CyrusOne (CONE) 10-K 20 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 14, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-35789
Entity Registrant Name	CyrusOne Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	46-0691837
Entity Address, Address Line One	2850 N. Harwood Street
Entity Address, Address Line Two	Suite 2200
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75201
City Area Code	972
Local Phone Number	350-0060
Title of 12(b) Security	Common Stock, $.01 par value
Trading Symbol	CONE
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 6.5
Entity Common Stock, Shares Outstanding		114,848,445
Entity Central Index Key	0001553023
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Investment in real estate:
Land	$ 147.6	$ 118.5
Buildings and improvements	1,761.4	1,677.5
Equipment	3,028.2	2,630.2
Gross operating real estate	4,937.2	4,426.2
Less accumulated depreciation	(1,379.2)	(1,054.5)
Net operating real estate	3,558	3,371.7
Construction in progress, including land under development	946.3	744.9
Land held for future development	206	176.4
Total investment in real estate, net	4,710.3	4,293
Cash and cash equivalents	76.4	64.4
Rent and other receivables (net of allowance for doubtful accounts of $1.8 and $1.7 as of December 31, 2019 and December 31, 2018, respectively)	291.9	234.9
Restricted cash	1.3	0
Operating lease right-of-use assets, net	161.9
Equity investments	135.1	198.1
Goodwill	455.1	455.1
Intangible assets (net of accumulated amortization of $207.5 and $166.9 as of December 31, 2019 and December 31, 2018, respectively)	196.1	235.7
Other assets	113.9	111.3
Total assets	6,142	5,592.5
Liabilities and equity
Debt	2,886.6	2,624.7
Finance lease liabilities	31.8
Finance lease liabilities		156.7
Operating lease liabilities	195.8	0
Construction costs payable	176.3	195.3
Accounts payable and accrued expenses	122.7	121.3
Dividends payable	58.6	51
Deferred revenue and prepaid rents	163.7	148.6
Deferred tax liability	60.5	68.9
Other liabilities	11.4	0
Total liabilities	3,707.4	3,366.5
Commitment 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 114,808,898 and 108,329,314 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	1.1	1.1
Additional paid in capital	3,202	2,837.4
Accumulated deficit	(767.3)	(600.2)
Accumulated other comprehensive loss	(1.2)	(12.3)
Total stockholders’ equity	2,434.6	2,226
Total liabilities and equity	$ 6,142	$ 5,592.5

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 1.8	$ 1.7
Accumulated amortization, net	$ 207.5	$ 166.9
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares 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, shares issued (in shares)	114,808,898	108,329,314
Common stock, shares outstanding (in shares)	114,808,898	108,329,314

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 981,300,000	$ 821,400,000	$ 672,000,000
Operating expenses:
Property operating expenses	383,400,000	292,400,000	235,100,000
Sales and marketing	20,200,000	19,600,000	17,000,000
General and administrative	83,500,000	80,600,000	67,000,000
Depreciation and amortization	417,700,000	334,100,000	258,900,000
Transaction, acquisition, integration and other related expenses	8,800,000	5,000,000	11,900,000
Impairment losses	700,000	0	58,000,000
Total operating expenses	914,300,000	731,700,000	647,900,000
Operating income	67,000,000	89,700,000	24,100,000
Interest expense, net	(82,000,000)	(94,700,000)	(68,100,000)
Gain on marketable equity investment	132,300,000	9,900,000	0
Loss on early extinguishment of debt	(71,800,000)	(3,100,000)	(36,500,000)
Foreign currency and derivative losses, net	(7,500,000)	0	0
Other expense	(300,000)	0	0
Net income (loss) before income taxes	37,700,000	1,800,000	(80,500,000)
Income tax benefit (expense)	3,700,000	(600,000)	(3,000,000)
Net income (loss)	$ 41,400,000	$ 1,200,000	$ (83,500,000)
Weighted average number of common shares outstanding - basic (in shares)	112.1	99.8	88.9
Weighted average number of common shares outstanding - diluted (in shares)	112.5	100.4	88.9
Income (loss) per share - basic (in dollars per share)	$ 0.36	$ 0	$ (0.95)
Income (loss) per share - diluted (in dollars per share)	$ 0.36	$ 0	$ (0.95)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (52.1)	$ 12.6	$ (8.5)	$ 89.4	$ (105.8)	$ (42.4)	$ 105.9	$ 43.5	$ 41.4	$ 1.2	$ (83.5)
Other comprehensive income (loss):
Foreign currency translation adjustment									11.8	(10.9)	(0.1)
Net loss on cash flow hedging instruments									(0.7)	0	0
Unrealized gain on equity investment									0	0	75.6
Comprehensive income (loss)									$ 52.5	$ (9.7)	$ (8)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Total Stockholders' Equity
Beginning Balance (in shares) at Dec. 31, 2016		83.5
Beginning Balance at Dec. 31, 2016		$ 0.8	$ 1,412.3	$ (249.8)	$ (1.3)	$ 1,162
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (83.5)			(83.5)		(83.5)
Issuance of common stock, net (in shares)		12.8
Issuance of common stock, net		$ 0.2	705.5			705.7
Stock-based compensation expense (in shares)		(0.1)
Stock-based compensation expense			14.7			14.7
Tax payment upon exercise of equity awards (in shares)		(0.1)
Tax payment upon exercise of equity awards			(6.9)			(6.9)
Foreign currency translation adjustment	(0.1)				(0.1)	(0.1)
Unrealized gain on equity investment	75.6				75.6	75.6
Net loss on cash flow hedging instruments	0
Dividends declared				(153.6)		(153.6)
Ending Balance (in shares) at Dec. 31, 2017		96.1
Ending Balance at Dec. 31, 2017		$ 1	2,125.6	(486.9)	74.2	1,713.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 1.2			1.2		1.2
Issuance of common stock, net (in shares)	12.2	12.3
Issuance of common stock, net		$ 0.1	699.5			699.6
Stock-based compensation expense			17.5			17.5
Tax payment upon exercise of equity awards (in shares)		(0.1)
Tax payment upon exercise of equity awards			(5.2)			(5.2)
Foreign currency translation adjustment	$ (10.9)				(10.9)	(10.9)
Unrealized gain on equity investment	0
Net loss on cash flow hedging instruments	0
Dividends declared				(190.4)		(190.4)
Ending Balance (in shares) at Dec. 31, 2018		108.3
Ending Balance at Dec. 31, 2018	2,226	$ 1.1	2,837.4	(600.2)	(12.3)	2,226
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 41.4			41.4		41.4
Issuance of common stock, net (in shares)	6.5	6.5
Issuance of common stock, net			357.2			357.2
Stock-based compensation expense			16.7			16.7
Tax payment upon exercise of equity awards			(9.3)			(9.3)
Foreign currency translation adjustment	$ 11.8				11.8	11.8
Unrealized gain on equity investment	0
Net loss on cash flow hedging instruments	(0.7)				(0.7)	(0.7)
Dividends declared				(218)		(218)
Ending Balance (in shares) at Dec. 31, 2019		114.8
Ending Balance at Dec. 31, 2019	$ 2,434.6	$ 1.1	$ 3,202	$ (767.3)	$ (1.2)	$ 2,434.6

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends declared (in dollars per share)	$ 1.92	$ 1.84	$ 1.68

