CyrusOne (CONE) 10-Q 2 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 29, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	CyrusOne Inc.
Entity Central Index Key	1,553,023
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Trading Symbol	CONE
Amendment Flag	false
Entity Common Stock, Shares Outstanding		80,097,124

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Investment in real estate:
Land	$ 122.9	$ 93
Buildings and improvements	995.2	905.3
Equipment	917.8	598.2
Construction in progress	178.9	231.1
Subtotal	2,214.8	1,827.6
Accumulated depreciation	(503.2)	(435.6)
Net investment in real estate	1,711.6	1,392
Cash and cash equivalents	13.2	14.3
Rent and other receivables (net of allowance for doubtful accounts of $1.8 and $1.0 as of June 30, 2016 and December 31, 2015, respectively)	66.4	76.1
Restricted cash	0.3	1.5
Goodwill	453.4	453.4
Intangible assets (net of accumulated amortization of $100.3 and $90.6 as of June 30, 2016 and December 31, 2015, respectively)	160.6	170.3
Other assets	105.8	88
Total assets	2,511.3	2,195.6
Liabilities and equity
Accounts payable and accrued expenses	163.7	136.6
Deferred revenue	71.7	78.7
Capital lease obligations	10.9	12.2
Long-term debt, net	1,096.2	996.5
Lease financing arrangements	144.3	150
Total liabilities	1,486.8	1,374
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 79,619,202 and 72,556,334 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively	0.8	0.7
Additional paid in capital	1,215.7	967.2
Accumulated deficit	(191.5)	(145.9)
Accumulated other comprehensive loss	(0.5)	(0.4)
Total stockholders’ equity	1,024.5	821.6
Total liabilities and equity	$ 2,511.3	$ 2,195.6

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 1.8	$ 1
Accumulated amortization, net	$ 100.3	$ 90.6
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)	79,619,202	72,556,334
Common stock outstanding (in shares)	79,619,202	72,556,334

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue	$ 130,100,000	$ 89,100,000	$ 247,900,000	$ 174,800,000
Costs and expenses:
Property operating expenses	44,800,000	32,800,000	85,100,000	65,100,000
Sales and marketing	4,200,000	2,800,000	8,200,000	5,700,000
General and administrative	14,900,000	9,900,000	28,900,000	19,000,000
Depreciation and amortization	44,700,000	31,400,000	84,000,000	62,500,000
Transaction and acquisition integration costs	400,000	9,600,000	2,700,000	9,700,000
Asset impairments and loss on disposal	0	0	0	8,600,000
Total costs and expenses	109,000,000	86,500,000	208,900,000	170,600,000
Operating income	21,100,000	2,600,000	39,000,000	4,200,000
Interest expense	11,500,000	8,700,000	23,600,000	17,100,000
Net income (loss) before income taxes	9,600,000	(6,100,000)	15,400,000	(12,900,000)
Income tax expense	(500,000)	(400,000)	(700,000)	(800,000)
Net income (loss)	9,100,000	(6,500,000)	14,700,000	(13,700,000)
Noncontrolling interest in net loss	0	(1,000,000)	0	(3,900,000)
Net income (loss) attributed to common stockholders	$ 9,100,000	$ (5,500,000)	$ 14,700,000	$ (9,800,000)
Basic weighted average common shares outstanding (in shares)	78.3	51.1	75.2	44.1
Diluted weighted average common shares outstanding (in shares)	79	51.1	76	44.1
Income (loss) per share - basic and diluted (in dollars per share)	$ 0.11	$ (0.11)	$ 0.19	$ (0.23)
Dividends declared per share (in dollars per share)	$ 0.38	$ 0.315	$ 0.76	$ 0.63

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 9.1	$ (6.5)	$ 14.7	$ (13.7)
Other comprehensive income (loss):
Foreign currency translation adjustments	(0.1)	0.3	(0.1)	0
Comprehensive income (loss)	9	(6.2)	14.6	(13.7)
Comprehensive loss attributable to noncontrolling interests	0	(1)	0	(3.9)
Comprehensive income (loss) attributable to CyrusOne Inc.	$ 9	$ (5.2)	$ 14.6	$ (9.8)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Total Stockholders' Equity/ Parent’s Net Investment	Non- controlling Interest
Beginning Balance (in shares) at Dec. 31, 2014		38.7
Beginning Balance at Dec. 31, 2014	$ 717	$ 0.4	$ 516.5	$ (55.9)	$ (0.3)	$ 460.7	$ 256.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(13.7)			(13.7)		(13.7)
Noncontrolling interest allocated net loss	3.9			3.9		3.9	(3.9)
Stock issuance costs	(0.6)		(0.6)			(0.6)
Stock based compensation (in shares)		0.3
Stock based compensation	6.2		6.2			6.2
Tax payment upon exercise of equity awards	(0.7)		(0.7)			(0.7)
Issuance of common stock (in shares)		27.3
Issuance of common stock	799.3	$ 0.2	799.1			799.3
Redemption of noncontrolling interest	(596.4)		(412.2)			(412.2)	(184.2)
Foreign currency translation adjustment	0
Dividends and distributions	(45.5)			(33.2)		(33.2)	(12.3)
Ending Balance (in shares) at Jun. 30, 2015		66.3
Ending Balance at Jun. 30, 2015	865.6	$ 0.6	908.3	(98.9)	(0.3)	809.7	55.9
Beginning Balance (in shares) at Dec. 31, 2015		72.6
Beginning Balance at Dec. 31, 2015	821.6	$ 0.7	967.2	(145.9)	(0.4)	821.6	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	14.7			14.7		14.7
Noncontrolling interest allocated net loss	0						0
Stock issuance costs	(0.5)		(0.5)			(0.5)
Stock based compensation (in shares)		0.6
Stock based compensation	6.2		6.2			6.2
Tax payment upon exercise of equity awards (in shares)		(0.5)
Tax payment upon exercise of equity awards	(13.6)		(13.6)			(13.6)
Issuance of common stock (in shares)		6.9
Issuance of common stock	256.5	$ 0.1	256.4			256.5
Foreign currency translation adjustment	(0.1)				(0.1)	(0.1)
Dividends and distributions	(60.3)			(60.3)		(60.3)	0
Ending Balance (in shares) at Jun. 30, 2016		79.6
Ending Balance at Jun. 30, 2016	$ 1,024.5	$ 0.8	$ 1,215.7	$ (191.5)	$ (0.5)	$ 1,024.5	$ 0

Consolidated Statements of Equ7

Consolidated Statements of Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)	$ 0.38	$ 0.315	$ 0.76	$ 0.63

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ 14,700,000	$ (13,700,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	84,000,000	62,500,000
Non-cash interest expense	1,500,000	1,400,000
Stock-based compensation expense	6,200,000	6,200,000
Provision for bad debt	700,000	200,000
Asset impairments and loss on disposal	0	8,600,000
Change in operating assets and liabilities:
Rent receivables and other assets	(8,900,000)	(7,800,000)
Accounts payable and accrued expenses	1,700,000	5,400,000
Deferred revenues	(7,000,000)	800,000
Due to affiliates	0	(1,900,000)
Net cash provided by operating activities	92,900,000	61,700,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets	(131,100,000)	(17,300,000)
Capital expenditures – other development	(247,100,000)	(74,200,000)
Changes in restricted cash	1,200,000	0
Net cash used in investing activities	(377,000,000)	(91,500,000)
Cash flows from financing activities:
Issuance of common stock	256,500,000	799,300,000
Stock issuance costs	(500,000)	(600,000)
Acquisition of operating partnership units	0	(426,000,000)
Dividends paid	(52,900,000)	(33,800,000)
Borrowings from credit facility	415,000,000	70,000,000
Payments on credit facility	(315,000,000)	0
Payments on capital leases and leasing financing arrangements	(4,400,000)	(2,100,000)
Debt issuance costs	(2,100,000)	0
Tax payment upon exercise of equity awards	(13,600,000)	0
Net cash provided by financing activities	283,000,000	406,800,000
Net increase (decrease) in cash and cash equivalents	(1,100,000)	377,000,000
Cash and cash equivalents at beginning of period	14,300,000	36,500,000
Cash and cash equivalents at end of period	13,200,000	413,500,000
Supplemental disclosures
Cash paid for interest, net of amount capitalized	27,200,000	18,500,000
Cash paid for income taxes	1,200,000	1,900,000
Capitalized interest	5,000,000	2,500,000
Non-cash investing and financing activities
Forward contract for purchase of operating partnership units	0	170,300,000
Acquisition and development of properties in accounts payable and other liabilities	77,400,000	27,200,000
Dividends payable	31,800,000	25,300,000
Debt issuance costs	0	3,100,000
Taxes on vesting of shares	$ 0	$ 700,000

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2016
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. wholly owns 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 information technology, financial services, energy, oil and gas, mining, medical and consumer goods and services. We currently operate 35 data centers and 2 recovery centers located in the United States, United Kingdom and Singapore.

Formation and Recent Developmen

Formation and Recent Developments	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Formation and Recent Developments	Formation and Recent Developments Formation Prior to November 20, 2012, CyrusOne was not an operative legal entity or a combination of legal entities. 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 of CyrusOne LP to CBI. On January 24, 2013 , CyrusOne Inc. completed its initial public offering (the IPO) of common stock, issuing approximately 19.0 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% . The Company completed public offerings in June 2014, April 2015, June 2015 and March 2016 of 16.0 million , 14.3 million , 13.0 million and 6.9 million shares of its common stock, respectively. The Company received $355.9 million , $426.0 million , $373.3 million and $255.0 million net proceeds from the public offerings in June 2014, April 2015, June 2015 and March 2016, respectively. On December 14, 2015, CyrusOne Inc. completed a public secondary offering of 1,350,000 shares of common stock on behalf of CBI. The Company received no proceeds from the offering. On December 31, 2015, CyrusOne Inc. completed an issuance of approximately 6.3 million newly issued shares of common stock in exchange for an equal number of operating partnership units of CyrusOne LP, held by a subsidiary of CBI. As of June 30, 2016 , CBI owned approximately 4.7% of the common stock of CyrusOne Inc. All of the 79.6 million outstanding operating partnership units of CyrusOne LP are owned, directly or indirectly, by CyrusOne Inc. Recent Developments On March 17, 2016 , CyrusOne LP entered into a first amended and restated credit agreement (the Credit Agreement) which amended and restated in its entirety the credit agreement governing its senior unsecured revolving credit facility and senior unsecured term loan facility, originally dated as of October 9, 2014. The Credit Agreement provided for an additional $250.0 million senior unsecured term loan facility in addition to the existing senior unsecured term loan facility and senior unsecured revolving credit facility. CyrusOne LP borrowed $250.0 million under the additional senior unsecured term loan facility and used the proceeds to repay a portion of the amount outstanding under the revolving credit facility. On March 21, 2016 , CyrusOne Inc. completed a public offering of 6.9 million shares of its common stock for $255.0 million , net of underwriting discounts of approximately $10.6 million . CyrusOne Inc. used the proceeds of $255.0 million to acquire 6.9 million units of operating partnership units. During the first quarter of 2016, the Company issued $0.9 million of common shares related to the exercise of stock options and $0.1 million of common shares related to the employee stock purchase plan. In total, offerings of common stock during the first quarter of 2016 resulted in $256.0 million of cash flow from financing activities on the consolidated statements of cash flows. On May 2, 2016, CyrusOne Inc. and CyrusOne GP amended and restated the Agreement of Limited Partnership of CyrusOne LP (Amended LP Agreement) to reflect that CBI and its subsidiaries have ceased to be partners or hold any partnership interests in CyrusOne LP and therefore have no rights under the Amended LP Agreement. The Amended LP Agreement also effects certain changes to clarify language, comply with or conform to Maryland and partnership tax law and make various technical corrections and ministerial changes. On May 4, 2016, CyrusOne Inc. filed a Form S-3 with the SEC as a "well-known seasoned issuer" ("WKSI") using an automatic shelf registration process. Under this process, CyrusOne Inc. or any selling security holders may sell any combination of the securities described in the registration statement from time to time in one or more offerings in amounts to be determined at the time of any offering. On July 1, 2016, the Company filed a prospectus supplement and entered into sales agreements (the Sales Agreements) with each of Raymond James & Associates, Inc., Jefferies LLC, KeyBanc Capital Markets Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and SunTrust Robinson Humphrey, Inc., as sales agents, pursuant to which CyrusOne Inc. may issue and sell from time to time shares of its common stock having an aggregate gross sales price of up to $320.0 million, pursuant to an “at the market” program. Sales of shares of CyrusOne Inc. common stock under the Sales Agreements are made by means of ordinary brokers’ transactions on the NASDAQ Global Select Market or otherwise at market prices prevailing at the time of sale, subject to specific instructions of CyrusOne Inc., at negotiated prices. On July 1, 2016, CyrusOne Inc. filed a Form S-8 with the SEC to increase the number of common shares available for issuance under the 2012 Long Term Incentive Plan from 4.0 million to 8.9 million .

