
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			3,000,000				900,000			900,000	3,000,000	900,000
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			3,200,000				3,200,000			3,200,000	3,200,000	3,200,000
Total assets			44,400,000				46,300,000			46,300,000	44,400,000	46,300,000
Accounts payable and accrued expenses			500,000				400,000			400,000	500,000	400,000
Deferred revenue			600,000				800,000			800,000	600,000	800,000
Intercompany and loan payable			0				200,000			200,000	0	200,000
Due to affiliates			0				0			0	0	0
Capital lease obligations			7,200,000				8,100,000			8,100,000	7,200,000	8,100,000
Long-term debt			0				0			0	0	0
Other financing arrangements			32,500,000				34,700,000			34,700,000	32,500,000	34,700,000
Total liabilities			40,800,000				44,200,000			44,200,000	40,800,000	44,200,000
Total shareholders’ equity			3,600,000				2,100,000			2,100,000	3,600,000	2,100,000
Noncontrolling interest			0				0			0	0	0
Total equity			3,600,000				2,100,000			2,100,000	3,600,000	2,100,000
Total liabilities and equity			44,400,000				46,300,000			46,300,000	44,400,000	46,300,000
Condensed Consolidating Statements of Operations
Revenue										4,100,000	5,800,000
Costs and expenses:
Property operating expenses										2,500,000	2,600,000
Sales and marketing										200,000	200,000
General and administrative										200,000	400,000
Depreciation and amortization										2,800,000	3,000,000
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										5,700,000	6,200,000
Operating income (loss)										-1,600,000	-400,000
Interest expense										2,900,000	3,500,000
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										-4,500,000	-3,900,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										0	0
(Loss) gain on sale of real estate improvements										0
Net loss										-4,500,000	-3,900,000
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										-4,500,000	-3,900,000
Condensed Consolidating Statements of Cash Flows
Net loss										-4,500,000	-3,900,000
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										2,800,000	3,000,000
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-3,000,000	-2,100,000
Increase (decrease) in accounts payable and accrued expenses										300,000	100,000
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										200,000	-200,000
Net cash provided by operating activities										-4,200,000	-3,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	-300,000
Investment in subsidiaries										0
Release of restricted cash										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										0	-300,000
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
IPO costs										0
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										0	0
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										-900,000	-600,000
Payments on financing obligations										-200,000	-200,000
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										6,300,000	5,200,000
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										5,200,000	4,400,000
Net (decrease) increase in cash and cash equivalents										1,000,000	1,000,000
Cash and cash equivalents at beginning of period		1,000,000				2,000,000				1,000,000	2,000,000
Cash and cash equivalents at end of period			3,000,000				2,000,000			2,000,000	3,000,000	2,000,000
Successor [Member] | Eliminations/Consolidations [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			2,200,000				0			0	2,200,000	0
Subtotal			2,200,000				0			0	2,200,000	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			2,200,000				0			0	2,200,000	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			-1,203,500,000				-1,126,900,000			-1,126,900,000	-1,203,500,000	-1,126,900,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			-1,844,200,000				-1,635,200,000			-1,635,200,000	-1,844,200,000	-1,635,200,000
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Total shareholders’ equity			-1,457,600,000				-1,582,500,000			-1,582,500,000	-1,457,600,000	-1,582,500,000
Noncontrolling interest			256,300,000				455,600,000			455,600,000	256,300,000	455,600,000
Total equity			-1,201,300,000				-1,126,900,000			-1,126,900,000	-1,201,300,000	-1,126,900,000
Total liabilities and equity			-1,844,200,000				-1,635,200,000			-1,635,200,000	-1,844,200,000	-1,635,200,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	-2,200,000
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	2,200,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										-10,900,000	-21,000,000
(Loss) gain on sale of real estate improvements										0
Net loss										-10,900,000	-18,800,000
Noncontrolling interest in net loss										-10,300,000	-6,700,000
Net loss attributed to common shareholders										-600,000	-12,100,000
Condensed Consolidating Statements of Cash Flows
Net loss										-10,900,000	-18,800,000
Equity earnings (loss) related to investment in subsidiaries										10,900,000	21,000,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										36,700,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-12,200,000	0
Increase (decrease) in accounts payable and accrued expenses										-17,600,000	0
(Decrease) increase in payables to related parties										-6,800,000	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										100,000	2,200,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										674,200,000
Release of restricted cash										0
Return of investment										-77,100,000	-77,100,000
Intercompany receipts											-180,200,000
Intercompany distributions											315,000,000
Other										0
Net cash used in investing activities										597,100,000	57,700,000
Cash flows from financing activities:
Issuance of common stock/partnership units										-337,100,000	0
IPO costs										0
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										41,600,000	74,900,000
Intercompany borrowings											-315,000,000
Intercompany payments											180,200,000
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0	0
Payments on financing obligations										0	0
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										-301,700,000	0
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										-597,200,000	-59,900,000
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | General Partner [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			7,100,000				7,800,000			7,800,000	7,100,000	7,800,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			7,100,000				7,800,000			7,800,000	7,100,000	7,800,000
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			0				0			0	0	0
Total shareholders’ equity			7,100,000				7,800,000			7,800,000	7,100,000	7,800,000
Noncontrolling interest			0				0			0	0	0
Total equity			7,100,000				7,800,000			7,800,000	7,100,000	7,800,000
Total liabilities and equity			7,100,000				7,800,000			7,800,000	7,100,000	7,800,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	0
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	0
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										-200,000	-200,000
(Loss) gain on sale of real estate improvements										0
Net loss										-200,000	-200,000
Noncontrolling interest in net loss										0	0
Net loss attributed to common shareholders										-200,000	-200,000
Condensed Consolidating Statements of Cash Flows
Net loss										-200,000	-200,000
Equity earnings (loss) related to investment in subsidiaries										200,000	200,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										0	0
Increase (decrease) in accounts payable and accrued expenses										0	0
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										0	0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										0
Release of restricted cash										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										0	0
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
IPO costs										0
Stock issuance costs											0
Acquisition of operating partnership units											0
Dividends/Distributions paid										0	0
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0	0
Payments on financing obligations										0	0
Payments to buyout capital leases										0
Payment to buyout other financing arrangements										0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										0	0
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										0	0
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | CyrusOne L.P. [Member]
Condensed Consolidating Balance Sheets
Land			89,700,000				89,300,000			89,300,000	89,700,000	89,300,000
Buildings and improvements			812,600,000				783,700,000			783,700,000	812,600,000	783,700,000
Equipment			349,100,000				190,200,000			190,200,000	349,100,000	190,200,000
Construction in progress			127,000,000				57,300,000			57,300,000	127,000,000	57,300,000
Subtotal			1,378,400,000				1,120,500,000			1,120,500,000	1,378,400,000	1,120,500,000
Accumulated depreciation			-327,000,000				-236,700,000			-236,700,000	-327,000,000	-236,700,000
Net investment in real estate			1,051,400,000				883,800,000			883,800,000	1,051,400,000	883,800,000
Cash and cash equivalents			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			60,900,000				41,200,000			41,200,000	60,900,000	41,200,000
Intercompany receivable			0				0			0	0	0
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			91,800,000				70,300,000			70,300,000	91,800,000	70,300,000
Total assets			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Accounts payable and accrued expenses			69,900,000				66,800,000			66,800,000	69,900,000	66,800,000
Deferred revenue			65,700,000				55,900,000			55,900,000	65,700,000	55,900,000
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			7,300,000				8,500,000			8,500,000	7,300,000	8,500,000
Capital lease obligations			13,400,000				16,700,000			16,700,000	13,400,000	16,700,000
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			53,400,000				56,300,000			56,300,000	53,400,000	56,300,000
Total liabilities			869,500,000				729,200,000			729,200,000	869,500,000	729,200,000
Total equity			717,000,000				777,600,000			777,600,000	717,000,000	777,600,000
Total liabilities and equity			1,586,500,000				1,506,800,000			1,506,800,000	1,586,500,000	1,506,800,000
Condensed Consolidating Statements of Operations
Revenue										248,400,000	330,900,000
Costs and expenses:
