CyrusOne (CONE) 10-Q 2 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 25, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	CyrusOne Inc.
Entity Central Index Key	0001553023
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	CONE
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		113,172,973

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Investment in real estate:
Land	$ 124.9	$ 118.5
Buildings and improvements	1,649.2	1,677.5
Equipment	2,799.6	2,630.2
Gross operating real estate	4,573.7	4,426.2
Less accumulated depreciation	(1,122.5)	(1,054.5)
Net operating real estate	3,451.2	3,371.7
Construction in progress, including land under development	734.7	744.9
Land held for future development	200.4	176.4
Total investment in real estate, net	4,386.3	4,293
Cash and cash equivalents	126	64.4
Rent and other receivables	248.7	234.9
Restricted cash	1.3	0
Operating lease right-of-use assets	83.8	0
Equity investments	299.3	198.1
Goodwill	455.1	455.1
Intangible assets (net of accumulated amortization of $177.0 and $166.9 as of March 31, 2019 and December 31, 2018, respectively)	226.1	235.7
Other assets	114.8	111.3
Total assets	5,941.4	5,592.5
Liabilities and equity
Debt	2,898.6	2,624.7
Finance lease liabilities	33.4	156.7
Operating lease liabilities	119.6	0
Construction costs payable	155.5	195.3
Accounts payable and accrued expenses	81.6	121.3
Dividends payable	51.5	51
Deferred revenue and prepaid rents	155.9	148.6
Deferred tax liability	67.2	68.9
Total liabilities	3,563.3	3,366.5
Commitments and contingencies
Stockholders' 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 110,316,652 and 108,329,314 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	1.1	1.1
Additional paid in capital	2,938.2	2,837.4
Accumulated deficit	(552.2)	(600.2)
Accumulated other comprehensive loss	(9)	(12.3)
Total stockholders’ equity	2,378.1	2,226
Total liabilities and equity	$ 5,941.4	$ 5,592.5

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Accumulated amortization for intangible assets	$ 177	$ 166.9
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)	110,316,652	108,329,314
Common stock outstanding (in shares)	110,316,652	108,329,314

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 225	$ 196.6
Operating expenses:
Property operating expenses	83.3	67.8
Sales and marketing	5.3	5.3
General and administrative	22.2	19.3
Depreciation and amortization	102.1	74.6
Transaction, acquisition, integration and other related expenses	0.3	1.9
Total operating expenses	213.2	168.9
Operating income	11.8	27.7
Interest expense	(23.7)	(20.8)
Unrealized gain on marketable equity investment	101.2	40.5
Loss on early extinguishment of debt	0	(3.1)
Other expense	(0.1)	0
Net income before income taxes	89.2	44.3
Income tax benefit (expense)	0.2	(0.8)
Net income (loss)	$ 89.4	$ 43.5
Weighted average common shares outstanding - basic (in shares)	108.3	96
Weighted average common shares outstanding - diluted (in shares)	108.8	96.6
Income (loss) per share - basic (in dollars per share)	$ 0.82	$ 0.45
Income (loss) per share - diluted (in dollars per share)	$ 0.82	$ 0.45

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 89.4	$ 43.5
Other comprehensive income:
Foreign currency translation adjustment	0.6	0.1
Net derivative gain (loss) on cash flow hedging instruments	2.7	0
Comprehensive income	$ 92.7	$ 43.6

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Dec. 31, 2017		96.1
Beginning Balance at Dec. 31, 2017	$ 1,713.9	$ 1	$ 2,125.6	$ (486.9)	$ 74.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 43.5			43.5
Issuance of common stock, net (in shares)	2.8	2.8
Issuance of common stock, net	$ 142.9	$ 0	142.9
Stock-based compensation expense (in shares)		0
Stock-based compensation expense	3.9		3.9
Tax payment upon exercise of equity awards (in shares)		0
Tax payment upon exercise of equity awards	(4.4)		4.4
Foreign currency translation adjustment	0.1				0.1
Net derivative gain (loss) on cash flow hedging instruments	0
Dividends declared	(45.6)			45.6
Ending Balance (in shares) at Mar. 31, 2018		98.9
Ending Balance at Mar. 31, 2018	1,854.6	$ 1	2,268	(413.1)	(1.3)
Beginning Balance (in shares) at Dec. 31, 2018		108.3
Beginning Balance at Dec. 31, 2018	2,226	$ 1.1	2,837.4	(600.2)	(12.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	89.4			89.4
Issuance of common stock, net (in shares)		2
Issuance of common stock, net	105	$ 0	105
Stock-based compensation expense (in shares)		0
Stock-based compensation expense	4.5		4.5
Tax payment upon exercise of equity awards (in shares)		0
Tax payment upon exercise of equity awards	(8.7)		(8.7)
Foreign currency translation adjustment	0.6				0.6
Net derivative gain (loss) on cash flow hedging instruments	2.7				2.7
Dividends declared	(50.9)			(50.9)
Ending Balance (in shares) at Mar. 31, 2019		110.3
Ending Balance at Mar. 31, 2019	$ 2,378.1	$ 1.1	$ 2,938.2	$ (552.2)	$ (9)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)	$ 0.46	$ 0.46

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 89.4	$ 43.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	102.1	74.6
Provision for bad debt expense	0	0.5
Unrealized gain on marketable equity investment	(101.2)	(40.5)
Loss on early extinguishment of debt	0	3.1
Interest expense amortization, net	1.2	0.7
Stock-based compensation expense	4.5	3.9
Deferred income tax expense	(0.8)	0
Operating lease cost	5	0
Other	(0.5)	0
Change in operating assets and liabilities:
Rent and other receivables, net and other assets	(18)	(18)
Accounts payable and accrued expenses	(39.8)	(28.9)
Deferred revenue and prepaid rents	7.1	5.3
Operating lease liabilities	(5.1)	0
Net cash provided by operating activities	43.9	44.2
Cash flows from investing activities:
Investment in real estate	(301.9)	(145.2)
Net cash used in investing activities	(301.9)	(145.2)
Cash flows from financing activities:
Issuance of common stock, net	105	142.9
Dividends paid	(50.4)	(41)
Proceeds from revolving credit facility	275.7	0
Proceeds from unsecured term loan	0	985.6
Repayments of unsecured term loan	0	(902.7)
Payments on finance lease liabilities	(0.6)	(2.6)
Tax payment upon exercise of equity awards	(8.7)	(4.4)
Net cash provided by (used in) financing activities	321	177.8
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(0.1)	0
Net increase in cash, cash equivalents and restricted cash	62.9	76.8
Cash, cash equivalents and restricted cash at beginning of period	64.4	151.9
Cash, cash equivalents and restricted cash at end of period	127.3	228.7
Supplemental disclosure of cash flow information:
Cash paid for interest, including amounts capitalized of $9.3 million and $5.1 million in 2019 and 2018, respectively	46.7	42.2
Cash paid for income taxes	0	0.3
Non-cash investing and financing activities:
Construction costs and other payables	155.5	89
Dividends payable	$ 51.5	$ 46.4

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Cash Flows [Abstract]
Interest capitalized	$ 9.3	$ 5.1

Description of Business

Description of Business	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business CyrusOne Inc., together with CyrusOne GP (the "General Partner"), 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 and single-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 48 data centers and two recovery centers located in the United States, United Kingdom, Germany and Singapore. On January 24, 2013 , the Company completed its initial public offering (the "IPO") of common stock and its common stock currently trades on the NASDAQ Exchange under the ticker symbol "CONE". As of March 31, 2019 , all the issued and outstanding Operating Partnership units of CyrusOne LP are owned, directly or indirectly, by the Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Interim Unaudited Financial Information The accompanying condensed consolidated 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, 2018 , which was filed with the Securities and Exchange Commission ("SEC") on February 22, 2019. Certain information and footnote disclosures normally included in the consolidated 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 condensed consolidated financial statements include all adjustments necessary to present fairly our condensed consolidated financial statements as of March 31, 2019 and 2018 , and for the three months ended March 31, 2019 and 2018 . These adjustments are of a normal recurring nature and consistent with the adjustments recorded to prepare the annual audited consolidated financial statements as of December 31, 2018 . All amounts reflected are in millions except share and per share data. Basis of Presentation The accompanying condensed consolidated financial statements include the accounts of the Company, as well as all wholly-owned subsidiaries and any consolidated variable interest entities. All intercompany balances and transactions have been eliminated in consolidation. Reclassifications Certain financial information has been revised to conform to the current year presentation due to changes in the significance of the particular activity. The following items have been reclassified: Balance Sheet as of December 31, 2018 • Straight-line rent receivable of $128.7 million included in Rent and other receivables was previously included in Other assets. Statement of Cash Flows for the period ended March 31, 2018 • The cash flow effect of the change in proceeds from our unsecured term loan of $985.6 million included in Proceeds from unsecured term loan was previously included in Debt. • The cash flow effect of the change in repayments of our unsecured term loan of $902.7 million included in Repayments of unsecured term loan was previously included in Debt. Investment in Real Estate Acquisition of Properties Investment in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. We expect most acquisitions to be an acquisition of assets rather than a business combination as our typical acquisitions consist of properties whereby substantially all the fair value of gross assets acquired is concentrated in a single asset set (land, building and in-place leases), which are treated as asset acquisitions. See Business Combinations and Asset Acquisitions herein. Business Combinations and Asset Acquisitions We evaluate whether an acquisition is a business combination or an asset acquisition by determining whether the set of assets is a business. Asset Acquisitions When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. Asset acquisitions are recorded at the cumulative acquisition costs and allocated to the assets acquired and liabilities assumed on a relative fair value basis. The Company allocates the purchase price of real estate to identifiable tangible assets such as land, building, land improvements and tenant improvements acquired based on their fair value. In estimating the fair value of each component, management considers appraisals, replacement cost, its own analysis of recently acquired and existing comparable properties, market rental data and other related information. Transaction costs associated with asset acquisitions are capitalized. Business Combinations When substantially all of the fair value is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business and 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. The following discussion applies to our initial determination of fair value and the resulting subsequent accounting which is generally applicable to both asset acquisitions and business combinations. The fair value of any tangible real estate assets acquired is determined by valuing the building as if it were vacant, and the fair value is then allocated to land, buildings, equipment and improvements based on available information including replacement cost, appraisal or using net operating income capitalization rates, discounted cash flow analysis or similar fair value models. We determine in-place lease values based on our evaluation of the specific characteristics of each tenant’s lease agreement and by applying a fair value model. The estimates of fair value of in-place leases include an estimate of carrying costs during the expected lease up periods considering current market conditions. In estimating fair value of in-place leases, we consider items such as real estate taxes, insurance, leasing commissions, tenant improvements and other operating expenses to execute similar leases as well as projected rental revenue and carrying costs during the expected lease up period. We amortize the value of in-place leases acquired to expense over the approximate weighted average remaining term of the leases, adjusted for projected tenant turnover, on a composite basis. We determine the value of above-market and below-market in-place leases for acquired properties based on the present value (using an interest rate that reflects the risks associated with the leases acquired) of the difference between (1) the contractual amounts to be paid pursuant to the in-place leases and (2) estimates of current market lease rates for the corresponding in-place leases, measured over a period equal to (i) the remaining non-cancellable lease term for above-market leases, or (ii) the remaining non-cancellable lease term plus any renewal options that we consider are reasonably certain that a lessee will execute such renewal option when a lease commences. We record the fair value of above-market and below-market leases as intangible assets or liabilities, and amortize them as an adjustment to revenue over the lease term. We determine the fair value of assumed debt by calculating the net present value of the scheduled debt service payments using current market-based terms for interest rates for debt with similar terms that management believes we could obtain on similar structures and maturities. Any difference between the fair value and stated value of the assumed debt is recorded as a discount or premium and amortized over the remaining life of the loan. In a business combination or an acquisition, we retain the previous lease classification unless there is a lease modification and that modification is not accounted for as a separate new lease. We elected to apply the short-term lease measurement and recognition exemption available under the new accounting standard for leases (discussed below in Note 3. "Recently Adopted Accounting Standards") to leases that have a remaining lease term of 12 months or less at the acquisition date and would not recognize an intangible asset if the terms of an operating lease are favorable relative to market terms or a liability if the terms are unfavorable relative to market terms. Leasehold improvements are amortized over the shorter of the useful life of the assets and the remaining lease term at the date of acquisition. Capitalization of Costs We capitalize costs directly related to the development, pre-development or improvement of our investment in real estate, referred to as capital projects and other activities included within this paragraph. Costs associated with our capital projects are capitalized as incurred. If the project is abandoned, these costs are expensed during the period in which the project is abandoned. Costs considered for capitalization include, but are not limited to, construction costs, interest, real estate taxes, insurance and utilities, if appropriate. We capitalize indirect costs such as personnel, office and administrative expenses that are directly related to our development projects based on an estimate of the time spent on the construction and development activities. These costs are capitalized only during the period in which activities necessary to ready an asset for its intended use are in progress and such costs are incremental and identifiable to a specific activity to get the asset ready for its intended use. We determine when the capitalization period begins and ends through communication with project and other managers responsible for the tracking and oversight of individual projects. In the event that the activities to ready the asset for its intended use are suspended, the capitalization period will cease until such activities are resumed. In addition, we capitalize incremental initial direct costs incurred for successful origination of new leases which include internal and external leasing commissions. Interest expense is capitalized based on actual qualifying capital expenditures from the period when development commences until the asset is ready for its intended use, at the weighted average borrowing rate during the period. These costs are included in investment in real estate and depreciated over the estimated useful life of the related assets. Costs incurred for maintaining and repairing our properties, which do not extend their useful lives, are expensed as incurred. Impairment Losses When events or circumstances indicate that the carrying amount of a real estate investment may not be recoverable, we review the carrying value of the asset. When such impairment indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of the real estate investment and proceeds from its eventual disposition and compare such amount to the carrying amount of the real estate investment. If our undiscounted cash flows indicate that we are unable to recover the carrying value of the real estate investment, an impairment loss is recognized. An impairment loss is measured as the amount by which the real estate investment's carrying value exceeds its estimated fair value. We did not record any impairment losses for the three months ended March 31, 2019 or 2018. Cash and Cash Equivalents and Restricted Cash 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 of three months or less. Restricted cash includes cash equivalents held in our name to collateralize standby letters of credit or its use is restricted by contract or regulation. Equity Investments We hold investments in various joint ventures where the Company evaluates its ability to influence the operating or financial decisions of the investee in applying the appropriate method of accounting for such investments. Influence tends to be more effective as the investor's percent of ownership in the voting rights of the investee increases. Our equity investments represent less than 20% of the voting rights of the investees and we do not exercise influence over the investee's operating and financial decisions. Accordingly, we do not account for our equity investments using the equity method accounting. For further information about our equity investments, see Note 7. "Equity Investments". Our investment in GDS Holdings Limited ("GDS") is classified as "available for sale" and is carried at fair value. Revenue Recognition Our revenue consists of lease revenue and revenue from contracts with customers. The Company adopted Accounting Standards Codification (“ASC”) 842, Leases (“ASC 842”), the new accounting standard for leases, effective January 1, 2019 using the modified retrospective approach and prior periods were not restated. In addition, the Company adopted Revenue from Contracts with Customers (“ASC 606”), the new accounting standard for revenue from contracts with customers, effective January 1, 2018 using the modified retrospective approach. See Note 3. “Recently Adopted Accounting Standards” and Note 4. “Revenue Recognition”. Lease Revenue: Our leasing revenue primarily consists of colocation rent, metered power reimbursements and interconnection revenue and is accounted for under ASC 842, Leases. We generally are not entitled to reimbursements for rental expenses including real estate taxes, insurance or other common area operating expenses. a. Colocation Rent Revenue Colocation rent revenues, including interconnection revenue, are fixed minimum lease payments generally billed monthly in advance based on the contracted power or leased space. Some contracts may provide initial free rent periods and rents that escalate over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased power or space at the beginning of the lease term, the rental payments 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 power and or leased space, revenue is recognized in proportion to the additional power or space in the periods that the lessee has control over the use of the additional power or space. The excess of revenue recognized over amounts contractually due is recognized as a straight-line receivable, which is included in rent and other receivables in our consolidated balance sheet. Some of our leases are structured on a gross basis in which the customer pays a fixed amount for colocation rent and power. The revenue for these types of leases is recorded in colocation lease revenue. b. Metered Power Reimbursements Revenue Some of our leases provide that the customer is separately billed for power based upon actual or estimated metered usage at rates then in effect. Metered power reimbursement revenue is variable lease payments generally billed one month in arrears, and an estimate of this revenue is accrued in the month that the associated power is provided and recorded in metered power reimbursements. Revenue from Contracts with Customers Managed services, equipment sales, installations and other services are recognized under ASC 606. Equipment sold by us generally consists of servers, switches, networking equipment, cable infrastructure and cabinets. Revenue is recognized at a point-in-time when control of the equipment transfers to the customer from the Company, which generally occurs upon delivery to the customer. Managed services include providing of a full-service managed data center, monitoring customer computer equipment, managing backups and storage, utilization reporting and other related ancillary information technology services. Management service contracts generally range from one to five years. Other services generally include installation of customer equipment, performing customer system re-boots, server cabinet and cage management, power monitoring, shipping and receiving, resolving technical issues, and other services requested by the customer. Installation services include mounting, wiring, and testing of customer owned equipment. The installation period is typically short term in duration, and accordingly, revenue from the installation of customer equipment is recognized at a point-in-time once the installation is complete and the performance obligation is satisfied. Other service revenue is measured based on the consideration specified in the contract and recognized over time as we satisfy the performance obligation. Rent and Other Receivables Receivables consist principally of trade receivables from customers and straight-line rent receivables with estimated credit losses recorded as an allowance for doubtful accounts. Foreign Currency Translation and Transactions The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average exchange rates during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive income (loss). Gains or losses from foreign currency transactions are included in determining net income. Stock-Based Compensation We have a stock-based incentive award plan for our employees and directors. Stock-based compensation expense associated with these awards is recognized in general and administrative expenses, property operating expenses, and sales and marketing expenses in our consolidated statements of operations. We measure stock-based compensation at the estimated fair value on the grant date and recognize the amortization of stock-based compensation expense over the requisite service period. Fair value is determined based on assumptions related to volatility, interest rates and the market, and our company performance. Fair Value Measurements Fair value measurements are utilized in accounting for business combinations, asset acquisitions, testing of goodwill and other long-lived assets for impairment, recording unrealized gain/loss on available-for-sale securities and related disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy that prioritizes certain inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows: Level 1—Observable inputs for identical instruments such as quoted market prices; Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data. Derivative Instruments Derivative instruments are measured at fair value and recorded as assets or liabilities, depending on our rights or obligations under the applicable derivative contract. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. For a derivative designated and that qualified as a cash flow hedge, the effective portion of the change in fair value of the derivative is recognized in the condensed consolidated statement of comprehensive income (loss) until the hedged item is recognized in earnings. Any ineffective portion of a derivative's change in fair value is immediately recognized in earnings. For interest rate derivatives amounts recognized in earnings are reflected in interest expense. For a derivative designated and that qualified as a net investment hedge, the effective portion of the change in the fair value and/or the net settlement of the derivative are reported in the condensed consolidated statement of comprehensive income (loss) as part of the cumulative foreign currency translation adjustment. Any ineffective portion of the change in fair value of the derivative is recognized directly in earnings. Amounts are reclassified out of other comprehensive income (loss) into earnings when the hedged investment is either sold or substantially liquidated.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	3 Months Ended
	Mar. 31, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Recently Adopted Accounting Standards Leases We adopted ASU 2016-02 (codified in ASC 842, Leases ) on January 1, 2019, applied the package of practical expedients included therein and utilized the modified retrospective transition method with the cumulative effect of transition on the effective date. By applying the modified retrospective transition method, the presentation of financial information for periods prior to January 1, 2019 were not restated. We elected the package of practical expedients, which permits us to not reassess (1) whether any expired or existing contracts are or contain leases, (2) the lease classification for any expired or existing leases, and (3) any initial direct costs for any existing leases as of the effective date. We did not elect the hindsight practical expedient, which permits entities to use hindsight in determining the lease term and assessing impairment. As a Lessee The ASU requires that a liability be recorded on the balance sheet for all leases where the reporting entity is a lessee, based on the present value of future lease obligations. A corresponding right-of-use ("ROU") asset will also be recorded. Amortization of the lease obligation and the ROU asset for leases classified as operating leases are on a straight-line basis. Leases classified as financing leases are required to be accounted for as financing arrangements similar to the accounting treatment for capital leases under ASC 840, Leases (the former accounting standard for all leases, ("ASC 840")). We elected the practical expedient to combine our lease and related non-lease components by asset class for our leases. We elected a practical expedient to not evaluate land easements not previously accounted for as leases prior to the entity’s adoption of the new accounting standard for leases. We elected to apply the short-term lease measurement and recognition exemption available for leases under the new accounting standard for leases that have a remaining lease term of 12 months or less. The adoption of ASC 842 had a significant impact on our consolidated balance sheet due to the recognition of approximately $87.0 million of ROU assets and $123.2 million of lease liabilities for operating leases. We recognized a $9.5 million cumulative effect adjustment to retained earnings. The adjustment to retained earnings was driven principally by measurement of operating lease liabilities at the present value of the remaining lease payments at the adoption date of January 1, 2019. The increase was offset in part by impairment of ROU assets associated with one build-to-suit ("BTS") arrangement recognized as an operating lease under the new accounting standard for leases. Additionally, we de-recognized certain previously recognized BTS lease assets and liabilities which under the new accounting standard for leases are recognized as operating lease ROU assets and lease liabilities. Prior to the adoption of the new accounting standard for leases, these leases were accounted as financing arrangements or BTS leases assets and liabilities and recorded as buildings and improvement and lease financing arrangements. The table below reflects the impact of adoption of the lease standard on our consolidated balance sheet for the period ended March 31, 2019 (in millions) related to previously reported BTS leases: Impact to the consolidated balance sheets: For the period ended December 31, 2018 For the period ended March 31, 2019 Buildings and improvements $ 77.4 $ — Operating lease right-of-use assets — 50.0 Finance lease liabilities 123.3 — Operating lease liabilities — 85.5 Prior to the adoption of the new accounting standard for leases, BTS lease assets were amortized over the useful life of the asset and recorded as amortization expense and accretion of BTS lease liability was recorded as an interest expense in consolidated statement of operations. Upon adoption of the new accounting standard for leases, BTS leases are accounted as operating leases and amortization and accretion of lease liabilities of these operating leases are recorded as lease expenses in property operating expenses in our consolidated statement of operations. As a Lessor The accounting for lessors remained largely unchanged from ASC 840. However, the new accounting standard for leases requires that lessors expense certain costs to obtain a lease that are not incremental to origination of a lease. Upon adoption, initial direct cost that are not incremental are expensed as general and administrative expense in our consolidated statements of operations. Prior to the adoption of new standard, these costs were capitalizable. As a result of electing the package of practical expedients, initial direct costs have not been reassessed prior to the effective date and therefore adoption of the lease standard did not have an impact on our previously reported consolidated statements of operations with respect to initial direct costs. In addition, under the new accounting standard for leases certain exceptions under the previous standard for real estate no longer are applicable in the evaluation of the lease classification as an operating, sales type or direct financing lease. In the event that a real estate lease is classified as sales-type lease, subject to certain conditions, a gain or loss is recognized based on the present value of the lease payments and residual value. We elected the practical expedient to combine all of our lease and nonlease revenue components into a single combined lease component as nonlease components have the same pattern of transfer as the related predominant operating lease component. Our customer leases include options to extend or terminate the lease agreements. We do not generally include extension or termination options in a customer’s lease term for lease classification purposes or for recognizing lease revenue unless we are reasonably certain the customer will exercise these extension or termination options at lease commencement. Revenue from contracts with customers On January 1, 2018, we adopted the FASB pronouncement ASU 2014-09 with respect to revenue recognition. The revised guidance outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and superseded prior revenue recognition guidance, including industry-specific revenue guidance. The revised guidance replaced most existing revenue and real estate sale recognition guidance in GAAP. The standard specifically excludes lease contracts, which is our primary recurring revenue source; however, our revenue accounting for managed services and sales of real estate and equipment will follow the revised guidance. We adopted the new standard using the modified retrospective transition method, where financial statement presentations prior to the date of adoption are not adjusted. Transactions that were not closed as of the adoption date were adjusted to reflect the new standard and we recorded an adjustment to beginning retained earnings of $0.3 million . As allowed under GAAP, we have adopted the practical expedient that allows us not to disclose information about remaining performance obligations that have original expected durations of one year or less, the amount of the transaction price allocated to the remaining performance obligations and when we expect to recognize that amount as revenue for the year. We have also adopted the "as invoiced" practical expedient, whereby the Company recognizes revenue in the amount that directly corresponds to the amount of value transferred to the customer. Share based payments granted to nonemployees We adopted ASU 2018-07, Compensation-Stock Compensation (Topic 718) which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under this ASU, the guidance on such payments to nonemployees aligns with the requirements for share-based payments granted to employees. The adoption did not have a significant impact as the Company accounts for its share-based payments. Equity investments On January 1, 2018, we adopted ASU 2016-01 related to equity investments. Equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) are measured at fair value with changes in fair value recognized in net income. Prior to adoption of this update, changes in fair value for available for sale equity investments were recorded in other comprehensive income (loss). The adoption of the new standard was made through a cumulative-effect adjustment to beginning retained earnings of $75.6 million . New Accounting Pronouncements In August 2018, the SEC issued Securities Act Release No. 33-10532, Disclosure Update and Simplification, which amends certain of its disclosure requirements and is intended to facilitate the disclosure of information to investors and simplify compliance without significantly altering the total mix of information provided to investors. The amendments became effective on November 5, 2018. Among the amendments is the requirement to present the changes in shareholders' equity in the interim financial statements (either in a separate statement or footnote) in quarterly reports on Form 10-Q. In accordance with the SEC's rule, the company's first presentation of changes in shareholders’ equity is shown in this Form 10-Q for the quarter ended March 31, 2019. In August 2018, the FASB issued ASU 2018-15, which clarifies the accounting for implementation costs incurred in a hosting arrangement that is a service contract. Capitalization of these implementation costs are accounted for under the same guidance as implementation costs incurred to develop or obtain internal-use software and recorded as a prepaid asset. These capitalized costs are to be expensed ratably over the hosting arrangement term as operating expense, along with the service fees. The guidance is effective for periods beginning after December 15, 2019. Early adoption is allowed. The Company is evaluating the impact of the new standard but does not believe that adoption will have a significant impact on the Company. In August 2018, the FASB issued ASU 2018-13, which changes the fair value measurement disclosure requirements of ASC 820, Fair Value Measurement . The amendments are part of the FASB’s disclosure framework project to improve the effectiveness of disclosures in the notes to the financial statements by facilitating clear communication of the information required by GAAP that is most important to financial statement users and are intended to improve the effectiveness of disclosure requirements on fair value measurement by using those concepts. The guidance is effective for periods beginning after December 15, 2019. Early adoption is allowed. The Company is evaluating the impact of the new standard. In June 2016, the FASB issued ASU 2016-13 providing guidance which requires certain financial assets to be presented at the net amount expected to be collected. The guidance will apply to our trade receivables, notes receivable, net investments in leases and any other future financial assets that have the contractual right to receive cash that we may acquire in the future. The guidance is effective for periods beginning for us January 1, 2020. Early adoption is allowed. We are currently evaluating the impact of the new standard.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Lease Revenue Lease revenue primarily consists of colocation rent and metered power reimbursements from the lease of our data centers. Colocation leases may include all or portions of a data center, where customers may also lease office space to support their colocation operations. Revenue is primarily based on power usage as well as square footage. Customer lease arrangements customarily contain provisions that allow for renewal or continuation on a month-to-month arrangement, and certain leases contain early termination rights. We do not include any of these extension or termination options in a customer’s lease term for lease classification purposes or for recognizing lease revenue unless we are reasonably certain the customer will exercise these extension or termination options at lease commencement. At lease inception, early termination is generally not deemed probable due to the significant economic penalty incurred by the lessee to exercise its early termination right and to relocate their equipment installed in our facilities. Our customer lease arrangements generally do not provide any option to purchase a leased asset and are classified as operating leases. The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: For the Period Ended March 31, 2019 Minimum Lease Payments 2019 $ 520.1 2020 631.9 2021 542.8 2022 454.3 2023 365.2 2024 295.9 Thereafter 940.0 Total $ 3,750.2 Disclosures related to periods prior to adoption of the New Accounting Standard for Leases The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: For the Period Ended December 31, 2018 Minimum Lease Payments 2019 $ 647.6 2020 553.7 2021 453.0 2022 365.5 2023 284.4 Thereafter 835.9 Revenue from Contracts with Customers Revenue from equipment sales and the installation of customer equipment is recognized at a point-in-time. Title to such assets are transferred to the customer, and the benefits of the installation service are consumed at the completion of the service. Disaggregation of Revenue For the three months ended March 31, 2019 and 2018, revenue disaggregated by primary revenue stream is as follows (in millions). Lease Revenue For the period ended March 31, 2019 Colocation (Minimum lease payments) $ 188.4 Meter power reimbursements (Variable lease payments) 28.5 Total Lease revenue $ 216.9 Three Months Ended March 31, Revenue from contracts with customers 2019 2018 Equipment sales $ 3.9 $ 5.8 Other revenue 4.2 4.0 Total Revenue from contracts with customers $ 8.1 $ 9.8 Other revenue from contracts with customers includes $3.4 million and $3.2 million of revenue from managed services for the period ended March 31, 2019 and March 31, 2018, respectively. Total other revenues from customers generated from operations outside of the United States were insignificant for the three months ended March 31, 2019 and 2018. The balances from customers contract accounts receivables were $8.2 million and $4.8 million for the three months ended March 31, 2019 and 2018, respectively. Contract assets and contract liabilities were not material at March 31, 2019 and 2018. One customer represented approximately 21% and 19% of our revenue for the three months ended March 31, 2019 and 2018 .