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements as of June 30, 2016 and December 31, 2015 , and for the three and six months ended June 30, 2016 and June 30, 2015 , are prepared on a consolidated basis. In addition, the accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and should be read in conjunction with the financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2015 , which was filed with the Securities and Exchange Commission (SEC) on February 26, 2016. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been omitted from this report on Form 10-Q pursuant to the rules and regulations of the SEC. Results for the interim periods in this report are not necessarily indicative of future financial results and have not been audited by our independent registered public accounting firm. In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments necessary to present fairly our consolidated financial statements as of June 30, 2016 , and for the three and six months ended June 30, 2016 and 2015 . These adjustments are of a normal recurring nature and consistent with the adjustments recorded to prepare the annual audited financial statements as of December 31, 2015 . All amounts reflected are in millions except share and per share data.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Use of Estimates —Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated 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, including purchase price allocations for business combinations, 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. 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. As we have substantially all of the construction risks, we are deemed the “owner” of the asset under construction for accounting purposes during the construction period, and are therefore required to capitalize the construction costs on the accompanying consolidated balance sheets. At inception, the fair value of the building (excluding land) is recorded as an asset and the construction and modification costs to the building, which are not funded by us, would be recorded as a liability. As construction progresses, the value of the asset and obligation increases by the fair value of the structural improvements. At completion of the construction, Sales-Leaseback Accounting under ASC 840-40-25 is also evaluated. Due to our continuing involvement with the lessor, Sales-Leaseback Accounting is precluded and the liability is not derecognized. When the asset is placed in service, depreciation commences, and the 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. The associated obligation is presented as Lease financing arrangements in the accompanying consolidated balance sheets. When we are not deemed the accounting owner of leased real estate, we further evaluate the lease to determine whether it 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. Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to thirty years for buildings, three to thirty years for building improvements, and three to twenty years for 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. For the six months ended June 30, 2015 , we recognized impairments of $8.6 million related to the Austin 1 lease termination. There were no impairments recognized for the six months ended June 30, 2016 . Business Combinations —The Company applies the purchase method for business combinations, where all tangible and identifiable intangible assets acquired and all liabilities assumed are recorded at fair value. Any excess purchase price is recorded as goodwill. Transaction costs associated with business combinations are expensed as incurred. Revenues and the results of operations of the acquired business are included in the accompanying consolidated financial statements commencing on the date of acquisition. 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. Restricted Cash —Restricted cash includes cash equivalents held to collateralize standby letters of credit and/or deposited in escrow to fund construction or pending potential acquisition transactions. In addition, we may have other cash that is not immediately available for use in current operations. 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 any of the periods presented. 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. 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. Deferred Leasing Costs —Deferred leasing costs are presented with Other assets in the accompanying consolidated balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized over the term of the customer lease. Amortization of deferred leasing costs is presented with Depreciation and amortization in the accompanying consolidated statements of operations. If a lease terminates prior to the expiration of the lease, the remaining unamortized cost is written off to amortization expense. As of June 30, 2016 and December 31, 2015 , deferred leasing costs were $22.1 million and $14.2 million , respectively. Deferred Financing Costs —Deferred financing costs include costs incurred in connection with issuance of debt, including our senior notes, term loans and revolving credit facilities. These costs include deferred financing costs associated with our revolving line of credit and are presented in the balance sheet as a direct reduction from the carrying amount of the debt liability to conform to the 2015 presentation. These financing costs are capitalized and amortized to expense over the term of the instrument and are included as a component of Interest expense. 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 balance sheets. Some of our leases are structured on a full-service gross basis in which the customer pays a fixed amount for both colocation rent and power. Other leases provide that the customer will be billed for power based upon actual usage which is separately metered. In both cases, this revenue is presented as Revenue in the accompanying consolidated statements 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. Generally, we receive an administrative fee when we manage the meters for our customers. 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 June 30, 2016 and December 31, 2015, Deferred revenue was $71.7 million and $78.7 million , respectively. Certain customer leases 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. A provision for uncollectible accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible. 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 $38.3 million and $71.3 million for the three and six months ended June 30, 2016 , respectively, and $26.5 million and $52.7 million for the three and six months ended June 30, 2015 , respectively. Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. Finite-lived intangibles include trademarks, customer relationships, favorable leasehold interests and deferred leasing costs. As of June 30, 2016 , the estimated weighted average useful life of trademarks and customer relationships was 10 and 13 years, respectively. In addition, we have a favorable leasehold interest related to a land lease that is being amortized over the lease term of 51 years. Deferred leasing costs are amortized over 3 to 5 years. Amortization expense was $6.4 million and $12.7 million for the three and six months ended June 30, 2016 , respectively, and $4.9 million and $9.8 million for the three and six months ended June 30, 2015 , respectively. Transaction and Acquisition Integration Costs —Transaction costs represent incremental 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 and do not include any recurring costs from our ongoing operations. Integration costs represent incremental costs to integrate a consummated acquisition. Income Taxes —The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. has 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 stockholders. 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, and we may not be able to qualify as a REIT for four subsequent taxable years. 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 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. 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 2012, and we have no liabilities for uncertain tax positions as of June 30, 2016 . Earnings Per Share —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 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 stockholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS is applied. Stock-Based Compensation —In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan, (LTIP) which was amended and restated by our stockholders on May 2, 2016. The LTIP is administered by the compensation committee of the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. See Note 10 for additional details relating to these awards. Share-based compensation expense is based on the estimated grant-date fair value. CyrusOne Inc. recognizes share-based compensation expense, less estimated forfeitures, on a straight-line basis over the requisite service period for time-based awards and on a graded vesting basis for performance-based awards. CyrusOne estimates forfeitures based on historical activity, expected employee turnover, and other qualitative factors which are adjusted for changes in estimates and award vesting. All expenses for an award will be recognized by the time it becomes fully vested. CyrusOne Inc. uses the Black-Scholes-Merton option pricing model to calculate the fair value of stock options. This option valuation model requires the use of subjective assumptions, including the estimated fair value of the underlying common stock, the expected stock price volatility, and the expected term of the option. The estimated fair value of the underlying common stock is based on third-party valuations. Our volatility estimates are based on a peer group of companies. We estimate the expected term of the awards to be the weighted average mid-point between the vesting date and the end of the contractual term. We use this method to estimate the expected term since we do not have sufficient historical exercise data. For interim periods, we use our year-to-date actual results, financial forecasts, and other available information to estimate the probability of the award vesting based on the performance metrics. 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, and 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 business segment. Recently Issued Accounting Standards — Accounting Standards Update (ASU) No. 2014-09 (ASU 2014-09), Revenue from Contracts with Customers (Topic 606) In May 2014, the Financial Accounting Standards Board (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. In July 2015, the FASB voted to approve a one-year deferral of the effective date to December 15, 2017 for interim and annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. This guidance permits two implementation approaches. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). We are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements. ASU No. 2016-01 (ASU 2016-01), Financial instruments-Overall (Subtopic 825-10) In January 2016, the FASB amended its standards related to the accounting of certain financial instruments. This amendment addresses certain aspects of recognition, measurement, presentation and disclosure. The new rules will become effective for annual and interim periods beginning after December 15, 2017. Early adoption is not permitted. We are in the process of evaluating the impact the amendment will have on the consolidated financial statements. ASU No. 2016-02 (ASU 2016-02), Leases (Topic 842) In February 2016, the FASB issued accounting standard update (ASU) No. 2016-02, Leases (Topic 842). This new lease guidance requires that an entity should recognize assets and liabilities for leases with a maximum possible term of more than 12 months. A lessee would recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the leased asset (the underlying asset) for the lease term. Leases would be classified as either Type A leases (generally today’s capital leases) or Type B leases (generally today’s operating leases). For certain leases of assets other than property (for example, equipment, aircraft, cars, trucks), a lessee would classify the lease as a Type A lease and would do the following: (1) recognize a right-of-use asset and a lease liability, initially measured at the present value of lease payments and (2) recognize the unwinding of the discount on the lease liability as interest separately from the amortization of the right-of-use asset. For certain leases of property (that is, land and/or a building or part of a building), a lessee would classify the lease as a Type B lease and would do the following: (1) recognize a right-of-use asset and a lease liability, initially measured at the present value of lease payments and (2) recognize a single lease cost, combining the unwinding of the discount on the lease liability with the amortization of the right-of-use asset, on a straight-line basis. This guidance also provides accounting updates with respect to lessor accounting under a lease arrangement. This new lease guidance is effective for CyrusOne beginning in the first quarter of fiscal 2019. Entities have the option of using either a full retrospective or a modified approach (cumulative effect adjustment in period of adoption) to adopt the new guidance. Early adoption is permitted for all entities. We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements. ASU No. 2016-09 (ASU 2016-09), Improvements to Employee Share-Based Payment Accounting (Subtopic 718) In March 2016, the FASB issued guidance which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2016-12 (ASU 2016-12), Revenue from Contracts with Customers (Subtopic 606) In May 2016, the FASB issued guidance which amends certain aspects of the Board's new revenue standard, ASU 2014-09. The amendments include the collectibility of revenue, presentation of sales tax and other similar taxes collected from customers, contracts containing noncash considerations, and contract modifications and completed contracts at transition. The effective date and transition provisions are aligned with the requirements of ASU 2014-09.

Purchase of Fixed Assets

Purchase of Fixed Assets	6 Months Ended
	Jun. 30, 2016
Business Combinations [Abstract]
Purchase of Fixed Assets	Purchase of Fixed Assets On March 31, 2016 , CyrusOne LP purchased CME Group's suburban Chicago data center in Aurora, Illinois for $131.1 million , including transaction related costs, in an all cash transaction. CyrusOne LP financed the purchase with proceeds of CyrusOne Inc's March 2016 common stock offering. The purchase enhances the geographic diversification of CyrusOne, provides access to a high quality enterprise customer base and strengthens our product portfolio. The transaction adds to CyrusOne Inc.'s existing data center platform an approximately 428,000 square-foot facility data center serving the Chicago metropolitan region. In addition, CyrusOne acquired approximately 15 acres of land directly adjacent to the data center for future development. The CME Group entered into a 15 -year lease for data center space at the Aurora facility. The agreement is expected to enhance the range of services available to the Company and CME Group's mutual customers through connectivity, hosting and data offerings.

Long-Term Debt, Capital Lease O

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements	Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements Long-term debt, Capital lease obligations and Lease financing arrangements presented in the accompanying consolidated financial statements consist of the following: IN MILLIONS As of June 30, 2016 December 31, 2015 Credit facilities: Revolving credit facility $ 85.0 $ 235.0 Term loan 550.0 300.0 6.375% senior notes due 2022, including bond premium 477.5 477.6 Notes payable 1.4 1.5 Deferred financing costs (17.7 ) (17.6 ) Long-term debt 1,096.2 996.5 Capital lease obligations 10.9 12.2 Lease financing arrangements 144.3 150.0 Total $ 1,251.4 $ 1,158.7 Credit Facility —On March 17, 2016 , CyrusOne LP entered into a first amended and restated credit agreement (the Credit Agreement) which amended and restated in its entirety the 2014 Credit Facility, as amended previously. The Credit Agreement provides for an additional $250.0 million senior unsecured term loan facility (the Additional Term Loan) in addition to the existing $300.0 million Initial Term Loan and the existing $650.0 million Revolving Credit Facility. The Credit Agreement has an accordion feature under which CyrusOne LP may request an increase in the total commitments up to an amount not to exceed $250.0 million . Deferred financing costs of $2.1 million related to the Additional Term Loan were recorded as of June 30, 2016. The Revolving Credit 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 Initial Term Loan is scheduled to mature in October 2019. The Additional Term Loan is scheduled to mature in September 2021. The Revolving Credit Facility currently bears interest at a rate per annum equal to LIBOR plus 1.70% and the Initial Term Loan and the Additional Term Loan currently bear interest at a rate per annum equal to LIBOR plus 1.65% . We pay commitment fees for the unused amount of borrowings on the Revolving Credit Facility 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 $0.4 million and $0.1 million for the three months ended June 30, 2016 and 2015 , respectively. Commitment fees related to the Credit Agreement were $0.7 million and $0.3 million for the six months ended June 30, 2016 and 2015 , respectively. 6.375% Senior Notes due 2022 —On November 20, 2012, CyrusOne LP and CyrusOne Finance Corp. (Issuers) issued $525.0 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 wholly 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 Issuers 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. 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 being redeemed, together with accrued and unpaid interest, if any, to the date of redemption plus a “make-whole” premium. On or after November 15, 2017, the Issuers may, at their 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 a redemption price equal to 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 after the redemption and (ii) the redemption occurs within 90 days of the closing of any such equity offering. In November and December of 2014, we repurchased a portion of our 6.375% senior notes with an aggregate face value of $150.2 million for a purchase price of $163.0 million , including accrued and unpaid interest. This resulted in a loss on extinguishment of debt of $12.8 million . On July 1, 2015, the Issuers closed a private offering of $100.0 million aggregate principal amount of the 6.375% senior notes (New Notes) plus a premium of $3.8 million . The New Notes were issued as additional notes under the Indenture dated November 20, 2012 as supplemented by the first supplemental indenture dated July 1, 2015, and the New Notes have terms substantially identical to those of the 6.375% senior notes issued in November 2012. On December 29, 2015, all notes issued on July 1, 2015 were exchanged for registered notes. Debt Covenants —The Credit Agreement 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 stockholders 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 the 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 stockholders 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, 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. As of June 30, 2016 , we believe we were in compliance with all covenants. Notes payable —As of June 30, 2016 , the Company had a note payable for approximately $1.4 million with a third-party for electrical infrastructure at one of the Company's locations. The note payable matures in January 2034. We will pay approximately $9,000 per month until maturity under the note payable. 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 Credit Facility, the Initial Term Loan, the Existing Term Loan and 6.375% senior notes due 2022. As of June 30, 2016 and December 31, 2015 , deferred financing costs totaled $17.7 million and $17.6 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 Credit Facility and Initial Term Loan and Additional Term Loan are amortized using the straight-line method. Amortization of deferred financing costs, included in Interest expense in the consolidated statements of operations totaled $1.1 million and $2.0 million for the three and six months ended June 30, 2016 , respectively, and $0.7 million and $1.4 million for the three and six months ended June 30, 2015 , respectively. Capital lease obligations —We use leasing as a source of financing for certain of our data center facilities and related equipment. We currently operate eight data center facilities under leases 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. Lease financing arrangements —Lease 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. Interest expense on Capital lease obligations and Lease financing arrangements was $2.5 million and $4.9 million for the three and six months ended June 30, 2016 , respectively, and $1.3 million and $2.7 million for the three and six months ended June 30, 2015 , respectively.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments 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 at the measurement date under current market conditions. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs used in the methodologies of measuring fair value for assets 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. The fair value of Cash and cash equivalents, Restricted cash, Rent and other receivables, 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: IN MILLIONS As of June 30, 2016 December 31, 2015 Carrying Value Fair Value Carrying Value Fair Value 6.375% senior notes due 2022 $ 477.5 $ 491.0 $ 477.6 $ 493.8 Revolving credit facility and term loans 635.0 635.0 535.0 535.0 Note payable 1.4 1.1 1.5 1.2 The fair value of our 6.375% senior notes as of June 30, 2016 and December 31, 2015 was based on the quoted market price for these notes, which is considered Level 1 of the fair value hierarchy. The carrying value of the Revolving Credit Facility, the Initial Term Loan and the Additional Term Loan approximates estimated fair value as of June 30, 2016 , due to the variability of interest rates and the stability of our credit ratings. The fair value of the note payable at June 30, 2016 and December 31, 2015 , 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 3 of the fair value hierarchy.

Noncontrolling Interest - Opera

Noncontrolling Interest - Operating Partnership	6 Months Ended
	Jun. 30, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest - Operating Partnership	Noncontrolling Interest - Operating Partnership The following table shows the ownership interests as of June 30, 2016 and 2015 , and the portion of net income (loss) and distributions for the six months ended June 30, 2016 and 2015 : As of June 30, 2016 June 30, 2015 (in millions, except unit amount) The Company CBI The Company CBI Operating partnership units 79.6 — 66.3 6.3 Ownership % 100.0 % — % 91.3 % 8.7 % Portion of net income (loss) 14.7 — (9.8 ) (3.9 ) Distributions (60.3 ) — (33.2 ) (12.3 ) Prior to the IPO, 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 of CyrusOne LP to CBI. After the IPO on January 24, 2013, CBI retained a noncontrolling interest in the operating partnership of 66.1% . The Company completed public offerings in 2014 and 2015 in which the proceeds were used to acquire the limited partnership interests in the operating partnership from CBI. As of December 31, 2015 , CBI owned approximately 9.5% of the Company’s common stock, and all of the operating partnership units of CyrusOne LP were owned, directly or indirectly, by the Company. CyrusOne Inc. had no noncontrolling interests as of June 30, 2016 , and CBI owned approximately 4.7% of the Company's common stock.

Dividends

Dividends	6 Months Ended
	Jun. 30, 2016
Stockholders' Equity Note [Abstract]
Dividends	Dividends On May 4, 2016 , we announced a regular cash dividend of $0.38 per common share payable to stockholders of record at the close of business on June 24, 2016 . The dividends were paid on July 15, 2016 .