Property operating expenses										88,400,000	124,500,000
Sales and marketing										9,900,000	12,800,000
General and administrative										26,500,000	34,600,000
Depreciation and amortization										89,900,000	118,000,000
Restructuring charges										1,300,000
Transaction costs										700,000	1,000,000
Asset impairments										2,800,000
Total costs and expenses										219,500,000	290,900,000
Operating income (loss)										28,900,000	40,000,000
Interest expense										41,200,000	39,500,000
Loss on extinguishment of debt										1,300,000	13,600,000
Other income										-100,000
Net loss before income taxes										-13,500,000	-13,100,000
Income tax (expense) benefit										-1,900,000	-1,400,000
Equity loss related to investment in subsidiaries										0	0
Loss from continuing operations										-15,400,000
(Loss) gain on sale of real estate improvements										-200,000
Net loss										-15,600,000	-14,500,000
Net loss attributed to common shareholders										-15,600,000	-14,500,000
Condensed Consolidating Statements of Cash Flows
Net loss										-15,600,000	-14,500,000
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										89,900,000	118,000,000
Stock-based compensation expense										6,000,000	10,300,000
Noncash interest expense										4,000,000	3,400,000
Provision for bad debt write off										400,000	800,000
Loss on extinguishment of debt										1,300,000	13,600,000
Asset impairments										2,800,000
Deferred income tax expense (benefit), including valuation allowance change										600,000
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-15,700,000	-37,000,000
Increase (decrease) in accounts payable and accrued expenses										-14,600,000	6,900,000
(Decrease) increase in payables to related parties										18,400,000	-200,000
Increase (decrease) in deferred revenues										-100,000	9,800,000
Net cash provided by operating activities										77,400,000	111,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										-48,000,000
Capital expenditures – other										-172,900,000	-284,200,000
Investment in subsidiaries										0
Release of restricted cash										4,400,000
Intercompany advances, net										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										-200,000
Net cash used in investing activities										-216,700,000	-284,200,000
Cash flows from financing activities:
Issuance of common stock/partnership units										333,900,000	100,000
Stock issuance costs										-31,000,000
Dividends/Distributions paid										-5,300,000	-50,900,000
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											315,000,000
Payments on revolving credit facility											-30,000,000
Payments on senior notes											-150,200,000
Payments on capital lease obligations										-9,600,000
Payments on financing obligations										-700,000
Payments to buyout capital leases										-10,200,000	-3,000,000
Payment to buyout other financing arrangements											-900,000
Payment of debt extinguishment costs											-12,800,000
Contributions from/(distributions to) parent, net										0	-1,300,000
Debt issuance costs										-1,300,000	-5,200,000
Net cash provided by (used in) by financing activities										275,800,000	60,800,000
Net (decrease) increase in cash and cash equivalents										136,500,000	-112,300,000
Cash and cash equivalents at beginning of period		12,300,000				148,800,000				12,300,000	148,800,000
Cash and cash equivalents at end of period			36,500,000				148,800,000			148,800,000	36,500,000	148,800,000
Successor [Member] | CyrusOne L.P. [Member] | LP Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			734,300,000				795,000,000			795,000,000	734,300,000	795,000,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			642,900,000				508,100,000			508,100,000	642,900,000	508,100,000
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			15,500,000				14,100,000			14,100,000	15,500,000	14,100,000
Total assets			1,392,700,000				1,317,200,000			1,317,200,000	1,392,700,000	1,317,200,000
Accounts payable and accrued expenses			12,500,000				7,800,000			7,800,000	12,500,000	7,800,000
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			5,600,000				6,800,000			6,800,000	5,600,000	6,800,000
Capital lease obligations			0				0			0	0	0
Long-term debt			659,800,000				525,000,000			525,000,000	659,800,000	525,000,000
Other financing arrangements			0				0			0	0	0
Total liabilities			677,900,000				539,600,000			539,600,000	677,900,000	539,600,000
Total equity			714,800,000				777,600,000			777,600,000	714,800,000	777,600,000
Total liabilities and equity			1,392,700,000				1,317,200,000			1,317,200,000	1,392,700,000	1,317,200,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										36,500,000	38,200,000
Loss on extinguishment of debt										0	13,600,000
Other income										0
Net loss before income taxes										-36,500,000	-51,800,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										20,900,000	35,100,000
Loss from continuing operations										-15,600,000
(Loss) gain on sale of real estate improvements										0
Net loss										-15,600,000	-16,700,000
Net loss attributed to common shareholders										-15,600,000	-16,700,000
Condensed Consolidating Statements of Cash Flows
Net loss										-15,600,000	-16,700,000
Equity earnings (loss) related to investment in subsidiaries										-20,900,000	-35,100,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										4,000,000	3,400,000
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	13,600,000
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										-13,400,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										0	400,000
Increase (decrease) in accounts payable and accrued expenses										4,800,000	4,700,000
(Decrease) increase in payables to related parties										6,800,000	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										-34,300,000	-29,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										-337,100,000
Release of restricted cash										0
Intercompany advances, net										0
Return of investment										66,500,000	97,300,000
Intercompany receipts											180,200,000
Intercompany distributions											-315,000,000
Other										0
Net cash used in investing activities										-270,600,000	-37,500,000
Cash flows from financing activities:
Issuance of common stock/partnership units										337,100,000	100,000
Stock issuance costs										-31,000,000
Dividends/Distributions paid										0	-50,900,000
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											315,000,000
Payments on revolving credit facility											-30,000,000
Payments on senior notes											-150,200,000
Payments on capital lease obligations										0
Payments on financing obligations										0
Payments to buyout capital leases										0	0
Payment to buyout other financing arrangements											0
Payment of debt extinguishment costs											-12,800,000
Contributions from/(distributions to) parent, net										0	1,200,000
Debt issuance costs										-1,300,000	-5,200,000
Net cash provided by (used in) by financing activities										304,800,000	67,200,000
Net (decrease) increase in cash and cash equivalents										-100,000	0
Cash and cash equivalents at beginning of period		100,000				0				100,000	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | CyrusOne L.P. [Member] | Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			0				0			0	0	0
Subtotal			0				0			0	0	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			0				0			0	0	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			0				0			0	0	0
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			0				0			0	0	0
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			0				0			0	0	0
Total equity			0				0			0	0	0
Total liabilities and equity			0				0			0	0	0
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	0
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	0
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										0	0
Loss from continuing operations										0
(Loss) gain on sale of real estate improvements										0
Net loss										0	0
Net loss attributed to common shareholders										0	0
Condensed Consolidating Statements of Cash Flows
Net loss										0	0
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										0	0
Increase (decrease) in accounts payable and accrued expenses										0	0
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										0	0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										0
Release of restricted cash										0
Intercompany advances, net										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										0	0
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
Stock issuance costs										0
Dividends/Distributions paid										0	0
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0
Payments on financing obligations										0
Payments to buyout capital leases										0	0
Payment to buyout other financing arrangements											0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										0	0
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										0	0
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Successor [Member] | CyrusOne L.P. [Member] | Guarantors [Member]
Condensed Consolidating Balance Sheets
Land			89,700,000				89,300,000			89,300,000	89,700,000	89,300,000
Buildings and improvements			770,900,000				739,600,000			739,600,000	770,900,000	739,600,000
Equipment			348,300,000				189,400,000			189,400,000	348,300,000	189,400,000
Construction in progress			124,800,000				57,300,000			57,300,000	124,800,000	57,300,000
Subtotal			1,333,700,000				1,075,600,000			1,075,600,000	1,333,700,000	1,075,600,000
Accumulated depreciation			-319,700,000				-232,000,000			-232,000,000	-319,700,000	-232,000,000
Net investment in real estate			1,014,000,000				843,600,000			843,600,000	1,014,000,000	843,600,000
Cash and cash equivalents			33,500,000				146,800,000			146,800,000	33,500,000	146,800,000
Investment in subsidiary			3,600,000				2,100,000			2,100,000	3,600,000	2,100,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			57,900,000				40,300,000			40,300,000	57,900,000	40,300,000
Intercompany receivable			0				200,000			200,000	0	200,000
Goodwill			276,200,000				276,200,000			276,200,000	276,200,000	276,200,000