Leases - As a Lessee

Leases - As a Lessee	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases - As a Lessee	Leases - As a Lessee ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. Variable lease payments consist of non-lease components and services related to the lease. Variable lease payments are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred. For purposes of determining the lease liability we estimated our incremental borrowing rate, based on information available at the lease commencement date. Fixed contractual payments are recognized on a straight-line basis over the corresponding lease term. The new accounting standard for leases defines initial direct costs as only the incremental costs of signing a lease. Initial direct costs related to leasing that are not incremental and are expensed as general and administrative expense in our consolidated statements of operations. As a result of electing the package of practical expedients, initial direct costs have not been reassessed prior to the effective date and therefore adoption of the lease standard did not have an impact on our previously reported consolidated statements of operations with respect to initial direct costs. Our operating lease agreements primarily consist of leased real estate and are included within operating lease ROU assets and operating lease liabilities on the consolidated balance sheets. Many of our lessee agreements include options to extend the lease, which are not included in our minimum lease payments unless they are reasonably certain to be exercised at lease commencement. Rental expense related to operating leases is recognized on a straight-line basis over the lease term. We use leasing as a source of financing for certain data center facilities and related equipment. We currently operate five data center facilities subject to finance leases. The remaining terms of our finance leases range from two to twenty-two years. We have options to extend the initial lease term on all but one of these leases. Finance leases are included in buildings and equipment, finance lease liabilities in our consolidated balance sheets. We currently lease twelve other facilities under operating lease agreements for our data centers, sales offices, international location offices and our corporate headquarters located in Dallas, Texas. Our leases have remaining lease terms ranging from one to seventeen years. Some of the leases include options to extend the leases for up to an additional fifteen years. Additionally, our ground lease in Houston has a lease term that expires in 2066. The components of lease expense were as follows (in millions): Three months ended March 31, 2019 Operating lease cost $ 5.0 Finance lease cost: Amortization of assets 0.6 Interest on lease liabilities 0.5 Total net lease cost $ 6.1 Supplemental balance sheet information related to leases was as follows (in millions, except lease term and discount rate): March 31, 2019 Operating leases: Operating lease right-of-use assets $ 83.8 Operating lease liabilities $ 119.6 Finance leases: Property and equipment, at cost $ 34.0 Accumulated amortization (3.4 ) Property and equipment, net $ 30.6 Finance lease liabilities $ 33.4 Weighted average remaining lease term (in years): Operating leases 12.5 Finance leases 17.2 Weighted average discount rate: Operating leases 4.5 % Finance leases 5.3 % Supplemental cash flow and other information related to leases was as follows (in millions): Three months ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 5.1 Operating cash flows from finance leases 0.5 Financing cash flows from finance leases 0.6 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 87.0 Maturities of lease liabilities were as follows (in millions): March 31, 2019 Operating Leases Finance Leases 2019 $ 15.3 $ 3.3 2020 19.5 4.3 2021 15.3 4.2 2022 15.6 3.1 2023 13.4 2.0 2024 7.7 1.5 Thereafter 71.0 30.7 Total lease payments $ 157.8 $ 49.1 Less: Imputed interest (38.2 ) (15.7 ) Total lease obligations $ 119.6 $ 33.4 As of March 31, 2019, we have additional operating lease commitments that have not yet commenced of approximately $22.2 million fixed contractual payments for an office lease with a lease term of approximately 12 years. Disclosures related to periods prior to adoption of the New Accounting Standard for Leases The following table summarizes aggregate minimum principal payments of the finance lease obligations and future minimum lease payments required under operating leases for the five years subsequent to December 31, 2018, and thereafter (in millions): December 31, 2018 Operating Leases Finance Leases 2019 $ 5.0 $ 2.7 2020 4.9 2.8 2021 3.7 2.9 2022 3.7 2.0 2023 3.5 1.0 Thereafter 43.4 22.0 Total lease payments $ 64.2 $ 33.4
Leases - As a Lessee	Leases - As a Lessee ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. Variable lease payments consist of non-lease components and services related to the lease. Variable lease payments are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred. For purposes of determining the lease liability we estimated our incremental borrowing rate, based on information available at the lease commencement date. Fixed contractual payments are recognized on a straight-line basis over the corresponding lease term. The new accounting standard for leases defines initial direct costs as only the incremental costs of signing a lease. Initial direct costs related to leasing that are not incremental and are expensed as general and administrative expense in our consolidated statements of operations. As a result of electing the package of practical expedients, initial direct costs have not been reassessed prior to the effective date and therefore adoption of the lease standard did not have an impact on our previously reported consolidated statements of operations with respect to initial direct costs. Our operating lease agreements primarily consist of leased real estate and are included within operating lease ROU assets and operating lease liabilities on the consolidated balance sheets. Many of our lessee agreements include options to extend the lease, which are not included in our minimum lease payments unless they are reasonably certain to be exercised at lease commencement. Rental expense related to operating leases is recognized on a straight-line basis over the lease term. We use leasing as a source of financing for certain data center facilities and related equipment. We currently operate five data center facilities subject to finance leases. The remaining terms of our finance leases range from two to twenty-two years. We have options to extend the initial lease term on all but one of these leases. Finance leases are included in buildings and equipment, finance lease liabilities in our consolidated balance sheets. We currently lease twelve other facilities under operating lease agreements for our data centers, sales offices, international location offices and our corporate headquarters located in Dallas, Texas. Our leases have remaining lease terms ranging from one to seventeen years. Some of the leases include options to extend the leases for up to an additional fifteen years. Additionally, our ground lease in Houston has a lease term that expires in 2066. The components of lease expense were as follows (in millions): Three months ended March 31, 2019 Operating lease cost $ 5.0 Finance lease cost: Amortization of assets 0.6 Interest on lease liabilities 0.5 Total net lease cost $ 6.1 Supplemental balance sheet information related to leases was as follows (in millions, except lease term and discount rate): March 31, 2019 Operating leases: Operating lease right-of-use assets $ 83.8 Operating lease liabilities $ 119.6 Finance leases: Property and equipment, at cost $ 34.0 Accumulated amortization (3.4 ) Property and equipment, net $ 30.6 Finance lease liabilities $ 33.4 Weighted average remaining lease term (in years): Operating leases 12.5 Finance leases 17.2 Weighted average discount rate: Operating leases 4.5 % Finance leases 5.3 % Supplemental cash flow and other information related to leases was as follows (in millions): Three months ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 5.1 Operating cash flows from finance leases 0.5 Financing cash flows from finance leases 0.6 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 87.0 Maturities of lease liabilities were as follows (in millions): March 31, 2019 Operating Leases Finance Leases 2019 $ 15.3 $ 3.3 2020 19.5 4.3 2021 15.3 4.2 2022 15.6 3.1 2023 13.4 2.0 2024 7.7 1.5 Thereafter 71.0 30.7 Total lease payments $ 157.8 $ 49.1 Less: Imputed interest (38.2 ) (15.7 ) Total lease obligations $ 119.6 $ 33.4 As of March 31, 2019, we have additional operating lease commitments that have not yet commenced of approximately $22.2 million fixed contractual payments for an office lease with a lease term of approximately 12 years. Disclosures related to periods prior to adoption of the New Accounting Standard for Leases The following table summarizes aggregate minimum principal payments of the finance lease obligations and future minimum lease payments required under operating leases for the five years subsequent to December 31, 2018, and thereafter (in millions): December 31, 2018 Operating Leases Finance Leases 2019 $ 5.0 $ 2.7 2020 4.9 2.8 2021 3.7 2.9 2022 3.7 2.0 2023 3.5 1.0 Thereafter 43.4 22.0 Total lease payments $ 64.2 $ 33.4

Investment in Real Estate

Investment in Real Estate	3 Months Ended
	Mar. 31, 2019
Real Estate [Abstract]
Investment in Real Estate	Investment in Real Estate Land for future development During the three months ended March 31, 2019 , the Company purchased approximately 30 acres of land for $40.1 million . No land purchases were made during the comparable period in 2018. Real Estate Investments and Intangibles and Related Depreciation and Amortization As of March 31, 2019 and December 31, 2018 , major components of our real estate investments and intangibles and related accumulated depreciation and amortization are as follows (in millions): March 31, 2019 December 31, 2018 Investment in Real Estate Intangibles Investment in Real Estate Intangibles Buildings and Improvements Equipment Customer Relationships In Place Leases Other Contractual Buildings and Improvements Equipment Customer Relationships In Place Leases Other Contractual Cost $ 1,649.2 $ 2,799.6 $ 247.1 $ 136.6 $ 19.4 $ 1,677.5 $ 2,630.2 $ 247.1 $ 136.0 $ 19.5 Less: accumulated depreciation and amortization (483.8 ) (638.7 ) (141.2 ) (27.5 ) (8.3 ) (481.8 ) (572.7 ) (137.9 ) (21.1 ) (7.9 ) Net $ 1,165.4 $ 2,160.9 $ 105.9 $ 109.1 $ 11.1 $ 1,195.7 $ 2,057.5 $ 109.2 $ 114.9 $ 11.6 As of March 31, 2019 and December 31, 2018 , construction in progress includes $75.9 million and $69.1 million of land which is under active development, respectively. Depreciation and amortization are calculated using the straight-line method over the useful lives of the assets. The typical life of owned assets are as follows: Buildings 30 years Building improvements 30 years Equipment 20 years Leased real estate and leasehold improvements are depreciated over the shorter of the asset's useful life or the remaining lease term, including renewal options which are reasonably assured at lease commencement. Depreciation expense related to leased real estate and leasehold improvements was $88.9 million and $66.2 million for the three months ended March 31, 2019 and 2018, respectively. Other contractual intangibles include trademark/tradename, favorable leasehold interests and above market leases. Amortization expense related to other contractual intangibles was $13.2 million and $8.4 million for the three months ended March 31, 2019 and 2018, respectively.