Consolidated Statements of Cash

Consolidated Statements of Cash Flows	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Cash flows from operating activities:
Net income (loss)	$ 41,400,000	$ 1,200,000	$ (83,500,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	417,700,000	334,100,000	258,900,000
Provision for bad debt expense	1,700,000	2,600,000	200,000
Unrealized gain on marketable equity investment	(65,600,000)	(9,900,000)	0
Realized gain on marketable equity investment	(66,700,000)	0	0
Foreign currency and derivative losses, net	7,500,000	0	0
Proceeds from swap terminations	3,600,000
Loss on asset disposals	400,000	0	0
Impairment loss on real estate	700,000	0	58,000,000
Loss on early extinguishment of debt	71,800,000	3,100,000	36,500,000
Interest expense amortization, net	5,000,000	4,000,000	4,200,000
Stock-based compensation expense	16,700,000	17,500,000	14,700,000
Deferred income tax benefit	(7,500,000)	0	0
Operating lease cost	20,300,000	0	0
Other	200,000	(600,000)	1,500,000
Change in operating assets and liabilities:
Rent and other receivables, net and other assets	(74,200,000)	(80,200,000)	(64,300,000)
Accounts payable and accrued expenses	(800,000)	3,000,000	29,300,000
Deferred revenue and prepaid rents	15,600,000	34,500,000	34,000,000
Operating lease liabilities	(22,100,000)	0	0
Net cash provided by operating activities	365,700,000	309,300,000	289,500,000
Cash flows from investing activities:
Investment in real estate	(876,400,000)	(865,700,000)	(914,500,000)
Asset acquisitions, primarily real estate, net of cash acquired	0	(462,800,000)	(492,300,000)
Proceeds from sale of equity investments	199,000,000	0	0
Equity investments	(3,800,000)	(12,600,000)	(100,000,000)
Proceeds from the sale of real estate assets	1,300,000	0	0
Net cash used in investing activities	(679,900,000)	(1,341,100,000)	(1,506,800,000)
Cash flows from financing activities:
Issuance of common stock, net	357,200,000	699,600,000	705,700,000
Dividends paid	(210,400,000)	(181,100,000)	(145,700,000)
Proceeds from revolving credit facility	656,700,000	688,300,000	1,037,300,000
Repayments of revolving credit facility	(182,500,000)	(647,400,000)	(1,275,000,000)
Proceeds from unsecured term loan	0	1,300,000,000	350,000,000
Repayments of unsecured term loan	(200,000,000)	(900,000,000)	0
Proceeds from senior notes	1,197,400,000	0	1,217,800,000
Repayments of senior notes	(1,200,000,000)	0	(474,800,000)
Payment of debt extinguishment costs	(72,000,000)	0	(30,000,000)
Payment of deferred financing costs	(9,400,000)	0	(16,700,000)
Payments on finance lease liabilities	(2,900,000)	(9,500,000)	(9,800,000)
Interest paid by lenders on issuance of the senior notes	0	0	2,700,000
Tax payment upon exercise of equity awards	(9,300,000)	(5,200,000)	(6,900,000)
Net cash provided by financing activities	324,800,000	944,700,000	1,354,600,000
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,700,000	(400,000)	0
Net increase (decrease) in cash, cash equivalents and restricted cash	13,300,000	(87,500,000)	137,300,000
Cash, cash equivalents and restricted cash at beginning of period	64,400,000	151,900,000	14,600,000
Cash, cash equivalents and restricted cash at end of period	77,700,000	64,400,000	151,900,000
Supplemental disclosure of cash flow information:
Cash paid for interest, including amounts capitalized of $32.9 million, $24.4 million and $17.0 million in 2019, 2018 and 2017, respectively	123,000,000	115,400,000	68,800,000
Cash paid for income taxes	3,500,000	3,400,000	2,200,000
Non-cash investing and financing activities:
Construction costs payable	176,300,000	195,300,000	115,500,000
Dividends payable	$ 58,600,000	$ 51,000,000	$ 41,800,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Capitalized interest	$ 32.9	$ 24.4	$ 17

Description of Business

Description of Business	12 Months Ended
	Dec. 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. As of December 31, 2019 , all of the issued and outstanding Operating Partnership units of CyrusOne LP are owned, directly or indirectly, by the Company. Our customers operate in a number of industries, including information technology, financial services, energy, oil and gas, mining, medical, research and consulting services, and consumer goods and services. We currently operate 49 data centers, including two recovery centers, located in the United States, United Kingdom, Germany and Singapore.