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			68,900,000				85,900,000			85,900,000	68,900,000	85,900,000
Due from affiliates			800,000				600,000			600,000	800,000	600,000
Other assets			73,100,000				53,000,000			53,000,000	73,100,000	53,000,000
Total assets			1,528,000,000				1,448,700,000			1,448,700,000	1,528,000,000	1,448,700,000
Accounts payable and accrued expenses			56,900,000				58,600,000			58,600,000	56,900,000	58,600,000
Deferred revenue			65,100,000				55,100,000			55,100,000	65,100,000	55,100,000
Intercompany and loan payable			642,900,000				508,100,000			508,100,000	642,900,000	508,100,000
Due to affiliates			1,700,000				1,700,000			1,700,000	1,700,000	1,700,000
Capital lease obligations			6,200,000				8,600,000			8,600,000	6,200,000	8,600,000
Long-term debt			0				0			0	0	0
Other financing arrangements			20,900,000				21,600,000			21,600,000	20,900,000	21,600,000
Total liabilities			793,700,000				653,700,000			653,700,000	793,700,000	653,700,000
Total equity			734,300,000				795,000,000			795,000,000	734,300,000	795,000,000
Total liabilities and equity			1,528,000,000				1,448,700,000			1,448,700,000	1,528,000,000	1,448,700,000
Condensed Consolidating Statements of Operations
Revenue										244,300,000	325,100,000
Costs and expenses:
Property operating expenses										85,900,000	121,900,000
Sales and marketing										9,700,000	12,600,000
General and administrative										26,300,000	34,200,000
Depreciation and amortization										87,100,000	115,000,000
Restructuring charges										1,300,000
Transaction costs										700,000	1,000,000
Asset impairments										2,800,000
Total costs and expenses										213,800,000	284,700,000
Operating income (loss)										30,500,000	40,400,000
Interest expense										1,800,000	0
Loss on extinguishment of debt										1,300,000	0
Other income										-100,000
Net loss before income taxes										27,500,000	40,400,000
Income tax (expense) benefit										-1,900,000	-1,400,000
Equity loss related to investment in subsidiaries										-4,500,000	-3,900,000
Loss from continuing operations										21,100,000
(Loss) gain on sale of real estate improvements										-200,000
Net loss										20,900,000	35,100,000
Net loss attributed to common shareholders										20,900,000	35,100,000
Condensed Consolidating Statements of Cash Flows
Net loss										20,900,000	35,100,000
Equity earnings (loss) related to investment in subsidiaries										4,500,000	3,900,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										87,100,000	115,000,000
Stock-based compensation expense										6,000,000	10,300,000
Noncash interest expense										0	0
Provision for bad debt write off										400,000	800,000
Loss on extinguishment of debt										1,300,000	0
Asset impairments										2,800,000
Deferred income tax expense (benefit), including valuation allowance change										600,000
Other, net										-16,200,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-9,900,000	-35,300,000
Increase (decrease) in accounts payable and accrued expenses										200,000	2,100,000
(Decrease) increase in payables to related parties										18,400,000	-200,000
Increase (decrease) in deferred revenues										-300,000	10,000,000
Net cash provided by operating activities										115,800,000	141,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										-48,000,000
Capital expenditures – other										-172,900,000	-283,900,000
Investment in subsidiaries										0
Release of restricted cash										4,400,000
Intercompany advances, net										0
Return of investment										0	-45,400,000
Intercompany receipts											0
Intercompany distributions											0
Other										-200,000
Net cash used in investing activities										-216,700,000	-329,300,000
Cash flows from financing activities:
Issuance of common stock/partnership units										-3,200,000	0
Stock issuance costs										-31,000,000
Dividends/Distributions paid										-4,400,000	-50,900,000
Intercompany borrowings											315,000,000
Intercompany payments											-180,200,000
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										-9,600,000
Payments on financing obligations										-500,000
Payments to buyout capital leases										-10,200,000	-2,400,000
Payment to buyout other financing arrangements											-700,000
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										295,400,000	-6,500,000
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										236,500,000	74,300,000
Net (decrease) increase in cash and cash equivalents										135,600,000	-113,300,000
Cash and cash equivalents at beginning of period		11,200,000				146,800,000				11,200,000	146,800,000
Cash and cash equivalents at end of period			33,500,000				146,800,000			146,800,000	33,500,000	146,800,000
Successor [Member] | CyrusOne L.P. [Member] | Non-Guarantor [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			41,700,000				44,100,000			44,100,000	41,700,000	44,100,000
Equipment			800,000				800,000			800,000	800,000	800,000
Construction in progress			0				0			0	0	0
Subtotal			42,500,000				44,900,000			44,900,000	42,500,000	44,900,000
Accumulated depreciation			-7,300,000				-4,700,000			-4,700,000	-7,300,000	-4,700,000
Net investment in real estate			35,200,000				40,200,000			40,200,000	35,200,000	40,200,000
Cash and cash equivalents			3,000,000				2,000,000			2,000,000	3,000,000	2,000,000
Investment in subsidiary			0				0			0	0	0
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			3,000,000				900,000			900,000	3,000,000	900,000
Intercompany receivable			0				0			0	0	0
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			3,200,000				3,200,000			3,200,000	3,200,000	3,200,000
Total assets			44,400,000				46,300,000			46,300,000	44,400,000	46,300,000
Accounts payable and accrued expenses			500,000				400,000			400,000	500,000	400,000
Deferred revenue			600,000				800,000			800,000	600,000	800,000
Intercompany and loan payable			0				200,000			200,000	0	200,000
Due to affiliates			0				0			0	0	0
Capital lease obligations			7,200,000				8,100,000			8,100,000	7,200,000	8,100,000
Long-term debt			0				0			0	0	0
Other financing arrangements			32,500,000				34,700,000			34,700,000	32,500,000	34,700,000
Total liabilities			40,800,000				44,200,000			44,200,000	40,800,000	44,200,000
Total equity			3,600,000				2,100,000			2,100,000	3,600,000	2,100,000
Total liabilities and equity			44,400,000				46,300,000			46,300,000	44,400,000	46,300,000
Condensed Consolidating Statements of Operations
Revenue										4,100,000	5,800,000
Costs and expenses:
Property operating expenses										2,500,000	2,600,000
Sales and marketing										200,000	200,000
General and administrative										200,000	400,000
Depreciation and amortization										2,800,000	3,000,000
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										5,700,000	6,200,000
Operating income (loss)										-1,600,000	-400,000
Interest expense										2,900,000	3,500,000
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										-4,500,000	-3,900,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										0	0
Loss from continuing operations										-4,500,000
(Loss) gain on sale of real estate improvements										0
Net loss										-4,500,000	-3,900,000
Net loss attributed to common shareholders										-4,500,000	-3,900,000
Condensed Consolidating Statements of Cash Flows
Net loss										-4,500,000	-3,900,000
Equity earnings (loss) related to investment in subsidiaries										0	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										2,800,000	3,000,000
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-3,000,000	-2,100,000
Increase (decrease) in accounts payable and accrued expenses										300,000	100,000
(Decrease) increase in payables to related parties										0	0
Increase (decrease) in deferred revenues										200,000	-200,000
Net cash provided by operating activities										-4,200,000	-3,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	-300,000
Investment in subsidiaries										0
Release of restricted cash										0
Intercompany advances, net										0
Return of investment										0	0
Intercompany receipts											0
Intercompany distributions											0
Other										0
Net cash used in investing activities										0	-300,000
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
Stock issuance costs										0
Dividends/Distributions paid										-900,000	0
Intercompany borrowings											0
Intercompany payments											0
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0
Payments on financing obligations										-200,000
Payments to buyout capital leases										0	-600,000
Payment to buyout other financing arrangements											-200,000
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										6,300,000	5,200,000
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										5,200,000	4,400,000
Net (decrease) increase in cash and cash equivalents										1,000,000	1,000,000
Cash and cash equivalents at beginning of period		1,000,000				2,000,000				1,000,000	2,000,000
Cash and cash equivalents at end of period			3,000,000				2,000,000			2,000,000	3,000,000	2,000,000
Successor [Member] | CyrusOne L.P. [Member] | Eliminations/Consolidations [Member]
Condensed Consolidating Balance Sheets
Land			0				0			0	0	0
Buildings and improvements			0				0			0	0	0
Equipment			0				0			0	0	0
Construction in progress			2,200,000				0			0	2,200,000	0
Subtotal			2,200,000				0			0	2,200,000	0
Accumulated depreciation			0				0			0	0	0
Net investment in real estate			2,200,000				0			0	2,200,000	0
Cash and cash equivalents			0				0			0	0	0
Investment in subsidiary			-737,900,000				-797,100,000			-797,100,000	-737,900,000	-797,100,000
Rent and other receivables, net of allowance for doubtful accounts of $1.0 and $0.5 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Intercompany receivable			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Goodwill			0				0			0	0	0
Intangible assets, net of accumulated amortization of $72.1 and $55.1 as of December 31, 2014 and December 31, 2013, respectively			0				0			0	0	0
Due from affiliates			0				0			0	0	0
Other assets			0				0			0	0	0
Total assets			-1,378,600,000				-1,305,400,000			-1,305,400,000	-1,378,600,000	-1,305,400,000
Accounts payable and accrued expenses			0				0			0	0	0
Deferred revenue			0				0			0	0	0