Equity Investment

Equity Investment	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Equity Investment	Equity Investments The Company has an equity investment, accounted for using the fair value method in GDS, a developer and operator of high-performance, large-scale data centers in China. As of March 31, 2019 the American Depositary Share ("ADS") Class A ordinary share equivalent was $35.69 per ADS for an equity investment fair value of $286.7 million . For the three months ended March 31, 2019 and 2018, the unrealized gain on investment of $101.2 million and $40.5 million was recognized in the consolidated statement of operations in unrealized gain on marketable equity investment, respectively. On October 8, 2018, the Company made an $11.9 million investment in exchange for a 10% equity interest in ODATA Brasil S.A. and ODATA Colombia S.A.S. (collectively "ODATA"). ODATA, a Brazilian headquartered company, specializes in providing colocation services to wholesale customers, such as hyperscale cloud providers, financial services and telecommunications companies, and also to enterprises across multiple industries. On October 30, 2018, the Company made an additional $0.7 million investment in ODATA Colombia S.A.S. In connection with these investments, CyrusOne and ODATA entered a commercial agreement covering leasing activity with CyrusOne customers in the ODATA portfolio. In addition, our Chief Technology Officer joined the ODATA board of directors in October 2018. In evaluating the appropriate accounting method for its investment in ODATA, the Company considered its right to appoint a director to the ODATA board of directors, as well as other relevant factors, in evaluating the Company's ability to exercise significant influence over the operating and financial policies of ODATA as provided in ASC 323-10-15-6 and concluded that the investment should be accounted for under the cost method.

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets As of March 31, 2019 and December 31, 2018 , the components of other assets are as follows (in millions): March 31, 2019 December 31, 2018 Deferred leasing and other contract costs $ 45.6 $ 43.6 Prepaid expenses 28.1 26.4 Non-real estate assets, net 18.4 18.4 Other assets 22.7 22.9 Total $ 114.8 $ 111.3 Non-real estate assets primarily include administrative related equipment and office leasehold improvements, depreciated or amortized over the shorter of the assets useful life or the related lease term. Other assets primarily includes deposits, fuel inventory and other deferred costs.

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt As of March 31, 2019 and December 31, 2018 , the components of debt are as follows (unless otherwise noted, interest rate and maturity date information are as of March 31, 2019 ) (in millions): March 31, 2019 December 31, 2018 Interest Rate (a) Maturity Date $3.0 Billion Credit Facility: $1.7 Billion Revolving Credit Facility: March 2022 (b) US Revolver $ 270.0 $ — Monthly LIBOR + 1.45% EUR Revolver 145.8 143.0 Monthly EURIBOR + 1.45% 2023 Term Loan 1,000.0 1,000.0 Monthly LIBOR + 1.40% March 2023 2025 Term Loan 300.0 300.0 Monthly LIBOR + 1.70% March 2025 2024 Notes, including bond premium of $5.2 million 705.2 705.5 5.000 % March 2024 2027 Notes, including bond premium of $8.8 million 508.8 509.1 5.375 % March 2027 Deferred financing costs (31.2 ) (32.9 ) — — Total $ 2,898.6 $ 2,624.7 (a) - Monthly LIBOR at March 31, 2019 was 2.50% . (b) - The Company may exercise a one -year extension option, subject to certain conditions. In March 2019, the Company entered into a cross-currency interest rate swap pursuant to which, we will pay floating interest on €238.1 million and receive floating interest on $270.0 million , to hedge the variability of future cash flows attributable to changes in the 1-month USD LIBOR versus EUR LIBOR rates. The swap matures in December 2019 and net interest payments are recognized in earnings, including $0.3 million reduction in interest expense for the three months ended March 31, 2019. On March 29, 2018, the Company entered into a new $3.0 billion unsecured credit facility. The new credit facility consists of a $1.7 billion revolving credit facility (" $1.7 Billion Revolving Credit Facility"), which includes a $750.0 million multicurrency borrowing sublimit, a 5 -year term loan with commitments totaling $1.0 billion ("2023 Term Loan") and a $300.0 million 7 -year term loan ("2025 Term Loan") (collectively, the " $3.0 Billion Credit Facility"). We borrowed $700.0 million under the 2023 Term Loan on March 31, 2018, and the 2023 Term Loan includes a delayed draw feature which allows the Company to draw $300.0 million in up to three tranches over a six -month period in multiple currencies. The Company exercised the draw as a part of the acquisition of Zenium Topco Ltd. and certain other affiliated entities ("Zenium"). The $1.7 Billion Revolving Credit Facility has the option to borrow in non-USD currencies and includes a one -year option which, if exercised by the Company, would extend the final maturity to March 2023. The $3.0 Billion Credit Facility also includes an accordion feature providing for an aggregate increase in the revolving and term components to $4.0 billion , subject to certain conditions. The $1.7 Billion Revolving Credit Facility, 2023 Term Loan and 2025 Term Loan are prepayable at our option. On March 29, 2018, borrowings of $1.0 billion under the $3.0 Billion Credit Facility were used to fully retire a previous $2.0 billion credit facility. The previous $2.0 billion credit facility consisted of a $1.1 billion senior unsecured revolving credit facility (" $1.1 Billion Revolving Credit Facility"), a $250.0 million 5 -year term loan ("2021 Term Loan") and a $650.0 million 7 -year term loan ("2022 Term Loan") (collectively, the " $2.0 Billion Credit Facility"). The aggregate outstanding principal balance of the $2.0 Billion Credit Facility at the date of the prepayment was $900.0 million and we recognized a loss on early extinguishment of debt of $3.1 million . We pay commitment fees for the unused amount of borrowings on the $1.7 Billion Revolving Credit Facility and 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. The commitment fees decrease to 0.15% per annum upon 50% or greater utilization. We also paid commitment fees on the $1.1 Billion Revolving Credit Facility through its retirement in March 2018. Commitment fees were $0.5 million and $0.7 million for the three months ended March 31, 2019 and 2018 , respectively. As of March 31, 2019 , we had $1,000.0 million , $300.0 million and $415.8 million outstanding under the 2023 Term Loan, the 2025 Term Loan and the $1.7 Billion Revolving Credit Facility, respectively, and additional borrowing capacity under the $3.0 Billion Credit Facility was approximately $1.3 billion (all under the $1.7 Billion Revolving Credit Facility), net of $8.0 million of outstanding letters of credit as of March 31, 2019. On March 17, 2017, the Operating Partnership and CyrusOne Finance Corp., a single-purpose finance subsidiary, both wholly-owned subsidiaries of the Company (together, the "Note Issuers") completed an offering of $500.0 million aggregate principal amount of 5.000% senior notes due 2024 ("Original 2024 Notes") and $300.0 million aggregate principal amount of 5.375% senior notes due 2027 ("Original 2027 Notes") in a private offering. The Company received proceeds of $791.2 million , net of underwriting costs and other deferred financing costs related to the notes. On November 3, 2017, the Note Issuers completed an offering of $200.0 million aggregate principal amount of 5.000% senior notes due 2024 ("Additional 2024 Notes") and $200.0 million aggregate principal amount of 5.375% senior notes due 2027 ("Additional 2027 Notes") in a private offering. The Additional 2024 Notes have terms substantially identical to the Original 2024 Notes and the Additional 2027 Notes have terms substantially identical to the Original 2027 Notes. The Original 2024 Notes and the Additional 2024 Notes form a single class of securities ("2024 Notes"), and the Original 2027 Notes and the Additional 2027 Notes form a single class of securities ("2027 Notes"). The Company received proceeds of $416.1 million , net of underwriting costs of $4.4 million . The Original 2024 Notes and the Additional 2024 Notes are referred to as the 2024 Notes and the Original 2027 Notes and the Additional 2027 Notes are referred to as the 2027 Notes. On January 8, 2018, the Note Issuers completed an exchange offer with respect to the 2024 Notes and the 2027 Notes and all validly tendered 2024 Notes and 2027 Notes were exchanged for notes registered with the SEC. The 2024 Notes and 2027 Notes are senior unsecured obligations of the Note Issuers, which rank equally in right of payment with all existing and future unsecured senior indebtedness of the Note Issuers. The 2024 Notes and 2027 Notes are effectively subordinated in right of payment to any secured indebtedness of the Note Issuers to the extent of the value of the assets securing such indebtedness. The senior notes are guaranteed on a joint and several basis by the Company, the General Partner and all of CyrusOne LP’s existing domestic subsidiaries that guarantee the $3.0 Billion Credit Facility. Each of CyrusOne LP’s restricted subsidiaries (other than any designated excluded subsidiary or receivables entity) that guarantees any other indebtedness of CyrusOne LP or other indebtedness of the guarantors will be required to guarantee the senior notes in the future. Each such guarantee is a senior unsecured obligation of the applicable guarantor, ranking equally with all existing and future unsecured senior indebtedness 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 2024 Notes and 2027 Notes are structurally subordinated to all liabilities (including trade payables) of each subsidiary of CyrusOne LP that does not guarantee the 2024 Notes and 2027 Notes. The 2024 Notes and 2027 Notes may be redeemed at our option prior to their scheduled maturity dates at the prices and premiums and on the terms set forth in the respective indentures governing the notes. Our debt agreements contain customary provisions with respect to events of default, affirmative and negative covenants and borrowing conditions. The most restrictive covenants are generally included in the $3.0 Billion Credit Agreement. The $3.0 Billion 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 requirement, a maximum secured recourse indebtedness ratio, a minimum unencumbered debt yield ratio and a maximum ratio of unsecured indebtedness to unencumbered asset value. In order to continue to have access to amounts available under the $3.0 Billion Credit Agreement, the Company must remain in compliance with all of that agreement's covenants. As of March 31, 2019 , we believe we are in compliance with all provisions of our debt agreements.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments and Hedging Activities Fair value measurements are based on the assumptions that market participants would use in pricing the asset or liability. As a basis for considering assumptions in fair value measurements, a fair value hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within Levels 1 and 2 of the hierarchy) and the reporting entity's own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy) has been established. Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets and liabilities that we have the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability that are typically based on an entity's own assumptions, as there is little, if any, related market activity. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. Our assessment of the significance of a particular input to the fair value measurement requires judgment and considers factors specific to the asset or liability. The fair value of cash and cash equivalents, rent and other receivables, construction costs payable, dividends payable and accounts payable and accrued expenses approximate their carrying value because of the short-term nature of these financial instruments. The carrying value, exclusive of deferred financing costs, for the revolving credit facilities and the floating rate term loans approximate estimated fair value as of March 31, 2019 and December 31, 2018 , due to the floating rate nature of the interest rates and the stability of our credit ratings. The carrying value and fair value of other financial instruments are as follows (in millions): March 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value 2024 Notes $ 705.2 $ 720.1 $ 705.5 $ 684.1 2027 Notes 508.8 515.0 509.1 488.0 GDS Equity investment 286.7 286.7 185.5 185.5 The fair values of our 2024 Notes and 2027 Notes as of March 31, 2019 were based on the quoted market prices for these notes, which is considered Level 1 of the fair value hierarchy. The fair value of the equity investment as of March 31, 2019 was based on the quoted market price for the stock which is considered Level 1 of the fair value hierarchy. Hedging Activities When we use derivative instruments, it is generally to reduce our exposure to fluctuations in interest rates and foreign currency exchange rate movements. We have not entered into, and do not plan to enter into, financial instruments for trading or speculative purposes. To manage foreign currency exposure, we have entered into Euro denominated debt and cross-currency swap to hedge the Company's net investment in its Euro functional currency consolidated subsidiaries and the variability in EUR-USD exchange rate. Accounting for changes in the fair value of derivatives depends on the intended use of the derivative and the designation of the derivative, including whether we have elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as foreign currency risk or interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. For derivatives designated as "cash flow" hedges, the change in the fair value of the derivative is initially reported in "Other comprehensive income" ("OCI") in our consolidated statements of comprehensive income (loss) and subsequently reclassified into gain (loss) when the hedged transaction affects earnings, or the hedging relationship is no longer highly effective. We assess the effectiveness of each hedging relationship whenever financial statements are issued, or earnings are reported and at least every three months. During March 2019, the Company entered into a cross-currency swap whereby the Company pays floating interest on €238.1 million and receives floating interest rate on $270.0 million (a "pay-floating, receive-floating interest rate swap") to hedge the variability of future cash flows attributable to changes in the 1-month USD LIBOR versus EUR LIBOR rates. The pay-floating, receive-floating interest rate swap has an effective date of March 2019 and a maturity date of December 2019 and is recognized in earnings. This interest rate swap effectively convert $270.0 million to €238.1 million debt floating based on the Eur-Euribor rate. As of March 31, 2019, we had borrowings subject to this pay-floating, receive-floating interest rate swaps with aggregate principal balances of approximately $270.0 million . Net Investment Hedges In addition to the $270.0 million borrowings subject to a cross-currency swap discussed above we have $130.0 million included in our $415.8 million outstanding on our unsecured $1.7 Billion Revolving Credit Facility, see Note 9. "Debt" as of March 31, 2019. These borrowings are designated as, and are effective as, economic hedges of our net investments in foreign entities. Exchange rate variations impact our financial results because the financial results of our foreign subsidiaries are translated to U.S. dollars each period, with the effect of exchange rate variations being recorded in OCI as part of the cumulative foreign currency translation adjustment. As a result, changes in the value of our borrowings under the Euro-denominated revolver under our $1.7 Billion Revolving Credit Facility and synthetically swapped debt will be reported in the same manner as foreign currency translation adjustments, which are recorded in OCI as part of the cumulative foreign currency translation adjustment. The following table presents the effect of our derivative financial instruments on our accompanying consolidated financial statements (in millions): For the Three Months Ended March 31, 2019 2018 Derivatives in Cash Flow Hedging Relationships Cross-Currency Swaps: Amount of gain (loss) recognized in OCI for derivatives $ 2.7 $ — Amount of gain (loss) reclassified from accumulated OCI for derivatives $ — $ — Amount of gain (loss) recognized in earnings $ — $ — During the next 12 months, we estimate that no amounts will be reclassified from "Accumulated OCI" to net income (loss).

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity	Stockholders' Equity Capitalization During the first quarter of 2018, the Board authorized the Company to enter into sales agreements pursuant to which the Company may issue and sell from time to time shares of its common stock having an aggregate sales price of up to $500.0 million (the "2018 ATM Stock Offering Program"). During the fourth quarter of 2018, the Board authorized the Company to enter into sales agreements pursuant to which the Company may issue and sell from time to time shares of its common stock having an aggregate sales price of up to $750.0 million (the "New 2018 ATM Stock Offering Program"). The New 2018 ATM Stock Offering Program replaced the 2018 ATM Stock Offering Program. For the three months ended March 31, 2019 , the Company sold approximately 2.0 million shares of its common stock under its ATM stock offering programs at an average price of $52.19 , generating net proceeds of approximately $104.1 million after giving effect to sales agent commissions of $1.3 million . As of March 31, 2019 , there was $644.6 million under the New 2018 ATM Stock Offering Program available for future offerings. During the three months ended March 31, 2018 , the Company sold 2.8 million common shares at an average price of $51.24 . At March 31, 2019 , the Company had approximately 110.3 million common shares outstanding. Distributions During each of the three months ended March 31, 2019 and 2018 , regular dividends were paid to our stockholders of $0.46 per common share. On May 1, 2019 , the Company will announce a cash dividend of $0.46 per common share payable on July 12, 2019 , to stockholders of record at the close of business on June 28, 2019 . Stock Plans The board of directors of CyrusOne Inc. adopted the 2012 Long-Term Incentive Plan ("LTIP"), prior to the IPO, which was amended and restated on May 2, 2016. The LTIP is administered by the compensation committee of the board of directors. Awards issuable under the LTIP include common stock, restricted stock, restricted stock units, 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 March 31, 2019 , were approximately 4.5 million . Shares vest according to each award agreement and as long as the employee remains employed with the Company. The Company has granted awards with time-based vesting, performance-based vesting and market-based vesting features. Restricted stock units and restricted stock are issued as either time-based (where the award vests ratably over time and is not subject to future performance targets and, accordingly, is initially recorded at the current market price at the time of grant) or performance-based (where the award is recorded at fair value at the time of grant and vesting of the award, if any, is based on achieving certain financial targets, currently based on shareholder return). The restricted stock units have the right to receive dividend equivalents in cash and holders of restricted stock have the right to receive dividends. The performance-based awards accrue dividends that are payable upon settlement of the award. Expense for time-based grants is recognized under a straight-line method. For grants with a market condition, which is generally a factor outside of the Company's financial performance, such as a market index, expense is recognized under a graded expense attribution method. For grants based solely on the Company's financial performance, expense is recognized under a graded expense attribution method if it is probable that the performance targets will be achieved. Total stock-based compensation expense for the three months ended March 31, 2019 and 2018 was $4.5 million and $3.9 million , respectively. The following tables present the stock plan activity for the three months ended March 31, 2019 and 2018 for restricted stock units, restricted stock and stock options (performance-based awards are reflected at the target amount of the grant): Restricted Stock Units ("RSU") 2019 2018 Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Outstanding January 1, 511,049 $ 56.23 265,002 $ 56.08 Granted 360,362 47.97 322,063 51.92 Exercised (123,159 ) 44.87 (80,965 ) 43.47 Forfeited (2,691 ) 49.69 (3,131 ) 51.20 Outstanding March 31, 745,561 $ 54.14 502,969 $ 55.47 Time-based RSUs outstanding 359,400 $ 53.12 256,609 $ 50.71 Performance-based RSUs outstanding 386,161 $ 55.08 246,360 $ 60.41 Restricted Stock ("RS") 2019 2018 Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Outstanding January 1, 419,356 $ 35.73 715,098 $ 32.21 Granted 16,681 52.46 17,052 51.31 Exercised (364,822 ) 35.23 (209,415 ) 27.02 Forfeited (34,603 ) 37.09 (44,034 ) 28.45 Outstanding March 31, 36,612 $ 47.02 478,701 $ 35.50 Time-based RSs outstanding 36,612 $ 47.02 362,084 $ 38.08 Performance-based RSs outstanding — $ — 116,617 $ 28.57 Stock Options 2019 2018 Options Weighted Average Exercise Price Options Weighted Average Exercise Price Outstanding January 1, 401,223 $ 31.96 415,459 $ 31.67 Granted — — — — Exercised (25,586 ) 36.70 — — Forfeited — — — — Outstanding March 31, 375,637 $ 31.63 415,459 $ 31.67 Time-based stock options outstanding 323,101 $ 32.94 348,137 $ 33.23 Performance-based stock options outstanding 52,536 $ 23.58 67,322 $ 23.58