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements are prepared on a consolidated basis. In addition, the accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the U.S. (GAAP) and include the accounts of the Company, as well as all wholly-owned subsidiaries and any consolidated variable interest entities. All intercompany transactions and balances have been eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies 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 term of the loan. In a business combination, 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 4, Recently Issued Accounting Standards) to leases that have a remaining lease term of 12 months or less at the acquisition date, and accordingly, do 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 recognized an impairment loss of $0.7 million for the year ended December 31, 2019 on our South Bend - Monroe facility. We did not record any impairment losses for the year ended December 31, 2018 . We recognized impairment losses of $58.0 million for the year ended December 31, 2017 related to our leased data center facilities in the Connecticut markets and our leased facility in Singapore. 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 restricted by contract or regulation, including letters of credit. 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 9, Equity Investments. Our investment in GDS Holdings Limited (“GDS”) is classified as “available for sale” and is carried at fair value. Changes in the fair value are reported as a component of net income (loss) in Gain (loss) on marketable equity investments. Our other equity investment is carried at cost because we do not exercise influence over the operating and financial decisions of the venture and there is no readily determinable fair value and our investment is recorded at cost less impairment, if any. Dividends paid from operating profits are reported as a component of net income (loss), while other dividends are reported as a return of capital. Goodwill We evaluate goodwill for possible impairment at least annually or upon the occurrence of events or circumstances that indicate that they would more likely than not reduce the fair value of a reporting unit below its carrying amount. For our annual impairment evaluation, we have the option of performing a qualitative or quantitative goodwill impairment analysis. A qualitative analysis, step zero, analyzes the macro-economic environment in which we operate for any significant changes such as deterioration in the market that the Company operates or overall financial performance such as declining cash flows. Also, entity specific changes are analyzed such as change in management, strategy or composition of reporting unit. This assessment of qualitative factors serves as a basis for determining whether it is necessary to perform the step one test. A quantitative analysis, step one, requires the Company to estimate the fair value of the reporting unit and compare the fair value to the carrying value to identify whether the value of the recorded goodwill is impaired. Changes in certain assumptions could have a significant impact on the impairment test for goodwill under step one. The most critical assumptions are projected future growth rates, operating margins, capital expenditures, tax rates, terminal values and discount rates. These assumptions are subject to change as our long-term plans and strategies are updated each year. During the fourth quarters of 2019, 2018 and 2017, we performed a qualitative evaluation and determined that the fair value of the reporting unit is substantially in excess of the carrying amount and therefore determined that further quantitative impairment testing was not necessary. Rent and Other Receivables Receivables consist principally of rent receivables from customers and straight-line rent receivables with estimated credit losses recorded as an allowance for doubtful accounts. Straight-line rent receivable, net was $156.8 million and $128.7 million at December 31, 2019 and 2018, respectively. The allowance for doubtful accounts is estimated based upon historic patterns of credit losses for aged receivables as well as specific provisions for certain identifiable, potentially uncollectible balances. Deferred Revenue and Prepaid Rents Deferred revenue is recorded when a customer makes a contractual payment in excess of revenues recognized in accordance with GAAP. Prepaid rent liability is recorded when a customer makes an advance payment or they are contractually obligated to pay any amounts in advance of the associated lease or service period. Finance Lease Liabilities Finance lease liabilities represent leases of land and real estate we classified as finance leases. 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. Prior to the adoption of ASC 842, the Company had lease arrangements where we were involved in the construction of structural improvements to develop buildings into data centers. We substantially bore all the construction period risk, such as managing or funding construction, we were deemed to be the accounting owner of the leased property and, we were required to record at fair value the property and associated liability on our Consolidated Balance Sheets. These transactions did not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. Following the adoption of ASC 842, these leases are classified as operating leases and the liability is included in the Consolidated Balance Sheets under Operating lease liabilities, see Note 6, Leases - As a Lessee, for further information. Revenue Recognition Our revenue consists of lease revenue and revenue from contracts with customers. 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 space and power. The revenue for these types of leases is recorded in colocation rent 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. 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. 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 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. Other service revenue is measured based on the consideration specified in the contract and recognized over time as we satisfy the performance obligation. We adopted the practical expedient in ASC 606 that allows the Company to not 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. Depreciation and Amortization Expense Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal is reasonably certain. Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. Finite-lived intangibles include trademarks, customer relationships, favorable leasehold interests, in-place leases, trade names and deferred leasing costs. See Note 10, Goodwill, Intangible and Other Long-Lived Assets, for details. 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 (loss). 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, market and 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 on available-for-sale securities, derivatives 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 We primarily hedge our foreign currency risk by borrowing in the currencies in which we invest. We may use derivative financial instruments, such as cross-currency swaps to manage foreign currency exchange rate risk related to both our foreign investments and the related earnings. In addition, we occasionally use interest rate swap contracts to manage interest rate risk and limit the impact of future interest rate changes on earnings and cash flows, primarily related to variable-rate debt. Derivative instruments are measured at fair value and recorded as other assets or other liabilities. The accounting for gains and losses resulting from changes in fair value is dependent on the use of the derivative and whether it is designated and qualifies for hedge accounting. Designated Derivatives. We may choose to designate our derivative financial instruments, generally cross-currency swaps as net investment hedges in foreign operations. At inception of the transaction, we designate the derivative financial instrument as a hedge of a specific underlying exposure, including the risk management objective and the strategy for undertaking the hedge transaction. We formally assess both at inception and at least quarterly thereafter, the effectiveness of our hedging transactions. Due to the high degree of effectiveness between the hedging instruments and the underlying exposures hedged, fluctuations in the value of the derivative financial instruments will generally be offset by changes in the cash flows or fair values of the underlying exposures being hedged. In addition to the net investment hedges described above, we may issue debt in a currency that is not the same functional currency of the borrowing entity to hedge our international investments. We designate the debt and related accrued interest as a net investment hedge to offset the translation and economic exposures related to our international investments. If the debt and related accrued interest exceeds the designated amount of our international investment, the foreign currency remeasurement on the unhedged portion of the debt during the period is recognized in Foreign currency and derivative losses, net. For cash flow hedges, such as interest rate swaps, we report the effective portion of the gain or loss as a component of other comprehensive income (loss) and reclassify it to the applicable line item in the Consolidated Statements of Operations, generally Interest expense, net over the corresponding period of the underlying hedged item. The ineffective portion of a derivative financial instrument’s change in fair value is recognized in earnings, generally Interest expense, net at the time the ineffectiveness occurred. To the extent the hedged debt related to our interest rate swaps and forwards is paid off early, we write off the remaining balance in other comprehensive income (loss) and recognize the amount in Interest expense, net in the Consolidated Statements of Operations. Undesignated Derivatives . Derivative instruments, such as cross-currency swaps, for which hedge accounting is not applied are recorded at fair value in other assets and other liabilities and gains and losses resulting from changes in the fair value are reported in Foreign currency and derivative losses, net in the Consolidated Statements of Operations. In addition, we may choose to not designate our interest rate swap and forward contracts. If a swap or forward contract is not designated as a hedge, the changes in fair value of these instruments is immediately recognized in earnings in Interest expense, net in the Consolidated Statements of Operations. Segment Information Our data centers have similar revenues and operating expenses across all geographic locations. The service offerings and delivery of services are provided in a similar manner, using the same types of facilities and similar technologies. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis and makes decisions about the allocations of Company resources and as a result, we have one reportable business segment. One customer represented approximately 21% and 18% of our revenue for the years ended December 31, 2019 and 2018 . Revenues from properties were $981.3 million , $821.4 million and $672.0 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. We had net investment in real estate of $4.7 billion and $4.3 billion , at December 31, 2019 and 2018 , respectively. Use of Estimates Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Significant estimates include and are related to determining lease terms and revenue recognition, the fair value for purchase price allocations for business combinations and asset acquisitions, and the useful lives of real estate and other long-lived assets. Actual results may differ from these estimates and assumptions. 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, net, ( $128.7 million ) is classified within rent and other receivables, net. This item was previously included in other assets. Statement of Cash Flows for the year ended December 31, 2018 • Proceeds from revolving credit facility and proceeds from unsecured term loan are separate line items in the current presentation. These items were previously combined in proceeds from debt, net ( $1,988.3 million ) in the comparable prior year period. Repayments of revolving credit facility and repayments of unsecured term loan are separate line items in the current presentation. These items were previously combined in payments on debt ( $1,547.4 million ) in the comparable prior year period. Statement of Cash Flows for the year ended December 31, 2017 • Proceeds from revolving credit facility, proceeds from unsecured term loan, proceeds from senior notes, payment of debt extinguishment costs and payment of deferred financing costs are separate line items in the current presentation. These items were previously combined in proceeds from debt, net ( $2,558.4 million ) in the comparable prior year period. Repayments of revolving credit facility and repayments of senior notes are separate line items in the current presentation. These items were previously combined in payments on debt ( $1,749.8 million ) in the comparable prior year period.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	12 Months Ended
	Dec. 31, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards Recently Adopted 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 recorded as an adjustment to retained earnings on the effective date. By applying the modified retrospective transition method, the presentation of financial information for periods prior to January 1, 2019 was 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) the treatment of 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 discounted based on the implicit rate or alternatively our incremental borrowing rate. The implicit rate is generally not determinable and, as a result, we use our incremental borrowing rate at the lease commencement date to determine the present value. We determine our incremental borrowing rate based on an estimate of our existing yield curve at the lease commencement. The rates are then adjusted for various factors to estimate the company’s secured rate, including the lease term and collateralization. The determination of our incremental borrowing rate requires judgment. 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 the 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 an original lease term of 12 months or less. The adoption of ASC 842 had a significant impact on our Consolidated Balance Sheets 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 Sheets as of December 31, 2019 and 2018 (in millions) related to previously reported BTS leases: Impact to the Consolidated Balance Sheets: As of December 31, 2019 As of December 31, 2018 Buildings and improvements, net of accumulated depreciation $ — $ 77.4 Operating lease right-of-use assets, net of amortization 44.9 — Finance lease liabilities — 123.3 Operating lease liabilities, net of accretion 77.9 — 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 the Consolidated Statements 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 Statements 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 costs that are not incremental are expensed as general and administrative expense in our Consolidated Statements of Operations. Prior to the adoption of the 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 a 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 components. 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. Share-based payments granted to nonemployees On January 1, 2019, 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 to how 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 . Changes in Shareholders' Equity 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) for interim periods on Form 10-Q. In accordance with the SEC's rule, the Company’s first presentation of changes in shareholders’ equity was shown in its Form 10-Q for the quarter ending March 31, 2019. New Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies various aspects related to the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. The guidance is effective for periods beginning after December 15, 2020, with early adoption permitted. The Company is evaluating the impact of the new standard. In August 2018, the FASB issued ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software, 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 and 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, Fair Value Measurement, 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 disclosures of fair value measurement by using those concepts. The guidance is effective for periods beginning after December 15, 2019 and 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 June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses, providing guidance which requires certain financial assets to be presented at the net amount expected to be collected. The FASB has subsequently issued various amendments to further clarify the scope of the initial guidance. ASU 2016-13 and its related amendments will apply to our rent 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. FASB further clarified that receivables arising from operating leases are not within the scope of this sub-topic. The guidance is effective for periods beginning after December 15, 2019 and early adoption is allowed. The Company has evaluated the impact of the new standard and does not believe the adoption will have a significant impact on the Company because the Company has limited exposure to financial instruments subject to this standard.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 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 commencement, 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. Generally, our customer lease arrangements do not provide any option to purchase and are classified as operating leases. At December 31, 2019 , the future minimum lease payments to be received for the next five years under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: IN MILLIONS 2020 $ 736.2 2021 620.2 2022 528.2 2023 426.5 2024 328.7 Thereafter 973.9 Total $ 3,613.7 Disclosures related to periods prior to adoption of the New Accounting Standard for Leases The future minimum lease payments as of December 31, 2018 to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: IN MILLIONS 2019 $ 647.6 2020 553.7 2021 453.0 2022 365.5 2023 284.4 Thereafter 835.9 Total $ 3,140.1 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 typically consumed at the completion of the service. Disaggregation of Revenue For the year ended December 31, 2019 , lease revenue disaggregated by primary revenue stream is as follows (in millions): Lease revenue Year Ended December 31, 2019 Colocation (Minimum lease payments) $ 793.5 Metered power reimbursements (Variable lease payments) 138.8 Total lease revenue $ 932.3 For the years ended December 31, 2019 and 2018 revenue from contracts with customers disaggregated by primary revenue stream is as follows (in millions): Revenue from contracts with customers Year Ended December 31, 2019 Year Ended December 31, 2018 Equipment sales and services $ 29.7 $ 15.3 Other revenue 19.3 17.4 Total revenue from contracts with customers $ 49.0 $ 32.7 Other revenue from contracts with customers includes $15.9 million and $13.5 million of revenue from managed services for the years ended December 31, 2019 and 2018 , respectively. Total revenues from contracts with customers generated from operations outside of the United States were $2.9 million for the year ended December 31, 2019 and insignificant for the year ended December 31, 2018 . The balances from managed services customers accounts receivables were $6.4 million and $9.4 million as of December 31, 2019 and 2018 , respectively. Contract assets and liabilities were not material as of both December 31, 2019 and 2018 . The Company had revenue of $981.3 million and $821.4 million for the years ended December 31, 2019 and 2018, respectively. One customer represented approximately 21% and 18% of our revenue for the years ended December 31, 2019 and 2018 , respectively.