Intercompany and loan payable			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Due to affiliates			0				0			0	0	0
Capital lease obligations			0				0			0	0	0
Long-term debt			0				0			0	0	0
Other financing arrangements			0				0			0	0	0
Total liabilities			-642,900,000				-508,300,000			-508,300,000	-642,900,000	-508,300,000
Total equity			-735,700,000				-797,100,000			-797,100,000	-735,700,000	-797,100,000
Total liabilities and equity			-1,378,600,000				-1,305,400,000			-1,305,400,000	-1,378,600,000	-1,305,400,000
Condensed Consolidating Statements of Operations
Revenue										0	0
Costs and expenses:
Property operating expenses										0	0
Sales and marketing										0	0
General and administrative										0	0
Depreciation and amortization										0	0
Restructuring charges										0
Transaction costs										0	0
Asset impairments										0
Total costs and expenses										0	0
Operating income (loss)										0	0
Interest expense										0	-2,200,000
Loss on extinguishment of debt										0	0
Other income										0
Net loss before income taxes										0	2,200,000
Income tax (expense) benefit										0	0
Equity loss related to investment in subsidiaries										-16,400,000	-31,200,000
Loss from continuing operations										-16,400,000
(Loss) gain on sale of real estate improvements										0
Net loss										-16,400,000	-29,000,000
Net loss attributed to common shareholders										-16,400,000	-29,000,000
Condensed Consolidating Statements of Cash Flows
Net loss										-16,400,000	-29,000,000
Equity earnings (loss) related to investment in subsidiaries										16,400,000	31,200,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization										0	0
Stock-based compensation expense										0	0
Noncash interest expense										0	0
Provision for bad debt write off										0	0
Loss on extinguishment of debt										0	0
Asset impairments										0
Deferred income tax expense (benefit), including valuation allowance change										0
Other, net										29,600,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets										-2,800,000	0
Increase (decrease) in accounts payable and accrued expenses										-19,900,000	0
(Decrease) increase in payables to related parties										-6,800,000	0
Increase (decrease) in deferred revenues										0	0
Net cash provided by operating activities										100,000	2,200,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate										0
Capital expenditures – other										0	0
Investment in subsidiaries										337,100,000
Release of restricted cash										0
Intercompany advances, net										0
Return of investment										-66,500,000	-51,900,000
Intercompany receipts											-180,200,000
Intercompany distributions											315,000,000
Other										0
Net cash used in investing activities										270,600,000	82,900,000
Cash flows from financing activities:
Issuance of common stock/partnership units										0	0
Stock issuance costs										31,000,000
Dividends/Distributions paid										0	50,900,000
Intercompany borrowings											-315,000,000
Intercompany payments											180,200,000
Borrowings from revolving credit agreement											0
Payments on revolving credit facility											0
Payments on senior notes											0
Payments on capital lease obligations										0
Payments on financing obligations										0
Payments to buyout capital leases										0	0
Payment to buyout other financing arrangements											0
Payment of debt extinguishment costs											0
Contributions from/(distributions to) parent, net										-301,700,000	-1,200,000
Debt issuance costs										0	0
Net cash provided by (used in) by financing activities										-270,700,000	-85,100,000
Net (decrease) increase in cash and cash equivalents										0	0
Cash and cash equivalents at beginning of period		0				0				0	0
Cash and cash equivalents at end of period			0				0			0	0	0
Predecessor [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	12,300,000												16,500,000
Total equity													500,100,000			0
Condensed Consolidating Statements of Operations
Revenue	15,100,000												220,800,000
Costs and expenses:
Property operating expenses	4,800,000												76,000,000
Sales and marketing	700,000												9,700,000
General and administrative	1,500,000												20,700,000
Transaction-related compensation	20,000,000												0
Depreciation and amortization	5,300,000												73,400,000
Restructuring charges	0												0
Transaction costs	100,000												5,700,000
Management fees charged by CBI	0												2,500,000
Loss on sale of receivables to an affiliate	0												3,200,000
Asset impairments	0												13,300,000
Total costs and expenses	32,400,000												204,500,000
Operating income (loss)	-17,300,000												16,300,000
Interest expense	2,500,000												41,800,000
Loss on extinguishment of debt	0												0
Other income	0												0
Net loss before income taxes	-19,800,000												-25,500,000
Income tax (expense) benefit	-400,000												5,100,000
Equity loss related to investment in subsidiaries	0												0
(Loss) gain on sale of real estate improvements	0												100,000
Net loss	-20,200,000												-20,300,000
Net loss attributed to common shareholders	-20,200,000												-20,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000												-20,300,000
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	5,900,000												85,600,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,300,000												73,400,000
Stock-based compensation expense	200,000												0
Noncash interest expense	100,000												300,000
Provision for bad debt write off	0												100,000
Loss on extinguishment of debt	0												0
Asset impairments	0												13,300,000
Deferred income tax expense (benefit), including valuation allowance change	300,000												-4,500,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9,600,000												-24,000,000
Increase (decrease) in accounts payable and accrued expenses	20,500,000												-600,000
(Decrease) increase in payables to related parties	1,500,000												0
Increase (decrease) in deferred revenues	3,200,000												3,800,000
Other changes in assets and liabilities	3,900,000
Net cash provided by operating activities	2,000,000												44,500,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	0												-25,400,000
Capital expenditures – other	-7,700,000												-202,900,000
Proceeds from the sale of assets	0												200,000
Increase in restricted cash	0												-11,100,000
Release of restricted cash	1,900,000												4,800,000
Advances to affiliate													-18,300,000
Intercompany advances, net	0												0
Other	0												100,000
Net cash used in investing activities	-5,800,000												-252,600,000
Cash flows from financing activities:
Issuance of common stock/partnership units	0												0
IPO costs	0												0
Stock issuance costs	0												0
Acquisition of operating partnership units	0												0
Dividends/Distributions paid	0												0
Borrowings from revolving credit agreement	0												0
Payments on revolving credit facility	0												0
Payments on senior notes	0												0
Borrowings from affiliates, net	0												119,800,000
Repayment of related party note	0												-400,000,000
Proceeds from issuance of debt	0												525,000,000
Payments on capital lease obligations	-600,000												-9,000,000
Payments on financing obligations	0												0
Payment to buyout other financing arrangements	0												0
Payment of debt extinguishment costs	0												0
Contributions from/(distributions to) parent, net	200,000												5,400,000
Debt issuance costs	0												-17,200,000
Net cash provided by (used in) by financing activities	-400,000												224,000,000
Net (decrease) increase in cash and cash equivalents	-4,200,000												15,900,000
Cash and cash equivalents at beginning of period	16,500,000											16,500,000	600,000
Cash and cash equivalents at end of period	12,300,000												16,500,000
Predecessor [Member] | Parent Company [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
(Loss) gain on sale of real estate improvements													0
Net loss	0												0
Net loss attributed to common shareholders	0												0
Condensed Consolidating Statements of Cash Flows
Net loss	0												0
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												-7,900,000
Increase (decrease) in accounts payable and accrued expenses	0												800,000
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												-7,100,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	0												0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												7,100,000
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												7,100,000
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
Predecessor [Member] | CyrusOne LP [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	12,300,000												16,500,000
Condensed Consolidating Statements of Operations
Revenue	15,100,000												220,800,000
Costs and expenses:
Property operating expenses	4,800,000												76,000,000
Sales and marketing	700,000												9,700,000
General and administrative	1,500,000												20,700,000
Transaction-related compensation	20,000,000												0
Depreciation and amortization	5,300,000												73,400,000
Restructuring charges	0												0
Transaction costs	100,000												5,700,000
Management fees charged by CBI	0												2,500,000
Loss on sale of receivables to an affiliate	0												3,200,000
Asset impairments	0												13,300,000
Total costs and expenses	32,400,000												204,500,000
Operating income (loss)	-17,300,000												16,300,000
Interest expense	2,500,000												41,800,000
Loss on extinguishment of debt	0												0
Other income	0												0
Net loss before income taxes	-19,800,000												-25,500,000
Income tax (expense) benefit	-400,000												5,100,000
(Loss) gain on sale of real estate improvements	0												100,000
Net loss	-20,200,000												-20,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000												-20,300,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,300,000												73,400,000
Stock-based compensation expense	200,000												0
Noncash interest expense	100,000												300,000