Income (Loss) per Share

Income (Loss) per Share	3 Months Ended
	Mar. 31, 2019
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 participating securities are both 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 per share for the three months ended March 31, 2019 and 2018 : IN MILLIONS, except per share amounts Three months ended March 31, 2019 2018 Basic Diluted Basic Diluted Numerator: Net income $ 89.4 $ 89.4 $ 43.5 $ 43.5 Less: Restricted stock dividends (0.2 ) (0.2 ) (0.3 ) (0.3 ) Net income available to stockholders $ 89.2 $ 89.2 $ 43.2 $ 43.2 Denominator: Weighted average shares outstanding-basic 108.3 108.3 96.0 96.0 Performance-based restricted stock and units 0.5 0.6 Weighted average shares outstanding-diluted 108.8 96.6 EPS: Net income per share-basic $ 0.82 $ 0.45 Effect of dilutive shares: Net income per share-diluted $ 0.82 $ 0.45

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company has a strategic partnership with GDS, a developer and operator of high-performance, large-scale data centers in China. In connection with our investment in GDS, the Company entered into an agreement with GDS for the joint marketing of each company's data centers. Also as a part of the agreement, the Company's Chief Executive Officer joined the board of directors of GDS on June 22, 2018. For the three months ended March 31, 2019 , the Company incurred $0.5 million of commission and referral charges and accrued expenses payable to GDS. The commission and referral charges were capitalized as deferred leasing costs and will be amortized over the terms of the respective customer leases. The Company has not recognized any referral revenue related to the agreement with GDS in 2019 or 2018. See Note 7. "Equity Investments" for additional information related to our GDS investment. The Company has a 10% equity interest in ODATA, a Brazilian headquartered company that specializes in providing colocation services to wholesale customers, such as hyperscale cloud providers, financial services and telecommunications companies, and also to enterprises across multiple industries. In connection with these investments, CyrusOne and ODATA entered a commercial agreement covering leasing activity with CyrusOne customers in the ODATA portfolio. Also as a part of the agreement, the Company's Chief Technology Officer joined the ODATA board of directors in October 2018. See Note 7. "Equity Investments" for additional information related to our ODATA investment.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CyrusOne Inc. elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Code"), commencing with its taxable year ended December 31, 2013. To remain qualified as a REIT, the Company is required to distribute at least 90% of its taxable income to its 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 the Company continues to qualify for taxation as a REIT, the Company is generally not subject to corporate level federal income tax on the earnings distributed currently to its stockholders. It is the Company's policy and intent, subject to change, to distribute 100% of its 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. The REIT and certain of its subsidiaries are subject to state and local income taxes, franchise taxes, and gross receipts taxes. The Company has elected to treat certain of its subsidiaries as taxable REIT subsidiaries ("TRSs"). The Company's TRSs are subject to U.S. federal, state and local corporate income taxes. The Company's foreign subsidiaries are subject to corporate income taxes in the jurisdictions in which they operate.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As of March 31, 2019 , the Company had outstanding letters of credit of $8.0 million as security for obligations under the terms of its lessee agreements. The Company has entered into non-cancellable contracted commitments for construction of data center facilities and acquisition of equipment. As of March 31, 2019 , these commitments were approximately $272.7 million and are expected to be incurred over the next one to two years. In addition, the Company has entered into equipment and utility power contracts, which require minimum purchase commitments for power. These agreements range from one to two years and provide for payments for early termination or require minimum payments for the remaining term. As of March 31, 2019 , the minimum commitments for these arrangements were approximately $51.0 million . During the normal course of business, the Company and its subsidiaries have made certain indemnities and commitments to customers, vendors and associated parties related to the use, protection and security of intellectual property and claims for negligence or willful misconduct. Further, customer contracts generally require specified levels of performance related to uninterrupted service and cooling temperatures. Also in the normal course of our business, the Company is involved in legal, tax and regulatory proceedings arising from the conduct of its business activities. Management assesses the probability that these performance standards, credits, claims or indemnities have been incurred and liabilities or asset reserves are established for loss contingencies when the losses associated are deemed to be probable and the loss can be reasonably estimated. Based on information currently available, the Company believes that the outcome of such matters will not, individually or in the aggregate, have a material effect on its consolidated financial statements.

Guarantors

Guarantors	3 Months Ended
	Mar. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Guarantors	Guarantors The 2024 Notes and 2027 Notes issued by CyrusOne LP (the "LP Co-Issuer") and CyrusOne Finance Corp. (the "Finance Co-Issuer" and, together with the LP Co-Issuer, the "Co-Issuers") are fully and unconditionally and jointly and severally guaranteed on a senior unsecured basis. The guarantors include CyrusOne Inc. (the "Parent Guarantor"), the General Partner and certain domestic wholly-owned subsidiaries of the Operating Partnership (together with the General Partner, the "Guarantor Subsidiaries"; the Guarantor Subsidiaries together with the Parent Guarantor, the "Guarantors"). As of March 31, 2019 and 2018 , non-guarantors are all of the Company's foreign subsidiaries and certain domestic subsidiaries (collectively, the "Non-Guarantors"). The foreign subsidiaries the Company acquired upon its acquisition of Zenium are classified as Non-Guarantors. The indentures governing the 2024 Notes and 2027 Notes contain affirmative and negative covenants customarily found in indebtedness of this type, including covenants that 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. 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, subject to certain qualifications set forth in the indenture. Notwithstanding the foregoing, the covenants contained in the indentures 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 indentures and (ii) the Company believes in good faith that it qualifies 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. Subject to the provisions of the indentures governing the 2024 Notes and 2027 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 indentures, • 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 indentures, • if such Guarantor is no longer a guarantor or other obligor of any other indebtedness of the LP Co-issuer or the Parent Guarantor, • upon the LP Co-issuer designating such Guarantor as an excluded subsidiary under the terms of the indentures, • upon the defeasance or discharge of the 2024 Notes or 2027 Notes, as applicable, in accordance with the terms of the indentures, and • upon the 2024 Notes or 2027 Notes, as applicable, being rated investment grade by at least two rating agencies and no default or event of default shall have occurred and be continuing. The Parent Guarantor is a REIT whose only material asset is its ownership of operating partnership units of the LP Co-Issuer. The LP Co-Issuer and its subsidiaries hold substantially all the assets of the Company. The LP Co-Issuer conducts the operations of the business, along with its subsidiaries. The Finance Co-Issuer does not have any operations or revenues. The Guarantor Subsidiaries include substantially all of the Company's domestic operations and include approximately 85% of its gross operating real estate. The Non-Guarantors include substantially all of the Company's foreign operations, primarily in the United Kingdom, Germany and Singapore. The Non-Guarantors' assets also include the ownership of the Company's equity investment in GDS of $286.7 million and $185.5 million as of March 31, 2019 and December 31, 2018, respectively. The following schedules present the condensed consolidating balance sheets as of March 31, 2019 and December 31, 2018 , and the condensed consolidating statements of operations, comprehensive income (loss) and the statements of cash flows for the three months ended March 31, 2019 and 2018 for the Parent Guarantor, General Partner, each Co-Issuer, Guarantor Subsidiaries, and Non-Guarantors. Eliminations and consolidation adjustments primarily relate to the elimination of investments in subsidiaries and equity earnings (loss) related to investments in subsidiaries (in millions). Condensed Consolidating Balance Sheets As of March 31, 2019 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 3,680.6 $ 659.6 $ 46.1 $ 4,386.3 Cash and cash equivalents — — — — 106.9 19.1 — 126.0 Investment in subsidiaries 2,368.2 18.9 3,352.6 — — — (5,739.7 ) — Rent and other receivables — — 0.3 — 229.5 18.9 — 248.7 Restricted cash — — — — — 1.3 — 1.3 Operating lease right-of-use assets — — — — 45.2 38.6 — 83.8 Intercompany receivable 15.2 — 1,930.6 — 8.8 — (1,954.6 ) — Equity investments — — — — — 299.3 — 299.3 Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 172.3 53.8 — 226.1 Other assets — — 3.2 — 99.0 12.6 — 114.8 Total assets $ 2,383.4 $ 18.9 $ 5,286.7 $ — $ 4,797.4 $ 1,103.2 $ (7,648.2 ) $ 5,941.4 Debt $ — $ — $ 2,898.6 $ — $ — $ — $ — $ 2,898.6 Intercompany payable — — 15.2 — 1,930.6 8.8 (1,954.6 ) — Finance lease liabilities — — — — 5.6 27.8 — 33.4 Operating lease liabilities — — — — 79.8 39.8 — 119.6 Construction costs payable — — — — 122.4 33.1 — 155.5 Accounts payable and accrued expenses — — 4.7 — 73.1 3.8 — 81.6 Dividends payable 51.5 — — — — — — 51.5 Deferred revenue and prepaid rents — — — — 152.1 3.8 — 155.9 Deferred tax liability — — — — — 67.2 — 67.2 Total liabilities 51.5 — 2,918.5 — 2,363.6 184.3 (1,954.6 ) 3,563.3 Total stockholders' equity 2,331.9 18.9 2,368.2 — 2,433.8 918.9 (5,693.6 ) 2,378.1 Total liabilities and equity $ 2,383.4 $ 18.9 $ 5,286.7 $ — $ 4,797.4 $ 1,103.2 $ (7,648.2 ) $ 5,941.4 As of December 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 3,611.2 $ 644.9 $ 36.9 $ 4,293.0 Cash and cash equivalents — — — — 27.2 37.2 — 64.4 Investment in subsidiaries 2,216.9 22.2 3,122.5 — — — (5,361.6 ) — Rent and other receivables — — — — 218.7 16.2 — 234.9 Intercompany receivable 23.2 — 1,761.5 — 6.8 — (1,791.5 ) — Equity investments — — — — — 198.1 — 198.1 Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 178.1 57.6 — 235.7 Other assets — — 0.5 — 94.4 16.4 — 111.3 Total assets $ 2,240.1 $ 22.2 $ 4,884.5 $ — $ 4,591.5 $ 970.4 $ (7,116.2 ) $ 5,592.5 Debt $ — $ — $ 2,624.7 $ — $ — $ — $ — $ 2,624.7 Intercompany payable — — 23.2 — 1,761.5 6.8 (1,791.5 ) — Finance lease liabilities — — — — 104.0 52.7 — 156.7 Construction costs payable — — — — 175.6 19.7 — 195.3 Accounts payable and accrued expenses — — 19.7 — 95.9 5.7 — 121.3 Dividends payable 51.0 — — — — — — 51.0 Deferred revenue and prepaid rents — — — — 144.9 3.7 — 148.6 Deferred tax liability — — — — — 68.9 — 68.9 Total liabilities 51.0 — 2,667.6 — 2,281.9 157.5 (1,791.5 ) 3,366.5 Total stockholders' equity 2,189.1 22.2 2,216.9 — 2,309.6 812.9 (5,324.7 ) 2,226.0 Total liabilities and equity $ 2,240.1 $ 22.2 $ 4,884.5 $ — $ 4,591.5 $ 970.4 $ (7,116.2 ) $ 5,592.5 Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) Three Months Ended March 31, 2019 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 209.2 $ 15.8 $ — $ 225.0 Total operating expenses — — — — 189.3 23.9 — 213.2 Operating income — — — — 19.9 (8.1 ) — 11.8 Interest expense — — (32.5 ) — — (0.4 ) 9.2 (23.7 ) Unrealized gain on marketable equity investment — — — — — 101.2 — 101.2 Other expense — — — — — (0.1 ) — (0.1 ) (Loss) income before income taxes — — (32.5 ) — 19.9 92.6 9.2 89.2 Income tax (expense) benefit — — — — (0.8 ) 1.0 — 0.2 Equity earnings (loss) related to investment in subsidiaries 83.5 0.8 113.3 — — — (197.6 ) — Net income (loss) 83.5 0.8 80.8 — 19.1 93.6 (188.4 ) 89.4 Other comprehensive income — — 2.7 — — 0.6 — 3.3 Comprehensive income (loss) $ 83.5 $ 0.8 $ 83.5 $ — $ 19.1 $ 94.2 $ (188.4 ) $ 92.7 Three Months Ended March 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 194.9 $ 1.7 $ — $ 196.6 Total operating expenses — — — — 167.6 1.3 — 168.9 Operating income — — — — 27.3 0.4 — 27.7 Interest expense — — (23.9 ) — — (0.7 ) 3.8 (20.8 ) Unrealized gain on marketable equity investment — — — — — 40.5 — 40.5 Loss on early extinguishment of debt — — (3.1 ) — — — — (3.1 ) Net (loss) income before income taxes — — (27.0 ) — 27.3 40.2 3.8 44.3 Income tax expense — — — — (0.8 ) — — (0.8 ) Equity earnings (loss) related to investment in subsidiaries 39.8 0.4 66.8 — — — (107.0 ) — Net income (loss) 39.8 0.4 39.8 — 26.5 40.2 (103.2 ) 43.5 Other comprehensive income — — — — — 0.1 — 0.1 Comprehensive income (loss) $ 39.8 $ 0.4 $ 39.8 $ — $ 26.5 $ 40.3 $ (103.2 ) $ 43.6 Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, 2019 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (46.5 ) $ — $ 79.9 $ 1.3 $ 9.2 $ 43.9 Cash flows from investing activities: Investment in real estate — — — — (258.6 ) (34.1 ) (9.2 ) (301.9 ) Investment in subsidiaries (105.0 ) (0.8 ) (106.0 ) — — — 211.8 — Return of investment 50.4 — — — — — (50.4 ) — Intercompany borrowings 8.7 — (169.1 ) — (2.0 ) — 162.4 — Net cash (used in) provided by investing activities (45.9 ) (0.8 ) (275.1 ) — (260.6 ) (34.1 ) 314.6 (301.9 ) Cash flows from financing activities: Issuance of common stock, net 105.0 — — — — — — 105.0 Dividends paid (50.4 ) — (50.4 ) — — — 50.4 (50.4 ) Intercompany borrowings — — (8.7 ) — 169.1 2.0 (162.4 ) — Proceeds from revolving credit facility — — 275.7 — — — — 275.7 Payments on finance lease liabilities — — — — (0.3 ) (0.3 ) — (0.6 ) Tax payment upon exercise of equity awards (8.7 ) — — — — — — (8.7 ) Contributions/distributions from parent — 0.8 105.0 — 91.6 14.4 (211.8 ) — Net cash provided by (used in) financing activities 45.9 0.8 321.6 — 260.4 16.1 (323.8 ) 321.0 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — — — — (0.1 ) — (0.1 ) Net (decrease) increase in cash, cash equivalents and restricted cash — — — — 79.7 (16.8 ) — 62.9 Cash, cash equivalents and restricted cash at beginning of period — — — — 27.2 37.2 — 64.4 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 106.9 $ 20.4 $ — $ 127.3 Three Months Ended March 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (37.3 ) $ — $ 77.4 $ 0.3 $ 3.8 $ 44.2 Cash flows from investing activities: Investment in real estate — — — — (141.4 ) — (3.8 ) (145.2 ) Investment in subsidiaries (142.9 ) (1.4 ) (143.4 ) — — — 287.7 — Return of investment 41.0 — — — — — (41.0 ) — Intercompany borrowings 4.4 — 0.3 — — — (4.7 ) — Net cash (used in) provided by investing activities (97.5 ) (1.4 ) (143.1 ) — (141.4 ) — 238.2 (145.2 ) Cash flows from financing activities: Issuance of common stock, net 142.9 — — — — — — 142.9 Dividends paid (41.0 ) — (41.0 ) — — — 41.0 (41.0 ) Intercompany borrowings — — (4.4 ) — (0.3 ) — 4.7 — Proceeds from unsecured term loan — — 985.6 — — — — 985.6 Repayments of unsecured term loan — — (902.7 ) — — — — (902.7 ) Payments on finance lease liabilities — — — — (2.2 ) (0.4 ) — (2.6 ) Tax payment upon exercise of equity awards (4.4 ) — — — — — — (4.4 ) Contributions/distributions from parent — 1.4 142.9 — 142.9 0.5 (287.7 ) — Net cash provided by (used in) financing activities 97.5 1.4 180.4 — 140.4 0.1 (242.0 ) 177.8 Net increase (decrease) in cash, cash equivalents and restricted cash — — — — 76.4 0.4 — 76.8 Cash, cash equivalents and restricted cash at beginning of period — — — — 151.2 0.7 — 151.9 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 227.6 $ 1.1 $ — $ 228.7