Stock-Based Compensation Plans

Stock-Based Compensation Plans	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans Stock-based compensation expense was as follows: Three Months Ended June 30, 2016 Three Months Ended June 30, 2015 Six Months Ended June 30, 2016 Six Months Ended June 30, 2015 Founders $ — $ 1.3 $ 0.3 $ 2.6 2013 Grants — 0.1 0.1 0.4 2014 Grants 0.3 0.5 0.6 1.3 2015 Grants 0.8 1.3 1.9 1.9 2016 Grants 2.1 — 3.3 — Total $ 3.2 $ 3.2 $ 6.2 $ 6.2 In conjunction with the IPO, the board of directors of CyrusOne Inc. adopted the LTIP. On May 2, 2016, our stockholders approved the amended and restated 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 8.9 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. is allocated to the operating partnership. Shares available under the LTIP at June 30, 2016 , were approximately 0.8 million . Shares vest according to each agreement and as long as the employee remains employed with the Company. The Company uses the Black-Scholes option-pricing model for time and performance-based options and a Monte Carlo simulation for market-based awards. Compensation expense is measured based on the estimated grant-date fair value. Expense for time-based grants is recognized under a straight-line method. For market-based grants, expense is recognized under a graded expense attribution method. For performance-based grants, expense is recognized under a graded expense attribution method if it is probable that the performance targets will be achieved. Founders Grants On January 24, 2013, the Company granted 1.0 million shares of time-based restricted stock, which had an aggregate value of $19.0 million on the grant date. Holders of the restricted stock have all of the rights and privileges of stockholders including but not limited to the right to vote, receive dividends and distributions upon liquidation of CyrusOne. These shares vested on January 24, 2016 . 2013 Grants On April 17, 2013, the Company issued performance and market-based awards under the LTIP in the form of stock options and restricted stock. The grant date fair value of the restricted stock was $23.58 per share. For these awards, vesting was tied 50% to the achievement of cumulative EBITDA targets and 50% to a market-based performance measure. These awards generally vest annually over a three -year period upon the achievement of cumulative EBITDA targets. The first two years are capped at 100% of the target with a cumulative true-up in year three. The portion of the award tied to market-based measures cliff vest at the end of three years upon the achievement of the applicable targets. There were additional shares of time-based restricted stock issued during 2013 that cliff vest at the end of three years. The stock option awards have a contractual life of 10 years from the award date and were granted with an exercise price equal to $23.58 per share. The holders of restricted stock shall have all of the rights and privileges of stockholders including the right to vote. Any dividends paid with respect to the shares shall be accrued by the Company and distributed on the vesting date provided that the applicable performance goal has been attained. As of June 30, 2016 , there was no unearned compensation representing the unvested portion of the awards granted during 2013. 2014 Grants On February 7, 2014, the Company issued performance and market-based awards under the LTIP in the form of restricted stock. The grant date fair value of the restricted stock was $20.65 per share. For these awards, vesting was tied 50% to the achievement of cumulative Adjusted EBITDA targets and 50% to a market-based performance measure. These awards generally vest annually over a three -year period upon the achievement of cumulative Adjusted EBITDA targets. The first two years are capped at 100% of the target with a cumulative true-up in year three. The portion of the award tied to market-based measures cliff vest at the end of three years upon the achievement of the applicable targets. There were additional shares of time-based restricted stock issued during 2014 that cliff vest at the end of three years. As of June 30, 2016 , unearned compensation representing the unvested portion of the awards granted during 2014, net of forfeitures, totaled $0.7 million , with a weighted average vesting period of 0.6 years. 2015 Grants On February 10, 2015, the Company issued time, performance and market-based awards under the LTIP in the form of stock options and restricted stock. The grant date fair value of the restricted stock was $28.42 per share. Twenty-five percent of the restricted stock awards are subject to time-based vesting and seventy-five percent of the restricted stock awards are equally split between performance-based and market-based vesting. The time-based restricted stock awards vest pro-rata annually over three years. The performance and market-based restricted stock awards vest annually based upon the achievement of certain criteria for each of the three -year measurement periods. The first two years are capped at 100% of the target with a cumulative true-up in year three. The stock options are time-based and vest annually on a pro-rata basis over 3 years. The stock option awards have a contractual life of 10 years from the award date and were granted with an exercise price equal to $28.44 . There were additional time and performance-based restricted stock issued and options granted during 2015. These awards generally vest annually over a three year period or cliff vest at the end of three years based on the employee's agreement. As of June 30, 2016 , unearned compensation representing the unvested portion of the awards granted in 2015, net of forfeitures, totaled $4.5 million , with a weighted average vesting period of 1.4 years. 2016 Grants On January 29, 2016, the Company issued time, performance and market-based awards under the LTIP in the form of restricted stock. The grant date fair value of the shares was $36.85 per share. On February 1, 2016, the Company issued time-based restricted stock awards to Board members, and the grant date fair value of the restricted stock was $36.99 per share. The Company also issued a total of 587,536 shares of restricted stock. The Company issued stock options on February 1, 2016. The stock option awards have a contractual life of 10 years from the award date and were granted with an exercise price equal to $36.99 . The Company issued 222,461 options with a grant date fair value of $6.99 . In addition, on May 2, 2016, the Company issued 7,275 time-based restricted stock awards under the LTIP to a Board member and various employees. The time-based restricted stock awards generally vest pro-rata annually over a three -year period. The performance and market-based restricted stock awards vest annually based upon the achievement of certain criteria for each of the three -year measurement periods. The first two years are capped at 100% of the target with a cumulative true-up in year three. Certain employees were also awarded time-based restricted stock that cliff vest at the end of three years. The stock options are time-based and vest annually on a pro-rata basis over 3 years. As of June 30, 2016 , unearned compensation representing the unvested portion of the awards granted in 2016, net of forfeitures, totaled $15.6 million , with a weighted average vesting period of 2.1 years.

Income (Loss) per Share

Income (Loss) per Share	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Income (Loss) per Share	Income (Loss) per Share Basic income (loss) per share is calculated using the weighted average number of shares of common stock outstanding during the period. In addition, net income (loss) applicable to participating securities and the related participating securities are excluded from the computation of basic income (loss) per share. Diluted income (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 the computation of basic and diluted net income (loss) per share for the three and six months ended June 30, 2016 and 2015 : IN MILLIONS, except per share amounts Three Months Ended June 30, 2016 Three Months Ended June 30, 2015 Six Months Ended June 30, 2016 Six Months Ended June 30, 2015 Basic Diluted Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) attributed to common stockholders $ 9.1 $ 9.1 $ (5.5 ) $ (5.5 ) $ 14.7 $ 14.7 $ (9.8 ) $ (9.8 ) Less: Restricted stock dividends (0.2 ) (0.2 ) (0.3 ) (0.3 ) (0.3 ) (0.3 ) (0.5 ) (0.5 ) Net income (loss) available to stockholders $ 8.9 $ 8.9 $ (5.8 ) $ (5.8 ) $ 14.4 $ 14.4 $ (10.3 ) $ (10.3 ) Denominator: Weighted average common outstanding-basic 78.3 78.3 51.1 51.1 75.2 75.2 44.1 44.1 Performance-based restricted stock (1) 0.6 — 0.7 — Convertible securities (1) 0.1 — 0.1 — Weighted average shares outstanding-diluted 79.0 51.1 76.0 44.1 EPS: Net income (loss) per share-basic $ 0.11 $ (0.11 ) $ 0.19 $ (0.23 ) Effect of dilutive shares: Net income (loss) per share-diluted $ 0.11 $ (0.11 ) $ 0.19 $ (0.23 ) (1) We have excluded 1.1 million weighted average shares of restricted stock, and 19.7 million of operating partnership units which are securities convertible into our common stock, from our diluted earnings per share as of June 30, 2015 . These amounts were deemed anti-dilutive.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2016
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. The consolidated 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. Total revenues were $5.8 million and $11.2 million for the three and six months ended June 30, 2015 , respectively. Total operating costs and expenses were $0.4 million and $0.9 million for the three and six months ended June 30, 2015 , respectively. At December 31, 2015 , CBI owned 9.5% of the outstanding common stock of CyrusOne Inc. and no operating partnership units, at which point it ceased to be a related party of CyrusOne Inc. As of June 30, 2016 , CBI owned approximately 4.7% of the outstanding common stock of CyrusOne Inc. The dividends payable as of June 30, 2016 , reflect the balance due to subsidiaries of CBI related to the dividend and distribution announced on May 4, 2016 of $0.38 per share based on CBI's ownership of common shares of CyrusOne Inc. as of the Record Date of June 24, 2016 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CyrusOne Inc. elected to be taxed as a REIT under the Code, 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 continue to qualify for taxation as a REIT, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our stockholders. 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 CyrusOne Inc. and its subsidiary pass-through entities. We have elected to designate two subsidiaries as taxable REIT subsidiaries (each a TRS). 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 federal and state corporate rates. 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. Income tax expense was $0.5 million and $0.7 million for the three and six months ended June 30, 2016 , respectively, and $0.4 million and $0.8 million for the three and six months ended June 30, 2015 , respectively. 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 June 30, 2016 and December 31, 2015 . 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 June 30, 2016 and December 31, 2015 , the net domestic and foreign deferred tax assets were zero .