Provision for bad debt write off	0												100,000
Loss on extinguishment of debt	0												0
Asset impairments	0												13,300,000
Deferred income tax expense (benefit), including valuation allowance change	300,000												-4,500,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9,600,000												-16,100,000
Increase (decrease) in accounts payable and accrued expenses	20,500,000												-1,400,000
(Decrease) increase in payables to related parties	1,500,000												0
Increase (decrease) in deferred revenues	3,200,000												3,800,000
Net cash provided by operating activities	2,000,000												51,600,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	0												-25,400,000
Capital expenditures – other	-7,700,000												-202,900,000
Proceeds from the sale of assets	0												200,000
Increase in restricted cash	0												-11,100,000
Release of restricted cash	1,900,000												4,800,000
Other	0												100,000
Net cash used in investing activities	-5,800,000												-252,600,000
Cash flows from financing activities:
Issuance of common stock/partnership units	0												0
Dividends/Distributions paid	0												0
Borrowings from revolving credit agreement	0												0
Payments on revolving credit facility	0												0
Payments on senior notes	0												0
Borrowings from affiliates, net	0												119,800,000
Repayment of related party note	0												-400,000,000
Proceeds from issuance of debt	0												525,000,000
Payments on capital lease obligations	-600,000												-9,000,000
Payments on financing obligations	0												0
Payment to buyout other financing arrangements	0												0
Payment of debt extinguishment costs	0												0
Contributions from/(distributions to) parent, net	200,000												-1,700,000
Debt issuance costs	0												-17,200,000
Net cash provided by (used in) by financing activities	-400,000												216,900,000
Net (decrease) increase in cash and cash equivalents	-4,200,000												15,900,000
Cash and cash equivalents at beginning of period	16,500,000											16,500,000	600,000
Cash and cash equivalents at end of period	12,300,000												16,500,000
Predecessor [Member] | LP Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	100,000												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												5,700,000
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												5,700,000
Operating income (loss)	0												-5,700,000
Interest expense	2,300,000												4,200,000
Net loss before income taxes	-2,300,000												-9,900,000
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	-17,900,000												-10,400,000
(Loss) gain on sale of real estate improvements													0
Net loss	-20,200,000												-20,300,000
Net loss attributed to common shareholders	-20,200,000												-20,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000												-20,300,000
Equity earnings (loss) related to investment in subsidiaries	17,900,000												10,400,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	200,000												200,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	2,100,000												4,400,000
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												-5,300,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	100,000												-508,200,000
Other													0
Net cash used in investing activities	100,000												-508,200,000
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													525,000,000
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												5,700,000
Debt issuance costs													-17,200,000
Net cash provided by (used in) by financing activities	0												513,500,000
Net (decrease) increase in cash and cash equivalents	100,000												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	100,000												0
Predecessor [Member] | Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
(Loss) gain on sale of real estate improvements													0
Net loss	0												0
Net loss attributed to common shareholders	0												0
Condensed Consolidating Statements of Cash Flows
Net loss	0												0
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	0												0
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	0												0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												0
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												0
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
Predecessor [Member] | Guarantors [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	11,200,000												15,600,000
Condensed Consolidating Statements of Operations
Revenue	14,900,000												219,400,000
Costs and expenses:
Property operating expenses	4,800,000												74,100,000
Sales and marketing	700,000												9,500,000
General and administrative	1,400,000												20,600,000
Transaction-related compensation	20,000,000
Depreciation and amortization	5,200,000												71,900,000
Transaction costs	100,000												0
Management fees charged by CBI													2,500,000
Loss on sale of receivables to an affiliate													3,200,000
Asset impairments													13,300,000
Total costs and expenses	32,200,000												195,100,000
Operating income (loss)	-17,300,000												24,300,000
Interest expense	100,000												35,000,000
Net loss before income taxes	-17,400,000												-10,700,000
Income tax (expense) benefit	-400,000												5,100,000
Equity loss related to investment in subsidiaries	-100,000												-4,900,000
(Loss) gain on sale of real estate improvements													100,000
Net loss	-17,900,000												-10,400,000
Net loss attributed to common shareholders	-17,900,000												-10,400,000
Condensed Consolidating Statements of Cash Flows
Net loss	-17,900,000												-10,400,000
Equity earnings (loss) related to investment in subsidiaries	100,000												4,900,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	5,600,000												83,900,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,200,000												71,900,000
Asset impairments													13,300,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9,600,000												-15,500,000
Increase (decrease) in accounts payable and accrued expenses	18,400,000												-5,500,000
(Decrease) increase in payables to related parties	1,500,000
Increase (decrease) in deferred revenues													3,300,000
Other changes in assets and liabilities	3,800,000
Net cash provided by operating activities	1,900,000												60,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													-25,100,000
Capital expenditures – other	-7,700,000												-202,900,000
Proceeds from the sale of assets													200,000
Increase in restricted cash													-11,100,000
Release of restricted cash	1,900,000												4,800,000
Advances to affiliate													-18,300,000
Intercompany advances, net	-100,000												508,100,000
Other													100,000
Net cash used in investing activities	-5,900,000												255,800,000
Cash flows from financing activities:
Borrowings from affiliates, net													119,800,000
Repayment of related party note													-400,000,000
Proceeds from issuance of debt													0
Payments on capital lease obligations	-600,000												-8,400,000
Contributions from/(distributions to) parent, net	200,000												-12,700,000
Debt issuance costs													0
Net cash provided by (used in) by financing activities	-400,000												-301,300,000
Net (decrease) increase in cash and cash equivalents	-4,400,000												15,200,000
Cash and cash equivalents at beginning of period	15,600,000											15,600,000	400,000
Cash and cash equivalents at end of period	11,200,000												15,600,000
Predecessor [Member] | Non-Guarantor [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	1,000,000												900,000
Condensed Consolidating Statements of Operations
Revenue	200,000												1,400,000
Costs and expenses:
Property operating expenses	0												1,900,000
Sales and marketing	0												200,000
General and administrative	100,000												100,000
Transaction-related compensation	0
Depreciation and amortization	100,000												1,500,000
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	200,000												3,700,000
Operating income (loss)	0												-2,300,000
Interest expense	100,000												2,600,000
Net loss before income taxes	-100,000												-4,900,000
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
(Loss) gain on sale of real estate improvements													0
Net loss	-100,000												-4,900,000
Net loss attributed to common shareholders	-100,000												-4,900,000
Condensed Consolidating Statements of Cash Flows
Net loss	-100,000												-4,900,000
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	100,000												1,500,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	100,000												1,500,000
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												-600,000
Increase (decrease) in accounts payable and accrued expenses	0												-300,000
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													500,000
Other changes in assets and liabilities	100,000
Net cash provided by operating activities	100,000												-3,800,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													-300,000
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	0												100,000
Other													0
Net cash used in investing activities	0												-200,000
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												-600,000
Contributions from/(distributions to) parent, net	0												5,300,000
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												4,700,000
Net (decrease) increase in cash and cash equivalents	100,000												700,000
Cash and cash equivalents at beginning of period	900,000											900,000	200,000
Cash and cash equivalents at end of period	1,000,000												900,000
Predecessor [Member] | Eliminations/Consolidations [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	18,000,000												15,300,000
(Loss) gain on sale of real estate improvements													0
Net loss	18,000,000												15,300,000
Net loss attributed to common shareholders	18,000,000												15,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	18,000,000												15,300,000