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events During the first two days of April 2019, the Company settled approximately 2.9 million shares of its common stock at an average price of $52.24 . The Company received net proceeds of approximately $148.1 million after giving effect to sales agent commissions of $1.2 million resulting in approximately $495.4 million available for future offerings under the New 2018 ATM Stock Offering Program. On April 12, 2019, CyrusOne sold approximately 5.7 million ADSs, each representing eight Class A ordinary shares, par value $0.00005 per share, of GDS through a block trade made in reliance on Rule 144 of the Securities Act of 1933, as amended, for a total sales price of approximately $200.0 million . CyrusOne continues to hold approximately 2.3 million ADSs, valued at approximately $90.0 million based on the GDS closing price on April 11, 2019 with the remaining ADSs being subject to a lock-up period expiring October 12, 2019, subject to customary carve outs. The commercial agreement between CyrusOne and GDS remains in place, and Gary Wojtaszek, CyrusOne’s President and Chief Executive Officer, remains a member of the GDS Board of Directors. The transaction settled on April 16, 2019. The proceeds were used to pay down $200.0 million of the 2023 Term Loan.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements include the accounts of the Company, as well as all wholly-owned subsidiaries and any consolidated variable interest entities. All intercompany balances and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications Certain financial information has been revised to conform to the current year presentation due to changes in the significance of the particular activity. The following items have been reclassified: Balance Sheet as of December 31, 2018 • Straight-line rent receivable of $128.7 million included in Rent and other receivables was previously included in Other assets. Statement of Cash Flows for the period ended March 31, 2018 • The cash flow effect of the change in proceeds from our unsecured term loan of $985.6 million included in Proceeds from unsecured term loan was previously included in Debt. • The cash flow effect of the change in repayments of our unsecured term loan of $902.7 million included in Repayments of unsecured term loan was previously included in Debt.
Investment in Real Estate	Investment in Real Estate Acquisition of Properties Investment in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. We expect most acquisitions to be an acquisition of assets rather than a business combination as our typical acquisitions consist of properties whereby substantially all the fair value of gross assets acquired is concentrated in a single asset set (land, building and in-place leases), which are treated as asset acquisitions. See Business Combinations and Asset Acquisitions herein.
Business Combinations and Asset Acquisitions	Business Combinations and Asset Acquisitions We evaluate whether an acquisition is a business combination or an asset acquisition by determining whether the set of assets is a business. Asset Acquisitions When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. Asset acquisitions are recorded at the cumulative acquisition costs and allocated to the assets acquired and liabilities assumed on a relative fair value basis. The Company allocates the purchase price of real estate to identifiable tangible assets such as land, building, land improvements and tenant improvements acquired based on their fair value. In estimating the fair value of each component, management considers appraisals, replacement cost, its own analysis of recently acquired and existing comparable properties, market rental data and other related information. Transaction costs associated with asset acquisitions are capitalized. Business Combinations When substantially all of the fair value is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business and 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. The following discussion applies to our initial determination of fair value and the resulting subsequent accounting which is generally applicable to both asset acquisitions and business combinations. The fair value of any tangible real estate assets acquired is determined by valuing the building as if it were vacant, and the fair value is then allocated to land, buildings, equipment and improvements based on available information including replacement cost, appraisal or using net operating income capitalization rates, discounted cash flow analysis or similar fair value models. We determine in-place lease values based on our evaluation of the specific characteristics of each tenant’s lease agreement and by applying a fair value model. The estimates of fair value of in-place leases include an estimate of carrying costs during the expected lease up periods considering current market conditions. In estimating fair value of in-place leases, we consider items such as real estate taxes, insurance, leasing commissions, tenant improvements and other operating expenses to execute similar leases as well as projected rental revenue and carrying costs during the expected lease up period. We amortize the value of in-place leases acquired to expense over the approximate weighted average remaining term of the leases, adjusted for projected tenant turnover, on a composite basis. We determine the value of above-market and below-market in-place leases for acquired properties based on the present value (using an interest rate that reflects the risks associated with the leases acquired) of the difference between (1) the contractual amounts to be paid pursuant to the in-place leases and (2) estimates of current market lease rates for the corresponding in-place leases, measured over a period equal to (i) the remaining non-cancellable lease term for above-market leases, or (ii) the remaining non-cancellable lease term plus any renewal options that we consider are reasonably certain that a lessee will execute such renewal option when a lease commences. We record the fair value of above-market and below-market leases as intangible assets or liabilities, and amortize them as an adjustment to revenue over the lease term. We determine the fair value of assumed debt by calculating the net present value of the scheduled debt service payments using current market-based terms for interest rates for debt with similar terms that management believes we could obtain on similar structures and maturities. Any difference between the fair value and stated value of the assumed debt is recorded as a discount or premium and amortized over the remaining life of the loan. In a business combination or an acquisition, we retain the previous lease classification unless there is a lease modification and that modification is not accounted for as a separate new lease. We elected to apply the short-term lease measurement and recognition exemption available under the new accounting standard for leases (discussed below in Note 3. "Recently Adopted Accounting Standards") to leases that have a remaining lease term of 12 months or less at the acquisition date and would not recognize an intangible asset if the terms of an operating lease are favorable relative to market terms or a liability if the terms are unfavorable relative to market terms. Leasehold improvements are amortized over the shorter of the useful life of the assets and the remaining lease term at the date of acquisition.
Capitalization of Costs	Capitalization of Costs We capitalize costs directly related to the development, pre-development or improvement of our investment in real estate, referred to as capital projects and other activities included within this paragraph. Costs associated with our capital projects are capitalized as incurred. If the project is abandoned, these costs are expensed during the period in which the project is abandoned. Costs considered for capitalization include, but are not limited to, construction costs, interest, real estate taxes, insurance and utilities, if appropriate. We capitalize indirect costs such as personnel, office and administrative expenses that are directly related to our development projects based on an estimate of the time spent on the construction and development activities. These costs are capitalized only during the period in which activities necessary to ready an asset for its intended use are in progress and such costs are incremental and identifiable to a specific activity to get the asset ready for its intended use. We determine when the capitalization period begins and ends through communication with project and other managers responsible for the tracking and oversight of individual projects. In the event that the activities to ready the asset for its intended use are suspended, the capitalization period will cease until such activities are resumed. In addition, we capitalize incremental initial direct costs incurred for successful origination of new leases which include internal and external leasing commissions. Interest expense is capitalized based on actual qualifying capital expenditures from the period when development commences until the asset is ready for its intended use, at the weighted average borrowing rate during the period. These costs are included in investment in real estate and depreciated over the estimated useful life of the related assets. Costs incurred for maintaining and repairing our properties, which do not extend their useful lives, are expensed as incurred.
Impairment Losses	Impairment Losses When events or circumstances indicate that the carrying amount of a real estate investment may not be recoverable, we review the carrying value of the asset. When such impairment indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of the real estate investment and proceeds from its eventual disposition and compare such amount to the carrying amount of the real estate investment. If our undiscounted cash flows indicate that we are unable to recover the carrying value of the real estate investment, an impairment loss is recognized. An impairment loss is measured as the amount by which the real estate investment's carrying value exceeds its estimated fair value.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash 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 of three months or less. Restricted cash includes cash equivalents held in our name to collateralize standby letters of credit or its use is restricted by contract or regulation.
Equity Investment	Equity Investments We hold investments in various joint ventures where the Company evaluates its ability to influence the operating or financial decisions of the investee in applying the appropriate method of accounting for such investments. Influence tends to be more effective as the investor's percent of ownership in the voting rights of the investee increases. Our equity investments represent less than 20% of the voting rights of the investees and we do not exercise influence over the investee's operating and financial decisions. Accordingly, we do not account for our equity investments using the equity method accounting. For further information about our equity investments, see Note 7. "Equity Investments". Our investment in GDS Holdings Limited ("GDS") is classified as "available for sale" and is carried at fair value.
Revenue Recognition	Revenue Recognition Our revenue consists of lease revenue and revenue from contracts with customers. The Company adopted Accounting Standards Codification (“ASC”) 842, Leases (“ASC 842”), the new accounting standard for leases, effective January 1, 2019 using the modified retrospective approach and prior periods were not restated. In addition, the Company adopted Revenue from Contracts with Customers (“ASC 606”), the new accounting standard for revenue from contracts with customers, effective January 1, 2018 using the modified retrospective approach. See Note 3. “Recently Adopted Accounting Standards” and Note 4. “Revenue Recognition”. Lease Revenue: Our leasing revenue primarily consists of colocation rent, metered power reimbursements and interconnection revenue and is accounted for under ASC 842, Leases. We generally are not entitled to reimbursements for rental expenses including real estate taxes, insurance or other common area operating expenses. a. Colocation Rent Revenue Colocation rent revenues, including interconnection revenue, are fixed minimum lease payments generally billed monthly in advance based on the contracted power or leased space. Some contracts may provide initial free rent periods and rents that escalate over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased power or space at the beginning of the lease term, the rental payments 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 power and or leased space, revenue is recognized in proportion to the additional power or space in the periods that the lessee has control over the use of the additional power or space. The excess of revenue recognized over amounts contractually due is recognized as a straight-line receivable, which is included in rent and other receivables in our consolidated balance sheet. Some of our leases are structured on a gross basis in which the customer pays a fixed amount for colocation rent and power. The revenue for these types of leases is recorded in colocation lease revenue. b. Metered Power Reimbursements Revenue Some of our leases provide that the customer is separately billed for power based upon actual or estimated metered usage at rates then in effect. Metered power reimbursement revenue is variable lease payments generally billed one month in arrears, and an estimate of this revenue is accrued in the month that the associated power is provided and recorded in metered power reimbursements. Revenue from Contracts with Customers Managed services, equipment sales, installations and other services are recognized under ASC 606. Equipment sold by us generally consists of servers, switches, networking equipment, cable infrastructure and cabinets. Revenue is recognized at a point-in-time when control of the equipment transfers to the customer from the Company, which generally occurs upon delivery to the customer. Managed services include providing of a full-service managed data center, monitoring customer computer equipment, managing backups and storage, utilization reporting and other related ancillary information technology services. Management service contracts generally range from one to five years. Other services generally include installation of customer equipment, performing customer system re-boots, server cabinet and cage management, power monitoring, shipping and receiving, resolving technical issues, and other services requested by the customer. Installation services include mounting, wiring, and testing of customer owned equipment. The installation period is typically short term in duration, and accordingly, revenue from the installation of customer equipment is recognized at a point-in-time once the installation is complete and the performance obligation is satisfied. Other service revenue is measured based on the consideration specified in the contract and recognized over time as we satisfy the performance obligation.
Rent and Other Receivables	Rent and Other Receivables Receivables consist principally of trade receivables from customers and straight-line rent receivables with estimated credit losses recorded as an allowance for doubtful accounts.
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average exchange rates during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive income (loss). Gains or losses from foreign currency transactions are included in determining net income.
Stock-Based Compensation Expense	Stock-Based Compensation We have a stock-based incentive award plan for our employees and directors. Stock-based compensation expense associated with these awards is recognized in general and administrative expenses, property operating expenses, and sales and marketing expenses in our consolidated statements of operations. We measure stock-based compensation at the estimated fair value on the grant date and recognize the amortization of stock-based compensation expense over the requisite service period. Fair value is determined based on assumptions related to volatility, interest rates and the market, and our company performance.
Fair Value Measurements	Fair Value Measurements Fair value measurements are utilized in accounting for business combinations, asset acquisitions, testing of goodwill and other long-lived assets for impairment, recording unrealized gain/loss on available-for-sale securities and related disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy that prioritizes certain inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows: Level 1—Observable inputs for identical instruments such as quoted market prices; Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data.
Derivative Instruments	Derivative Instruments Derivative instruments are measured at fair value and recorded as assets or liabilities, depending on our rights or obligations under the applicable derivative contract. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. For a derivative designated and that qualified as a cash flow hedge, the effective portion of the change in fair value of the derivative is recognized in the condensed consolidated statement of comprehensive income (loss) until the hedged item is recognized in earnings. Any ineffective portion of a derivative's change in fair value is immediately recognized in earnings. For interest rate derivatives amounts recognized in earnings are reflected in interest expense. For a derivative designated and that qualified as a net investment hedge, the effective portion of the change in the fair value and/or the net settlement of the derivative are reported in the condensed consolidated statement of comprehensive income (loss) as part of the cumulative foreign currency translation adjustment. Any ineffective portion of the change in fair value of the derivative is recognized directly in earnings. Amounts are reclassified out of other comprehensive income (loss) into earnings when the hedged investment is either sold or substantially liquidated.
Recently Adopted Accounting Pronouncements and New Accounting Pronouncements	Leases We adopted ASU 2016-02 (codified in ASC 842, Leases ) on January 1, 2019, applied the package of practical expedients included therein and utilized the modified retrospective transition method with the cumulative effect of transition on the effective date. By applying the modified retrospective transition method, the presentation of financial information for periods prior to January 1, 2019 were not restated. We elected the package of practical expedients, which permits us to not reassess (1) whether any expired or existing contracts are or contain leases, (2) the lease classification for any expired or existing leases, and (3) any initial direct costs for any existing leases as of the effective date. We did not elect the hindsight practical expedient, which permits entities to use hindsight in determining the lease term and assessing impairment. As a Lessee The ASU requires that a liability be recorded on the balance sheet for all leases where the reporting entity is a lessee, based on the present value of future lease obligations. A corresponding right-of-use ("ROU") asset will also be recorded. Amortization of the lease obligation and the ROU asset for leases classified as operating leases are on a straight-line basis. Leases classified as financing leases are required to be accounted for as financing arrangements similar to the accounting treatment for capital leases under ASC 840, Leases (the former accounting standard for all leases, ("ASC 840")). We elected the practical expedient to combine our lease and related non-lease components by asset class for our leases. We elected a practical expedient to not evaluate land easements not previously accounted for as leases prior to the entity’s adoption of the new accounting standard for leases. We elected to apply the short-term lease measurement and recognition exemption available for leases under the new accounting standard for leases that have a remaining lease term of 12 months or less. The adoption of ASC 842 had a significant impact on our consolidated balance sheet due to the recognition of approximately $87.0 million of ROU assets and $123.2 million of lease liabilities for operating leases. We recognized a $9.5 million cumulative effect adjustment to retained earnings. The adjustment to retained earnings was driven principally by measurement of operating lease liabilities at the present value of the remaining lease payments at the adoption date of January 1, 2019. The increase was offset in part by impairment of ROU assets associated with one build-to-suit ("BTS") arrangement recognized as an operating lease under the new accounting standard for leases. Additionally, we de-recognized certain previously recognized BTS lease assets and liabilities which under the new accounting standard for leases are recognized as operating lease ROU assets and lease liabilities. Prior to the adoption of the new accounting standard for leases, these leases were accounted as financing arrangements or BTS leases assets and liabilities and recorded as buildings and improvement and lease financing arrangements. The table below reflects the impact of adoption of the lease standard on our consolidated balance sheet for the period ended March 31, 2019 (in millions) related to previously reported BTS leases: Impact to the consolidated balance sheets: For the period ended December 31, 2018 For the period ended March 31, 2019 Buildings and improvements $ 77.4 $ — Operating lease right-of-use assets — 50.0 Finance lease liabilities 123.3 — Operating lease liabilities — 85.5 Prior to the adoption of the new accounting standard for leases, BTS lease assets were amortized over the useful life of the asset and recorded as amortization expense and accretion of BTS lease liability was recorded as an interest expense in consolidated statement of operations. Upon adoption of the new accounting standard for leases, BTS leases are accounted as operating leases and amortization and accretion of lease liabilities of these operating leases are recorded as lease expenses in property operating expenses in our consolidated statement of operations. As a Lessor The accounting for lessors remained largely unchanged from ASC 840. However, the new accounting standard for leases requires that lessors expense certain costs to obtain a lease that are not incremental to origination of a lease. Upon adoption, initial direct cost that are not incremental are expensed as general and administrative expense in our consolidated statements of operations. Prior to the adoption of new standard, these costs were capitalizable. As a result of electing the package of practical expedients, initial direct costs have not been reassessed prior to the effective date and therefore adoption of the lease standard did not have an impact on our previously reported consolidated statements of operations with respect to initial direct costs. In addition, under the new accounting standard for leases certain exceptions under the previous standard for real estate no longer are applicable in the evaluation of the lease classification as an operating, sales type or direct financing lease. In the event that a real estate lease is classified as sales-type lease, subject to certain conditions, a gain or loss is recognized based on the present value of the lease payments and residual value. We elected the practical expedient to combine all of our lease and nonlease revenue components into a single combined lease component as nonlease components have the same pattern of transfer as the related predominant operating lease component. Our customer leases include options to extend or terminate the lease agreements. We do not generally include extension or termination options in a customer’s lease term for lease classification purposes or for recognizing lease revenue unless we are reasonably certain the customer will exercise these extension or termination options at lease commencement. Revenue from contracts with customers On January 1, 2018, we adopted the FASB pronouncement ASU 2014-09 with respect to revenue recognition. The revised guidance outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and superseded prior revenue recognition guidance, including industry-specific revenue guidance. The revised guidance replaced most existing revenue and real estate sale recognition guidance in GAAP. The standard specifically excludes lease contracts, which is our primary recurring revenue source; however, our revenue accounting for managed services and sales of real estate and equipment will follow the revised guidance. We adopted the new standard using the modified retrospective transition method, where financial statement presentations prior to the date of adoption are not adjusted. Transactions that were not closed as of the adoption date were adjusted to reflect the new standard and we recorded an adjustment to beginning retained earnings of $0.3 million . As allowed under GAAP, we have adopted the practical expedient that allows us not to disclose information about remaining performance obligations that have original expected durations of one year or less, the amount of the transaction price allocated to the remaining performance obligations and when we expect to recognize that amount as revenue for the year. We have also adopted the "as invoiced" practical expedient, whereby the Company recognizes revenue in the amount that directly corresponds to the amount of value transferred to the customer. Share based payments granted to nonemployees We adopted ASU 2018-07, Compensation-Stock Compensation (Topic 718) which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under this ASU, the guidance on such payments to nonemployees aligns with the requirements for share-based payments granted to employees. The adoption did not have a significant impact as the Company accounts for its share-based payments. Equity investments On January 1, 2018, we adopted ASU 2016-01 related to equity investments. Equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) are measured at fair value with changes in fair value recognized in net income. Prior to adoption of this update, changes in fair value for available for sale equity investments were recorded in other comprehensive income (loss). The adoption of the new standard was made through a cumulative-effect adjustment to beginning retained earnings of $75.6 million . New Accounting Pronouncements In August 2018, the SEC issued Securities Act Release No. 33-10532, Disclosure Update and Simplification, which amends certain of its disclosure requirements and is intended to facilitate the disclosure of information to investors and simplify compliance without significantly altering the total mix of information provided to investors. The amendments became effective on November 5, 2018. Among the amendments is the requirement to present the changes in shareholders' equity in the interim financial statements (either in a separate statement or footnote) in quarterly reports on Form 10-Q. In accordance with the SEC's rule, the company's first presentation of changes in shareholders’ equity is shown in this Form 10-Q for the quarter ended March 31, 2019. In August 2018, the FASB issued ASU 2018-15, which clarifies the accounting for implementation costs incurred in a hosting arrangement that is a service contract. Capitalization of these implementation costs are accounted for under the same guidance as implementation costs incurred to develop or obtain internal-use software and recorded as a prepaid asset. These capitalized costs are to be expensed ratably over the hosting arrangement term as operating expense, along with the service fees. The guidance is effective for periods beginning after December 15, 2019. Early adoption is allowed. The Company is evaluating the impact of the new standard but does not believe that adoption will have a significant impact on the Company. In August 2018, the FASB issued ASU 2018-13, which changes the fair value measurement disclosure requirements of ASC 820, Fair Value Measurement . The amendments are part of the FASB’s disclosure framework project to improve the effectiveness of disclosures in the notes to the financial statements by facilitating clear communication of the information required by GAAP that is most important to financial statement users and are intended to improve the effectiveness of disclosure requirements on fair value measurement by using those concepts. The guidance is effective for periods beginning after December 15, 2019. Early adoption is allowed. The Company is evaluating the impact of the new standard. In June 2016, the FASB issued ASU 2016-13 providing guidance which requires certain financial assets to be presented at the net amount expected to be collected. The guidance will apply to our trade receivables, notes receivable, net investments in leases and any other future financial assets that have the contractual right to receive cash that we may acquire in the future. The guidance is effective for periods beginning for us January 1, 2020. Early adoption is allowed. We are currently evaluating the impact of the new standard.