Guarantors

Guarantors	6 Months Ended
	Jun. 30, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Guarantors	Guarantors CyrusOne Inc. CyrusOne LP and CyrusOne Finance Corp., as “LP Co-issuer” and “Finance Co-issuer,” respectively (together, the Issuers), had $477.5 million aggregate principal amount of 6.375% senior notes outstanding, including bond premium, at June 30, 2016 . As of June 30, 2016 , the 6.375% 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 wholly owned subsidiaries, CyrusOne LLC, CyrusOne TRS Inc., CyrusOne Foreign Holdings LLC, Cervalis Holdings LLC, and Cervalis LLC (such subsidiaries, together the Guarantor Subsidiaries). None of CyrusOne LP's subsidiaries organized outside of the United States (collectively, the Non-Guarantor Subsidiaries) guarantee the 6.375% senior notes. Subject to the provisions of the indenture governing the 6.375% 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 6.375% senior notes in accordance with the terms of the indenture. The entity structure of each Issuer and guarantor of the 6.375% senior notes is described below. 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. is 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 is a wholly owned subsidiary of CyrusOne Inc. 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 are CyrusOne LP and CyrusOne Finance Corp. CyrusOne Finance Corp., a wholly owned subsidiary of CyrusOne LP, was formed for the sole purpose of acting as co-issuer of the 6.375% senior notes and has no other assets or operations. CyrusOne LP, in addition to being the co-issuer of the 6.375% senior notes, is also the 100% owner, either directly or indirectly, of the Guarantor Subsidiaries and Non-Guarantor Subsidiaries. Guarantor Subsidiaries – The guarantors of the 6.375% senior notes include CyrusOne LLC, CyrusOne TRS Inc., CyrusOne Foreign Holdings LLC, Cervalis and Cervalis LLC (the Guarantor Subsidiaries) agreed to provide unconditional guarantees of the issuers’ obligations under the 6.375% senior notes. The guarantee of each Guarantor Subsidiary is (i) a senior unsecured obligation of such Guarantor Subsidiary, (ii) pari passu in right of payment with any existing and future unsecured senior indebtedness of such Guarantor Subsidiary, (iii) senior in right of payment to any future subordinated indebtedness of such Guarantor Subsidiary and (iv) effectively subordinated in right of payment to all existing and future secured indebtedness of such Guarantor Subsidiary, to the extent of the value of the collateral securing that indebtedness. CyrusOne LLC, together with CyrusOne Foreign Holdings LLC, directly or indirectly, owns 100% of the Non-Guarantor Subsidiaries. Non-Guarantor Subsidiaries consist of wholly owned subsidiaries which conduct operations in the United Kingdom and Singapore, as well as CyrusOne Government Services LLC, a Delaware limited liability company and wholly owned subsidiary of CyrusOne LP. The following schedules present the balance sheets as of June 30, 2016 and December 31, 2015 , and the statements of operations and comprehensive income (loss) for the three and six months ended June 30, 2016 and June 30, 2015 , and the statements of cash flows for the six months ended June 30, 2016 and June 30, 2015 for the Parent Guarantor, General Partner, LP Co-issuer, Finance Co-issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries. The consolidating statements of cash flows for the six months ended June 30, 2016 , includes the acquisition of Cervalis in July 2015. The results for Cervalis are included in the Guarantor Subsidiaries financial statements subsequent to the acquisition. Consolidating Balance Sheets IN MILLIONS As of June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 122.9 $ — $ — $ 122.9 Buildings and improvements — — — — 958.1 37.0 0.1 995.2 Equipment — — — — 913.5 1.0 3.3 917.8 Construction in progress — — — — 176.7 — 2.2 178.9 Subtotal — — — — 2,171.2 38.0 5.6 2,214.8 Accumulated depreciation — — — — (492.7 ) (10.5 ) — (503.2 ) Net investment in real estate — — — — 1,678.5 27.5 5.6 1,711.6 Cash and cash equivalents — — — — 10.9 2.3 — 13.2 Investment in subsidiaries 1,032.8 10.3 1,149.9 — — — (2,193.0 ) — Restricted cash — — — — 0.3 — — 0.3 Rent and other receivables — — — — 65.0 1.4 — 66.4 Intercompany receivable 17.9 — 1,000.2 — — 0.3 (1,018.4 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 160.6 — — 160.6 Other assets — — — — 103.0 2.8 — 105.8 Total assets $ 1,050.7 $ 10.3 $ 2,150.1 $ — $ 2,471.7 $ 34.3 $ (3,205.8 ) $ 2,511.3 Accounts payable and accrued expenses $ 31.8 $ — $ 4.6 $ — $ 126.5 $ 0.8 $ — $ 163.7 Deferred revenue — — — — 71.0 0.7 — 71.7 Intercompany payable — — 17.9 — 1,001.4 — (1,019.3 ) — Capital lease obligations — — — — 4.9 6.0 — 10.9 Long-term debt — — 1,094.8 — 1.4 — — 1,096.2 Lease financing arrangements — — — — 116.6 27.7 — 144.3 Total liabilities 31.8 — 1,117.3 — 1,321.8 35.2 (1,019.3 ) 1,486.8 Total stockholders' equity 1,018.9 10.3 1,032.8 — 1,149.9 (0.9 ) (2,186.5 ) 1,024.5 Total liabilities and equity $ 1,050.7 $ 10.3 $ 2,150.1 $ — $ 2,471.7 $ 34.3 $ (3,205.8 ) $ 2,511.3 IN MILLIONS As of December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 93.0 $ — $ — $ 93.0 Buildings and improvements — — — — 865.6 39.6 0.1 905.3 Equipment — — — — 594.7 0.9 2.6 598.2 Construction in progress — — — — 229.8 0.1 1.2 231.1 Subtotal — — — — 1,783.1 40.6 3.9 1,827.6 Accumulated depreciation — — — — (426.0 ) (9.6 ) — (435.6 ) Net investment in real estate — — — — 1,357.1 31.0 3.9 1,392.0 Cash and cash equivalents — — — — 10.4 3.9 — 14.3 Investment in subsidiaries 817.7 8.2 850.6 — 0.7 — (1,677.2 ) — Restricted cash — — — — 1.5 — — 1.5 Rent and other receivables — — — — 74.8 1.3 — 76.1 Intercompany receivable — — 991.3 — — — (991.3 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 170.3 — — 170.3 Other assets — — — — 85.3 2.7 — 88.0 Total assets $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Accounts payable and accrued expenses $ — $ — $ 29.2 $ — $ 106.8 $ 0.6 $ — $ 136.6 Deferred revenue — — — — 78.0 0.7 — 78.7 Intercompany payable — — — — 991.3 — (991.3 ) — Capital lease obligations — — — — 6.1 6.1 — 12.2 Long-term debt — — 995.0 — 1.5 — — 996.5 Lease financing arrangements — — — — 119.2 30.8 — 150.0 Total liabilities — — 1,024.2 — 1,302.9 38.2 (991.3 ) 1,374.0 Total stockholders' equity 817.7 8.2 817.7 — 850.6 0.7 (1,673.3 ) 821.6 Total liabilities and equity $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Consolidating Statements of Operations and Comprehensive Income (Loss) IN MILLIONS Three Months Ended June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 128.8 $ 1.3 $ — $ 130.1 Costs and expenses: Property operating expenses — — — — 44.2 0.6 — 44.8 Sales and marketing — — — — 4.2 — — 4.2 General and administrative — — — — 14.8 0.1 — 14.9 Depreciation and amortization — — — — 44.1 0.6 — 44.7 Transaction and acquisition integration costs — — — — 0.4 — — 0.4 Total costs and expenses — — — — 107.7 1.3 — 109.0 Operating income — — — — 21.1 — — 21.1 Interest expense — — 12.1 — — 0.7 (1.3 ) 11.5 Income (loss) before income taxes — — (12.1 ) — 21.1 (0.7 ) 1.3 9.6 Income tax expense — — — — (0.5 ) — — (0.5 ) Equity earnings (loss) related to investment in subsidiaries 7.8 — 19.9 — (0.7 ) — (27.0 ) — Net income (loss) 7.8 — 7.8 — 19.9 (0.7 ) (25.7 ) 9.1 Noncontrolling interest in net income (loss) — — — — — — — — Net income (loss) attributed to common stockholders 7.8 — 7.8 — 19.9 (0.7 ) (25.7 ) 9.1 Other comprehensive loss — — — — — (0.1 ) — (0.1 ) Comprehensive income (loss) attributable to common stockholders $ 7.8 $ — $ 7.8 $ — $ 19.9 $ (0.8 ) $ (25.7 ) $ 9.0 IN MILLIONS Three Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 87.8 $ 1.3 $ — $ 89.1 Costs and expenses: Property operating expenses — — — — 32.1 0.7 — 32.8 Sales and marketing — — — — 2.7 0.1 — 2.8 General and administrative — — — — 10.1 (0.2 ) — 9.9 Depreciation and amortization — — — — 30.7 0.7 — 31.4 Transaction and acquisition integration costs — — — — 9.6 — — 9.6 Total costs and expenses — — — — 85.2 1.3 — 86.5 Operating income — — — — 2.6 — — 2.6 Interest expense — — 8.6 — — 0.8 (0.7 ) 8.7 Income (loss) before income taxes — — (8.6 ) — 2.6 (0.8 ) 0.7 (6.1 ) Income tax expense — — — — (0.4 ) — — (0.4 ) Equity earnings (loss) related to investment in subsidiaries (6.2 ) (0.1 ) 1.4 — (0.8 ) — 5.7 — Net income (loss) (6.2 ) (0.1 ) (7.2 ) — 1.4 (0.8 ) 6.4 (6.5 ) Noncontrolling interest in net loss — — — — — — (1.0 ) (1.0 ) Net income (loss) attributed to common stockholders (6.2 ) (0.1 ) (7.2 ) — 1.4 (0.8 ) 7.4 (5.5 ) Other comprehensive loss — — — — — 0.3 — 0.3 Comprehensive loss attributable to noncontrolling interests — — — — — — — — Comprehensive income (loss) attributable to common stockholders $ (6.2 ) $ (0.1 ) $ (7.2 ) $ — $ 1.4 $ (0.5 ) $ 7.4 $ (5.2 ) IN MILLIONS Six Months Ended June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 245.2 $ 2.7 $ — $ 247.9 Costs and expenses: Property operating expenses — — — — 83.9 1.2 — 85.1 Sales and marketing — — — — 8.2 — — 8.2 General and administrative — — — — 28.8 0.1 — 28.9 Depreciation and amortization — — — — 82.7 1.3 — 84.0 Transaction and acquisition integration costs — — — — 2.7 — — 2.7 Asset impairments and loss on disposal — — — — — — — — Total costs and expenses — — — — 206.3 2.6 — 208.9 Operating income — — — — 38.9 0.1 — 39.0 Interest expense — — 23.8 — — 1.5 (1.7 ) 23.6 Income (loss) before income taxes — — (23.8 ) — 38.9 (1.4 ) 1.7 15.4 Income tax expense — — — — (0.7 ) — — (0.7 ) Equity earnings (loss) related to investment in subsidiaries 13.0 0.1 36.8 — (1.4 ) — (48.5 ) — Net income (loss) 13.0 0.1 13.0 — 36.8 (1.4 ) (46.8 ) 14.7 Noncontrolling interest in net income (loss) — — — — — — — — Net income (loss) attributed to common stockholders 13.0 0.1 13.0 — 36.8 (1.4 ) (46.8 ) 14.7 Other comprehensive loss — — — — — (0.1 ) — (0.1 ) Comprehensive income (loss) attributable to common stockholders $ 13.0 $ 0.1 $ 13.0 $ — $ 36.8 $ (1.5 ) $ (46.8 ) $ 14.6 IN MILLIONS Six Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 172.2 $ 2.6 $ — $ 174.8 Costs and expenses: Property operating expenses — — — — 63.8 1.3 — 65.1 Sales and marketing — — — — 5.6 0.1 — 5.7 General and administrative — — — — 19.1 (0.1 ) — 19.0 Depreciation and amortization — — — — 61.2 1.3 — 62.5 Transaction and acquisition integration costs — — — — 9.7 — — 9.7 Asset impairments and loss on disposal — — — — 8.6 — — 8.6 Total costs and expenses — — — — 168.0 2.6 — 170.6 Operating income — — — — 4.2 — — 4.2 Interest expense — — 16.9 — — 1.6 (1.4 ) 17.1 Income (loss) before income taxes — — (16.9 ) — 4.2 (1.6 ) 1.4 (12.9 ) Income tax expense — — — — (0.8 ) — — (0.8 ) Equity earnings (loss) related to investment in subsidiaries (11.2 ) (0.2 ) 1.8 — (1.6 ) — 11.2 — Net income (loss) (11.2 ) (0.2 ) (15.1 ) — 1.8 (1.6 ) 12.6 (13.7 ) Noncontrolling interest in net loss — — — — — — (3.9 ) (3.9 ) Net income (loss) attributed to common stockholders (11.2 ) (0.2 ) (15.1 ) — 1.8 (1.6 ) 16.5 (9.8 ) Other comprehensive loss — — — — — — — — Comprehensive loss attributable to noncontrolling interests — — — — — — — — Comprehensive income (loss) attributable to common stockholders $ (11.2 ) $ (0.2 ) $ (15.1 ) $ — $ 1.8 $ (1.6 ) $ 16.5 $ (9.8 ) Consolidating Statements of Cash Flows IN MILLIONS Six Months Ended June 30, 2016 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations/Consolidations Total Cash flows from operating activities: Net income (loss) $ 13.0 $ 0.1 13.0 $ — $ 36.8 $ (1.4 ) $ (46.8 ) $ 14.7 Equity income (loss) related to investment in subsidiaries (13.0 ) (0.1 ) (36.8 ) — 1.4 — 48.5 — Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities: Depreciation and amortization — — — — 82.7 1.3 — 84.0 Non-cash interest expense — — 1.5 — — — — 1.5 Stock-based compensation expense — — — — 6.2 — — 6.2 Provision for bad debt — — — — 0.7 — — 0.7 Change in operating assets and liabilities: Rent receivables and other assets — — — — (8.7 ) (0.2 ) — (8.9 ) Accounts payable and accrued expenses — — — — 1.5 0.2 — 1.7 Deferred revenues — — — — (7.0 ) — — (7.0 ) Net cash provided by (used in) operating activities — — (22.3 ) — 113.6 (0.1 ) 1.7 92.9 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (131.1 ) — — (131.1 ) Capital expenditures - other development — — — — (246.5 ) (0.6 ) — (247.1 ) Investment in subsidiaries (256.3 ) (2.6 ) (256.3 ) — — — 515.2 — Changes in restricted cash — — — — 1.2 — — 1.2 Return of investment 50.8 — — — — — (50.8 ) — Intercompany borrowings 14.0 — (8.8 ) — — (0.3 ) (4.9 ) — Net cash provided by (used in) investing activities (191.5 ) (2.6 ) (265.1 ) — (376.4 ) (0.9 ) 459.5 (377.0 ) Cash flows from financing activities: Issuance of common stock 256.5 — — — — — — 256.5 Stock issuance costs (0.5 ) — — — — — — (0.5 ) Dividends paid (50.9 ) — (52.8 ) — — — 50.8 (52.9 ) Intercompany borrowings — — (14.0 ) — 10.8 — 3.2 — Borrowings from credit facility — — 415.0 — — — — 415.0 Payments on credit facility — — (315.0 ) — — — — (315.0 ) Payments on capital leases and lease financing arrangements — — — — (3.8 ) (0.6 ) — (4.4 ) Tax payment upon exercise of equity awards (13.6 ) — — — — — — (13.6 ) Contributions/distributions from parent — 2.6 256.3 — 256.3 — (515.2 ) — Debt issuance costs — — (2.1 ) — — — — (2.1 ) Net cash provided by (used in) financing activities 191.5 2.6 287.4 — 263.3 (0.6 ) (461.2 ) 283.0 Net increase in cash and cash equivalents — — — — 0.5 (1.6 ) — (1.1 ) Cash and cash equivalents at beginning of period — — — — 10.4 3.9 — 14.3 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 10.9 $ 2.3 $ — $ 13.2 IN MILLIONS Six Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Cash flows from operating activities: Net income (loss) $ (11.2 ) $ (0.2 ) $ (15.1 ) $ — $ 1.8 $ (1.6 ) $ 12.6 $ (13.7 ) Equity earnings (loss) related to investment in subsidiaries 11.2 0.2 (1.8 ) — 1.6 — (11.2 ) — Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 61.2 1.3 — 62.5 Non-cash interest expense — — 1.4 — — — — 1.4 Stock-based compensation expense — — — — 6.2 — — 6.2 Provision for bad debt — — — — 0.2 — — 0.2 Asset impairments — — — — 8.6 — — 8.6 Change in operating assets and liabilities, net of effects of acquisitions: Rent receivables and other assets — — (2.9 ) — (6.6 ) 1.7 — (7.8 ) Accounts payable and accrued expenses — — 13.0 — (7.7 ) 0.1 — 5.4 Deferred revenues — — — — 0.8 — — 0.8 Due to affiliates — — — — (1.9 ) — — (1.9 ) Net cash provided by operating activities — — (5.4 ) — 64.2 1.5 1.4 61.7 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (17.3 ) — — (17.3 ) Capital expenditures - other development — — — — (74.4 ) 0.2 — (74.2 ) Investment in and loans to subsidiaries (373.3 ) — — — 373.3 — — — Return of investment 26.0 (2.0 ) 39.2 — (5.2 ) — (58.0 ) — Intercompany contributions/distributions — — (70.0 ) — — — 70.0 — Net cash provided by (used in) investing activities (347.3 ) (2.0 ) (30.8 ) — 276.4 0.2 12.0 (91.5 ) Cash flows from financing activities: Issuance of common stock 799.3 — — — — — — 799.3 Stock issuance costs (0.6 ) — — — — — — (0.6 ) Acquisition of partnership units (426.0 ) — — — — — — (426.0 ) Dividends paid (25.4 ) — (33.8 ) — (33.8 ) — 59.2 (33.8 ) Intercompany borrowings — — — — 70.0 — (70.0 ) — Borrowings from credit facility — — 70.0 — — — — 70.0 Payments on capital leases and lease financing arrangements — — — — (1.6 ) (0.5 ) — (2.1 ) Contributions/distributions from parent — 2.0 — — — 0.6 (2.6 ) — Net cash provided by (used in) financing activities 347.3 2.0 36.2 — 34.6 0.1 (13.4 ) 406.8 Net increase (decrease) in cash and cash equivalents — — — — 375.2 1.8 — 377.0 Cash and cash equivalents at beginning of period — — — — 33.5 3.0 — 36.5 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 408.7 $ 4.8 $ — $ 413.5

Significant Accounting Polici23

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates —Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated 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, including purchase price allocations for business combinations, 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. 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. As we have substantially all of the construction risks, we are deemed the “owner” of the asset under construction for accounting purposes during the construction period, and are therefore required to capitalize the construction costs on the accompanying consolidated balance sheets. At inception, the fair value of the building (excluding land) is recorded as an asset and the construction and modification costs to the building, which are not funded by us, would be recorded as a liability. As construction progresses, the value of the asset and obligation increases by the fair value of the structural improvements. At completion of the construction, Sales-Leaseback Accounting under ASC 840-40-25 is also evaluated. Due to our continuing involvement with the lessor, Sales-Leaseback Accounting is precluded and the liability is not derecognized. When the asset is placed in service, depreciation commences, and the 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. The associated obligation is presented as Lease financing arrangements in the accompanying consolidated balance sheets. When we are not deemed the accounting owner of leased real estate, we further evaluate the lease to determine whether it 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. Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to thirty years for buildings, three to thirty years for building improvements, and three to twenty years for 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.
Business Combinations	Business Combinations —The Company applies the purchase method for business combinations, where all tangible and identifiable intangible assets acquired and all liabilities assumed are recorded at fair value. Any excess purchase price is recorded as goodwill. Transaction costs associated with business combinations are expensed as incurred. Revenues and the results of operations of the acquired business are included in the accompanying consolidated financial statements commencing on the date of acquisition.
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.
Restricted Cash	Restricted Cash —Restricted cash includes cash equivalents held to collateralize standby letters of credit and/or deposited in escrow to fund construction or pending potential acquisition transactions. In addition, we may have other cash that is not immediately available for use in current operations.
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.
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.
Rent and Other 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.
Deferred Leasing and Financing Costs	Deferred Leasing Costs —Deferred leasing costs are presented with Other assets in the accompanying consolidated balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized over the term of the customer lease. Amortization of deferred leasing costs is presented with Depreciation and amortization in the accompanying consolidated statements of operations. If a lease terminates prior to the expiration of the lease, the remaining unamortized cost is written off to amortization expense. As of June 30, 2016 and December 31, 2015 , deferred leasing costs were $22.1 million and $14.2 million , respectively. Deferred Financing Costs —Deferred financing costs include costs incurred in connection with issuance of debt, including our senior notes, term loans and revolving credit facilities. These costs include deferred financing costs associated with our revolving line of credit and are presented in the balance sheet as a direct reduction from the carrying amount of the debt liability to conform to the 2015 presentation. These financing costs are capitalized and amortized to expense over the term of the instrument and are included as a component of Interest expense.
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 balance sheets. Some of our leases are structured on a full-service gross basis in which the customer pays a fixed amount for both colocation rent and power. Other leases provide that the customer will be billed for power based upon actual usage which is separately metered. In both cases, this revenue is presented as Revenue in the accompanying consolidated statements 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. Generally, we receive an administrative fee when we manage the meters for our customers. 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 June 30, 2016 and December 31, 2015, Deferred revenue was $71.7 million and $78.7 million , respectively. Certain customer leases 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. A provision for uncollectible accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible.
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 $38.3 million and $71.3 million for the three and six months ended June 30, 2016 , respectively, and $26.5 million and $52.7 million for the three and six months ended June 30, 2015 , respectively. Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. Finite-lived intangibles include trademarks, customer relationships, favorable leasehold interests and deferred leasing costs.
Transaction and Acquisition Integration Costs	Transaction and Acquisition Integration Costs —Transaction costs represent incremental 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 and do not include any recurring costs from our ongoing operations. Integration costs represent incremental costs to integrate a consummated acquisition.
Income Taxes	Income Taxes —The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. has 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 stockholders. 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, and we may not be able to qualify as a REIT for four subsequent taxable years. 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 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. 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 2012, and we have no liabilities for uncertain tax positions as of June 30, 2016 .
Earnings Per Share	Earnings Per Share —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 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 stockholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS is applied.
Stock-Based Compensation	Stock-Based Compensation —In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan, (LTIP) which was amended and restated by our stockholders on May 2, 2016. The LTIP is administered by the compensation committee of the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. See Note 10 for additional details relating to these awards. Share-based compensation expense is based on the estimated grant-date fair value. CyrusOne Inc. recognizes share-based compensation expense, less estimated forfeitures, on a straight-line basis over the requisite service period for time-based awards and on a graded vesting basis for performance-based awards. CyrusOne estimates forfeitures based on historical activity, expected employee turnover, and other qualitative factors which are adjusted for changes in estimates and award vesting. All expenses for an award will be recognized by the time it becomes fully vested. CyrusOne Inc. uses the Black-Scholes-Merton option pricing model to calculate the fair value of stock options. This option valuation model requires the use of subjective assumptions, including the estimated fair value of the underlying common stock, the expected stock price volatility, and the expected term of the option. The estimated fair value of the underlying common stock is based on third-party valuations. Our volatility estimates are based on a peer group of companies. We estimate the expected term of the awards to be the weighted average mid-point between the vesting date and the end of the contractual term. We use this method to estimate the expected term since we do not have sufficient historical exercise data. For interim periods, we use our year-to-date actual results, financial forecasts, and other available information to estimate the probability of the award vesting based on the performance metrics.
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, and our service offerings have similar production processes, deliver services in a similar manner and use the same types of facilities and similar technologies.
Recently Issued Accounting Standards	Recently Issued Accounting Standards — Accounting Standards Update (ASU) No. 2014-09 (ASU 2014-09), Revenue from Contracts with Customers (Topic 606) In May 2014, the Financial Accounting Standards Board (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. In July 2015, the FASB voted to approve a one-year deferral of the effective date to December 15, 2017 for interim and annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. This guidance permits two implementation approaches. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). We are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements. ASU No. 2016-01 (ASU 2016-01), Financial instruments-Overall (Subtopic 825-10) In January 2016, the FASB amended its standards related to the accounting of certain financial instruments. This amendment addresses certain aspects of recognition, measurement, presentation and disclosure. The new rules will become effective for annual and interim periods beginning after December 15, 2017. Early adoption is not permitted. We are in the process of evaluating the impact the amendment will have on the consolidated financial statements. ASU No. 2016-02 (ASU 2016-02), Leases (Topic 842) In February 2016, the FASB issued accounting standard update (ASU) No. 2016-02, Leases (Topic 842). This new lease guidance requires that an entity should recognize assets and liabilities for leases with a maximum possible term of more than 12 months. A lessee would recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the leased asset (the underlying asset) for the lease term. Leases would be classified as either Type A leases (generally today’s capital leases) or Type B leases (generally today’s operating leases). For certain leases of assets other than property (for example, equipment, aircraft, cars, trucks), a lessee would classify the lease as a Type A lease and would do the following: (1) recognize a right-of-use asset and a lease liability, initially measured at the present value of lease payments and (2) recognize the unwinding of the discount on the lease liability as interest separately from the amortization of the right-of-use asset. For certain leases of property (that is, land and/or a building or part of a building), a lessee would classify the lease as a Type B lease and would do the following: (1) recognize a right-of-use asset and a lease liability, initially measured at the present value of lease payments and (2) recognize a single lease cost, combining the unwinding of the discount on the lease liability with the amortization of the right-of-use asset, on a straight-line basis. This guidance also provides accounting updates with respect to lessor accounting under a lease arrangement. This new lease guidance is effective for CyrusOne beginning in the first quarter of fiscal 2019. Entities have the option of using either a full retrospective or a modified approach (cumulative effect adjustment in period of adoption) to adopt the new guidance. Early adoption is permitted for all entities. We are currently evaluating the impact of the adoption of this guidance in our consolidated financial statements. ASU No. 2016-09 (ASU 2016-09), Improvements to Employee Share-Based Payment Accounting (Subtopic 718) In March 2016, the FASB issued guidance which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2016-12 (ASU 2016-12), Revenue from Contracts with Customers (Subtopic 606) In May 2016, the FASB issued guidance which amends certain aspects of the Board's new revenue standard, ASU 2014-09. The amendments include the collectibility of revenue, presentation of sales tax and other similar taxes collected from customers, contracts containing noncash considerations, and contract modifications and completed contracts at transition. The effective date and transition provisions are aligned with the requirements of ASU 2014-09.