Equity earnings (loss) related to investment in subsidiaries	-18,000,000												-15,300,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	0												0
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	0												0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												0
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												0
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
Predecessor [Member] | General Partner [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
(Loss) gain on sale of real estate improvements													0
Net loss	0												0
Net loss attributed to common shareholders	0												0
Condensed Consolidating Statements of Cash Flows
Net loss	0												0
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	0												0
(Decrease) increase in payables to related parties	0
Increase (decrease) in deferred revenues													0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate													0
Intercompany advances, net	0												0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												0
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												0
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
Predecessor [Member] | CyrusOne L.P. [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	12,300,000												16,500,000
Condensed Consolidating Statements of Operations
Revenue	15,100,000												220,800,000
Costs and expenses:
Property operating expenses	4,800,000												76,000,000
Sales and marketing	700,000												9,700,000
General and administrative	1,500,000												20,700,000
Transaction-related compensation	20,000,000
Depreciation and amortization	5,300,000												73,400,000
Transaction costs	100,000												5,700,000
Management fees charged by CBI													2,500,000
Loss on sale of receivables to an affiliate													3,200,000
Asset impairments													13,300,000
Total costs and expenses	32,400,000												204,500,000
Operating income (loss)	-17,300,000												16,300,000
Interest expense	2,500,000												41,800,000
Net loss before income taxes	-19,800,000												-25,500,000
Income tax (expense) benefit	-400,000												5,100,000
Equity loss related to investment in subsidiaries	0												0
Loss from continuing operations													-20,400,000
(Loss) gain on sale of real estate improvements													100,000
Net loss	-20,200,000												-20,300,000
Net loss attributed to common shareholders	-20,200,000												-20,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000												-20,300,000
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	5,900,000												85,600,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,300,000												73,400,000
Asset impairments													13,300,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9,600,000												-16,100,000
Increase (decrease) in accounts payable and accrued expenses	20,500,000												-1,400,000
(Decrease) increase in payables to related parties	1,500,000												3,800,000
Other changes in assets and liabilities	3,900,000
Net cash provided by operating activities	2,000,000												51,600,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													-25,400,000
Capital expenditures – other	-7,700,000												-202,900,000
Proceeds from the sale of assets													200,000
Increase in restricted cash													-11,100,000
Release of restricted cash	1,900,000												4,800,000
Advances to affiliate	0												0
Intercompany advances, net													-18,300,000
Other													100,000
Net cash used in investing activities	-5,800,000												-252,600,000
Cash flows from financing activities:
Borrowings from affiliates, net													119,800,000
Repayment of related party note													-400,000,000
Proceeds from issuance of debt													525,000,000
Payments on capital lease obligations	-600,000												-9,000,000
Contributions from/(distributions to) parent, net	200,000												-1,700,000
Debt issuance costs													-17,200,000
Net cash provided by (used in) by financing activities	-400,000												216,900,000
Net (decrease) increase in cash and cash equivalents	-4,200,000												15,900,000
Cash and cash equivalents at beginning of period	16,500,000											16,500,000	600,000
Cash and cash equivalents at end of period	12,300,000												16,500,000
Predecessor [Member] | CyrusOne L.P. [Member] | LP Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	100,000												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												5,700,000
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												5,700,000
Operating income (loss)	0												-5,700,000
Interest expense	2,300,000												4,200,000
Net loss before income taxes	-2,300,000												-9,900,000
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	-17,900,000												-10,400,000
Loss from continuing operations													-20,300,000
(Loss) gain on sale of real estate improvements													0
Net loss	-20,200,000												-20,300,000
Net loss attributed to common shareholders	-20,200,000												-20,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	-20,200,000												-20,300,000
Equity earnings (loss) related to investment in subsidiaries	17,900,000												10,400,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	200,000												200,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	2,100,000												4,400,000
(Decrease) increase in payables to related parties	0												0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												-5,300,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate	100,000												-508,200,000
Intercompany advances, net													0
Other													0
Net cash used in investing activities	100,000												-508,200,000
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													525,000,000
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												5,700,000
Debt issuance costs													-17,200,000
Net cash provided by (used in) by financing activities	0												513,500,000
Net (decrease) increase in cash and cash equivalents	100,000												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	100,000												0
Predecessor [Member] | CyrusOne L.P. [Member] | Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
Loss from continuing operations													0
(Loss) gain on sale of real estate improvements													0
Net loss	0												0
Net loss attributed to common shareholders	0												0
Condensed Consolidating Statements of Cash Flows
Net loss	0												0
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	0												0
(Decrease) increase in payables to related parties	0												0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate	0												0
Intercompany advances, net													0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												0
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												0
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
Predecessor [Member] | CyrusOne L.P. [Member] | Guarantors [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	11,200,000												15,600,000
Condensed Consolidating Statements of Operations
Revenue	14,900,000												219,400,000
Costs and expenses:
Property operating expenses	4,800,000												74,100,000
Sales and marketing	700,000												9,500,000
General and administrative	1,400,000												20,600,000
Transaction-related compensation	20,000,000
Depreciation and amortization	5,200,000												71,900,000
Transaction costs	100,000												0
Management fees charged by CBI													2,500,000
Loss on sale of receivables to an affiliate													3,200,000
Asset impairments													13,300,000
Total costs and expenses	32,200,000												195,100,000
Operating income (loss)	-17,300,000												24,300,000
Interest expense	100,000												35,000,000
Net loss before income taxes	-17,400,000												-10,700,000
Income tax (expense) benefit	-400,000												5,100,000
Equity loss related to investment in subsidiaries	-100,000												-4,900,000
Loss from continuing operations													-10,500,000
(Loss) gain on sale of real estate improvements													100,000
Net loss	-17,900,000												-10,400,000
Net loss attributed to common shareholders	-17,900,000												-10,400,000
Condensed Consolidating Statements of Cash Flows
Net loss	-17,900,000												-10,400,000
Equity earnings (loss) related to investment in subsidiaries	100,000												4,900,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	5,600,000												83,900,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,200,000												71,900,000
Asset impairments													13,300,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	-9,600,000												-15,500,000
Increase (decrease) in accounts payable and accrued expenses	18,400,000												-5,500,000
(Decrease) increase in payables to related parties	1,500,000												3,300,000
Other changes in assets and liabilities	3,800,000
Net cash provided by operating activities	1,900,000												60,700,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													-25,100,000
Capital expenditures – other	-7,700,000												-202,900,000
Proceeds from the sale of assets													200,000
Increase in restricted cash													-11,100,000
Release of restricted cash	1,900,000												4,800,000
Advances to affiliate	-100,000												508,100,000
Intercompany advances, net													-18,300,000
Other													100,000
Net cash used in investing activities	-5,900,000												255,800,000
Cash flows from financing activities:
Borrowings from affiliates, net													119,800,000
Repayment of related party note													-400,000,000
Proceeds from issuance of debt													0
Payments on capital lease obligations	-600,000												-8,400,000
Contributions from/(distributions to) parent, net	200,000												-12,700,000
Debt issuance costs													0
Net cash provided by (used in) by financing activities	-400,000												-301,300,000
Net (decrease) increase in cash and cash equivalents	-4,400,000												15,200,000
Cash and cash equivalents at beginning of period	15,600,000											15,600,000	400,000