Leases - As a Lessee

Leases - As a Lessee	12 Months Ended
	Dec. 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 consisting of non-lease components and services are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation is incurred. 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 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 incurred prior to the effective date have not been reassessed. 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 lease 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 operate five data center facilities and have a data center under development subject to finance leases. During the third quarter of 2019, the Company entered into one ground lease in Dublin, the Republic of Ireland for a term of 999 years (see Note 7, Acquisitions and Purchases of Fixed Assets, for more information). The Dublin finance lease was capitalized as land and included in Construction in progress, including land under development on the Consolidated Balance Sheets. The remaining term of our data center finance leases range from two to twenty-one years with options to extend the initial lease term on all but one lease. As a result of electing the package of practical expedients, data center finance leases are included in buildings and improvements, equipment and finance lease liabilities in our Consolidated Balance Sheets consistent with the presentation under ASC 840 in the prior year. In addition, we lease 12 data centers and 4 offices supporting our sales and corporate activities under operating lease agreements. Our operating leases have remaining lease terms ranging from one to twenty-five years and one ground lease in Houston has a lease term that expires in 2066. The components of lease expense are as follows (in millions): Year Ended December 31, 2019 Operating lease cost $ 20.3 Finance lease cost: Amortization of assets 2.3 Interest on lease liabilities 1.7 Total net lease cost $ 24.3 Supplemental balance sheet information related to leases is as follows (in millions, except lease term and discount rate): December 31, 2019 Operating leases: Operating lease right-of-use assets $ 161.9 Operating lease liabilities $ 195.8 Finance leases: Property and equipment, at cost $ 34.9 Accumulated amortization (5.0 ) Property and equipment, net $ 29.9 Finance lease liabilities $ 31.8 Weighted average remaining lease term (in years): Operating leases 15.8 Finance leases (a) 18.1 Weighted average discount rate: Operating leases 3.9 % Finance leases (a) 4.9 % (a) Excludes the 999 -year ground lease in Dublin, the Republic of Ireland. Supplemental cash flow and other information related to leases is as follows (in millions): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 22.1 Operating cash flows from finance leases 1.7 Financing cash flows from finance leases 2.9 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 175.1 Finance leases 0.8 Maturities of lease liabilities were as follows (in millions): As of December 31, 2019 Operating Leases Finance Leases 2020 $ 22.4 $ 5.0 2021 21.0 4.1 2022 22.4 2.9 2023 18.5 1.9 2024 13.9 1.4 Thereafter 165.4 31.1 Total lease payments $ 263.6 $ 46.4 Less: Imputed interest (67.8 ) (14.6 ) Total lease obligations $ 195.8 $ 31.8 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): Operating Leases Capital Leases Lease Financing Arrangements 2019 $ 5.0 $ 2.7 $ 15.0 2020 4.9 2.8 27.6 2021 3.7 2.9 11.4 2022 3.7 2.0 11.6 2023 3.5 1.0 10.0 Thereafter 43.4 22.0 89.1 Total lease payments $ 64.2 $ 33.4 $ 164.7
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 consisting of non-lease components and services are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation is incurred. 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 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 incurred prior to the effective date have not been reassessed. 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 lease 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 operate five data center facilities and have a data center under development subject to finance leases. During the third quarter of 2019, the Company entered into one ground lease in Dublin, the Republic of Ireland for a term of 999 years (see Note 7, Acquisitions and Purchases of Fixed Assets, for more information). The Dublin finance lease was capitalized as land and included in Construction in progress, including land under development on the Consolidated Balance Sheets. The remaining term of our data center finance leases range from two to twenty-one years with options to extend the initial lease term on all but one lease. As a result of electing the package of practical expedients, data center finance leases are included in buildings and improvements, equipment and finance lease liabilities in our Consolidated Balance Sheets consistent with the presentation under ASC 840 in the prior year. In addition, we lease 12 data centers and 4 offices supporting our sales and corporate activities under operating lease agreements. Our operating leases have remaining lease terms ranging from one to twenty-five years and one ground lease in Houston has a lease term that expires in 2066. The components of lease expense are as follows (in millions): Year Ended December 31, 2019 Operating lease cost $ 20.3 Finance lease cost: Amortization of assets 2.3 Interest on lease liabilities 1.7 Total net lease cost $ 24.3 Supplemental balance sheet information related to leases is as follows (in millions, except lease term and discount rate): December 31, 2019 Operating leases: Operating lease right-of-use assets $ 161.9 Operating lease liabilities $ 195.8 Finance leases: Property and equipment, at cost $ 34.9 Accumulated amortization (5.0 ) Property and equipment, net $ 29.9 Finance lease liabilities $ 31.8 Weighted average remaining lease term (in years): Operating leases 15.8 Finance leases (a) 18.1 Weighted average discount rate: Operating leases 3.9 % Finance leases (a) 4.9 % (a) Excludes the 999 -year ground lease in Dublin, the Republic of Ireland. Supplemental cash flow and other information related to leases is as follows (in millions): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 22.1 Operating cash flows from finance leases 1.7 Financing cash flows from finance leases 2.9 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 175.1 Finance leases 0.8 Maturities of lease liabilities were as follows (in millions): As of December 31, 2019 Operating Leases Finance Leases 2020 $ 22.4 $ 5.0 2021 21.0 4.1 2022 22.4 2.9 2023 18.5 1.9 2024 13.9 1.4 Thereafter 165.4 31.1 Total lease payments $ 263.6 $ 46.4 Less: Imputed interest (67.8 ) (14.6 ) Total lease obligations $ 195.8 $ 31.8 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): Operating Leases Capital Leases Lease Financing Arrangements 2019 $ 5.0 $ 2.7 $ 15.0 2020 4.9 2.8 27.6 2021 3.7 2.9 11.4 2022 3.7 2.0 11.6 2023 3.5 1.0 10.0 Thereafter 43.4 22.0 89.1 Total lease payments $ 64.2 $ 33.4 $ 164.7

Acquisitions and Purchases of F

Acquisitions and Purchases of Fixed Assets	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions and Purchases of Fixed Assets	Acquisitions and Purchases of Fixed Assets Land for future development During the year ended December 31, 2019 , the Company purchased approximately 74 acres of land for $54.7 million in Dublin, the Republic of Ireland, San Antonio, Santa Clara and Council Bluffs, Iowa. During the year ended December 31, 2018 , the Company purchased approximately 182 acres of land for $182.3 million in Dallas, Frankfurt, Germany, Northern Virginia, Phoenix and Santa Clara. Leases of real estate The Company entered into a 999 -year ground lease in September 2019 for 16 acres in Dublin, the Republic of Ireland, and purchased 9 acres of land totaling 24 acres for future development of a 6 MW data center. Construction commenced in July 2019. The Company prepaid $6.3 million of the lease payments and concluded that the present value of lease payments was equal to substantially all of the fair value of the land and classified the lease as a finance lease. In August 2019, the Company entered into a lease for land comprising 3 acres and a building shell of approximately 51,000 square feet in London, UK for 25 years, including an option to extend for an additional 25 years. The Company immediately began development and construction of a 6 MW data center in London. We determined that the option to renew was not reasonably certain to be exercised. The fixed lease payments are £0.9 million per year and we classified the lease as an operating lease because the lease term was not for a major part of the remaining economic life of the building shell; nor did the lease qualify as a finance lease based on the other criteria under ASC 842. In November 2019, the Company entered into a lease for land comprising 6.5 acres and a building shell of approximately 105,000 square feet in London, UK for 20 years, including an option to extend for an additional 15 years. We determined that the option to renew was not reasonably certain to be exercised. The fixed lease payments are £2.1 million per year and we classified the lease as an operating lease because the lease term was not for a major part of the remaining economic life of the building shell; nor did the lease qualify as a finance lease based on the other criteria under ASC 842. Acquisitions of Data Centers On August 24, 2018, the Company completed its previously announced acquisition of Zenium Topco Ltd. and certain other affiliated entities ("Zenium"). Zenium is a hyperscale data center provider in Europe with four operating data centers in London and Frankfurt, and land sites available for development in London and Frankfurt. In connection with the acquisition, and after giving effect to a post-closing working capital adjustment, the Company paid aggregate cash consideration of approximately $462.8 million , net of approximately $12.7 million of cash acquired, and assumed outstanding indebtedness of approximately $86.3 million . In the fourth quarter of 2018, the Company paid approximately $1.0 million related to the post-closing working capital adjustment which is included above in the aggregate cash consideration. The Company financed the acquisition with proceeds from the $300.0 million delayed draw term loan included in the 2023 Term Loan and $174.5 million of borrowings under the $1.7 Billion Revolving Credit Facility (each as defined below). The Company evaluated the acquisition and determined that substantially all of the fair value of the gross assets was concentrated in a group of similar identifiable assets and accounted for the transaction as an acquisition of assets. The consolidated financial statements of CyrusOne Inc. include the operating results of Zenium since the acquisition date, which was August 24, 2018. The following table summarizes the estimated fair values of all assets acquired at the date of acquisition: IN MILLIONS Investment in real estate $ 597.3 Cash and cash equivalents 12.7 Rent and other receivables 9.0 Intangible assets: Trade name 1.8 Leasehold interest 1.7 In-place leases 61.5 Other assets 1.1 Accounts payable (22.3 ) Deferred revenue (3.3 ) Capital lease obligations (25.0 ) Deferred tax liability (72.7 ) Debt (86.3 ) Net assets acquired attributable to CyrusOne Inc. $ 475.5 Cash acquired (12.7 ) Net cash paid at acquisition $ 462.8 Real Estate Investments and Intangibles and Related Depreciation and Amortization As of December 31, 2019 and 2018 , major components of our real estate investments and intangibles and related accumulated depreciation and amortization are as follows (in millions): December 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 $ 1,761.4 $ 3,028.2 $ 247.1 $ 137.1 $ 19.4 $ 1,677.5 $ 2,630.2 $ 247.1 $ 136.0 $ 19.5 Less: accumulated depreciation and amortization (545.1 ) (834.1 ) (151.1 ) (46.7 ) (9.7 ) (481.8 ) (572.7 ) (137.9 ) (21.1 ) (7.9 ) Net $ 1,216.3 $ 2,194.1 $ 96.0 $ 90.4 $ 9.7 $ 1,195.7 $ 2,057.5 $ 109.2 $ 114.9 $ 11.6