Long-Term Debt, Capital Lease24

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements (Tables)	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Long-Term Debt and Capital Lease Obligations	Long-term debt, Capital lease obligations and Lease financing arrangements presented in the accompanying consolidated financial statements consist of the following: IN MILLIONS As of June 30, 2016 December 31, 2015 Credit facilities: Revolving credit facility $ 85.0 $ 235.0 Term loan 550.0 300.0 6.375% senior notes due 2022, including bond premium 477.5 477.6 Notes payable 1.4 1.5 Deferred financing costs (17.7 ) (17.6 ) Long-term debt 1,096.2 996.5 Capital lease obligations 10.9 12.2 Lease financing arrangements 144.3 150.0 Total $ 1,251.4 $ 1,158.7

Fair Value of Financial Instr25

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2016
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: IN MILLIONS As of June 30, 2016 December 31, 2015 Carrying Value Fair Value Carrying Value Fair Value 6.375% senior notes due 2022 $ 477.5 $ 491.0 $ 477.6 $ 493.8 Revolving credit facility and term loans 635.0 635.0 535.0 535.0 Note payable 1.4 1.1 1.5 1.2

Noncontrolling Interest - Ope26

Noncontrolling Interest - Operating Partnership (Tables)	6 Months Ended
	Jun. 30, 2016
Noncontrolling Interest [Abstract]
Schedule of Ownership Interests in Operating Partnership	The following table shows the ownership interests as of June 30, 2016 and 2015 , and the portion of net income (loss) and distributions for the six months ended June 30, 2016 and 2015 : As of June 30, 2016 June 30, 2015 (in millions, except unit amount) The Company CBI The Company CBI Operating partnership units 79.6 — 66.3 6.3 Ownership % 100.0 % — % 91.3 % 8.7 % Portion of net income (loss) 14.7 — (9.8 ) (3.9 ) Distributions (60.3 ) — (33.2 ) (12.3 )

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Compensation Expense	Stock-based compensation expense was as follows: Three Months Ended June 30, 2016 Three Months Ended June 30, 2015 Six Months Ended June 30, 2016 Six Months Ended June 30, 2015 Founders $ — $ 1.3 $ 0.3 $ 2.6 2013 Grants — 0.1 0.1 0.4 2014 Grants 0.3 0.5 0.6 1.3 2015 Grants 0.8 1.3 1.9 1.9 2016 Grants 2.1 — 3.3 — Total $ 3.2 $ 3.2 $ 6.2 $ 6.2

Income (Loss) per Share (Tables

Income (Loss) per Share (Tables)	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) per Share	The following table reflects the computation of basic and diluted net income (loss) per share for the three and six months ended June 30, 2016 and 2015 : IN MILLIONS, except per share amounts Three Months Ended June 30, 2016 Three Months Ended June 30, 2015 Six Months Ended June 30, 2016 Six Months Ended June 30, 2015 Basic Diluted Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) attributed to common stockholders $ 9.1 $ 9.1 $ (5.5 ) $ (5.5 ) $ 14.7 $ 14.7 $ (9.8 ) $ (9.8 ) Less: Restricted stock dividends (0.2 ) (0.2 ) (0.3 ) (0.3 ) (0.3 ) (0.3 ) (0.5 ) (0.5 ) Net income (loss) available to stockholders $ 8.9 $ 8.9 $ (5.8 ) $ (5.8 ) $ 14.4 $ 14.4 $ (10.3 ) $ (10.3 ) Denominator: Weighted average common outstanding-basic 78.3 78.3 51.1 51.1 75.2 75.2 44.1 44.1 Performance-based restricted stock (1) 0.6 — 0.7 — Convertible securities (1) 0.1 — 0.1 — Weighted average shares outstanding-diluted 79.0 51.1 76.0 44.1 EPS: Net income (loss) per share-basic $ 0.11 $ (0.11 ) $ 0.19 $ (0.23 ) Effect of dilutive shares: Net income (loss) per share-diluted $ 0.11 $ (0.11 ) $ 0.19 $ (0.23 ) (1) We have excluded 1.1 million weighted average shares of restricted stock, and 19.7 million of operating partnership units which are securities convertible into our common stock, from our diluted earnings per share as of June 30, 2015 . These amounts were deemed anti-dilutive.

Guarantors (Tables)

Guarantors (Tables)	6 Months Ended
	Jun. 30, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Consolidating Balance Sheets	Consolidating Balance Sheets IN MILLIONS As of June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 122.9 $ — $ — $ 122.9 Buildings and improvements — — — — 958.1 37.0 0.1 995.2 Equipment — — — — 913.5 1.0 3.3 917.8 Construction in progress — — — — 176.7 — 2.2 178.9 Subtotal — — — — 2,171.2 38.0 5.6 2,214.8 Accumulated depreciation — — — — (492.7 ) (10.5 ) — (503.2 ) Net investment in real estate — — — — 1,678.5 27.5 5.6 1,711.6 Cash and cash equivalents — — — — 10.9 2.3 — 13.2 Investment in subsidiaries 1,032.8 10.3 1,149.9 — — — (2,193.0 ) — Restricted cash — — — — 0.3 — — 0.3 Rent and other receivables — — — — 65.0 1.4 — 66.4 Intercompany receivable 17.9 — 1,000.2 — — 0.3 (1,018.4 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 160.6 — — 160.6 Other assets — — — — 103.0 2.8 — 105.8 Total assets $ 1,050.7 $ 10.3 $ 2,150.1 $ — $ 2,471.7 $ 34.3 $ (3,205.8 ) $ 2,511.3 Accounts payable and accrued expenses $ 31.8 $ — $ 4.6 $ — $ 126.5 $ 0.8 $ — $ 163.7 Deferred revenue — — — — 71.0 0.7 — 71.7 Intercompany payable — — 17.9 — 1,001.4 — (1,019.3 ) — Capital lease obligations — — — — 4.9 6.0 — 10.9 Long-term debt — — 1,094.8 — 1.4 — — 1,096.2 Lease financing arrangements — — — — 116.6 27.7 — 144.3 Total liabilities 31.8 — 1,117.3 — 1,321.8 35.2 (1,019.3 ) 1,486.8 Total stockholders' equity 1,018.9 10.3 1,032.8 — 1,149.9 (0.9 ) (2,186.5 ) 1,024.5 Total liabilities and equity $ 1,050.7 $ 10.3 $ 2,150.1 $ — $ 2,471.7 $ 34.3 $ (3,205.8 ) $ 2,511.3 IN MILLIONS As of December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 93.0 $ — $ — $ 93.0 Buildings and improvements — — — — 865.6 39.6 0.1 905.3 Equipment — — — — 594.7 0.9 2.6 598.2 Construction in progress — — — — 229.8 0.1 1.2 231.1 Subtotal — — — — 1,783.1 40.6 3.9 1,827.6 Accumulated depreciation — — — — (426.0 ) (9.6 ) — (435.6 ) Net investment in real estate — — — — 1,357.1 31.0 3.9 1,392.0 Cash and cash equivalents — — — — 10.4 3.9 — 14.3 Investment in subsidiaries 817.7 8.2 850.6 — 0.7 — (1,677.2 ) — Restricted cash — — — — 1.5 — — 1.5 Rent and other receivables — — — — 74.8 1.3 — 76.1 Intercompany receivable — — 991.3 — — — (991.3 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 170.3 — — 170.3 Other assets — — — — 85.3 2.7 — 88.0 Total assets $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Accounts payable and accrued expenses $ — $ — $ 29.2 $ — $ 106.8 $ 0.6 $ — $ 136.6 Deferred revenue — — — — 78.0 0.7 — 78.7 Intercompany payable — — — — 991.3 — (991.3 ) — Capital lease obligations — — — — 6.1 6.1 — 12.2 Long-term debt — — 995.0 — 1.5 — — 996.5 Lease financing arrangements — — — — 119.2 30.8 — 150.0 Total liabilities — — 1,024.2 — 1,302.9 38.2 (991.3 ) 1,374.0 Total stockholders' equity 817.7 8.2 817.7 — 850.6 0.7 (1,673.3 ) 821.6 Total liabilities and equity $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6
Consolidating Statements of Operations and Comprehensive Income (Loss)	Consolidating Statements of Operations and Comprehensive Income (Loss) IN MILLIONS Three Months Ended June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 128.8 $ 1.3 $ — $ 130.1 Costs and expenses: Property operating expenses — — — — 44.2 0.6 — 44.8 Sales and marketing — — — — 4.2 — — 4.2 General and administrative — — — — 14.8 0.1 — 14.9 Depreciation and amortization — — — — 44.1 0.6 — 44.7 Transaction and acquisition integration costs — — — — 0.4 — — 0.4 Total costs and expenses — — — — 107.7 1.3 — 109.0 Operating income — — — — 21.1 — — 21.1 Interest expense — — 12.1 — — 0.7 (1.3 ) 11.5 Income (loss) before income taxes — — (12.1 ) — 21.1 (0.7 ) 1.3 9.6 Income tax expense — — — — (0.5 ) — — (0.5 ) Equity earnings (loss) related to investment in subsidiaries 7.8 — 19.9 — (0.7 ) — (27.0 ) — Net income (loss) 7.8 — 7.8 — 19.9 (0.7 ) (25.7 ) 9.1 Noncontrolling interest in net income (loss) — — — — — — — — Net income (loss) attributed to common stockholders 7.8 — 7.8 — 19.9 (0.7 ) (25.7 ) 9.1 Other comprehensive loss — — — — — (0.1 ) — (0.1 ) Comprehensive income (loss) attributable to common stockholders $ 7.8 $ — $ 7.8 $ — $ 19.9 $ (0.8 ) $ (25.7 ) $ 9.0 IN MILLIONS Three Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 87.8 $ 1.3 $ — $ 89.1 Costs and expenses: Property operating expenses — — — — 32.1 0.7 — 32.8 Sales and marketing — — — — 2.7 0.1 — 2.8 General and administrative — — — — 10.1 (0.2 ) — 9.9 Depreciation and amortization — — — — 30.7 0.7 — 31.4 Transaction and acquisition integration costs — — — — 9.6 — — 9.6 Total costs and expenses — — — — 85.2 1.3 — 86.5 Operating income — — — — 2.6 — — 2.6 Interest expense — — 8.6 — — 0.8 (0.7 ) 8.7 Income (loss) before income taxes — — (8.6 ) — 2.6 (0.8 ) 0.7 (6.1 ) Income tax expense — — — — (0.4 ) — — (0.4 ) Equity earnings (loss) related to investment in subsidiaries (6.2 ) (0.1 ) 1.4 — (0.8 ) — 5.7 — Net income (loss) (6.2 ) (0.1 ) (7.2 ) — 1.4 (0.8 ) 6.4 (6.5 ) Noncontrolling interest in net loss — — — — — — (1.0 ) (1.0 ) Net income (loss) attributed to common stockholders (6.2 ) (0.1 ) (7.2 ) — 1.4 (0.8 ) 7.4 (5.5 ) Other comprehensive loss — — — — — 0.3 — 0.3 Comprehensive loss attributable to noncontrolling interests — — — — — — — — Comprehensive income (loss) attributable to common stockholders $ (6.2 ) $ (0.1 ) $ (7.2 ) $ — $ 1.4 $ (0.5 ) $ 7.4 $ (5.2 ) IN MILLIONS Six Months Ended June 30, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 245.2 $ 2.7 $ — $ 247.9 Costs and expenses: Property operating expenses — — — — 83.9 1.2 — 85.1 Sales and marketing — — — — 8.2 — — 8.2 General and administrative — — — — 28.8 0.1 — 28.9 Depreciation and amortization — — — — 82.7 1.3 — 84.0 Transaction and acquisition integration costs — — — — 2.7 — — 2.7 Asset impairments and loss on disposal — — — — — — — — Total costs and expenses — — — — 206.3 2.6 — 208.9 Operating income — — — — 38.9 0.1 — 39.0 Interest expense — — 23.8 — — 1.5 (1.7 ) 23.6 Income (loss) before income taxes — — (23.8 ) — 38.9 (1.4 ) 1.7 15.4 Income tax expense — — — — (0.7 ) — — (0.7 ) Equity earnings (loss) related to investment in subsidiaries 13.0 0.1 36.8 — (1.4 ) — (48.5 ) — Net income (loss) 13.0 0.1 13.0 — 36.8 (1.4 ) (46.8 ) 14.7 Noncontrolling interest in net income (loss) — — — — — — — — Net income (loss) attributed to common stockholders 13.0 0.1 13.0 — 36.8 (1.4 ) (46.8 ) 14.7 Other comprehensive loss — — — — — (0.1 ) — (0.1 ) Comprehensive income (loss) attributable to common stockholders $ 13.0 $ 0.1 $ 13.0 $ — $ 36.8 $ (1.5 ) $ (46.8 ) $ 14.6 IN MILLIONS Six Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 172.2 $ 2.6 $ — $ 174.8 Costs and expenses: Property operating expenses — — — — 63.8 1.3 — 65.1 Sales and marketing — — — — 5.6 0.1 — 5.7 General and administrative — — — — 19.1 (0.1 ) — 19.0 Depreciation and amortization — — — — 61.2 1.3 — 62.5 Transaction and acquisition integration costs — — — — 9.7 — — 9.7 Asset impairments and loss on disposal — — — — 8.6 — — 8.6 Total costs and expenses — — — — 168.0 2.6 — 170.6 Operating income — — — — 4.2 — — 4.2 Interest expense — — 16.9 — — 1.6 (1.4 ) 17.1 Income (loss) before income taxes — — (16.9 ) — 4.2 (1.6 ) 1.4 (12.9 ) Income tax expense — — — — (0.8 ) — — (0.8 ) Equity earnings (loss) related to investment in subsidiaries (11.2 ) (0.2 ) 1.8 — (1.6 ) — 11.2 — Net income (loss) (11.2 ) (0.2 ) (15.1 ) — 1.8 (1.6 ) 12.6 (13.7 ) Noncontrolling interest in net loss — — — — — — (3.9 ) (3.9 ) Net income (loss) attributed to common stockholders (11.2 ) (0.2 ) (15.1 ) — 1.8 (1.6 ) 16.5 (9.8 ) Other comprehensive loss — — — — — — — — Comprehensive loss attributable to noncontrolling interests — — — — — — — — Comprehensive income (loss) attributable to common stockholders $ (11.2 ) $ (0.2 ) $ (15.1 ) $ — $ 1.8 $ (1.6 ) $ 16.5 $ (9.8 )
Consolidating Statements of Cash Flows	Consolidating Statements of Cash Flows IN MILLIONS Six Months Ended June 30, 2016 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations/Consolidations Total Cash flows from operating activities: Net income (loss) $ 13.0 $ 0.1 13.0 $ — $ 36.8 $ (1.4 ) $ (46.8 ) $ 14.7 Equity income (loss) related to investment in subsidiaries (13.0 ) (0.1 ) (36.8 ) — 1.4 — 48.5 — Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities: Depreciation and amortization — — — — 82.7 1.3 — 84.0 Non-cash interest expense — — 1.5 — — — — 1.5 Stock-based compensation expense — — — — 6.2 — — 6.2 Provision for bad debt — — — — 0.7 — — 0.7 Change in operating assets and liabilities: Rent receivables and other assets — — — — (8.7 ) (0.2 ) — (8.9 ) Accounts payable and accrued expenses — — — — 1.5 0.2 — 1.7 Deferred revenues — — — — (7.0 ) — — (7.0 ) Net cash provided by (used in) operating activities — — (22.3 ) — 113.6 (0.1 ) 1.7 92.9 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (131.1 ) — — (131.1 ) Capital expenditures - other development — — — — (246.5 ) (0.6 ) — (247.1 ) Investment in subsidiaries (256.3 ) (2.6 ) (256.3 ) — — — 515.2 — Changes in restricted cash — — — — 1.2 — — 1.2 Return of investment 50.8 — — — — — (50.8 ) — Intercompany borrowings 14.0 — (8.8 ) — — (0.3 ) (4.9 ) — Net cash provided by (used in) investing activities (191.5 ) (2.6 ) (265.1 ) — (376.4 ) (0.9 ) 459.5 (377.0 ) Cash flows from financing activities: Issuance of common stock 256.5 — — — — — — 256.5 Stock issuance costs (0.5 ) — — — — — — (0.5 ) Dividends paid (50.9 ) — (52.8 ) — — — 50.8 (52.9 ) Intercompany borrowings — — (14.0 ) — 10.8 — 3.2 — Borrowings from credit facility — — 415.0 — — — — 415.0 Payments on credit facility — — (315.0 ) — — — — (315.0 ) Payments on capital leases and lease financing arrangements — — — — (3.8 ) (0.6 ) — (4.4 ) Tax payment upon exercise of equity awards (13.6 ) — — — — — — (13.6 ) Contributions/distributions from parent — 2.6 256.3 — 256.3 — (515.2 ) — Debt issuance costs — — (2.1 ) — — — — (2.1 ) Net cash provided by (used in) financing activities 191.5 2.6 287.4 — 263.3 (0.6 ) (461.2 ) 283.0 Net increase in cash and cash equivalents — — — — 0.5 (1.6 ) — (1.1 ) Cash and cash equivalents at beginning of period — — — — 10.4 3.9 — 14.3 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 10.9 $ 2.3 $ — $ 13.2 IN MILLIONS Six Months Ended June 30, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Cash flows from operating activities: Net income (loss) $ (11.2 ) $ (0.2 ) $ (15.1 ) $ — $ 1.8 $ (1.6 ) $ 12.6 $ (13.7 ) Equity earnings (loss) related to investment in subsidiaries 11.2 0.2 (1.8 ) — 1.6 — (11.2 ) — Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 61.2 1.3 — 62.5 Non-cash interest expense — — 1.4 — — — — 1.4 Stock-based compensation expense — — — — 6.2 — — 6.2 Provision for bad debt — — — — 0.2 — — 0.2 Asset impairments — — — — 8.6 — — 8.6 Change in operating assets and liabilities, net of effects of acquisitions: Rent receivables and other assets — — (2.9 ) — (6.6 ) 1.7 — (7.8 ) Accounts payable and accrued expenses — — 13.0 — (7.7 ) 0.1 — 5.4 Deferred revenues — — — — 0.8 — — 0.8 Due to affiliates — — — — (1.9 ) — — (1.9 ) Net cash provided by operating activities — — (5.4 ) — 64.2 1.5 1.4 61.7 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (17.3 ) — — (17.3 ) Capital expenditures - other development — — — — (74.4 ) 0.2 — (74.2 ) Investment in and loans to subsidiaries (373.3 ) — — — 373.3 — — — Return of investment 26.0 (2.0 ) 39.2 — (5.2 ) — (58.0 ) — Intercompany contributions/distributions — — (70.0 ) — — — 70.0 — Net cash provided by (used in) investing activities (347.3 ) (2.0 ) (30.8 ) — 276.4 0.2 12.0 (91.5 ) Cash flows from financing activities: Issuance of common stock 799.3 — — — — — — 799.3 Stock issuance costs (0.6 ) — — — — — — (0.6 ) Acquisition of partnership units (426.0 ) — — — — — — (426.0 ) Dividends paid (25.4 ) — (33.8 ) — (33.8 ) — 59.2 (33.8 ) Intercompany borrowings — — — — 70.0 — (70.0 ) — Borrowings from credit facility — — 70.0 — — — — 70.0 Payments on capital leases and lease financing arrangements — — — — (1.6 ) (0.5 ) — (2.1 ) Contributions/distributions from parent — 2.0 — — — 0.6 (2.6 ) — Net cash provided by (used in) financing activities 347.3 2.0 36.2 — 34.6 0.1 (13.4 ) 406.8 Net increase (decrease) in cash and cash equivalents — — — — 375.2 1.8 — 377.0 Cash and cash equivalents at beginning of period — — — — 33.5 3.0 — 36.5 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 408.7 $ 4.8 $ — $ 413.5