Cash and cash equivalents at end of period	11,200,000												15,600,000
Predecessor [Member] | CyrusOne L.P. [Member] | Non-Guarantor [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	1,000,000												900,000
Condensed Consolidating Statements of Operations
Revenue	200,000												1,400,000
Costs and expenses:
Property operating expenses	0												1,900,000
Sales and marketing	0												200,000
General and administrative	100,000												100,000
Transaction-related compensation	0
Depreciation and amortization	100,000												1,500,000
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	200,000												3,700,000
Operating income (loss)	0												-2,300,000
Interest expense	100,000												2,600,000
Net loss before income taxes	-100,000												-4,900,000
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	0												0
Loss from continuing operations													-4,900,000
(Loss) gain on sale of real estate improvements													0
Net loss	-100,000												-4,900,000
Net loss attributed to common shareholders	-100,000												-4,900,000
Condensed Consolidating Statements of Cash Flows
Net loss	-100,000												-4,900,000
Equity earnings (loss) related to investment in subsidiaries	0												0
Adjustments to reconcile net (loss) income to net cash provided by operating activities	100,000												1,500,000
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	100,000												1,500,000
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												-600,000
Increase (decrease) in accounts payable and accrued expenses	0												-300,000
(Decrease) increase in payables to related parties	0												500,000
Other changes in assets and liabilities	100,000
Net cash provided by operating activities	100,000												-3,800,000
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													-300,000
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate	0												100,000
Intercompany advances, net													0
Other													0
Net cash used in investing activities	0												-200,000
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												-600,000
Contributions from/(distributions to) parent, net	0												5,300,000
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												4,700,000
Net (decrease) increase in cash and cash equivalents	100,000												700,000
Cash and cash equivalents at beginning of period	900,000											900,000	200,000
Cash and cash equivalents at end of period	1,000,000												900,000
Predecessor [Member] | CyrusOne L.P. [Member] | Eliminations/Consolidations [Member]
Condensed Consolidating Balance Sheets
Cash and cash equivalents	0												0
Condensed Consolidating Statements of Operations
Revenue	0												0
Costs and expenses:
Property operating expenses	0												0
Sales and marketing	0												0
General and administrative	0												0
Transaction-related compensation	0
Depreciation and amortization	0												0
Transaction costs	0												0
Management fees charged by CBI													0
Loss on sale of receivables to an affiliate													0
Asset impairments													0
Total costs and expenses	0												0
Operating income (loss)	0												0
Interest expense	0												0
Net loss before income taxes	0												0
Income tax (expense) benefit	0												0
Equity loss related to investment in subsidiaries	18,000,000												15,300,000
Loss from continuing operations													15,300,000
(Loss) gain on sale of real estate improvements													0
Net loss	18,000,000												15,300,000
Net loss attributed to common shareholders	18,000,000												15,300,000
Condensed Consolidating Statements of Cash Flows
Net loss	18,000,000												15,300,000
Equity earnings (loss) related to investment in subsidiaries	-18,000,000												-15,300,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities	0												0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	0												0
Asset impairments													0
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables and other assets	0												0
Increase (decrease) in accounts payable and accrued expenses	0												0
(Decrease) increase in payables to related parties	0												0
Other changes in assets and liabilities	0
Net cash provided by operating activities	0												0
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate													0
Capital expenditures – other	0												0
Proceeds from the sale of assets													0
Increase in restricted cash													0
Release of restricted cash	0												0
Advances to affiliate	0												0
Intercompany advances, net													0
Other													0
Net cash used in investing activities	0												0
Cash flows from financing activities:
Borrowings from affiliates, net													0
Repayment of related party note													0
Proceeds from issuance of debt													0
Payments on capital lease obligations	0												0
Contributions from/(distributions to) parent, net	0												0
Debt issuance costs													0
Net cash provided by (used in) by financing activities	0												0
Net (decrease) increase in cash and cash equivalents	0												0
Cash and cash equivalents at beginning of period	0											0	0
Cash and cash equivalents at end of period	0												0
IPO [Member]
Condensed Financial Statements, Captions [Line Items]
Net proceeds from IPO after underwriting discounts and commissions														371,700,000
IPO [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net proceeds from IPO after underwriting discounts and commissions															337,100,000
IPO [Member] | CyrusOne L.P. [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net proceeds from IPO after underwriting discounts and commissions															337,100,000
6.375% Senior Notes Due 2022 [Member]
Condensed Consolidating Balance Sheets
Long-term debt			374,800,000				525,000,000			525,000,000	374,800,000	525,000,000
6.375% Senior Notes Due 2022 [Member] | CyrusOne GP [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of senior notes								100.00%
6.375% Senior Notes Due 2022 [Member] | LP Co-Issuer and Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Long-term debt			374,800,000								374,800,000
6.375% Senior Notes Due 2022 [Member] | CyrusOne L.P. [Member] | CyrusOne LP [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of senior notes								100.00%
6.375% Senior Notes Due 2022 [Member] | CyrusOne L.P. [Member] | LP Co-Issuer and Finance Co-Issuer [Member]
Condensed Consolidating Balance Sheets
Long-term debt			$525,000,000								$525,000,000

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Details) (USD $)	0 Months Ended	1 Months Ended	2 Months Ended	3 Months Ended							12 Months Ended		0 Months Ended	1 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 25, 2013	Jan. 23, 2013	Mar. 31, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Jun. 25, 2014	Jun. 30, 2014
Revenue		$15.10	$45	$86.90	$84.80	$81.70	$77.50	$72.30	$67.50	$63.60	$330.90	$263.50
Operating income (loss)		-17.3	5.8	11.2	9.6	7.4	11.8	9	8.5	5.6	40	11.6
Net loss		-20.2	-2.8	-11.8	0.2	-3.6	0.7	-3.8	-2.2	-6.8	-14.5	-35.8
Net loss attributed to common shareholders		$0	($0.90)	($7)	$0.10	($1.10)	$0.20	($1.30)	($0.80)	($2.30)	($7.80)	($5.30)
Net loss per share- basic (in dollars per share)											($0.30)	($0.28)
Basic and diluted loss per share (in dollars per share)		$0	($0.05)	($0.19)	$0	($0.06)	$0	($0.06)	($0.05)	($0.12)	($0.25)	($0.28)
Common stock issued (in shares)	400,000
IPO [Member]
Common stock issued (in shares)	19,000,000												16,000,000	16,000,000

Subsequent_Event_Details

Subsequent Event (Details) (Subsequent Event [Member], Austin Met 2 [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 19, 2015
Subsequent Event [Member] | Austin Met 2 [Member]
Subsequent Event [Line Items]
Real estate acquired	$17.30

Valuation_and_Qualifying_Accou1

Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Accounts receivable sold, discount percentage of face amount				2.50%
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	$0.50	$0.30	$0
Charge to Expenses	0.8	0.4	0.1
Deductions/(Additions)	0.3	0.2	-0.2
Beginning of Period	1	0.5	0.3
Deferred Tax Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	3.6	1.9	0.3
Charge to Expenses	2.1	1.7	1.6
Deductions/(Additions)	0	0	0
Beginning of Period	$5.70	$3.60	$1.90

Real_Estate_Properties_and_Acc1

Real Estate Properties and Accumulated Depreciation (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	$89.30
Initial Costs, Buildings and Improvements	244.5
Initial Costs, Equipment	4.5
Costs Capitalized Subsequent to Acquisition, Land	0.6
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	568.1
Costs Capitalized Subsequent to Acquisition, Equipment	344.6
Gross Carrying Amount, Land	89.7	89.3
Gross Carrying Amount, Buildings and Improvements	812.6	783.7
Gross Carrying Amount, Equipment	349.1	190.2
Accumulated Depreciation	327	236.7	176.7	131.2
Aggregate cost of the total properties for federal income tax purposes	1,725
West Seventh St., Cincinnati, OH (7th Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0.9
Initial Costs, Buildings and Improvements	42.2
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	68.4
Costs Capitalized Subsequent to Acquisition, Equipment	12.7
Gross Carrying Amount, Land	0.9	0.9
Gross Carrying Amount, Buildings and Improvements	110.6	107.6
Gross Carrying Amount, Equipment	12.7	11
Accumulated Depreciation	69.5
Parkway Dr., Mason, OH (Mason) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	20.2
Costs Capitalized Subsequent to Acquisition, Equipment	0.9
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	20.2	20.2
Gross Carrying Amount, Equipment	0.9	0.6
Accumulated Depreciation	10.8
Industrial Rd., Florence, KY (Florence) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	2.2
Initial Costs, Buildings and Improvements	7.7
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	33.7
Costs Capitalized Subsequent to Acquisition, Equipment	3
Gross Carrying Amount, Land	2.2	2.2
Gross Carrying Amount, Buildings and Improvements	41.4	41.4
Gross Carrying Amount, Equipment	3	2.4
Accumulated Depreciation	18.6
Goldcoast Dr., Cincinnati, OH (Goldcoast) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0.6
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	6.7