Investment in Real Estate

Investment in Real Estate	12 Months Ended
	Dec. 31, 2019
Real Estate [Abstract]
Investment in Real Estate	Investment in Real Estate A schedule of our gross investment in real estate follows: IN MILLIONS As of December 31, 2019 2018 Acquisition Date Land Building and Equipment Land Building and Equipment Austin II 2011 $ 2.0 $ 23.5 $ 13.3 $ 2.0 $ 23.4 $ 8.7 Austin III 2015 3.3 12.6 64.0 3.3 11.7 47.0 Chicago - Aurora I 2016 2.4 32.4 136.3 2.4 32.4 132.9 Chicago - Aurora II 2016 2.6 22.9 70.3 2.6 22.6 68.6 Chicago - Aurora Tower 2018 — 6.4 0.9 — 4.9 0.4 Chicago - Lombard 2008 0.7 4.7 8.1 0.7 4.7 8.1 Cincinnati - 7th Street (1) 1999 0.9 114.1 37.2 0.9 114.1 37.4 Cincinnati - Blue Ash (2) 2009 — 0.7 0.2 — 0.7 0.2 Cincinnati - Goldcoast 2007 — — — 0.2 4.0 0.1 Cincinnati - Hamilton (2) 2007 — 43.7 7.8 — 43.7 7.9 Cincinnati - Mason 2004 — 20.3 1.7 — 20.3 1.7 Cincinnati - North Cincinnati 2008 0.9 77.8 16.0 0.9 77.9 12.4 Dallas - Allen 2017 6.5 15.0 39.5 — — — Dallas - Carrollton 2012 16.1 63.8 323.3 16.1 62.2 272.5 Dallas - Lewisville (2) 2010 — 58.1 41.1 — 76.8 39.6 Florence 2005 2.2 42.0 8.7 2.2 42.0 8.4 Frankfurt I 2018 4.0 36.0 123.7 4.1 35.7 124.9 Frankfurt II 2018 7.0 135.1 93.6 7.1 89.8 53.9 Houston - Galleria (3) 2010 — 71.0 24.4 — 71.0 20.2 Houston - Houston West I 2010 1.4 85.2 51.6 1.4 85.2 51.1 Houston - Houston West II 2013 2.7 22.8 52.0 2.7 22.9 50.9 Houston - Houston West III 2013 7.2 18.1 32.3 7.2 18.0 31.4 London - Great Bridgewater (4) 2011 — — 1.3 — 26.8 1.2 London I (2) 2018 — 44.3 46.4 — 34.1 26.3 London II (2) 2018 — 42.8 93.3 — 25.2 74.8 Northern Virginia - Sterling I 2013 6.9 20.2 62.2 6.9 20.2 60.4 Northern Virginia - Sterling II 2013 — 28.8 112.4 — 28.8 112.4 Northern Virginia - Sterling III 2017 — 22.3 61.8 — 22.2 61.3 Northern Virginia - Sterling IV 2016 4.6 20.1 78.1 4.6 20.0 76.0 Northern Virginia - Sterling V 2016 14.5 81.7 303.7 14.5 80.8 295.8 Northern Virginia - Sterling VI 2018 9.7 60.2 196.9 — — 77.5 Northern Virginia - Sterling VIII 2018 9.1 7.0 28.0 — — — Norwalk I (4) 2015 — 1.7 10.6 — 13.6 10.1 Phoenix - Chandler I 2011 10.5 58.3 71.5 10.5 58.3 68.7 Phoenix - Chandler II 2014 — 16.2 39.8 — 16.2 39.4 Phoenix - Chandler III 2016 — 11.4 51.3 — 11.4 50.8 Phoenix - Chandler IV 2017 — 18.4 44.3 — 18.4 43.3 Phoenix - Chandler V 2017 — 12.1 54.6 — 10.7 53.4 Phoenix - Chandler VI 2016 2.4 23.3 101.7 2.4 23.3 100.3 Phoenix - Chandler VII 2016 4.2 0.8 0.4 — — — Raleigh-Durham I 2017 2.1 79.8 80.0 2.1 79.8 75.4 San Antonio I 2011 4.6 31.7 36.3 4.6 31.7 35.3 San Antonio II 2013 7.0 30.3 61.0 7.0 30.3 60.8 San Antonio III 2017 — 40.2 99.5 — 40.2 99.0 IN MILLIONS As of December 31, 2019 2018 Land Building and Equipment Land Building and Equipment San Antonio IV 2017 $ — $ 56.3 $ 50.6 $ — $ 42.1 $ 48.2 Santa Clara II 2019 — 2.7 — — — — Singapore - Inter Business Park (4) 2011 — — — — — — Somerset I 2017 12.1 132.1 101.8 12.1 125.8 91.0 South Bend - Crescent (2) 2008 — — — — 1.7 0.2 South Bend - Monroe 2007 — 1.9 0.3 — 2.5 0.4 Stamford - Omega (4) 2015 — 0.1 0.8 — 2.6 0.7 Stamford - Riverbend (4) 2015 — 0.9 8.6 — 2.9 7.8 Totowa - Commerce (4) 2015 — 0.4 1.7 — 4.1 1.7 Totowa - Madison (4) 2015 — 6.1 60.1 — 28.5 57.7 Wappingers Falls I (4) 2015 — 3.1 23.2 — 11.3 22.0 Total $ 147.6 $ 1,761.4 $ 3,028.2 $ 118.5 $ 1,677.5 $ 2,630.2 Land held for future development $ 206.0 $ — $ — $ 176.4 $ — $ — 1) The information provided for the Cincinnati - 7th Street property includes data for two facilities, one of which we lease and one of which we own. 2) Indicates properties in which we hold a leasehold interest in the building shell and land. All data center infrastructure has been constructed by us and is owned by us. 3) Indicates properties in which we hold a leasehold interest in land. All data center infrastructure has been constructed by us and is owned by us. 4) Indicates properties in which we hold a leasehold interest in the building shell, land, and all data center infrastructure. As of December 31, 2019 and 2018 , construction in progress includes $61.8 million and $69.1 million of land which is under active development, respectively. In addition, construction in progress was $946.3 million and $744.9 million as of December 31, 2019 and December 31, 2018 , respectively, as we continue to build data center facilities. For the year ended December 31, 2019 , our capital expenditures were $876.4 million , as shown on the statement of cash flows. Substantially all of our investing activity related to our development and acquisition activities. Our capital expenditures for 2019 primarily related to the acquisition of land for future development and continued development in key markets, primarily in Amsterdam, Austin, Dallas, Frankfurt, London, Northern Virginia, Phoenix and Raleigh-Durham. Included in capital expenditures are land purchases of $54.7 million in Santa Clara, San Antonio, Dublin and Council Bluffs for future development. For the year ended December 31, 2018 , our capital expenditures were $1,328.5 million , as shown on the statement of cash flows. This included the purchase price of the properties acquired in the Zenium acquisition on August 24, 2018 for $462.8 million and $865.7 million for other developments primarily in Chicago, Cincinnati, Dallas, Northern Virginia, Phoenix and San Antonio; and the purchase of parcels of land in Phoenix, Northern Virginia, Allen, Amsterdam, Santa Clara and Frankfurt for future development. For the year ended December 31, 2019 , impairment charges of $0.7 million were recognized primarily due to an impairment on the South Bend - Monroe facility, which is being actively marketed for sale. No impairment charges were recognized during the year ended December 31, 2018 .