Description of Business - Narra

Description of Business - Narrative (Details)	6 Months Ended
	Jun. 30, 2016recovery_centerdata_center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of data operating centers | data_center	35
Number of recovery centers | recovery_center	2

Formation and Recent Developm31

Formation and Recent Developments - Narrative (Details)	May 04, 2016USD ($)	Mar. 21, 2016USD ($)shares	Dec. 31, 2015shares	Dec. 14, 2015USD ($)shares	Jan. 24, 2013USD ($)shares	Nov. 20, 2012shares	Mar. 31, 2016USD ($)shares	Jun. 30, 2015USD ($)shares	Apr. 30, 2015USD ($)shares	Jun. 30, 2014USD ($)shares	Mar. 31, 2016USD ($)shares	Jun. 30, 2016USD ($)shares	Jun. 30, 2015USD ($)shares	Jul. 01, 2016shares	Mar. 17, 2016USD ($)
Business Formation [Line Items]
Issuance of common stock (in shares)					400,000
Partners' capital units converted (in shares)					1,500,000
Proceeds from exchange of partnership units (in shares)					1,500,000
Number of common shares issued to directors and employees					1,100,000
Shares purchased of Operating partnership's units (in shares)		6,900,000
Tax payment upon exercise of equity awards (in shares)											900,000
Stock issued for ESPP (in shares)											100,000
Issuance of common stock | $											$ 256,000,000	$ 256,500,000	$ 799,300,000
Maximum proceeds from issuance of common stock | $	$ 320,000,000
Shares authorized (in shares)												4,000,000
Second Amendment to Credit Agreement | Revolving credit facility
Business Formation [Line Items]
Optional additional borrowing capacity | $															$ 250,000,000
Term Loan | Second Amendment to Credit Agreement
Business Formation [Line Items]
Optional additional borrowing capacity | $															$ 250,000,000
Total Stockholders' Equity/ Parent’s Net Investment
Business Formation [Line Items]
Operating partnership units (in shares)								66,300,000				79,600,000	66,300,000
Cyrus One Inc And Cyrus One Gp
Business Formation [Line Items]
Shares purchased of Operating partnership's units (in shares)					21,900,000
Combined interest held on completion of transactions					33.90%
Purchase of Operating partnership's units | $					$ 337,100,000
Cincinnati Bell Inc.
Business Formation [Line Items]
Operating partnership units owned (in shares)			0
Remaining combined interest held					66.10%
Ownership %			9.50%									4.70%
IPO
Business Formation [Line Items]
Issuance of common stock (in shares)		6,900,000	6,300,000	1,350,000	19,000,000		6,900,000	13,000,000	14,300,000	16,000,000
Net proceeds from IPO after underwriting discounts and commissions | $		$ 255,000,000		$ 0	$ 337,100,000		$ 255,000,000	$ 373,300,000	$ 426,000,000	$ 355,900,000
Underwriting discount | $		$ 10,600,000
CyrusOne L.P.
Business Formation [Line Items]
Issuance of partnership units (in shares)						123,700,000
Partnership reverse unit split, conversion ratio					2.8
Operating partnership units owned (in shares)					44,100,000
Subsequent event
Business Formation [Line Items]
Shares authorized (in shares)														8,900,000

Significant Accounting Polici32

Significant Accounting Policies - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)segment	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Summary Of Significant Accounting Policies [Line Items]
Percentage of lease term			75.00%
Percentage of lease payment			90.00%
Asset impairments and loss on disposal	$ 0	$ 0	$ 0	$ 8,600,000
Impairment of goodwill	0	0	0	0
Deferred leasing costs	22,100,000		22,100,000		$ 14,200,000
Deferred revenue	71,700,000		71,700,000		$ 78,700,000
Depreciation	38,300,000	26,500,000	71,300,000	52,700,000
Amortization	6,400,000	$ 4,900,000	12,700,000	9,800,000
Unrecognized tax benefits	$ 0		$ 0
Number of segments | segment			1
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Weighted-average remaining life (in years)			51 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Receivables due term			30 days
Minimum | Customer Relationships And Trademark
Summary Of Significant Accounting Policies [Line Items]
Weighted-average remaining life (in years)			10 years
Minimum | Deferred Leasing Costs
Summary Of Significant Accounting Policies [Line Items]
Weighted-average remaining life (in years)			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Receivables due term			120 days
Maximum | Customer Relationships And Trademark
Summary Of Significant Accounting Policies [Line Items]
Weighted-average remaining life (in years)			13 years
Maximum | Deferred Leasing Costs
Summary Of Significant Accounting Policies [Line Items]
Weighted-average remaining life (in years)			5 years
Austin I
Summary Of Significant Accounting Policies [Line Items]
Asset impairments and loss on disposal				$ 8,600,000
Buildings | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life			9 years
Buildings | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life			30 years
Building Improvements | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life			3 years
Building Improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life			30 years
Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life			3 years
Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life			20 years

Purchase of Fixed Assets - Narr

Purchase of Fixed Assets - Narrative (Details) - Mar. 31, 2016 - CME Data Center ft² in Thousands, $ in Millions	USD ($)ft²	a
Business Acquisition [Line Items]
Payments to data center	$ 131.1
Area acquired (in sqft or acre)	428	15
Lease term of favorable leasehold interest which being amortized	15 years

Long-Term Debt, Capital Lease34

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements - Long-Term Debt and Capital Lease Obligations (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Nov. 20, 2012
Debt Instrument [Line Items]
Long-term debt, net	$ 1,096.2	$ 996.5
Deferred financing costs	(17.7)	(17.6)
Capital lease obligations	10.9	12.2
Lease financing arrangements	144.3	150
Total	$ 1,251.4	$ 1,158.7
6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Stated interest rate	6.375%	6.375%	6.375%
Senior Notes | 6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Long-term debt, net	$ 477.5	$ 477.6
Stated interest rate	6.375%	6.375%
Notes payable
Debt Instrument [Line Items]
Long-term debt, net	$ 1.4	$ 1.5
Revolving credit facility
Debt Instrument [Line Items]
Revolving credit facility	85	235
Revolving credit facility | Term Loan
Debt Instrument [Line Items]
Revolving credit facility	550	$ 300
Deferred financing costs	$ (2.1)

Long-Term Debt, Capital Lease35

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements - Narrative (Details)	Jul. 01, 2015USD ($)	Nov. 20, 2012USD ($)	Dec. 31, 2014USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)data_center	Jun. 30, 2015USD ($)	Mar. 17, 2016USD ($)	Dec. 31, 2015USD ($)	Jun. 23, 2015USD ($)
Debt Instrument [Line Items]
Deferred financing costs				$ 17,700,000		$ 17,700,000			$ 17,600,000
Long-term debt, net				1,096,200,000		$ 1,096,200,000			996,500,000
Total unencumbered assets						150.00%
Amortization of deferred financing costs				1,100,000	$ 700,000	$ 2,000,000	$ 1,400,000
Number of data center facilities under capital leases | data_center						8
Interest expense on capital lease obligations				2,500,000	1,300,000	$ 4,900,000	2,700,000
Notes payable
Debt Instrument [Line Items]
Long-term debt, net				$ 1,400,000		1,400,000			$ 1,500,000
Periodic payment						$ 9,000
First Amendment to Credit Agreement | Term Loan
Debt Instrument [Line Items]
Credit agreement amount										$ 300,000,000
Second Amendment to Credit Agreement | Term Loan
Debt Instrument [Line Items]
Optional additional borrowing capacity								$ 250,000,000
Second Amendment to Credit Agreement | Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate						1.65%
6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Stated interest rate		6.375%		6.375%		6.375%			6.375%
6.375% senior notes due 2022, including bond premium | Senior Notes
Debt Instrument [Line Items]
Long-term debt, net				$ 477,500,000		$ 477,500,000			$ 477,600,000
Stated interest rate				6.375%		6.375%			6.375%
Repurchased face amount			$ 150,200,000
Repurchased amount			163,000,000
Gain (Loss) on Repurchase of Debt Instrument			$ (12,800,000)
Proceeds from Issuance of Private Placement	$ 100,000,000
Premium on debt	$ 3,800,000
6.375% senior notes due 2022, including bond premium | Senior Notes | Cyrus One Lp And Cyrus One Finance Corp
Debt Instrument [Line Items]
Long-term debt, net		$ 525,000,000
Stated interest rate		6.375%		6.375%		6.375%
Percentage of redemption price		100.00%
Percentage of senior notes declining redemption 1		103.188%
Percentage of senior notes declining redemption 2		102.125%
Percentage of senior notes declining redemption 3		101.063%
Percentage of senior notes declining redemption 4		100.00%
Percentage of redemption of the aggregate principal		35.00%
Percentage of equity offering on principal amount		106.375%
Percentage of redemption of the least aggregate principal		65.00%
Term of redemption occurs		90 days
Revolving credit facility
Debt Instrument [Line Items]
Commitment fee percent						0.25%
Commitment fee amount				$ 400,000	$ 100,000	$ 700,000	$ 300,000
Maximum percentage of dividends allowed to be distributed				95.00%		95.00%
Revolving credit facility | Term Loan
Debt Instrument [Line Items]
Deferred financing costs				$ 2,100,000		$ 2,100,000
Revolving credit facility | First Amendment to Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount										$ 650,000,000
Revolving credit facility | Second Amendment to Credit Agreement
Debt Instrument [Line Items]
Optional additional borrowing capacity								$ 250,000,000
Term of extension option						1 year
Revolving credit facility | Second Amendment to Credit Agreement | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate						1.70%