Recently Issued Accounting St_2

Recently Issued Accounting Standards (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The table below reflects the impact of adoption of the lease standard on our consolidated balance sheet for the period ended March 31, 2019 (in millions) related to previously reported BTS leases: Impact to the consolidated balance sheets: For the period ended December 31, 2018 For the period ended March 31, 2019 Buildings and improvements $ 77.4 $ — Operating lease right-of-use assets — 50.0 Finance lease liabilities 123.3 — Operating lease liabilities — 85.5

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Lessor, Operating Lease, Payments to be Received, Maturity	The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: For the Period Ended March 31, 2019 Minimum Lease Payments 2019 $ 520.1 2020 631.9 2021 542.8 2022 454.3 2023 365.2 2024 295.9 Thereafter 940.0 Total $ 3,750.2
Schedule Of Future Minimum Lease Payments To Be Received Under Operating Leases	The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: For the Period Ended December 31, 2018 Minimum Lease Payments 2019 $ 647.6 2020 553.7 2021 453.0 2022 365.5 2023 284.4 Thereafter 835.9
Disaggregation of Revenue	For the three months ended March 31, 2019 and 2018, revenue disaggregated by primary revenue stream is as follows (in millions). Lease Revenue For the period ended March 31, 2019 Colocation (Minimum lease payments) $ 188.4 Meter power reimbursements (Variable lease payments) 28.5 Total Lease revenue $ 216.9 Three Months Ended March 31, Revenue from contracts with customers 2019 2018 Equipment sales $ 3.9 $ 5.8 Other revenue 4.2 4.0 Total Revenue from contracts with customers $ 8.1 $ 9.8

Leases - As a Lessee (Tables)

Leases - As a Lessee (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Lease, Cost	The components of lease expense were as follows (in millions): Three months ended March 31, 2019 Operating lease cost $ 5.0 Finance lease cost: Amortization of assets 0.6 Interest on lease liabilities 0.5 Total net lease cost $ 6.1 Supplemental cash flow and other information related to leases was as follows (in millions): Three months ended March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 5.1 Operating cash flows from finance leases 0.5 Financing cash flows from finance leases 0.6 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 87.0
Assets And Liabilities, Lessee	Supplemental balance sheet information related to leases was as follows (in millions, except lease term and discount rate): March 31, 2019 Operating leases: Operating lease right-of-use assets $ 83.8 Operating lease liabilities $ 119.6 Finance leases: Property and equipment, at cost $ 34.0 Accumulated amortization (3.4 ) Property and equipment, net $ 30.6 Finance lease liabilities $ 33.4 Weighted average remaining lease term (in years): Operating leases 12.5 Finance leases 17.2 Weighted average discount rate: Operating leases 4.5 % Finance leases 5.3 %
Lessee, Operating Lease, Liability, Maturity	Maturities of lease liabilities were as follows (in millions): March 31, 2019 Operating Leases Finance Leases 2019 $ 15.3 $ 3.3 2020 19.5 4.3 2021 15.3 4.2 2022 15.6 3.1 2023 13.4 2.0 2024 7.7 1.5 Thereafter 71.0 30.7 Total lease payments $ 157.8 $ 49.1 Less: Imputed interest (38.2 ) (15.7 ) Total lease obligations $ 119.6 $ 33.4
Schedule of Future Minimum Rental Payments for Operating Leases	The following table summarizes aggregate minimum principal payments of the finance lease obligations and future minimum lease payments required under operating leases for the five years subsequent to December 31, 2018, and thereafter (in millions): December 31, 2018 Operating Leases Finance Leases 2019 $ 5.0 $ 2.7 2020 4.9 2.8 2021 3.7 2.9 2022 3.7 2.0 2023 3.5 1.0 Thereafter 43.4 22.0 Total lease payments $ 64.2 $ 33.4
Schedule of Future Minimum Lease Payments for Capital Leases	The following table summarizes aggregate minimum principal payments of the finance lease obligations and future minimum lease payments required under operating leases for the five years subsequent to December 31, 2018, and thereafter (in millions): December 31, 2018 Operating Leases Finance Leases 2019 $ 5.0 $ 2.7 2020 4.9 2.8 2021 3.7 2.9 2022 3.7 2.0 2023 3.5 1.0 Thereafter 43.4 22.0 Total lease payments $ 64.2 $ 33.4
Finance Lease, Liability, Maturity	Maturities of lease liabilities were as follows (in millions): March 31, 2019 Operating Leases Finance Leases 2019 $ 15.3 $ 3.3 2020 19.5 4.3 2021 15.3 4.2 2022 15.6 3.1 2023 13.4 2.0 2024 7.7 1.5 Thereafter 71.0 30.7 Total lease payments $ 157.8 $ 49.1 Less: Imputed interest (38.2 ) (15.7 ) Total lease obligations $ 119.6 $ 33.4

Investment in Real Estate (Tabl

Investment in Real Estate (Tables)	3 Months Ended
	Mar. 31, 2019
Real Estate [Abstract]
Schedule of Major Components of Real Estate Investments and Intangibles	As of March 31, 2019 and December 31, 2018 , major components of our real estate investments and intangibles and related accumulated depreciation and amortization are as follows (in millions): March 31, 2019 December 31, 2018 Investment in Real Estate Intangibles Investment in Real Estate Intangibles Buildings and Improvements Equipment Customer Relationships In Place Leases Other Contractual Buildings and Improvements Equipment Customer Relationships In Place Leases Other Contractual Cost $ 1,649.2 $ 2,799.6 $ 247.1 $ 136.6 $ 19.4 $ 1,677.5 $ 2,630.2 $ 247.1 $ 136.0 $ 19.5 Less: accumulated depreciation and amortization (483.8 ) (638.7 ) (141.2 ) (27.5 ) (8.3 ) (481.8 ) (572.7 ) (137.9 ) (21.1 ) (7.9 ) Net $ 1,165.4 $ 2,160.9 $ 105.9 $ 109.1 $ 11.1 $ 1,195.7 $ 2,057.5 $ 109.2 $ 114.9 $ 11.6
Schedule Of Useful Lives	Depreciation and amortization are calculated using the straight-line method over the useful lives of the assets. The typical life of owned assets are as follows: Buildings 30 years Building improvements 30 years Equipment 20 years

Other Assets (Tables)

Other Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Assets	As of March 31, 2019 and December 31, 2018 , the components of other assets are as follows (in millions): March 31, 2019 December 31, 2018 Deferred leasing and other contract costs $ 45.6 $ 43.6 Prepaid expenses 28.1 26.4 Non-real estate assets, net 18.4 18.4 Other assets 22.7 22.9 Total $ 114.8 $ 111.3

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	As of March 31, 2019 and December 31, 2018 , the components of debt are as follows (unless otherwise noted, interest rate and maturity date information are as of March 31, 2019 ) (in millions): March 31, 2019 December 31, 2018 Interest Rate (a) Maturity Date $3.0 Billion Credit Facility: $1.7 Billion Revolving Credit Facility: March 2022 (b) US Revolver $ 270.0 $ — Monthly LIBOR + 1.45% EUR Revolver 145.8 143.0 Monthly EURIBOR + 1.45% 2023 Term Loan 1,000.0 1,000.0 Monthly LIBOR + 1.40% March 2023 2025 Term Loan 300.0 300.0 Monthly LIBOR + 1.70% March 2025 2024 Notes, including bond premium of $5.2 million 705.2 705.5 5.000 % March 2024 2027 Notes, including bond premium of $8.8 million 508.8 509.1 5.375 % March 2027 Deferred financing costs (31.2 ) (32.9 ) — — Total $ 2,898.6 $ 2,624.7 (a) - Monthly LIBOR at March 31, 2019 was 2.50% . (b) - The Company may exercise a one -year extension option, subject to certain conditions.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
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): March 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value 2024 Notes $ 705.2 $ 720.1 $ 705.5 $ 684.1 2027 Notes 508.8 515.0 509.1 488.0 GDS Equity investment 286.7 286.7 185.5 185.5
Schedule of Derivative Instruments	The following table presents the effect of our derivative financial instruments on our accompanying consolidated financial statements (in millions): For the Three Months Ended March 31, 2019 2018 Derivatives in Cash Flow Hedging Relationships Cross-Currency Swaps: Amount of gain (loss) recognized in OCI for derivatives $ 2.7 $ — Amount of gain (loss) reclassified from accumulated OCI for derivatives $ — $ — Amount of gain (loss) recognized in earnings $ — $ —

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Restricted Stock and Restricted Stock Units Activity	The following tables present the stock plan activity for the three months ended March 31, 2019 and 2018 for restricted stock units, restricted stock and stock options (performance-based awards are reflected at the target amount of the grant): Restricted Stock Units ("RSU") 2019 2018 Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Outstanding January 1, 511,049 $ 56.23 265,002 $ 56.08 Granted 360,362 47.97 322,063 51.92 Exercised (123,159 ) 44.87 (80,965 ) 43.47 Forfeited (2,691 ) 49.69 (3,131 ) 51.20 Outstanding March 31, 745,561 $ 54.14 502,969 $ 55.47 Time-based RSUs outstanding 359,400 $ 53.12 256,609 $ 50.71 Performance-based RSUs outstanding 386,161 $ 55.08 246,360 $ 60.41 Restricted Stock ("RS") 2019 2018 Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Outstanding January 1, 419,356 $ 35.73 715,098 $ 32.21 Granted 16,681 52.46 17,052 51.31 Exercised (364,822 ) 35.23 (209,415 ) 27.02 Forfeited (34,603 ) 37.09 (44,034 ) 28.45 Outstanding March 31, 36,612 $ 47.02 478,701 $ 35.50 Time-based RSs outstanding 36,612 $ 47.02 362,084 $ 38.08 Performance-based RSs outstanding — $ — 116,617 $ 28.57
Schedule of Stock Option Activity	Stock Options 2019 2018 Options Weighted Average Exercise Price Options Weighted Average Exercise Price Outstanding January 1, 401,223 $ 31.96 415,459 $ 31.67 Granted — — — — Exercised (25,586 ) 36.70 — — Forfeited — — — — Outstanding March 31, 375,637 $ 31.63 415,459 $ 31.67 Time-based stock options outstanding 323,101 $ 32.94 348,137 $ 33.23 Performance-based stock options outstanding 52,536 $ 23.58 67,322 $ 23.58

Income (Loss) per Share (Tables

Income (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2019
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 per share for the three months ended March 31, 2019 and 2018 : IN MILLIONS, except per share amounts Three months ended March 31, 2019 2018 Basic Diluted Basic Diluted Numerator: Net income $ 89.4 $ 89.4 $ 43.5 $ 43.5 Less: Restricted stock dividends (0.2 ) (0.2 ) (0.3 ) (0.3 ) Net income available to stockholders $ 89.2 $ 89.2 $ 43.2 $ 43.2 Denominator: Weighted average shares outstanding-basic 108.3 108.3 96.0 96.0 Performance-based restricted stock and units 0.5 0.6 Weighted average shares outstanding-diluted 108.8 96.6 EPS: Net income per share-basic $ 0.82 $ 0.45 Effect of dilutive shares: Net income per share-diluted $ 0.82 $ 0.45

Guarantors (Tables)

Guarantors (Tables)	3 Months Ended
	Mar. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Consolidating Balance Sheets	Condensed Consolidating Balance Sheets As of March 31, 2019 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 3,680.6 $ 659.6 $ 46.1 $ 4,386.3 Cash and cash equivalents — — — — 106.9 19.1 — 126.0 Investment in subsidiaries 2,368.2 18.9 3,352.6 — — — (5,739.7 ) — Rent and other receivables — — 0.3 — 229.5 18.9 — 248.7 Restricted cash — — — — — 1.3 — 1.3 Operating lease right-of-use assets — — — — 45.2 38.6 — 83.8 Intercompany receivable 15.2 — 1,930.6 — 8.8 — (1,954.6 ) — Equity investments — — — — — 299.3 — 299.3 Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 172.3 53.8 — 226.1 Other assets — — 3.2 — 99.0 12.6 — 114.8 Total assets $ 2,383.4 $ 18.9 $ 5,286.7 $ — $ 4,797.4 $ 1,103.2 $ (7,648.2 ) $ 5,941.4 Debt $ — $ — $ 2,898.6 $ — $ — $ — $ — $ 2,898.6 Intercompany payable — — 15.2 — 1,930.6 8.8 (1,954.6 ) — Finance lease liabilities — — — — 5.6 27.8 — 33.4 Operating lease liabilities — — — — 79.8 39.8 — 119.6 Construction costs payable — — — — 122.4 33.1 — 155.5 Accounts payable and accrued expenses — — 4.7 — 73.1 3.8 — 81.6 Dividends payable 51.5 — — — — — — 51.5 Deferred revenue and prepaid rents — — — — 152.1 3.8 — 155.9 Deferred tax liability — — — — — 67.2 — 67.2 Total liabilities 51.5 — 2,918.5 — 2,363.6 184.3 (1,954.6 ) 3,563.3 Total stockholders' equity 2,331.9 18.9 2,368.2 — 2,433.8 918.9 (5,693.6 ) 2,378.1 Total liabilities and equity $ 2,383.4 $ 18.9 $ 5,286.7 $ — $ 4,797.4 $ 1,103.2 $ (7,648.2 ) $ 5,941.4 As of December 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 3,611.2 $ 644.9 $ 36.9 $ 4,293.0 Cash and cash equivalents — — — — 27.2 37.2 — 64.4 Investment in subsidiaries 2,216.9 22.2 3,122.5 — — — (5,361.6 ) — Rent and other receivables — — — — 218.7 16.2 — 234.9 Intercompany receivable 23.2 — 1,761.5 — 6.8 — (1,791.5 ) — Equity investments — — — — — 198.1 — 198.1 Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 178.1 57.6 — 235.7 Other assets — — 0.5 — 94.4 16.4 — 111.3 Total assets $ 2,240.1 $ 22.2 $ 4,884.5 $ — $ 4,591.5 $ 970.4 $ (7,116.2 ) $ 5,592.5 Debt $ — $ — $ 2,624.7 $ — $ — $ — $ — $ 2,624.7 Intercompany payable — — 23.2 — 1,761.5 6.8 (1,791.5 ) — Finance lease liabilities — — — — 104.0 52.7 — 156.7 Construction costs payable — — — — 175.6 19.7 — 195.3 Accounts payable and accrued expenses — — 19.7 — 95.9 5.7 — 121.3 Dividends payable 51.0 — — — — — — 51.0 Deferred revenue and prepaid rents — — — — 144.9 3.7 — 148.6 Deferred tax liability — — — — — 68.9 — 68.9 Total liabilities 51.0 — 2,667.6 — 2,281.9 157.5 (1,791.5 ) 3,366.5 Total stockholders' equity 2,189.1 22.2 2,216.9 — 2,309.6 812.9 (5,324.7 ) 2,226.0 Total liabilities and equity $ 2,240.1 $ 22.2 $ 4,884.5 $ — $ 4,591.5 $ 970.4 $ (7,116.2 ) $ 5,592.5
Consolidating Statements of Operations and Comprehensive Income (Loss)	Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) Three Months Ended March 31, 2019 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/ Consolidations Total Revenue $ — $ — $ — $ — $ 209.2 $ 15.8 $ — $ 225.0 Total operating expenses — — — — 189.3 23.9 — 213.2 Operating income — — — — 19.9 (8.1 ) — 11.8 Interest expense — — (32.5 ) — — (0.4 ) 9.2 (23.7 ) Unrealized gain on marketable equity investment — — — — — 101.2 — 101.2 Other expense — — — — — (0.1 ) — (0.1 ) (Loss) income before income taxes — — (32.5 ) — 19.9 92.6 9.2 89.2 Income tax (expense) benefit — — — — (0.8 ) 1.0 — 0.2 Equity earnings (loss) related to investment in subsidiaries 83.5 0.8 113.3 — — — (197.6 ) — Net income (loss) 83.5 0.8 80.8 — 19.1 93.6 (188.4 ) 89.4 Other comprehensive income — — 2.7 — — 0.6 — 3.3 Comprehensive income (loss) $ 83.5 $ 0.8 $ 83.5 $ — $ 19.1 $ 94.2 $ (188.4 ) $ 92.7 Three Months Ended March 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 194.9 $ 1.7 $ — $ 196.6 Total operating expenses — — — — 167.6 1.3 — 168.9 Operating income — — — — 27.3 0.4 — 27.7 Interest expense — — (23.9 ) — — (0.7 ) 3.8 (20.8 ) Unrealized gain on marketable equity investment — — — — — 40.5 — 40.5 Loss on early extinguishment of debt — — (3.1 ) — — — — (3.1 ) Net (loss) income before income taxes — — (27.0 ) — 27.3 40.2 3.8 44.3 Income tax expense — — — — (0.8 ) — — (0.8 ) Equity earnings (loss) related to investment in subsidiaries 39.8 0.4 66.8 — — — (107.0 ) — Net income (loss) 39.8 0.4 39.8 — 26.5 40.2 (103.2 ) 43.5 Other comprehensive income — — — — — 0.1 — 0.1 Comprehensive income (loss) $ 39.8 $ 0.4 $ 39.8 $ — $ 26.5 $ 40.3 $ (103.2 ) $ 43.6
Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, 2019 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (46.5 ) $ — $ 79.9 $ 1.3 $ 9.2 $ 43.9 Cash flows from investing activities: Investment in real estate — — — — (258.6 ) (34.1 ) (9.2 ) (301.9 ) Investment in subsidiaries (105.0 ) (0.8 ) (106.0 ) — — — 211.8 — Return of investment 50.4 — — — — — (50.4 ) — Intercompany borrowings 8.7 — (169.1 ) — (2.0 ) — 162.4 — Net cash (used in) provided by investing activities (45.9 ) (0.8 ) (275.1 ) — (260.6 ) (34.1 ) 314.6 (301.9 ) Cash flows from financing activities: Issuance of common stock, net 105.0 — — — — — — 105.0 Dividends paid (50.4 ) — (50.4 ) — — — 50.4 (50.4 ) Intercompany borrowings — — (8.7 ) — 169.1 2.0 (162.4 ) — Proceeds from revolving credit facility — — 275.7 — — — — 275.7 Payments on finance lease liabilities — — — — (0.3 ) (0.3 ) — (0.6 ) Tax payment upon exercise of equity awards (8.7 ) — — — — — — (8.7 ) Contributions/distributions from parent — 0.8 105.0 — 91.6 14.4 (211.8 ) — Net cash provided by (used in) financing activities 45.9 0.8 321.6 — 260.4 16.1 (323.8 ) 321.0 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — — — — (0.1 ) — (0.1 ) Net (decrease) increase in cash, cash equivalents and restricted cash — — — — 79.7 (16.8 ) — 62.9 Cash, cash equivalents and restricted cash at beginning of period — — — — 27.2 37.2 — 64.4 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 106.9 $ 20.4 $ — $ 127.3 Three Months Ended March 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (37.3 ) $ — $ 77.4 $ 0.3 $ 3.8 $ 44.2 Cash flows from investing activities: Investment in real estate — — — — (141.4 ) — (3.8 ) (145.2 ) Investment in subsidiaries (142.9 ) (1.4 ) (143.4 ) — — — 287.7 — Return of investment 41.0 — — — — — (41.0 ) — Intercompany borrowings 4.4 — 0.3 — — — (4.7 ) — Net cash (used in) provided by investing activities (97.5 ) (1.4 ) (143.1 ) — (141.4 ) — 238.2 (145.2 ) Cash flows from financing activities: Issuance of common stock, net 142.9 — — — — — — 142.9 Dividends paid (41.0 ) — (41.0 ) — — — 41.0 (41.0 ) Intercompany borrowings — — (4.4 ) — (0.3 ) — 4.7 — Proceeds from unsecured term loan — — 985.6 — — — — 985.6 Repayments of unsecured term loan — — (902.7 ) — — — — (902.7 ) Payments on finance lease liabilities — — — — (2.2 ) (0.4 ) — (2.6 ) Tax payment upon exercise of equity awards (4.4 ) — — — — — — (4.4 ) Contributions/distributions from parent — 1.4 142.9 — 142.9 0.5 (287.7 ) — Net cash provided by (used in) financing activities 97.5 1.4 180.4 — 140.4 0.1 (242.0 ) 177.8 Net increase (decrease) in cash, cash equivalents and restricted cash — — — — 76.4 0.4 — 76.8 Cash, cash equivalents and restricted cash at beginning of period — — — — 151.2 0.7 — 151.9 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 227.6 $ 1.1 $ — $ 228.7