Costs Capitalized Subsequent to Acquisition, Equipment	0.1
Gross Carrying Amount, Land	0.6	0.6
Gross Carrying Amount, Buildings and Improvements	6.7	6.7
Gross Carrying Amount, Equipment	0.1	0.1
Accumulated Depreciation	2.2
Knightsbridge Dr., Hamilton, OH (Hamilton) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	9.5
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	39.7
Costs Capitalized Subsequent to Acquisition, Equipment	3.7
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	49.2	49.2
Gross Carrying Amount, Equipment	3.7	3.6
Accumulated Depreciation	20.3
E. Monroe St., South Bend, IN (Monroe St.) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	2.5
Costs Capitalized Subsequent to Acquisition, Equipment	0.1
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	2.5	2.5
Gross Carrying Amount, Equipment	0.1	0
Accumulated Depreciation	1.1
Springer St., Lombard, IL (Lombard) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0.7
Initial Costs, Buildings and Improvements	3.2
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	1.5
Costs Capitalized Subsequent to Acquisition, Equipment	5.7
Gross Carrying Amount, Land	0.7	0.7
Gross Carrying Amount, Buildings and Improvements	4.7	4.6
Gross Carrying Amount, Equipment	5.7	0.2
Accumulated Depreciation	1.3
Crescent Circle, South Bend, IN (Blackthorn) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	1.1
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	2.2
Costs Capitalized Subsequent to Acquisition, Equipment	0.1
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	3.3	3.3
Gross Carrying Amount, Equipment	0.1	0.2
Accumulated Depreciation	1.3
Kingsview Dr., Lebanon, OH (Lebanon) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	4
Initial Costs, Buildings and Improvements	12.3
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	64.7
Costs Capitalized Subsequent to Acquisition, Equipment	5.5
Gross Carrying Amount, Land	4	4
Gross Carrying Amount, Buildings and Improvements	77	71.7
Gross Carrying Amount, Equipment	5.5	2.2
Accumulated Depreciation	21.4
McAuley Place, Blue Ash, OH (Blue Ash) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	2.6
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	-2
Costs Capitalized Subsequent to Acquisition, Equipment	0.1
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	0.6	0.6
Gross Carrying Amount, Equipment	0.1	0
Accumulated Depreciation	0.2
Westway Park Blvd., Houston, TX (Houston West 1) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	1.4
Initial Costs, Buildings and Improvements	21.4
Initial Costs, Equipment	0.1
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	63
Costs Capitalized Subsequent to Acquisition, Equipment	43.7
Gross Carrying Amount, Land	1.4	1.4
Gross Carrying Amount, Buildings and Improvements	84.4	84.4
Gross Carrying Amount, Equipment	43.8	39.4
Accumulated Depreciation	39.6
Westway Park Blvd., Houston, TX (Houston West 2) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	2
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	22.5
Costs Capitalized Subsequent to Acquisition, Equipment	45.1
Gross Carrying Amount, Land	2	2
Gross Carrying Amount, Buildings and Improvements	22.5	22.4
Gross Carrying Amount, Equipment	45.1	15.8
Accumulated Depreciation	8
N. Sam Houston Pkwy., Houston, TX (Houston West 3) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	18.3
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0.1
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0
Gross Carrying Amount, Land	18.4	18.3
Gross Carrying Amount, Buildings and Improvements	0	0
Gross Carrying Amount, Equipment	0	0
Accumulated Depreciation	0
Southwest Fwy., Houston, TX (Galleria) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	56
Initial Costs, Equipment	2
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	12.6
Costs Capitalized Subsequent to Acquisition, Equipment	13
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	68.6	68.4
Gross Carrying Amount, Equipment	15	13.3
Accumulated Depreciation	29.4
E. Ben White Blvd., Austin, TX (Austin 1) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	11.9
Initial Costs, Equipment	0.2
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	10.6
Costs Capitalized Subsequent to Acquisition, Equipment	1
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	22.5	22.5
Gross Carrying Amount, Equipment	1.2	1.2
Accumulated Depreciation	8.2
S. State Highway 121 Business, Lewisville, TX (Lewisville) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	46.2
Initial Costs, Equipment	2.2
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	30.5
Costs Capitalized Subsequent to Acquisition, Equipment	20.6
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	76.7	77
Gross Carrying Amount, Equipment	22.8	20.3
Accumulated Depreciation	37.5
Marsh Lane, Carrollton, TX (Marsh Ln) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0.1
Costs Capitalized Subsequent to Acquisition, Equipment	0.5
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	0.1	0.1
Gross Carrying Amount, Equipment	0.5	0.5
Accumulated Depreciation	0.3
Midway Rd., Carrollton, TX (Midway) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	1.8
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0.2
Costs Capitalized Subsequent to Acquisition, Equipment	0.4
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	2	2
Gross Carrying Amount, Equipment	0.4	0.4
Accumulated Depreciation	2.2
W. Frankford Rd., Carrollton, TX (Carrollton) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	16.1
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	51.6
Costs Capitalized Subsequent to Acquisition, Equipment	85.3
Gross Carrying Amount, Land	16.1	16.1
Gross Carrying Amount, Buildings and Improvements	51.6	42.6
Gross Carrying Amount, Equipment	85.3	34.8
Accumulated Depreciation	17.4
Bryan St., Dallas, TX (Bryan St) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0.1
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0.2
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	0.1	0.1
Gross Carrying Amount, Equipment	0.2	0.1
Accumulated Depreciation	0.1
North Freeway, Houston, TX (Greenspoint) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	1.3
Costs Capitalized Subsequent to Acquisition, Equipment	0
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	1.3	1.3
Gross Carrying Amount, Equipment	0	0.4
Accumulated Depreciation	1.3
South Ellis Street Chandler, AZ (Phoenix 1) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	15
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	56.4
Costs Capitalized Subsequent to Acquisition, Equipment	43.9
Gross Carrying Amount, Land	14.8	15
Gross Carrying Amount, Buildings and Improvements	56.4	55.7
Gross Carrying Amount, Equipment	43.9	11.7
Accumulated Depreciation	11
South Ellis Street Chandler, AZ (Phoenix 2) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	13.2
Costs Capitalized Subsequent to Acquisition, Equipment	21.8
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	13.2	0
Gross Carrying Amount, Equipment	21.8	0
Accumulated Depreciation	0.7
Westover Hills Blvd., San Antonio, TX (San Antonio 1) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	4.6
Initial Costs, Buildings and Improvements	3
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	29.1
Costs Capitalized Subsequent to Acquisition, Equipment	32.4
Gross Carrying Amount, Land	4.6	4.6
Gross Carrying Amount, Buildings and Improvements	32.1	32.1
Gross Carrying Amount, Equipment	32.4	29.5
Accumulated Depreciation	10
Westover Hills Blvd., San Antonio, TX (San Antonio 2) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	6.7
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0.3
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0
Gross Carrying Amount, Land	7	6.7
Gross Carrying Amount, Buildings and Improvements	0	0
Gross Carrying Amount, Equipment	0	0
Accumulated Depreciation	0
Metropolis Dr., Austin, TX (Austin 2) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	2
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	23.2
Costs Capitalized Subsequent to Acquisition, Equipment	4
Gross Carrying Amount, Land	2	2
Gross Carrying Amount, Buildings and Improvements	23.2	23.1
Gross Carrying Amount, Equipment	4	1.7
Accumulated Depreciation	7.2
Kestral Way (London) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	16.5
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	16.2
Costs Capitalized Subsequent to Acquisition, Equipment	0.7
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	32.7	34.8
Gross Carrying Amount, Equipment	0.7	0.7
Accumulated Depreciation	4.4
Jurong East (Singapore) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	0
Initial Costs, Buildings and Improvements	9
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0.1
Gross Carrying Amount, Land	0	0
Gross Carrying Amount, Buildings and Improvements	9	9.4
Gross Carrying Amount, Equipment	0.1	0.1
Accumulated Depreciation	3
Ridgetop Circle, Sterling, VA (Northern VA) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	6.9
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0.1
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0
Gross Carrying Amount, Land	7	6.9
Gross Carrying Amount, Buildings and Improvements	0	0
Gross Carrying Amount, Equipment	0	0
Accumulated Depreciation	0
Metropolis Dr., Austin, TX (Austin 3) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Costs, Land	7.9
Initial Costs, Buildings and Improvements	0
Initial Costs, Equipment	0
Costs Capitalized Subsequent to Acquisition, Land	0.1
Costs Capitalized Subsequent to Acquisition, Buildings and Improvements	0
Costs Capitalized Subsequent to Acquisition, Equipment	0
Gross Carrying Amount, Land	8	7.9
Gross Carrying Amount, Buildings and Improvements	0	0
Gross Carrying Amount, Equipment	0	0
Accumulated Depreciation	$0

Real_Estate_Properties_and_Acc2

Real Estate Properties and Accumulated Depreciation - Historical Cost and Accumulated Depreciation and Amortization (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property
Balance—beginning of period	$1,120.50	$883.60	$660.20
Disposals	-0.1	-8.5	-1.2
Impairments	0	-4	-17.1
Additions (acquisitions and improvements)	258	249.4	241.7
Balance, end of period	1,378.40	1,120.50	883.6
Accumulated Depreciation
Balance—beginning of period	236.7	176.7	131.2
Disposals	0	-9.3	-1.2
Impairments	0	-0.9	-5.3
Additions (depreciation and amortization expense)	90.3	70.2	52
Balance, end of period	$327	$236.70	$176.70