Fair Value of Financial Instr36

Fair Value of Financial Instruments - Carrying Value and Fair Value of Other Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Nov. 20, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, net	$ 1,096.2	$ 996.5
Lease financing arrangements	144.3	150
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Lease financing arrangements	1.4	1.5
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Lease financing arrangements	1.1	1.2
Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	85	235
Revolving credit facility | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	635	535
Revolving credit facility | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	$ 635	$ 535
6.375% senior notes due 2022, including bond premium
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	6.375%	6.375%	6.375%
Senior Notes | 6.375% senior notes due 2022, including bond premium
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, net	$ 477.5	$ 477.6
Stated interest rate	6.375%	6.375%
Senior Notes | 6.375% senior notes due 2022, including bond premium | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, net	$ 477.5	$ 477.6
Senior Notes | 6.375% senior notes due 2022, including bond premium | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, net	$ 491	$ 493.8

Noncontrolling Interest - Ope37

Noncontrolling Interest - Operating Partnership - Schedule of Noncontrolling Interest (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Noncontrolling Interest [Line Items]
Portion of net income (loss)	$ 9.1	$ (5.5)	$ 14.7	$ (9.8)
Portion of net income (loss)	$ 0	$ 1	0	3.9
Distributions			$ (60.3)	$ (45.5)
The Company
Noncontrolling Interest [Line Items]
Operating partnership units (in shares)	79.6	66.3	79.6	66.3
Ownership %	100.00%	91.30%	100.00%	91.30%
Portion of net income (loss)			$ 14.7	$ (9.8)
Portion of net income (loss)				3.9
Distributions			$ (60.3)	$ (33.2)
CBI
Noncontrolling Interest [Line Items]
Operating partnership units (in shares)	0	6.3	0	6.3
Ownership %	0.00%	8.70%	0.00%	8.70%
Portion of net income (loss)			$ 0	$ (3.9)
Distributions			$ 0	$ (12.3)

Noncontrolling Interest - Ope38

Noncontrolling Interest - Operating Partnership - Narrative (Details) - shares shares in Millions	Nov. 20, 2012	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Jan. 24, 2013
CyrusOne L.P.
Noncontrolling Interest [Line Items]
Issuance of partnership units (in shares)	123.7
Cincinnati Bell Inc.
Noncontrolling Interest [Line Items]
Remaining combined interest held					66.10%
Ownership %		4.70%	9.50%
Non- controlling Interest
Noncontrolling Interest [Line Items]
Ownership %		0.00%		8.70%

Dividends - Narrative (Details)

Dividends - Narrative (Details)	May 04, 2016$ / shares
Affiliated entity | Common stock
Dividends Payable [Line Items]
Cash dividend payable to stockholders (in dollars per share)	$ 0.38

Stock-Based Compensation Plan40

Stock-Based Compensation Plans - Allocated Share-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$ 3.2	$ 3.2	$ 6.2	$ 6.2
2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	0	0.1	0.1	0.4
2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	0.3	0.5	0.6	1.3
2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	0.8	1.3	1.9	1.9
2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	2.1	0	3.3	0
Founders
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$ 0	$ 1.3	$ 0.3	$ 2.6

Stock-Based Compensation Plan41

Stock-Based Compensation Plans - Narrative (Details) - USD ($)	May 02, 2016	Feb. 01, 2016	Jan. 29, 2016	Feb. 10, 2015	Feb. 07, 2014	Apr. 17, 2013	Jan. 24, 2013	Jun. 30, 2016	Dec. 31, 2014	Dec. 31, 2013	Jul. 01, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)								4,000,000
Shares available for grant (in shares)								800,000
Founders | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)							1,000,000
Other than options grant date value							$ 19,000,000
2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options								$ 0
2013 Grants | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for grants (in dollars per share)						$ 23.58
2013 Grants | Restricted Stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period										3 years
2013 Grants | Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						50.00%
Award vesting period						3 years
Cap on award vesting						100.00%
2013 Grants | Market based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						50.00%
2013 Grants | Market based restricted stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period						3 years
2013 Grants | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for grants (in dollars per share)						$ 23.58
Expiration period for award						10 years
2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options								$ 700,000
Unrecognized compensation expense, period for recognition								7 months 6 days
2014 Grants | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for grants (in dollars per share)					$ 20.65
2014 Grants | Restricted Stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period									3 years
2014 Grants | Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage					50.00%
Award vesting period					3 years
Cap on award vesting					100.00%
2014 Grants | Market based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage					50.00%
2014 Grants | Market based restricted stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					3 years
2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options								$ 4,500,000
Unrecognized compensation expense, period for recognition								1 year 4 months 24 days
2015 Grants | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for grants (in dollars per share)				$ 28.42
Award vesting rights percentage				25.00%
Award vesting period				3 years
Cap on award vesting				100.00%
2015 Grants | Restricted Stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
2015 Grants | Performance and market based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				75.00%
2015 Grants | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for grants (in dollars per share)				$ 28.44
Award vesting period				3 years
Expiration period for award				10 years
2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options								$ 15,600,000
Unrecognized compensation expense, period for recognition								2 years 1 month 6 days
2016 Grants | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	7,275
Weighted average exercise price for grants (in dollars per share)			$ 36.85
Award vesting period		3 years
2016 Grants | Restricted Stock | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
2016 Grants | Performance and market based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Cap on award vesting		100.00%
2016 Grants | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)		222,461
Weighted average exercise price for grants (in dollars per share)		$ 36.99
Award vesting period		3 years
Expiration period for award		10 years
Option grant date fair value (in dollars per share)		$ 6.99
2016 Grants | Board of Directors | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)		587,536
Weighted average exercise price for grants (in dollars per share)		$ 36.99
Subsequent event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)											8,900,000

Income (Loss) per Share - Compu

Income (Loss) per Share - Computation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator:
Net income (loss) attributed to common stockholders	$ 9.1	$ (5.5)	$ 14.7	$ (9.8)
Less: Restricted stock dividends, Basic	(0.2)	(0.3)	(0.3)	(0.5)
Less: Restricted stock dividends, Diluted	(0.2)	(0.3)	(0.3)	(0.5)
Net income (loss) available to stockholders, Basic	8.9	(5.8)	14.4	(10.3)
Net income (loss) available to stockholders, Diluted	$ 8.9	$ (5.8)	$ 14.4	$ (10.3)
Denominator:
Weighted average common outstanding - basic (in shares)	78.3	51.1	75.2	44.1
Performance-based restricted stock (in shares)	0.6	0	0.7	0
Convertible securities (in shares)	0.1	0	0.1	0
Weighted average shares outstanding- diluted (in shares)	79	51.1	76	44.1
EPS:
Net income (loss) per share-basic (in dollars per share)	$ 0.11	$ (0.11)	$ 0.19	$ (0.23)
Net loss per share-diluted (in dollars per share)	$ 0.11	$ (0.11)	$ 0.19	$ (0.23)
Restricted Stock
EPS:
Anti-dilutive securities excluded from diluted earnings per share (in shares)				1.1
Operating Partnership Units
EPS:
Anti-dilutive securities excluded from diluted earnings per share (in shares)				19.7

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2016	May 04, 2016	Dec. 31, 2015
Cincinnati Bell Inc.
Related Party Transaction [Line Items]
Ownership %			4.70%		9.50%
Operating partnership units owned (in shares)					0
Affiliated entity
Related Party Transaction [Line Items]
Revenue from related party	$ 5.8	$ 11.2
Expenses to related party	$ 0.4	$ 0.9
Affiliated entity | Common stock
Related Party Transaction [Line Items]
Cash dividend payable to stockholders (in dollars per share)				$ 0.38

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)Subsidiary	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Income Taxes [Line Items]
Number of subsidiaries as taxable REIT | Subsidiary			2
Income tax expense	$ (500,000)	$ (400,000)	$ (700,000)	$ (800,000)
Deferred tax assets	$ 0		$ 0		$ 0
Minimum
Income Taxes [Line Items]
Percentage of taxable income			90.00%
Maximum
Income Taxes [Line Items]
Percentage of taxable income			100.00%

Guarantors - Narrative (Details

Guarantors - Narrative (Details) - USD ($)	Mar. 21, 2016	Dec. 14, 2015	Jan. 24, 2013	Mar. 31, 2016	Jun. 30, 2015	Apr. 30, 2015	Jun. 30, 2014	Jun. 30, 2016	Dec. 31, 2015	Nov. 20, 2012
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net								$ 1,096,200,000	$ 996,500,000
Total Stockholders' Equity/ Parent’s Net Investment
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net								0	0
Combined interest held on completion of transactions			33.90%
CyrusOne GP
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions			1.00%
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net								$ 0	$ 0
Ownership percent of senior notes								100.00%
6.375% senior notes due 2022, including bond premium
Condensed Financial Statements, Captions [Line Items]
Stated interest rate								6.375%	6.375%	6.375%
Senior Notes | 6.375% senior notes due 2022, including bond premium
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net								$ 477,500,000	$ 477,600,000
Stated interest rate								6.375%	6.375%
Senior Notes | 6.375% senior notes due 2022, including bond premium | Cyrus One Lp And Cyrus One Finance Corp
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net										$ 525,000,000
Stated interest rate								6.375%		6.375%
IPO
Condensed Financial Statements, Captions [Line Items]
Net proceeds from IPO after underwriting discounts and commissions	$ 255,000,000	$ 0	$ 337,100,000	$ 255,000,000	$ 373,300,000	$ 426,000,000	$ 355,900,000
IPO | Total Stockholders' Equity/ Parent’s Net Investment
Condensed Financial Statements, Captions [Line Items]
Net proceeds from IPO after underwriting discounts and commissions			$ 337,100,000

Guarantors - Consolidating Bala

Guarantors - Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Condensed Consolidating Balance Sheets
Land	$ 122.9	$ 93
Buildings and improvements	995.2	905.3
Equipment	917.8	598.2
Construction in progress	178.9	231.1
Subtotal	2,214.8	1,827.6
Accumulated depreciation	(503.2)	(435.6)
Net investment in real estate	1,711.6	1,392
Cash and cash equivalents	13.2	14.3	$ 413.5	$ 36.5
Investment in subsidiaries	0	0
Restricted cash	0.3	1.5
Rent and other receivables	66.4	76.1
Intercompany receivable	0	0
Goodwill	453.4	453.4
Intangible assets, net	160.6	170.3
Other assets	105.8	88
Total assets	2,511.3	2,195.6
Accounts payable and accrued expenses	163.7	136.6
Deferred revenue	71.7	78.7
Intercompany payable	0	0
Capital lease obligations	10.9	12.2
Long-term debt, net	1,096.2	996.5
Lease financing arrangements	144.3	150
Total liabilities	1,486.8	1,374
Total stockholders’ equity	1,024.5	821.6
Total liabilities and equity	2,511.3	2,195.6
Eliminations/Consolidations
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0.1	0.1
Equipment	3.3	2.6
Construction in progress	2.2	1.2
Subtotal	5.6	3.9
Accumulated depreciation	0	0
Net investment in real estate	5.6	3.9
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	(2,193)	(1,677.2)
Restricted cash	0	0
Rent and other receivables	0	0
Intercompany receivable	(1,018.4)	(991.3)
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	(3,205.8)	(2,664.6)
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	(1,019.3)	(991.3)
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	(1,019.3)	(991.3)
Total stockholders’ equity	(2,186.5)	(1,673.3)
Total liabilities and equity	(3,205.8)	(2,664.6)
General Partner
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	10.3	8.2
Restricted cash	0	0
Rent and other receivables	0	0
Intercompany receivable	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	10.3	8.2
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	0	0
Total stockholders’ equity	10.3	8.2
Total liabilities and equity	10.3	8.2
Total Stockholders' Equity/ Parent’s Net Investment
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	1,032.8	817.7
Restricted cash	0	0
Rent and other receivables	0	0
Intercompany receivable	17.9	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	1,050.7	817.7
Accounts payable and accrued expenses	31.8	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	31.8	0
Total stockholders’ equity	1,018.9	817.7
Total liabilities and equity	1,050.7	817.7
LP Co-issuer
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	1,149.9	850.6
Restricted cash	0	0
Rent and other receivables	0	0
Intercompany receivable	1,000.2	991.3
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	2,150.1	1,841.9
Accounts payable and accrued expenses	4.6	29.2
Deferred revenue	0	0
Intercompany payable	17.9	0
Capital lease obligations	0	0
Long-term debt, net	1,094.8	995
Lease financing arrangements	0	0
Total liabilities	1,117.3	1,024.2
Total stockholders’ equity	1,032.8	817.7
Total liabilities and equity	2,150.1	1,841.9
Finance Co-issuer
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	0	0
Restricted cash	0	0
Rent and other receivables	0	0
Intercompany receivable	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	0	0
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	0	0
Total stockholders’ equity	0	0
Total liabilities and equity	0	0
Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Land	122.9	93
Buildings and improvements	958.1	865.6
Equipment	913.5	594.7
Construction in progress	176.7	229.8
Subtotal	2,171.2	1,783.1
Accumulated depreciation	(492.7)	(426)
Net investment in real estate	1,678.5	1,357.1
Cash and cash equivalents	10.9	10.4	408.7	33.5
Investment in subsidiaries	0	0.7
Restricted cash	0.3	1.5
Rent and other receivables	65	74.8
Intercompany receivable	0	0
Goodwill	453.4	453.4
Intangible assets, net	160.6	170.3
Other assets	103	85.3
Total assets	2,471.7	2,153.5
Accounts payable and accrued expenses	126.5	106.8
Deferred revenue	71	78
Intercompany payable	1,001.4	991.3
Capital lease obligations	4.9	6.1
Long-term debt, net	1.4	1.5
Lease financing arrangements	116.6	119.2
Total liabilities	1,321.8	1,302.9
Total stockholders’ equity	1,149.9	850.6
Total liabilities and equity	2,471.7	2,153.5
Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	37	39.6
Equipment	1	0.9
Construction in progress	0	0.1
Subtotal	38	40.6
Accumulated depreciation	(10.5)	(9.6)
Net investment in real estate	27.5	31
Cash and cash equivalents	2.3	3.9	$ 4.8	$ 3
Investment in subsidiaries	0	0
Restricted cash	0	0
Rent and other receivables	1.4	1.3
Intercompany receivable	0.3	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	2.8	2.7
Total assets	34.3	38.9
Accounts payable and accrued expenses	0.8	0.6
Deferred revenue	0.7	0.7
Intercompany payable	0	0
Capital lease obligations	6	6.1
Long-term debt, net	0	0
Lease financing arrangements	27.7	30.8
Total liabilities	35.2	38.2
Total stockholders’ equity	(0.9)	0.7
Total liabilities and equity	$ 34.3	$ 38.9