Description of Business (Detail

Description of Business (Details)	3 Months Ended
	Mar. 31, 2019recovery_centerdata_center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of data operating centers | data_center	48
Number of recovery centers | recovery_center	2

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Rent and other receivables	$ 248.7		$ 234.9
Proceeds from unsecured term loan	0	$ 985.6
Repayments of unsecured term loan	$ 0	902.7
Minimum
Summary Of Significant Accounting Policies [Line Items]
Management service contracts, term	1 year
Maximum
Summary Of Significant Accounting Policies [Line Items]
Management service contracts, term	5 years
Restatement Adjustment
Summary Of Significant Accounting Policies [Line Items]
Rent and other receivables			$ 128.7
Proceeds from unsecured term loan		985.6
Repayments of unsecured term loan		$ 902.7

Recently Issued Accounting St_3

Recently Issued Accounting Standards (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (552.2)		$ (600.2)
Buildings and improvements	1,649.2		1,677.5
Operating lease right-of-use assets	83.8		0
Finance lease liabilities	33.4		156.7
Operating lease liabilities	119.6		0
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards		$ 9.5
Operating lease right-of-use assets		87
Operating lease liabilities		123.2
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards				$ 0.3
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards				0
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit				0.3
Accumulated Deficit | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards		$ 9.5
Accumulated Deficit | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards				0.3
Accumulated Deficit | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of accounting standards				$ 75.6
Build-To-Suit Lease
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Buildings and improvements			77.4
Finance lease liabilities			$ 123.3
Build-To-Suit Lease | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	50
Operating lease liabilities	$ 85.5

Revenue Recognition - Minimum L

Revenue Recognition - Minimum Lease Payments to be Received (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
2019	$ 520.1
2020	631.9
2021	542.8
2022	454.3
2023	365.2
2024	295.9
Thereafter	940
Total	$ 3,750.2
Operating Leases, Future Minimum Payments Receivable [Abstract]
2019		$ 647.6
2020		553.7
2021		453
2022		365.5
2023		284.4
Thereafter		$ 835.9

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	$ 225	$ 196.6
Total Lease revenue
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	216.9
Colocation (Minimum lease payments)
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	188.4
Meter power reimbursements (Variable lease payments)
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	28.5
Total Revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	8.1	9.8
Equipment sales
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	3.9	5.8
Other revenue
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	4.2	4
Managed Services
Disaggregation of Revenue [Line Items]
Total Revenue from contracts with customers	$ 3.4	$ 3.2

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable	$ 8.2	$ 4.8
Revenue | Customer Concentration Risk | One Customer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	21.00%	19.00%

Leases - As a Lessee - Addition

Leases - As a Lessee - Additional Information (Details) $ in Millions	Mar. 31, 2019USD ($)facility	Dec. 31, 2018USD ($)
Lessee, Lease, Description [Line Items]
Number of facilities, finance lease | facility	5
Number of facilities, operating lease | facility	12
Operating lease, renewal term	15 years
Operating lease liabilities | $	$ 119.6	$ 0
Minimum
Lessee, Lease, Description [Line Items]
Finance lease, term of contract	2 years
Operating lease, term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Finance lease, term of contract	22 years
Operating lease, term of contract	17 years
Leaseholds and Leasehold Improvements
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	12 years
Operating lease liabilities | $	$ 22.2

Leases - As a Lessee - Lease Co

Leases - As a Lessee - Lease Cost (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 5
Amortization of assets	0.6
Interest on lease liabilities	0.5
Total net lease cost	$ 6.1

Leases - As a Lessee - Suppleme

Leases - As a Lessee - Supplemental Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating leases:
Operating lease right-of-use assets	$ 83.8	$ 0
Operating lease liabilities	119.6	$ 0
Finance leases:
Property and equipment, at cost	34
Accumulated amortization	(3.4)
Property and equipment, net	30.6
Finance lease liabilities	$ 33.4
Weighted average remaining lease term (in years):
Operating leases	12 years 6 months
Finance leases	17 years 2 months 12 days
Weighted average discount rate:
Operating leases	4.50%
Finance leases	5.30%

Leases - As a Lessee - Supple_2

Leases - As a Lessee - Supplemental Cash Flow (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 5.1
Operating cash flows from finance leases	0.5
Financing cash flows from finance leases	0.6
Non-cash right-of-use assets obtained in exchange for lease liabilities:
Operating leases	$ 87

Leases - As a Lessee - Maturiti

Leases - As a Lessee - Maturities of Operating and Financing Lease Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019	$ 15.3
2020	19.5
2021	15.3
2022	15.6
2023	13.4
2024	7.7
Thereafter	71
Total lease payments	157.8
Less: Imputed interest	(38.2)
Operating lease liabilities	119.6	$ 0
Finance Leases
2019	3.3
2020	4.3
2021	4.2
2022	3.1
2023	2
2024	1.5
Thereafter	30.7
Total lease payments	49.1
Less: Imputed interest	(15.7)
Finance lease liabilities	$ 33.4

Leases - As a Lessee - Maturi_2

Leases - As a Lessee - Maturities Prior to Adoption of New Accounting Standard (Details) $ in Millions	Dec. 31, 2018USD ($)
December 31, 2018
2019	$ 5
2020	4.9
2021	3.7
2022	3.7
2023	3.5
Thereafter	43.4
Total lease payments	64.2
Finance Leases
2019	2.7
2020	2.8
2021	2.9
2022	2
2023	1
Thereafter	22
Total lease payments	$ 33.4

Investment in Real Estate - Nar

Investment in Real Estate - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)a	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Real Estate [Abstract]
Area of land acquired (in acres) | a	30
Payment to acquire land	$ 40.1
Land under development	75.9		$ 69.1
Depreciation expense	88.9	$ 66.2
Amortization expense	$ 13.2	$ 8.4

Investment in Real Estate - Rea

Investment in Real Estate - Real Estate Investments and Intangibles and Related Depreciation and Amortization (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Investment in Real Estate
Buildings and improvements, cost	$ 1,649.2	$ 1,677.5
Equipment, cost	2,799.6	2,630.2
Buildings and improvements, accumulated depreciation	(483.8)	(481.8)
Equipment, accumulated depreciation	(638.7)	(572.7)
Buildings and improvements, net	1,165.4	1,195.7
Equipment, net	2,160.9	2,057.5
Intangibles
Less: accumulated depreciation and amortization	(177)	(166.9)
Customer Relationships
Intangibles
Cost	247.1	247.1
Less: accumulated depreciation and amortization	(141.2)	(137.9)
Net	105.9	109.2
In Place Leases
Intangibles
Cost	136.6	136
Less: accumulated depreciation and amortization	(27.5)	(21.1)
Net	109.1	114.9
Other Contractual
Intangibles
Cost	19.4	19.5
Less: accumulated depreciation and amortization	(8.3)	(7.9)
Net	$ 11.1	$ 11.6
Buildings
Intangibles
Useful life of asset	30 years
Building improvements
Intangibles
Useful life of asset	30 years
Equipment
Intangibles
Useful life of asset	20 years

Equity Investment (Details)

Equity Investment (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Oct. 30, 2018	Oct. 08, 2018
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 299.3		$ 198.1
Unrealized gain (loss) on marketable equity investment	$ 101.2	$ 40.5
GDS
Schedule of Equity Method Investments [Line Items]
Price per ordinary share (in dollars per share)	$ 35.69
Unrealized gain (loss) on marketable equity investment		$ 40.5
Affiliated Entity | ODATA
Schedule of Equity Method Investments [Line Items]
Investments					$ 11.9
Ownership %					10.00%
Affiliated Entity | ODATA Colombia
Schedule of Equity Method Investments [Line Items]
Investments				$ 0.7
Fair Value | Level 1 | GDS
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 286.7

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing and other contract costs	$ 45.6	$ 43.6
Prepaid expenses	28.1	26.4
Non-real estate assets, net	18.4	18.4
Other assets	22.7	22.9
Total	$ 114.8	$ 111.3

Debt - Components of Debt (Deta

Debt - Components of Debt (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Mar. 29, 2018
Debt Instrument [Line Items]
Deferred financing costs	$ (31,200,000)	$ (32,900,000)
Total	$ 2,898,600,000	2,624,700,000
Monthly LIBOR	2.50%
$3 Billion Credit Facility
Debt Instrument [Line Items]
Credit agreement amount				$ 3,000,000,000
Term Loan | 2023 Term Loan
Debt Instrument [Line Items]
Credit agreement amount				1,000,000,000
Credit Facility	$ 1,000,000,000	1,000,000,000	$ 700,000,000
Term Loan | 2025 Term Loan
Debt Instrument [Line Items]
Credit agreement amount				300,000,000
Credit Facility	$ 300,000,000	300,000,000
Term Loan | LIBOR | 2023 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	1.40%
Term Loan | LIBOR | 2025 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	1.70%
Senior Notes | 2024 Notes, including bond premium of $5.2 million
Debt Instrument [Line Items]
Long-term debt	$ 705,200,000	705,500,000
Stated interest rate	5.00%
Bond premium	$ 5,200,000
Senior Notes | 2027 Notes, including bond premium of $8.8 million
Debt Instrument [Line Items]
Long-term debt	$ 508,800,000	509,100,000
Stated interest rate	5.375%
Bond premium	$ 8,700,000
Revolving Credit Facility | $3 Billion Credit Facility
Debt Instrument [Line Items]
Credit agreement amount	3,000,000,000			3,000,000,000
Revolving Credit Facility | $1.7 Billion Revolving Credit Facility:
Debt Instrument [Line Items]
Credit agreement amount	1,700,000,000			$ 1,700,000,000
Credit Facility	$ 415,800,000
Term of extension option	1 year
Revolving Credit Facility | US Revolver
Debt Instrument [Line Items]
Credit Facility	$ 270,000,000	0
Revolving Credit Facility | EUR Revolver
Debt Instrument [Line Items]
Credit Facility	$ 145,800,000	$ 143,000,000
Revolving Credit Facility | LIBOR | US Revolver
Debt Instrument [Line Items]
Basis spread on variable rate	1.45%
Revolving Credit Facility | LIBOR | EUR Revolver
Debt Instrument [Line Items]
Basis spread on variable rate	1.45%

Debt - Narrative (Details)

Debt - Narrative (Details) € in Millions	Mar. 29, 2018USD ($)tranche	Nov. 03, 2017USD ($)	Mar. 17, 2017USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Mar. 31, 2019EUR (€)
Line of Credit Facility [Line Items]
Loss on early extinguishment of debt				$ 0	$ 3,100,000
Letters of credit outstanding				8,000,000
$3 Billion Credit Facility
Line of Credit Facility [Line Items]
Credit agreement amount	$ 3,000,000,000
Available capacity under accordion feature	4,000,000,000
$3 Billion Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit agreement amount	3,000,000,000			3,000,000,000
Borrowings used to retire previous debt	1,000,000,000
Available capacity				1,300,000,000
$1.7 Billion Revolving Credit Facility: | Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit agreement amount	$ 1,700,000,000			1,700,000,000
Option to extend maturity	1 year
Multicurrency borrowing sublimit	$ 750,000,000
Line of credit				$ 415,800,000
Commitment fee percent				0.25%
Commitment fee rate per annum upon 50% or greater utilization				0.15%
Commitment fee amount				$ 500,000	700,000
2023 Term Loan
Line of Credit Facility [Line Items]
Term	5 years
2023 Term Loan | Term Loan
Line of Credit Facility [Line Items]
Credit agreement amount	$ 1,000,000,000
Line of credit				1,000,000,000	$ 700,000,000	$ 1,000,000,000
Delayed draw feature	$ 300,000,000
Delay draw feature, number of tranches | tranche	3
Delayed draw feature, period	6 months
2025 Term Loan
Line of Credit Facility [Line Items]
Term	7 years
2025 Term Loan | Term Loan
Line of Credit Facility [Line Items]
Credit agreement amount	$ 300,000,000
Line of credit				300,000,000		$ 300,000,000
$2.0 Billion Credit Facility
Line of Credit Facility [Line Items]
Credit agreement amount	2,000,000,000
$2.0 Billion Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit	900,000,000
Loss on early extinguishment of debt				$ 3,100,000
$1.1 Billion Revolving Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit agreement amount	1,100,000,000
2021 Term Loan
Line of Credit Facility [Line Items]
Term						5 years
2021 Term Loan | Term Loan
Line of Credit Facility [Line Items]
Line of credit	250,000,000
2022 Term Loan
Line of Credit Facility [Line Items]
Term						7 years
2022 Term Loan | Term Loan
Line of Credit Facility [Line Items]
Line of credit	$ 650,000,000
2024 Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				5.00%			5.00%
2024 Notes | Senior Notes | Cyrus One LP And Cyrus One Finance Corp
Line of Credit Facility [Line Items]
Debt principal amount		$ 200,000,000	$ 500,000,000
Stated interest rate		5.00%	5.00%
2027 Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				5.375%			5.375%
2027 Notes | Senior Notes | Cyrus One LP And Cyrus One Finance Corp
Line of Credit Facility [Line Items]
Debt principal amount		$ 200,000,000	$ 300,000,000
Stated interest rate		5.375%	5.375%
5.000% senior notes due 2024 and 5.375% senior notes due 2027 | Senior Notes
Line of Credit Facility [Line Items]
Debt proceeds, net of underwriting costs		$ 416,100,000	$ 791,200,000
Debt financing and underwriting costs		$ 4,400,000
Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative liability, notional amount | €							€ 238.1
Derivative asset, notional amount				$ 270,000,000
Increase (decrease) in interest expense, debt				$ (300,000)

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Carrying Value and Fair Value of Other Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	$ 2,898.6	$ 2,624.7
Equity investments	299.3	198.1
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investments	286.7	185.5
Senior Notes | 2024 Notes | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	705.2	705.5
Senior Notes | 2027 Notes | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	508.8	509.1
Level 1 | Senior Notes | 2024 Notes | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	720.1	684.1
Level 1 | Senior Notes | 2027 Notes | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	515	488
Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investments	$ 286.7	$ 185.5

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Derivative instruments (Details) € in Millions	Mar. 31, 2019USD ($)	Mar. 31, 2019EUR (€)	Mar. 29, 2018USD ($)
Cross Currency Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liability, notional amount | €		€ 238.1
Derivative asset, notional amount	$ 270,000,000
$1.7 Billion Revolving Credit Facility: | Revolving Credit Facility
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Line of credit	415,800,000
Credit agreement amount	1,700,000,000		$ 1,700,000,000
$1.7 Billion Revolving Credit Facility: | Revolving Credit Facility | Cross Currency Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Line of credit	$ 130,000,000

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Derivative Instruments Gain (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI for derivatives	$ 2.7	$ 0
Cross Currency Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI for derivatives	2.7	0
Amount of gain (loss) reclassified from accumulated OCI for derivatives	0	0
Amount of gain (loss) recognized in earnings	$ 0	$ 0

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($)	May 01, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, average price per share (in dollars per share)			$ 51.24
Proceeds from stock issuance		$ 105,000,000	$ 142,900,000
Issuance of common stock (in shares)			2,800,000
Common stock outstanding (in shares)		110,316,652		108,329,314
Dividends paid per share (in dollars per share)		$ 0.46
Dividends declared per share (in dollars per share)		$ 0.46	$ 0.46
Stock-based compensation expense		$ 4,500,000	$ 3,900,000
2018 ATM Stock Offering Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares authorized			$ 500,000,000
New 2018 ATM Stock Offering Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares authorized				$ 750,000,000
Stock issued during period, average price per share (in dollars per share)		$ 52.19
Proceeds from stock issuance		$ 104,100,000
Payments of stock issuance costs		1,300,000
Value of shares available to grant		$ 644,600,000
Issuance of common stock (in shares)		2,000,000
LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)		8,900,000
Shares available for grant (in shares)		4,500,000
Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends declared per share (in dollars per share)	$ 0.46

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Stock Unit Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restricted Stock Units
Units
Outstanding, beginning balance (in shares)	511,049	265,002
Granted (in shares)	360,362	322,063
Exercised (in shares)	(123,159)	(80,965)
Forfeited (in shares)	(2,691)	(3,131)
Outstanding, ending balance (in shares)	745,561	502,969
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in dollars per share)	$ 56.23	$ 56.08
Granted (in dollars per share)	47.97	51.92
Exercised (in dollars per share)	44.87	43.47
Forfeited (in dollars per share)	49.69	51.20
Outstanding, ending balance (in dollars per share)	$ 54.14	$ 55.47
Restricted Stock Units, Time-Based
Units
Outstanding, ending balance (in shares)	359,400	256,609
Weighted Average Grant Date Fair Value
Outstanding, ending balance (in dollars per share)	$ 53.12	$ 50.71
Restricted Stock Units, Performance-Based
Units
Outstanding, ending balance (in shares)	386,161	246,360
Weighted Average Grant Date Fair Value
Outstanding, ending balance (in dollars per share)	$ 55.08	$ 60.41

Stockholders' Equity - Restri_2

Stockholders' Equity - Restricted Stock Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restricted Stock
Shares
Outstanding, beginning balance (in shares)	419,356	715,098
Granted (in shares)	16,681	17,052
Exercised (in shares)	(364,822)	(209,415)
Forfeited (in shares)	(34,603)	(44,034)
Outstanding, ending balance (in shares)	36,612	478,701
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in dollars per share)	$ 35.73	$ 32.21
Granted (in dollars per share)	52.46	51.31
Exercised (in dollars per share)	35.23	27.02
Forfeited (in dollars per share)	37.09	28.45
Outstanding, ending balance (in dollars per share)	$ 47.02	$ 35.50
Restricted Stock, Time-Based
Shares
Outstanding, ending balance (in shares)	36,612	362,084
Weighted Average Grant Date Fair Value
Outstanding, ending balance (in dollars per share)	$ 47.02	$ 38.08
Restricted Stock, Performance-Based
Shares
Outstanding, ending balance (in shares)	0	116,617
Weighted Average Grant Date Fair Value
Outstanding, ending balance (in dollars per share)	$ 0	$ 28.57