Equity Investments

Equity Investments	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Equity Investments	Equity Investments The Company has an equity investment in GDS, a developer and operator of high-performance, large-scale data centers in China. We account for our equity investment in GDS using the fair value method. On October 18, 2017, the Company purchased newly issued unregistered ordinary shares equivalent to 8.0 million American depository shares (ADS) at a price per Class A ordinary share equivalent to $12.45 per ADS, a 4% discount to the October 17, 2017 closing price, for a total investment of $100.0 million . Each ADS is equivalent to eight ordinary shares. In April 2019, we sold approximately 5.7 million GDS ADSs for a total sales price of approximately $199.0 million . We continue to hold approximately 2.3 million GDS ADSs. As of December 31, 2019 the ADS Class A ordinary share equivalent was $51.58 per ADS for a total fair value of $118.7 million . IN MILLIONS Year Ended December 31, 2019 Year Ended December 31, 2018 Net gain on marketable equity investment $ 132.3 $ 9.9 Less: Net gain recognized on marketable equity investment sold 66.7 — Unrealized gain on marketable equity investment $ 65.6 $ 9.9 The gain on investment is recognized in the Consolidated Statements of Operations in gain on marketable equity investment. 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 investment totaling $0.7 million in ODATA Colombia S.A.S ("ODATA Colombia"). In connection with these investments, CyrusOne and ODATA entered into 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 and concluded that the investment should be accounted for under the cost method. During the year ended December 31, 2019 , the Company made additional investments totaling $3.8 million in ODATA.

Goodwill, Intangible and Other

Goodwill, Intangible and Other Long-Lived Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Intangible and Other Long-Lived Assets	Goodwill, Intangible and Other Long-Lived Assets The carrying amount of goodwill was $455.1 million as of December 31, 2019 and 2018 . See Note 7, Acquisition and Purchase of Fixed Assets, for the explanation of changes to intangible assets. Summarized below are the carrying values for the major classes of intangible assets: IN MILLIONS For the year ended December 31, 2019 2018 Weighted- Gross Carrying Amount Accumulated Amortization Total Gross Carrying Amount Accumulated Amortization Total Customer relationships 10 $ 247.1 $ (151.1 ) $ 96.0 $ 247.1 $ (137.9 ) $ 109.2 Trademark/tradename 4 11.5 (7.8 ) 3.7 11.5 (6.7 ) 4.8 Favorable leasehold interest 35 5.6 (1.2 ) 4.4 5.7 (0.7 ) 5.0 In-place customer leases 5 137.1 (46.7 ) 90.4 136.0 (21.1 ) 114.9 Above and below market leases 6 2.3 (0.7 ) 1.6 2.3 (0.5 ) 1.8 Total $ 403.6 $ (207.5 ) $ 196.1 $ 402.6 $ (166.9 ) $ 235.7 There were no goodwill or intangible asset impairments for the years ended December 31, 2019 or 2018 . Amortization expense for acquired intangible assets was $39.9 million , $30.6 million and $25.1 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. The following table presents estimated amortization expense for each of the next five years and thereafter, commencing January 1, 2020 : IN MILLIONS Total 2020 $ 39.3 2021 32.0 2022 28.6 2023 20.7 2024 18.6 Thereafter 56.9 Total $ 196.1

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets As of December 31, 2019 and 2018 , the components of other assets are as follows (in millions): 12/31/2019 12/31/2018 Deferred leasing and other contract costs $ 53.2 $ 43.6 Prepaid expenses 22.1 26.4 Non-real estate assets, net 16.3 18.4 Derivative assets 3.5 — Other assets 18.8 22.9 Total $ 113.9 $ 111.3 Non-real estate assets, net 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 land deposits, fuel inventory, notes receivable, net deferred tax assets and other deferred costs.

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt As of December 31, 2019 and 2018 , the components of debt are as follows (unless otherwise noted, interest rate and maturity date information are as of December 31, 2019 ) (in millions): December 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 (a) $ 555.0 $ — Monthly LIBOR + 1.20% EUR Revolver 33.6 143.0 Monthly EURIBOR + 1.20% GBP Revolver (a) 26.4 — Monthly LIBOR + 1.20% 2023 Term Loan 800.0 1,000.0 Monthly LIBOR + 1.35% March 2023 2025 Term Loan 300.0 300.0 Monthly LIBOR + 1.65% March 2025 Old 2024 Notes, including bond premium of $5.5 million — 705.5 5.000 % March 2024 Old 2027 Notes, including bond premium of $9.1 million — 509.1 5.375 % March 2027 2024 Notes, including bond discount of $0.8 million 599.2 — 2.900 % November 2024 2029 Notes, including bond discount of $1.8 million 598.2 — 3.450 % November 2029 Deferred financing costs (25.8 ) (32.9 ) — — Total $ 2,886.6 $ 2,624.7 (a) - Monthly USD LIBOR and GBP LIBOR as of December 31, 2019 was 1.80% and 0.71% , respectively. (b) - The Company has an option to exercise a one -year extension option, subject to certain conditions. Credit facilities 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. 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 loan components to $3.8 billion , subject to certain conditions. The $1.7 Billion Revolving Credit Facility, 2023 Term Loan and 2025 Term Loan are prepayable at our option. In April 2019, the Company used the proceeds from the sale of GDS shares to pay down $200.0 million of the 2023 Term Loan. 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 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 . In August 2018, the Company financed the acquisition of Zenium with proceeds from its $300.0 million delayed draw term loan included in the 2023 Term Loan and $174.5 million of borrowings under the $1.7 Billion Revolving Credit Facility. In connection with the acquisition, the Company assumed a six -year, €100.0 million construction facility, which was paid off in December 2018. Prior to obtaining an investment grade rating in September 2019 and shifting to a ratings-based pricing grid under the $1.7 Billion Revolving Credit Facility, we paid commitment fees for the unused amount of borrowings on the $1.7 Billion Revolving Credit Facility and fees on any outstanding letters of credit 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. Following the shift to a ratings-based pricing grid, we pay a facility fee calculated based on the aggregate revolving commitments. The facility fee rate varies based on ratings-based pricing levels, and is currently equal to 0.25% per annum of the aggregate revolving commitments. We also paid commitment fees on the $1.1 Billion Revolving Credit Facility through its retirement in March 2018. The facility fee or commitment fee, as applicable, was $2.6 million , $3.8 million and $1.9 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. As of December 31, 2019 , we had $800.0 million , $300.0 million and $615.0 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 $1.1 billion ( $1.1 billion under the $1.7 Billion Revolving Credit Facility and zero under the 2023 Term Loan), net of $8.2 million of outstanding letters of credit. Senior notes On December 5, 2019, the Operating Partnership and CyrusOne Finance Corp., a single-purpose finance subsidiary, both wholly-owned subsidiaries of the Company (together, the "Issuers") completed a public offering of $600.0 million aggregate principal amount of 2.900% senior notes due 2024 (the "2024 Notes") and $600.0 million aggregate principal amount of 3.450% senior notes due 2029 (the “2029 Notes”). The Company received proceeds of $1,197.4 million , net of underwriting costs and other deferred financing costs. The Company used the proceeds to finance the repurchase of all of its Old 2024 Notes and all of its Old 2027 Notes (each as defined below and together, the "Existing Notes"), including the payment of consent payments, for the redemption and discharge of Existing Notes that remained outstanding after the completion of the tender offers and consent solicitations, for the payment of related premiums, fees, discounts and expenses and for general corporate purposes. In connection with the repurchase of the Existing Notes, the Company recognized a loss on early extinguishment of debt of $71.8 million . The 2024 Notes and 2029 Notes are senior unsecured obligations of the Issuers guaranteed by CyrusOne Inc., which rank equally in right of payment with all existing and future unsecured senior indebtedness of the Issuers. The 2024 Notes and 2029 Notes are effectively subordinated in right of payment to any secured indebtedness of the Issuers to the extent of the value of the assets securing such indebtedness. The 2024 Notes and 2029 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. In September 2019, CyrusOne LP received an investment grade rating and the guarantees of the $3.0 Billion Credit Facility by CyrusOne LP’s existing domestic subsidiaries (“Subsidiary Guarantors”) were released. In connection therewith, the guarantees of the Old 2024 Notes and the Old 2027 Notes by such guarantors were also released. On March 17, 2017, the Operating Partnership and CyrusOne Finance Corp., completed an offering of $500.0 million aggregate principal amount of 5.000% senior notes due 2024 ("Original Old 2024 Notes") and $300.0 million aggregate principal amount of 5.375% senior notes due 2027 ("Original Old 2027 Notes") in a private offering. The Company received proceeds of $791.2 million , net of underwriting costs and other deferred financing costs. On November 3, 2017, the Issuers completed an offering of $200.0 million aggregate principal amount of 5.000% senior notes due 2024 ("Additional Old 2024 Notes") and $200.0 million aggregate principal amount of 5.375% senior notes due 2027 ("Additional Old 2027 Notes") in a private offering. The Additional Old 2024 Notes have terms substantially identical to the Original Old 2024 Notes and the Additional Old 2027 Notes have terms substantially identical to the Original Old 2027 Notes. The Original Old 2024 Notes and the Additional Old 2024 Notes form a single class of securities ("Old 2024 Notes"), and the Original Old 2027 Notes and the Additional Old 2027 Notes form a single class of securities ("Old 2027 Notes"). The Company received proceeds of $416.1 million , net of underwriting costs of $4.4 million . The Original Old 2024 Notes and the Additional Old 2024 Notes are referred to as the Old 2024 Notes and the Original Old 2027 Notes and the Additional Old 2027 Notes are referred to as the Old 2027 Notes. On January 8, 2018, the Issuers completed an exchange offer with respect to the Old 2024 Notes and the Old 2027 Notes and all validly tendered Old 2024 Notes and Old 2027 Notes were exchanged for notes registered with the SEC. In December 2019, all of the Old 2024 Notes and Old 2027 Notes were repurchased as described above. On November 20, 2012, wholly-owned subsidiaries of the Company issued $525.0 million of 6.375% senior notes due 2022 (the " 6.375% Notes"). In March 2017, the Company repurchased all of the 6.375% Notes with an aggregate face value of $474.8 million , a net carrying value of $469.0 million , for total consideration of $515.1 million , including accrued and unpaid interest of $10.3 million . In connection with the debt prepayment, we recognized a loss on early extinguishment of debt of $36.5 million . Financial debt covenants 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, maximum net operating income to debt service 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 December 31, 2019 , we believe we are in compliance with all provisions of our debt agreements. Debt Maturities The following table summarizes aggregate maturities of the $3.0 Billion Credit Facility and 2024 Notes and 2029 Notes for the five years subsequent to December 31, 2019 , and thereafter: IN MILLIONS $3.0 Billion Credit Facility (a) 2024 Notes and 2029 Notes Total 2020 $ — $ — $ — 2021 — — — 2022 615.0 — 615.0 2023 800.0 — 800.0 2024 — 600.0 600.0 Thereafter 300.0 600.0 900.0 Total debt $ 1,715.0 $ 1,200.0 $ 2,915.0 (a) - The Company has an option to exercise a one -year extension option on the $1.7 Billion Revolving Credit Facility, subject to certain conditions, which would extend the final maturity to March 2023.