Guarantors - Consolidating Stat

Guarantors - Consolidating Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Condensed Consolidating Statements of Operations
Revenue	$ 130,100,000	$ 89,100,000	$ 247,900,000	$ 174,800,000
Costs and expenses:
Property operating expenses	44,800,000	32,800,000	85,100,000	65,100,000
Sales and marketing	4,200,000	2,800,000	8,200,000	5,700,000
General and administrative	14,900,000	9,900,000	28,900,000	19,000,000
Depreciation and amortization	44,700,000	31,400,000	84,000,000	62,500,000
Transaction and acquisition integration costs	400,000	9,600,000	2,700,000	9,700,000
Asset impairments and loss on disposal	0	0	0	8,600,000
Total costs and expenses	109,000,000	86,500,000	208,900,000	170,600,000
Operating income	21,100,000	2,600,000	39,000,000	4,200,000
Interest expense	11,500,000	8,700,000	23,600,000	17,100,000
Net income (loss) before income taxes	9,600,000	(6,100,000)	15,400,000	(12,900,000)
Income tax expense	(500,000)	(400,000)	(700,000)	(800,000)
Equity earnings (loss) related to investment in subsidiaries	0	0	0	0
Net income (loss)	9,100,000	(6,500,000)	14,700,000	(13,700,000)
Noncontrolling interest allocated net income (loss)	0	(1,000,000)	0	(3,900,000)
Net income (loss) attributed to common stockholders	9,100,000	(5,500,000)	14,700,000	(9,800,000)
Other comprehensive loss	(100,000)	300,000	(100,000)	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	9,000,000	(5,200,000)	14,600,000	(9,800,000)
Eliminations/Consolidations
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Costs and expenses:
Property operating expenses	0	0	0	0
Sales and marketing	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense	(1,300,000)	(700,000)	(1,700,000)	(1,400,000)
Net income (loss) before income taxes	1,300,000	700,000	1,700,000	1,400,000
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	(27,000,000)	5,700,000	(48,500,000)	11,200,000
Net income (loss)	(25,700,000)	6,400,000	(46,800,000)	12,600,000
Noncontrolling interest allocated net income (loss)	0	(1,000,000)	0	(3,900,000)
Net income (loss) attributed to common stockholders	(25,700,000)	7,400,000	(46,800,000)	16,500,000
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	(25,700,000)	7,400,000	(46,800,000)	16,500,000
General Partner
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Costs and expenses:
Property operating expenses	0	0	0	0
Sales and marketing	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense	0	0	0	0
Net income (loss) before income taxes	0	0	0	0
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	0	(100,000)	100,000	(200,000)
Net income (loss)	0	(100,000)	100,000	(200,000)
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	0	(100,000)	100,000	(200,000)
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	0	(100,000)	100,000	(200,000)
Total Stockholders' Equity/ Parent’s Net Investment
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Costs and expenses:
Property operating expenses	0	0	0	0
Sales and marketing	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense	0	0	0	0
Net income (loss) before income taxes	0	0	0	0
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	7,800,000	(6,200,000)	13,000,000	(11,200,000)
Net income (loss)	7,800,000	(6,200,000)	13,000,000	(11,200,000)
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	7,800,000	(6,200,000)	13,000,000	(11,200,000)
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	7,800,000	(6,200,000)	13,000,000	(11,200,000)
LP Co-issuer
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Costs and expenses:
Property operating expenses	0	0	0	0
Sales and marketing	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense	12,100,000	8,600,000	23,800,000	16,900,000
Net income (loss) before income taxes	(12,100,000)	(8,600,000)	(23,800,000)	(16,900,000)
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	19,900,000	1,400,000	36,800,000	1,800,000
Net income (loss)	7,800,000	(7,200,000)	13,000,000	(15,100,000)
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	7,800,000	(7,200,000)	13,000,000	(15,100,000)
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	7,800,000	(7,200,000)	13,000,000	(15,100,000)
Finance Co-issuer
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Costs and expenses:
Property operating expenses	0	0	0	0
Sales and marketing	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense	0	0	0	0
Net income (loss) before income taxes	0	0	0	0
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	0	0	0	0
Net income (loss)	0	0	0	0
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	0	0	0	0
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	0	0	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Operations
Revenue	128,800,000	87,800,000	245,200,000	172,200,000
Costs and expenses:
Property operating expenses	44,200,000	32,100,000	83,900,000	63,800,000
Sales and marketing	4,200,000	2,700,000	8,200,000	5,600,000
General and administrative	14,800,000	10,100,000	28,800,000	19,100,000
Depreciation and amortization	44,100,000	30,700,000	82,700,000	61,200,000
Transaction and acquisition integration costs	400,000	9,600,000	2,700,000	9,700,000
Asset impairments and loss on disposal			0	8,600,000
Total costs and expenses	107,700,000	85,200,000	206,300,000	168,000,000
Operating income	21,100,000	2,600,000	38,900,000	4,200,000
Interest expense	0	0	0	0
Net income (loss) before income taxes	21,100,000	2,600,000	38,900,000	4,200,000
Income tax expense	(500,000)	(400,000)	(700,000)	(800,000)
Equity earnings (loss) related to investment in subsidiaries	(700,000)	(800,000)	(1,400,000)	(1,600,000)
Net income (loss)	19,900,000	1,400,000	36,800,000	1,800,000
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	19,900,000	1,400,000	36,800,000	1,800,000
Other comprehensive loss	0	0	0	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	19,900,000	1,400,000	36,800,000	1,800,000
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Operations
Revenue	1,300,000	1,300,000	2,700,000	2,600,000
Costs and expenses:
Property operating expenses	600,000	700,000	1,200,000	1,300,000
Sales and marketing	0	100,000	0	100,000
General and administrative	100,000	(200,000)	100,000	(100,000)
Depreciation and amortization	600,000	700,000	1,300,000	1,300,000
Transaction and acquisition integration costs	0	0	0	0
Asset impairments and loss on disposal			0	0
Total costs and expenses	1,300,000	1,300,000	2,600,000	2,600,000
Operating income	0	0	100,000	0
Interest expense	700,000	800,000	1,500,000	1,600,000
Net income (loss) before income taxes	(700,000)	(800,000)	(1,400,000)	(1,600,000)
Income tax expense	0	0	0	0
Equity earnings (loss) related to investment in subsidiaries	0	0	0	0
Net income (loss)	(700,000)	(800,000)	(1,400,000)	(1,600,000)
Noncontrolling interest allocated net income (loss)	0	0	0	0
Net income (loss) attributed to common stockholders	(700,000)	(800,000)	(1,400,000)	(1,600,000)
Other comprehensive loss	(100,000)	300,000	(100,000)	0
Comprehensive loss attributable to noncontrolling interests		0		0
Comprehensive income (loss) attributable to CyrusOne Inc.	$ (800,000)	$ (500,000)	$ (1,500,000)	$ (1,600,000)

Guarantors - Consolidating St48

Guarantors - Consolidating Statements of Cash Flows (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Condensed Consolidating Statements of Cash Flows
Net income (loss)	$ 9,100,000		$ (6,500,000)	$ 14,700,000	$ (13,700,000)
Equity income (loss) related to investment in subsidiaries				0	0
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	44,700,000		31,400,000	84,000,000	62,500,000
Non-cash interest expense				1,500,000	1,400,000
Stock-based compensation expense				6,200,000	6,200,000
Provision for bad debt				700,000	200,000
Asset impairments and loss on disposal	0		0	0	8,600,000
Change in operating assets and liabilities:
Rent receivables and other assets				(8,900,000)	(7,800,000)
Accounts payable and accrued expenses				1,700,000	5,400,000
Deferred revenues				(7,000,000)	800,000
Due to affiliates				0	(1,900,000)
Net cash provided by operating activities				92,900,000	61,700,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				(131,100,000)	(17,300,000)
Capital expenditures – other development				(247,100,000)	(74,200,000)
Investment in subsidiaries				0	0
Changes in restricted cash				1,200,000	0
Return of investment				0	0
Intercompany borrowings				0
Intercompany contributions/distributions					0
Net cash used in investing activities				(377,000,000)	(91,500,000)
Cash flows from financing activities:
Issuance of common stock		$ 256,000,000		256,500,000	799,300,000
Stock issuance costs				(500,000)	(600,000)
Acquisition of partnership units				0	(426,000,000)
Dividends paid				(52,900,000)	(33,800,000)
Intercompany borrowings				0	0
Borrowings from credit facility				415,000,000	70,000,000
Payments on credit facility				(315,000,000)	0
Payments on capital leases and leasing financing arrangements				(4,400,000)	(2,100,000)
Tax payment upon exercise of equity awards				13,600,000	0
Contributions/distributions from parent				0	0
Debt issuance costs				(2,100,000)	0
Net cash provided by financing activities				283,000,000	406,800,000
Net increase (decrease) in cash and cash equivalents				(1,100,000)	377,000,000
Cash and cash equivalents at beginning of period		14,300,000		14,300,000	36,500,000
Cash and cash equivalents at end of period	13,200,000		413,500,000	13,200,000	413,500,000
General Partner
Condensed Consolidating Statements of Cash Flows
Net income (loss)	0		(100,000)	100,000	(200,000)
Equity income (loss) related to investment in subsidiaries				(100,000)	200,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	0		0	0	0
Non-cash interest expense				0	0
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				0	0
Accounts payable and accrued expenses				0	0
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				0	0
Investment in subsidiaries				(2,600,000)	0
Changes in restricted cash				0
Return of investment				0	(2,000,000)
Intercompany borrowings				0
Intercompany contributions/distributions					0
Net cash used in investing activities				(2,600,000)	(2,000,000)
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				0	0
Intercompany borrowings				0	0
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				0	0
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				2,600,000	2,000,000
Debt issuance costs				0
Net cash provided by financing activities				2,600,000	2,000,000
Net increase (decrease) 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	0	0
Eliminations/Consolidations
Condensed Consolidating Statements of Cash Flows
Net income (loss)	(25,700,000)		6,400,000	(46,800,000)	12,600,000
Equity income (loss) related to investment in subsidiaries				48,500,000	(11,200,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	0		0	0	0
Non-cash interest expense				0	0
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				0	0
Accounts payable and accrued expenses				0	0
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				1,700,000	1,400,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				0	0
Investment in subsidiaries				515,200,000	0
Changes in restricted cash				0
Return of investment				(50,800,000)	(58,000,000)
Intercompany borrowings				(4,900,000)
Intercompany contributions/distributions					70,000,000
Net cash used in investing activities				459,500,000	12,000,000
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				50,800,000	59,200,000
Intercompany borrowings				3,200,000	(70,000,000)
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				0	0
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				(515,200,000)	(2,600,000)
Debt issuance costs				0
Net cash provided by financing activities				(461,200,000)	(13,400,000)
Net increase (decrease) 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	0	0
Total Stockholders' Equity/ Parent’s Net Investment
Condensed Consolidating Statements of Cash Flows
Net income (loss)	7,800,000		(6,200,000)	13,000,000	(11,200,000)
Equity income (loss) related to investment in subsidiaries				(13,000,000)	11,200,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	0		0	0	0
Non-cash interest expense				0	0
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				0	0
Accounts payable and accrued expenses				0	0
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				0	0
Investment in subsidiaries				(256,300,000)	(373,300,000)
Changes in restricted cash				0
Return of investment				50,800,000	26,000,000
Intercompany borrowings				14,000,000
Intercompany contributions/distributions					0
Net cash used in investing activities				(191,500,000)	(347,300,000)
Cash flows from financing activities:
Issuance of common stock				256,500,000	799,300,000
Stock issuance costs				(500,000)	(600,000)
Acquisition of partnership units					(426,000,000)
Dividends paid				(50,900,000)	(25,400,000)
Intercompany borrowings				0	0
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				0	0
Tax payment upon exercise of equity awards				13,600,000
Contributions/distributions from parent				0	0
Debt issuance costs				0
Net cash provided by financing activities				191,500,000	347,300,000
Net increase (decrease) 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	0	0
LP Co-issuer
Condensed Consolidating Statements of Cash Flows
Net income (loss)	7,800,000		(7,200,000)	13,000,000	(15,100,000)
Equity income (loss) related to investment in subsidiaries				(36,800,000)	(1,800,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	0		0	0	0
Non-cash interest expense				1,500,000	1,400,000
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				0	(2,900,000)
Accounts payable and accrued expenses				0	13,000,000
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				(22,300,000)	(5,400,000)
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				0	0
Investment in subsidiaries				(256,300,000)	0
Changes in restricted cash				0
Return of investment				0	39,200,000
Intercompany borrowings				(8,800,000)
Intercompany contributions/distributions					(70,000,000)
Net cash used in investing activities				(265,100,000)	(30,800,000)
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				(52,800,000)	(33,800,000)
Intercompany borrowings				(14,000,000)	0
Borrowings from credit facility				415,000,000	70,000,000
Payments on credit facility				(315,000,000)
Payments on capital leases and leasing financing arrangements				0	0
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				256,300,000	0
Debt issuance costs				(2,100,000)
Net cash provided by financing activities				287,400,000	36,200,000
Net increase (decrease) 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	0	0
Finance Co-issuer
Condensed Consolidating Statements of Cash Flows
Net income (loss)	0		0	0	0
Equity income (loss) related to investment in subsidiaries				0	0
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	0		0	0	0
Non-cash interest expense				0	0
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				0	0
Accounts payable and accrued expenses				0	0
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				0	0
Investment in subsidiaries				0	0
Changes in restricted cash				0
Return of investment				0	0
Intercompany borrowings				0
Intercompany contributions/distributions					0
Net cash used in investing activities				0	0
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				0	0
Intercompany borrowings				0	0
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				0	0
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				0	0
Debt issuance costs				0
Net cash provided by financing activities				0	0
Net increase (decrease) 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	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net income (loss)	19,900,000		1,400,000	36,800,000	1,800,000
Equity income (loss) related to investment in subsidiaries				1,400,000	1,600,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	44,100,000		30,700,000	82,700,000	61,200,000
Non-cash interest expense				0	0
Stock-based compensation expense				6,200,000	6,200,000
Provision for bad debt				700,000	200,000
Asset impairments and loss on disposal				0	8,600,000
Change in operating assets and liabilities:
Rent receivables and other assets				(8,700,000)	(6,600,000)
Accounts payable and accrued expenses				1,500,000	(7,700,000)
Deferred revenues				(7,000,000)	800,000
Due to affiliates					(1,900,000)
Net cash provided by operating activities				113,600,000	64,200,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				(131,100,000)	(17,300,000)
Capital expenditures – other development				(246,500,000)	(74,400,000)
Investment in subsidiaries				0	373,300,000
Changes in restricted cash				1,200,000
Return of investment				0	(5,200,000)
Intercompany borrowings				0
Intercompany contributions/distributions					0
Net cash used in investing activities				(376,400,000)	276,400,000
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				0	(33,800,000)
Intercompany borrowings				10,800,000	70,000,000
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				(3,800,000)	(1,600,000)
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				256,300,000	0
Debt issuance costs				0
Net cash provided by financing activities				263,300,000	34,600,000
Net increase (decrease) in cash and cash equivalents				500,000	375,200,000
Cash and cash equivalents at beginning of period		10,400,000		10,400,000	33,500,000
Cash and cash equivalents at end of period	10,900,000		408,700,000	10,900,000	408,700,000
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net income (loss)	(700,000)		(800,000)	(1,400,000)	(1,600,000)
Equity income (loss) related to investment in subsidiaries				0	0
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	600,000		700,000	1,300,000	1,300,000
Non-cash interest expense				0	0
Stock-based compensation expense				0	0
Provision for bad debt				0	0
Asset impairments and loss on disposal				0	0
Change in operating assets and liabilities:
Rent receivables and other assets				(200,000)	1,700,000
Accounts payable and accrued expenses				200,000	100,000
Deferred revenues				0	0
Due to affiliates					0
Net cash provided by operating activities				(100,000)	1,500,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets				0	0
Capital expenditures – other development				(600,000)	200,000
Investment in subsidiaries				0	0
Changes in restricted cash				0
Return of investment				0	0
Intercompany borrowings				(300,000)
Intercompany contributions/distributions					0
Net cash used in investing activities				(900,000)	200,000
Cash flows from financing activities:
Issuance of common stock				0	0
Stock issuance costs				0	0
Acquisition of partnership units					0
Dividends paid				0	0
Intercompany borrowings				0	0
Borrowings from credit facility				0	0
Payments on credit facility				0
Payments on capital leases and leasing financing arrangements				(600,000)	(500,000)
Tax payment upon exercise of equity awards				0
Contributions/distributions from parent				0	600,000
Debt issuance costs				0
Net cash provided by financing activities				(600,000)	100,000
Net increase (decrease) in cash and cash equivalents				(1,600,000)	1,800,000
Cash and cash equivalents at beginning of period		$ 3,900,000		3,900,000	3,000,000
Cash and cash equivalents at end of period	$ 2,300,000		$ 4,800,000	$ 2,300,000	$ 4,800,000