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Option Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Options
Outstanding, beginning balance (in shares)	401,223	415,459
Granted (in shares)	0	0
Exercised (in shares)	(25,586)	0
Forfeited (in shares)	0	0
Outstanding, ending balance (in shares)	375,637	415,459
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding (in dollars per share)	$ 31.96	$ 31.67
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	36.70	0
Forfeited (in dollars per share)	0	0
Outstanding (in dollars per share)	$ 31.63	$ 31.67
Stock Options, Time Based
Options
Outstanding, ending balance (in shares)	323,101	348,137
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding (in dollars per share)	$ 32.94	$ 33.23
Stock Options, Performance Based
Options
Outstanding, ending balance (in shares)	52,536	67,322
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding (in dollars per share)	$ 23.58	$ 23.58

Income (Loss) per Share - Compu

Income (Loss) per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income (loss)	$ 89.4	$ 43.5
Less: Restricted stock dividends, Basic	(0.2)	(0.3)
Less: Restricted stock dividends, Diluted	(0.2)	(0.3)
Net (loss) income available to stockholders, Basic	89.2	43.2
Net (loss) income available to stockholders, Diluted	$ 89.2	$ 43.2
Denominator:
Weighted average shares outstanding - basic (in shares)	108.3	96
Performance-based restricted stock and units (in shares)	0.5	0.6
Weighted average shares outstanding- diluted (in shares)	108.8	96.6
EPS:
Net income (loss) per share - basic (in dollars per share)	$ 0.82	$ 0.45
Effect of dilutive shares:
Net income (loss) per share - diluted (in dollars per share)	$ 0.82	$ 0.45

Related Party Transactions (Det

Related Party Transactions (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
GDS | Investee
Related Party Transaction [Line Items]
Commission and referral charges and accrued expensed payable to GDS	$ 0.5
ODATA | Affiliated Entity
Related Party Transaction [Line Items]
Ownership percentage	10.00%

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Letters of credit outstanding	$ 8
Data center facilities and equipment
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Amount of minimum purchase commitment	$ 272.7
Data center facilities and equipment | Minimum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	1 year
Data center facilities and equipment | Maximum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	2 years
Services
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Amount of minimum purchase commitment	$ 51
Services | Minimum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	1 year
Services | Maximum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	2 years

Guarantors - Narrative (Details

Guarantors - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Minimum unencumbered asset value percentage of unsecured debt	150.00%
Gross operating real estate included in guarantor subsidiaries	85.00%
Equity investments	$ 299.3		$ 198.1
Unrealized gain on marketable equity investment	101.2	$ 40.5
Non- Guarantors
Condensed Financial Statements, Captions [Line Items]
Equity investments	299.3		198.1
Unrealized gain on marketable equity investment	101.2	40.5
GDS
Condensed Financial Statements, Captions [Line Items]
Unrealized gain on marketable equity investment		$ 40.5
GDS | Non- Guarantors
Condensed Financial Statements, Captions [Line Items]
Equity investments	$ 286.7		$ 185.5

Guarantors - Condensed Consolid

Guarantors - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Condensed Consolidating Balance Sheets
Total investment in real estate, net	$ 4,386.3	$ 4,293
Cash and cash equivalents	126	64.4
Investment in subsidiaries	0	0
Rent and other receivables	248.7	234.9
Restricted cash	1.3	0
Operating lease right-of-use assets	83.8	0
Intercompany receivable	0	0
Equity investments	299.3	198.1
Goodwill	455.1	455.1
Intangible assets, net	226.1	235.7
Other assets	114.8	111.3
Total assets	5,941.4	5,592.5
Debt	2,898.6	2,624.7
Operating lease liabilities	119.6	0
Intercompany payable	0	0
Finance lease liabilities	33.4	156.7
Accounts payable and accrued expenses	81.6	121.3
Construction costs payable	155.5	195.3	$ 89
Dividends payable	51.5	51	46.4
Deferred revenue and prepaid rents	155.9	148.6
Deferred tax liability	67.2	68.9
Total liabilities	3,563.3	3,366.5
Total stockholders' equity	2,378.1	2,226	$ 1,854.6	$ 1,713.9
Total liabilities and equity	5,941.4	5,592.5
Eliminations/Consolidations
Condensed Consolidating Balance Sheets
Total investment in real estate, net	46.1	36.9
Cash and cash equivalents	0	0
Investment in subsidiaries	(5,739.7)	(5,361.6)
Rent and other receivables	0	0
Restricted cash	0
Operating lease right-of-use assets	0
Intercompany receivable	(1,954.6)	(1,791.5)
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	(7,648.2)	(7,116.2)
Debt	0	0
Operating lease liabilities	0
Intercompany payable	(1,954.6)	(1,791.5)
Finance lease liabilities	0	0
Accounts payable and accrued expenses	0	0
Construction costs payable	0	0
Dividends payable	0	0
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Total liabilities	(1,954.6)	(1,791.5)
Total stockholders' equity	(5,693.6)	(5,324.7)
Total liabilities and equity	(7,648.2)	(7,116.2)
General Partner
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	18.9	22.2
Rent and other receivables	0	0
Restricted cash	0
Operating lease right-of-use assets	0
Intercompany receivable	0	0
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	18.9	22.2
Debt	0	0
Operating lease liabilities	0
Intercompany payable	0	0
Finance lease liabilities	0	0
Accounts payable and accrued expenses	0	0
Construction costs payable	0	0
Dividends payable	0	0
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Total liabilities	0	0
Total stockholders' equity	18.9	22.2
Total liabilities and equity	18.9	22.2
Parent Guarantor
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	2,368.2	2,216.9
Rent and other receivables	0	0
Restricted cash	0
Operating lease right-of-use assets	0
Intercompany receivable	15.2	23.2
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	2,383.4	2,240.1
Debt	0	0
Operating lease liabilities	0
Intercompany payable	0	0
Finance lease liabilities	0	0
Accounts payable and accrued expenses	0	0
Construction costs payable	0	0
Dividends payable	51.5	51
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Total liabilities	51.5	51
Total stockholders' equity	2,331.9	2,189.1
Total liabilities and equity	2,383.4	2,240.1
LP Co-issuer
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	3,352.6	3,122.5
Rent and other receivables	0.3	0
Restricted cash	0
Operating lease right-of-use assets	0
Intercompany receivable	1,930.6	1,761.5
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	3.2	0.5
Total assets	5,286.7	4,884.5
Debt	2,898.6	2,624.7
Operating lease liabilities	0
Intercompany payable	15.2	23.2
Finance lease liabilities	0	0
Accounts payable and accrued expenses	4.7	19.7
Construction costs payable	0	0
Dividends payable	0	0
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Total liabilities	2,918.5	2,667.6
Total stockholders' equity	2,368.2	2,216.9
Total liabilities and equity	5,286.7	4,884.5
Finance Co-issuer
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	0	0
Rent and other receivables	0	0
Restricted cash	0
Operating lease right-of-use assets	0
Intercompany receivable	0	0
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	0	0
Debt	0	0
Operating lease liabilities	0
Intercompany payable	0	0
Finance lease liabilities	0	0
Accounts payable and accrued expenses	0	0
Construction costs payable	0	0
Dividends payable	0	0
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Total liabilities	0	0
Total stockholders' equity	0	0
Total liabilities and equity	0	0
Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Total investment in real estate, net	3,680.6	3,611.2
Cash and cash equivalents	106.9	27.2
Investment in subsidiaries	0	0
Rent and other receivables	229.5	218.7
Restricted cash	0
Operating lease right-of-use assets	45.2
Intercompany receivable	8.8	6.8
Equity investments	0	0
Goodwill	455.1	455.1
Intangible assets, net	172.3	178.1
Other assets	99	94.4
Total assets	4,797.4	4,591.5
Debt	0	0
Operating lease liabilities	79.8
Intercompany payable	1,930.6	1,761.5
Finance lease liabilities	5.6	104
Accounts payable and accrued expenses	73.1	95.9
Construction costs payable	122.4	175.6
Dividends payable	0	0
Deferred revenue and prepaid rents	152.1	144.9
Deferred tax liability	0	0
Total liabilities	2,363.6	2,281.9
Total stockholders' equity	2,433.8	2,309.6
Total liabilities and equity	4,797.4	4,591.5
Non- Guarantors
Condensed Consolidating Balance Sheets
Total investment in real estate, net	659.6	644.9
Cash and cash equivalents	19.1	37.2
Investment in subsidiaries	0	0
Rent and other receivables	18.9	16.2
Restricted cash	1.3
Operating lease right-of-use assets	38.6
Intercompany receivable	0	0
Equity investments	299.3	198.1
Goodwill	0	0
Intangible assets, net	53.8	57.6
Other assets	12.6	16.4
Total assets	1,103.2	970.4
Debt	0	0
Operating lease liabilities	39.8
Intercompany payable	8.8	6.8
Finance lease liabilities	27.8	52.7
Accounts payable and accrued expenses	3.8	5.7
Construction costs payable	33.1	19.7
Dividends payable	0	0
Deferred revenue and prepaid rents	3.8	3.7
Deferred tax liability	67.2	68.9
Total liabilities	184.3	157.5
Total stockholders' equity	918.9	812.9
Total liabilities and equity	$ 1,103.2	$ 970.4

Guarantors - Condensed Consol_2

Guarantors - Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Consolidating Statements of Operations
Revenue	$ 225	$ 196.6
Total operating expenses	213.2	168.9
Operating income	11.8	27.7
Interest expense	(23.7)	(20.8)
Unrealized gain on marketable equity investment	101.2	40.5
Loss on early extinguishment of debt	0	(3.1)
Other expense	(0.1)	0
Net income before income taxes	89.2	44.3
Income tax benefit (expense)	0.2	(0.8)
Equity earnings (loss) related to investment in subsidiaries	0	0
Net income (loss)	89.4	43.5
Other comprehensive income	3.3	0.1
Comprehensive income	92.7	43.6
Eliminations/Consolidations
Condensed Consolidating Statements of Operations
Revenue	0	0
Total operating expenses	0	0
Operating income	0	0
Interest expense	9.2	3.8
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		0
Other expense	0
Net income before income taxes	9.2	3.8
Income tax benefit (expense)	0	0
Equity earnings (loss) related to investment in subsidiaries	(197.6)	(107)
Net income (loss)	(188.4)	(103.2)
Other comprehensive income	0	0
Comprehensive income	(188.4)	(103.2)
General Partner
Condensed Consolidating Statements of Operations
Revenue	0	0
Total operating expenses	0	0
Operating income	0	0
Interest expense	0	0
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		0
Other expense	0
Net income before income taxes	0	0
Income tax benefit (expense)	0	0
Equity earnings (loss) related to investment in subsidiaries	0.8	0.4
Net income (loss)	0.8	0.4
Other comprehensive income	0	0
Comprehensive income	0.8	0.4
Parent Guarantor
Condensed Consolidating Statements of Operations
Revenue	0	0
Total operating expenses	0	0
Operating income	0	0
Interest expense	0	0
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		0
Other expense	0
Net income before income taxes	0	0
Income tax benefit (expense)	0	0
Equity earnings (loss) related to investment in subsidiaries	83.5	39.8
Net income (loss)	83.5	39.8
Other comprehensive income	0	0
Comprehensive income	83.5	39.8
LP Co-issuer
Condensed Consolidating Statements of Operations
Revenue	0	0
Total operating expenses	0	0
Operating income	0	0
Interest expense	(32.5)	(23.9)
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		(3.1)
Other expense	0
Net income before income taxes	(32.5)	(27)
Income tax benefit (expense)	0	0
Equity earnings (loss) related to investment in subsidiaries	113.3	66.8
Net income (loss)	80.8	39.8
Other comprehensive income	2.7	0
Comprehensive income	83.5	39.8
Finance Co-issuer
Condensed Consolidating Statements of Operations
Revenue	0	0
Total operating expenses	0	0
Operating income	0	0
Interest expense	0	0
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		0
Other expense	0
Net income before income taxes	0	0
Income tax benefit (expense)	0	0
Equity earnings (loss) related to investment in subsidiaries	0	0
Net income (loss)	0	0
Other comprehensive income	0	0
Comprehensive income	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Operations
Revenue	209.2	194.9
Total operating expenses	189.3	167.6
Operating income	19.9	27.3
Interest expense	0	0
Unrealized gain on marketable equity investment	0	0
Loss on early extinguishment of debt		0
Other expense	0
Net income before income taxes	19.9	27.3
Income tax benefit (expense)	(0.8)	(0.8)
Equity earnings (loss) related to investment in subsidiaries	0	0
Net income (loss)	19.1	26.5
Other comprehensive income	0	0
Comprehensive income	19.1	26.5
Non- Guarantors
Condensed Consolidating Statements of Operations
Revenue	15.8	1.7
Total operating expenses	23.9	1.3
Operating income	(8.1)	0.4
Interest expense	(0.4)	(0.7)
Unrealized gain on marketable equity investment	101.2	40.5
Loss on early extinguishment of debt		0
Other expense	(0.1)
Net income before income taxes	92.6	40.2
Income tax benefit (expense)	1	0
Equity earnings (loss) related to investment in subsidiaries	0	0
Net income (loss)	93.6	40.2
Other comprehensive income	0.6	0.1
Comprehensive income	$ 94.2	$ 40.3

Guarantors - Condensed Consol_3

Guarantors - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	$ 43.9	$ 44.2
Cash flows from investing activities:
Investment in real estate	(301.9)	(145.2)
Investment in subsidiaries	0	0
Return of investment	0	0
Intercompany borrowings	0	0
Net cash used in investing activities	(301.9)	(145.2)
Cash flows from financing activities:
Issuance of common stock, net	105	142.9
Dividends paid	(50.4)	(41)
Intercompany borrowings	0	0
Proceeds from revolving credit facility	275.7	0
Proceeds from unsecured term loan	0	985.6
Repayments of unsecured term loan	0	(902.7)
Payments on finance lease liabilities	(0.6)	(2.6)
Tax payment upon exercise of equity awards	(8.7)	(4.4)
Contributions/distributions from parent	0	0
Net cash provided by (used in) financing activities	321	177.8
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(0.1)	0
Net increase in cash, cash equivalents and restricted cash	62.9	76.8
Cash, cash equivalents and restricted cash at beginning of period	64.4	151.9
Cash, cash equivalents and restricted cash at end of period	127.3	228.7
General Partner
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	0	0
Cash flows from investing activities:
Investment in real estate	0	0
Investment in subsidiaries	(0.8)	(1.4)
Return of investment	0	0
Intercompany borrowings	0	0
Net cash used in investing activities	(0.8)	(1.4)
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	0	0
Intercompany borrowings	0	0
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	0	0
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	0.8	1.4
Net cash provided by (used in) financing activities	0.8	1.4
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Eliminations/Consolidations
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	9.2	3.8
Cash flows from investing activities:
Investment in real estate	(9.2)	(3.8)
Investment in subsidiaries	211.8	287.7
Return of investment	(50.4)	(41)
Intercompany borrowings	162.4	(4.7)
Net cash used in investing activities	314.6	238.2
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	50.4	41
Intercompany borrowings	(162.4)	4.7
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	0	0
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	(211.8)	(287.7)
Net cash provided by (used in) financing activities	(323.8)	(242)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Parent Guarantor
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	0	0
Cash flows from investing activities:
Investment in real estate	0	0
Investment in subsidiaries	(105)	(142.9)
Return of investment	50.4	41
Intercompany borrowings	8.7	4.4
Net cash used in investing activities	(45.9)	(97.5)
Cash flows from financing activities:
Issuance of common stock, net	105	142.9
Dividends paid	(50.4)	(41)
Intercompany borrowings	0	0
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	0	0
Tax payment upon exercise of equity awards	(8.7)	(4.4)
Contributions/distributions from parent	0	0
Net cash provided by (used in) financing activities	45.9	97.5
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
LP Co-issuer
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	(46.5)	(37.3)
Cash flows from investing activities:
Investment in real estate	0	0
Investment in subsidiaries	(106)	(143.4)
Return of investment	0	0
Intercompany borrowings	(169.1)	0.3
Net cash used in investing activities	(275.1)	(143.1)
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	(50.4)	(41)
Intercompany borrowings	(8.7)	(4.4)
Proceeds from revolving credit facility	275.7
Proceeds from unsecured term loan		985.6
Repayments of unsecured term loan		(902.7)
Payments on finance lease liabilities	0	0
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	105	142.9
Net cash provided by (used in) financing activities	321.6	180.4
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Finance Co-issuer
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	0	0
Cash flows from investing activities:
Investment in real estate	0	0
Investment in subsidiaries	0	0
Return of investment	0	0
Intercompany borrowings	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	0	0
Intercompany borrowings	0	0
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	0	0
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	0	0
Net cash provided by (used in) financing activities	0	0
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	79.9	77.4
Cash flows from investing activities:
Investment in real estate	(258.6)	(141.4)
Investment in subsidiaries	0	0
Return of investment	0	0
Intercompany borrowings	(2)	0
Net cash used in investing activities	(260.6)	(141.4)
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	0	0
Intercompany borrowings	169.1	(0.3)
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	(0.3)	(2.2)
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	91.6	142.9
Net cash provided by (used in) financing activities	260.4	140.4
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0
Net increase in cash, cash equivalents and restricted cash	79.7	76.4
Cash, cash equivalents and restricted cash at beginning of period	27.2	151.2
Cash, cash equivalents and restricted cash at end of period	106.9	227.6
Non- Guarantors
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	1.3	0.3
Cash flows from investing activities:
Investment in real estate	(34.1)	0
Investment in subsidiaries	0	0
Return of investment	0	0
Intercompany borrowings	0	0
Net cash used in investing activities	(34.1)	0
Cash flows from financing activities:
Issuance of common stock, net	0	0
Dividends paid	0	0
Intercompany borrowings	2	0
Proceeds from revolving credit facility	0
Proceeds from unsecured term loan		0
Repayments of unsecured term loan		0
Payments on finance lease liabilities	(0.3)	(0.4)
Tax payment upon exercise of equity awards	0	0
Contributions/distributions from parent	14.4	0.5
Net cash provided by (used in) financing activities	16.1	0.1
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(0.1)
Net increase in cash, cash equivalents and restricted cash	(16.8)	0.4
Cash, cash equivalents and restricted cash at beginning of period	37.2	0.7
Cash, cash equivalents and restricted cash at end of period	$ 20.4	$ 1.1

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 12, 2019	Apr. 02, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Subsequent Event [Line Items]
Proceeds from stock issuance			$ 105	$ 142.9
Equity investments			$ 299.3		$ 198.1
Subsequent Event
Subsequent Event [Line Items]
Sale of stock (number of shares)		2,900,000
Sale of stock, price per share (in dollars per share)		$ 52.24
Payments of stock issuance costs		$ 1.2
Value of shares available to grant		495.4
Proceeds from stock issuance		$ 148.1
GDS
Subsequent Event [Line Items]
Price per ordinary share (in dollars per share)			$ 35.69
GDS | Subsequent Event
Subsequent Event [Line Items]
Equity method investment, share equivalent sold (shares)	5,700,000
Equity method investment, share equivalent (shares)	8
Price per ordinary share (in dollars per share)	$ 0.00005
Proceeds from sale of equity method investments	$ 200
Equity method investment, share equivalent, shares (in shares)	2,300,000
Equity investments	$ 90
2023 Term Loan | Term Loan | Subsequent Event
Subsequent Event [Line Items]
Repayments of debt	$ 200

Uncategorized Items - cone-2019

Label	Element	Value
Accounting Standards Update 2016-01 [Member] | AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (75,600,000)