Fair Value of Financial Instrum

Fair Value of Financial Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments and Hedging Activities	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 December 31, 2019 and 2018 , due to the floating rate nature of the interest rates and the stability of our credit ratings. We determine the fair value of our derivative financial instruments using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves, foreign exchange rates and implied volatilities. We determine the fair values of our interest rate swaps using the market standard methodology of netting the discounted future fixed cash receipts or payments and the discounted expected variable cash payments. We base the variable cash payments on an expectation of future interest rates, or forward curves, derived from observable market interest rate curves. We base the fair values of our net investment hedges on the change in the spot rate at the end of the period as compared with the strike price at inception. We incorporate credit valuation adjustments to appropriately reflect nonperformance risk for us and the respective counterparty in the fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we consider the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts and guarantees. We have determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy. Although the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by us and our counterparties, we assess the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and have determined that the credit valuation adjustments are not significant to the overall valuation of our derivatives. The carrying value and fair value of other financial instruments are as follows (in millions): IN MILLIONS For the year ended December 31, 2019 2018 Carrying Value Fair Value Carrying Value Fair Value Old 2024 Notes - 5.000% $ — $ — $ 705.5 $ 684.1 Old 2027 Notes - 5.375% — — 509.1 488.0 2024 Notes - 2.900% 599.2 602.1 — — 2029 Notes - 3.450% 598.2 603.1 — — GDS Equity investment 118.7 118.7 185.5 185.5 The fair values of our 2024 Notes and 2029 Notes as of December 31, 2019 and Old 2024 Notes and Old 2027 Notes as of December 31, 2018 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 GDS equity investment as of December 31, 2019 and 2018 were based on the quoted market price for the stock which is considered Level 1 of the fair value hierarchy. For the year ended December 31, 2019, we recognized impairment losses of $0.7 million included in Impairment losses in our Consolidated Statements of Operations. We utilize estimates of the fair value of assets to determine impairment losses. These estimates include Level 3 inputs including market rents, expected occupancy and estimates of additional capital expenditures, and cashflows from each investment. There were no impairment losses for the year ended December 31, 2018. 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 swaps 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. We also use derivatives, such as foreign currency swaps, that are not designated as hedges to manage foreign currency exchange rate risks. The changes in fair values of these derivatives that were not designated or did not qualify as hedging instruments are immediately, recognized in earnings within the line item Foreign currency and derivative losses, net in the Consolidated Statements of Operations. The following table summarizes the Company's derivative positions as of December 31, 2019 and 2018 (in millions): December 31, 2019 December 31, 2018 Maturity Date Notional Amount Hedged Risk Asset Liability Asset Liability Undesignated derivatives Cross Currency Swaps EUR - USD 01/15/2020 $ 265.3 Foreign currency exchange $ — $ 2.1 $ — $ — EUR - USD 01/15/2020 25.6 Foreign currency exchange — 0.2 — — Designated derivatives Cross Currency Swaps EUR - USD 3/29/2023 250.0 Net investment hedge — 3.8 — — EUR - USD 3/29/2023 250.0 Net investment hedge — 3.9 — — EUR - USD 1/15/2020 155.9 Net investment hedge — 1.4 — — Interest Rate Swaps USD Libor 3/29/2023 300.0 Interest rate hedge - Float to fixed 3.5 — — — Total $ 1,246.8 $ 3.5 $ 11.4 $ — $ — Cross-Currency Swaps The Company has entered into cross-currency swaps whereby the Company pays floating interest rate and receives floating interest rate to hedge the variability of future cash flows attributable to changes in the 1-month USD LIBOR versus EUR LIBOR rates (a pay-floating, receive-floating interest rate swap). As of December 31, 2019, the Company has the following cross-currency contracts: • EUR/USD contracts to sell $446.8 million and purchase €401.1 million maturing in January 2020 representing a fair value liability of $3.7 million . • EUR/USD contracts to sell $500.0 million and purchase €450.7 million maturing in March 2023 representing a fair value liability of $7.7 million . The pay-floating, receive-floating interest rate swap payments are recognized in interest expense, net in the Consolidated Statements of Operations. The Company recognized a $7.5 million loss on cross-currency contracts for the year ended December 31, 2019, which are recognized in Foreign currency and derivative losses, net in the Consolidated Statements of Operations. Interest Rate Swaps On September 3, 2019, the Company entered into a floating-fixed interest rate swap agreement to convert $300.0 million outstanding of term loan to 1.19% fixed rate debt. Net Investment Hedges 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 foreign currency 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. As of December 31, 2019 , our cross-currency swaps were a liability of $11.4 million reported in Other liabilities, and interest rate swaps were an asset of $3.5 million reported in Other assets. The fair values of qualifying instruments used in hedging transactions as of December 31, 2019 and 2018 are as follows (in millions): Balance Sheet Location December 31, 2019 December 31, 2018 Derivatives Designated as Hedging Instruments Assets: Interest Rate Swap Other Assets $ 3.5 $ — Total $ 3.5 $ — Liabilities: Cross-Currency Swaps Other Liabilities 9.1 — Total $ 9.1 $ — The following table presents the effect of our derivative financial instruments on our accompanying consolidated financial statements (in millions): December 31, 2019 December 31, 2018 Derivatives in Cash Flow Hedging Relationships Cross-Currency Swaps: Amount of gain (loss) recognized in OCI for derivatives $ (0.7 ) $ — Amount of gain (loss) reclassified from accumulated OCI for derivatives $ — $ — Amount of gain (loss) recognized in earnings $ (7.5 ) $ — During the next 12 months, we estimate that immaterial amounts will be reclassified from "Accumulated OCI" to net income (loss).

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Currently, our employees participate in health care plans sponsored by CyrusOne, which provide for medical, dental and vision. We incurred $3.9 million , $3.3 million and $2.7 million of expenses related to these plans for the years ended December 31, 2019 , 2018 and 2017 , respectively. CyrusOne offers a defined contribution 401(k) retirement savings plan to its employees. CyrusOne's matching contribution to its retirement savings plan was $1.9 million , $1.8 million and $1.5 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.

Income (Loss) per Share

Income (Loss) per Share	12 Months Ended
	Dec. 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 are also reflected. On November 20, 2019, CyrusOne Inc. entered into a forward sale agreement with Jefferies LLC with respect to 1.6 million shares of its common stock at an initial forward price of $61.67 per share. The hedge completion date was November 29, 2019. The Company has twelve months to settle the forward sale agreement. On September 28, 2018, CyrusOne Inc. completed a public offering of 6.7 million shares of its common stock for $397.3 million , net of underwriting discounts and expenses of approximately $18.1 million . In connection with this offering, on September 25, 2018, CyrusOne Inc. entered into a forward sale agreement with Morgan Stanley & Co. LLC with respect to an additional 2.5 million shares of its common stock. On December 28, 2018, the Company effected a full physical settlement of the previously announced forward sale agreement entered into with Morgan Stanley & Co. LLC. Upon settlement, the Company issued all such shares to Morgan Stanley & Co. LLC in its capacity as forward purchaser, in exchange for net proceeds of approximately $148.2 million , in accordance with the provisions of the forward sales agreement. This agreement and the settlement thereof had no effect on our diluted share count at December 31, 2018. The following table reflects the computation of basic and diluted net (loss) income per share: IN MILLIONS, except per share amounts Year Ended Year Ended Year Ended For December 31, 2019 2018 2017 Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) $ 41.4 $ 41.4 $ 1.2 $ 1.2 $ (83.5 ) $ (83.5 ) Less: Restricted stock dividends (0.7 ) (0.7 ) (1.1 ) (1.1 ) (0.9 ) (0.9 ) Net income (loss) available to stockholders $ 40.7 $ 40.7 $ 0.1 $ 0.1 $ (84.4 ) $ (84.4 ) Denominator: Weighted average common outstanding-basic 112.1 112.1 99.8 99.8 88.9 88.9 Performance-based restricted stock and units (1) 0.4 0.6 — Weighted average shares outstanding-diluted 112.5 100.4 88.9 EPS: Net income (loss) per share-basic $ 0.36 $ — $ (0.95 ) Effect of dilutive shares: Net income (loss) per share-diluted $ 0.36 $ — $ (0.95 ) (1) We have excluded 0.4 million weighted average shares of restricted stock, and 0.1 million of weighted average stock options which are securities convertible into common stock from our diluted earnings per share as of December 31, 2017. These amounts were deemed anti-dilutive.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 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 and February 18, 2019. 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 December 31, 2019 , were approximately 4.6 million . Shares vest according to each 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. The performance-based vesting metrics granted have varied and are described in each of the grant years below. The market-based metric is total stockholder return (TSR) compared to the MSCI US REIT Index (REIT Index) as defined in the award agreements. The market-based restricted stock/units vest annually based upon the achievement of certain criteria for each of the three-year measurement periods. In each of the first two years vesting is limited to 100% of the target. If at the end of the third year total performance over the three-year period exceeds the REIT Index by 2% or more, up to 200% of these awards may vest. The market-based awards will vest based on the below scales. The scales are linear between each point and awards are interpolated between the points. - If CyrusOne's TSR is less than the return of the REIT Index equals 0% - If CyrusOne's TSR is equal to or greater than the return of the REIT Index equals 100% ; up to 200% if CyrusOne's TSR exceeds the return of the REIT Index by 2% - If CyrusOne's TSR exceeds the return of the REIT Index, but is negative, any calculated vesting amount will be reduced by 50% The Company uses the Black-Scholes option-pricing model for time and performance-based options and a Monte Carlo simulation for market-based awards. The fair values of these awards use assumptions such as volatility, risk-free interest rate, and expected term of the awards. The holders of restricted stock have all the rights and privileges of shareholders including the right to vote. The holders of restricted stock units do not have all of the rights and privileges of shareholders and do not have the right to vote. These rights will be acquired upon the settlement of the restricted stock units and the issuance of shares. The time-based restricted stock units have the right to receive dividends that are payable within ten days following the date the dividends are payable to shareholders. Market-based restricted stock units accrue dividends which are paid upon the vesting and settlement of the units. Compensation expense is measured based on the estimated grant-date fair value. Expense for time-based grants is recognized under a straight-line method. For market-based grants, expense is recognized under a graded expense attribution method. For performance-based grants, expense is recognized under a graded expense attribution method if it is probable that the performance targets will be achieved. Any dividends declared with respect to the performance and market-based shares shall be accrued by the Company and distributed on the vesting date provided that the applicable performance goal has been attained. Stock-based compensation expense was as follows: For the periods ended December 31, 2019 2018 2017 2014 Grants $ — $ — $ 0.1 2015 Grants — 0.4 1.8 2016 Grants 1.1 5.7 6.6 2017 Grants 3.1 4.6 6.2 2018 Grants 5.4 6.8 — 2019 Grants and ESPP expense 7.1 — — Total $ 16.7 $ 17.5 $ 14.7 2014 Grants On February 7, 2014, the Company issued performance and market-based awards under the LTIP in the form of restricted stock. For these awards, vesting was tied 50% to the achievement of a non-GAAP financial measure related to the Company's performance (cumulative Adjusted EBITDA targets, as defined in the agreement) over the 2014-2016 performance period, and 50% to a market-based performance measure. The portion of the awards tied to cumulative Adjusted EBITDA vested annually over a three -year period based on the Company attaining predetermined cumulative Adjusted EBITDA targets and as long as the employee remained employed with the Company. The cumulative EBITDA targets are based on the below scales. The scales are linear between each point and awards are interpolated between the points. - Below 90% of performance target equals 0% - At 90% of performance target equals 50% - At 100% of performance target equals 100% - At or above 115% of performance target equals up to 200% In addition, during the year ended December 31, 2014, the Company also granted from time-to-time a total of 46,313 additional time-based restricted shares which had an aggregate value of $1.0 million on the grant date. These shares cliff vested either one year after the grant date or three years after the grant date. Total awards granted in 2014 had a grant date fair value of $12.9 million . As of December 31, 2019 , there was no unearned compensation related to the awards granted in 2014 as all such awards are fully vested. 2015 Grants On February 10, 2015, the Company issued awards under the LTIP in the form of options and restricted stock. The stock options are time-based and vest annually on a pro-rata basis over three years. Twenty percent of the restricted stock awards are subject to time-based vesting and eighty percent of the restricted stock awards are equally split between performance-based and market-based vesting. The performance-based metric is return on assets, which is a non-GAAP financial measure that is defined in the award agreement. The time-based restricted stock will vest pro-rata annually over three years . The performance and market-based restricted stock will vest annually based upon the achievement of certain criteria for each year of the three -year measurement periods. The first two years are capped at 100% of the target with a cumulative true-up to a maximum of 200% possible in year three. The performance-based awards will vest based on the same scales as the awards granted during 2014. In addition, during the year ended December 31, 2015, the Company also granted from time to time a total of 50,300 shares of time-based restricted stock and 67,012 shares of performance-based restricted stock for various new employee hires with vesting schedules ranging from annual to cliff vesting in three years. Total awards granted in 2015 had a grant date fair value of $13.8 million . As of December 31, 2019 , there was no unearned compensation related to the awards granted in 2015 as all such awards are fully vested. 2016 Grants On February 1, 2016, the Company issued 641,097 shares of time, performance and market-based awards under the LTIP in the form of restricted stock. The grant date fair value of time and performance-based restricted shares was $36.99 . The grant date fair value of market-based restricted shares was $43.66 . The Company issued stock options on February 1, 2016. The stock option awards have a contractual life of 10 years from the award date and were granted with an exercise price equal to $36.99 . The Company issued 222,461 options with a grant date fair value of $6.99 . The performance-based metric is return on assets, which is a non-GAAP financial measure and is defined in the award agreement. The time-based restricted stock awards generally vest pro-rata annually over a three -year period. The performance and market-based restricted stock awards vest annually based upon the achievement of certain criteria for each of the three -year measurement periods. The first two years are capped at 100% of the target with a cumulative true-up to a maximum of 200% possible in year three. Certain employees were also awarded time-based restricted stock that cliff vest at the end of three years. The stock options are time-based and vest annually on a pro-rata basis over three years . The performance-based awards will vest based on the same scales as the awards granted during 2014. In addition, during the year ended December 31, 2016, for various new employee hires, the following grants were made: • 5,894 shares of time-based restricted stock which cliff vest in three years from the date of each grant. • 47,667 shares of time-based restricted stock which vest annually on a pro rata basis over a three -year period from the date of each grant. Total awards granted in 2016 had a grant date fair value of $22.6 million . As of December 31, 2019 , there was no unearned compensation related to the awards granted in 2016 as all such awards are fully vested. 2017 Grants On February 13, 2017, the Company issued time and market-based awards under the LTIP in the form of restricted stock units and restricted stock. The Company granted 119,218 time-based restricted stock units that generally vest annually on a pro-rata basis over a three -year period and 18,179 shares of time-based restricted stock that generally vest over a one -year period with a grant date fair value of $48.13 , and 129,146 market-based restricted stock units, at target, with a grant date fair value of $63.23 . In addition, during the year ended December 31, 2017 the Company granted from time to time a total of 20,852 time-based restricted stock units that vest annually on a pro rata basis over a three -year period. Total awards granted in 2017 had a grant date fair value of $15.9 million . As of December 31, 2019 , unearned compensation representing the unvested portion of the awards granted in 2017 totaled $0.5 million , with a weighted average vesting period of 0.1 years. 2018 Grants On February 26, 2018, the Company issued time and market-based awards under the LTIP in the form of restricted stock units and restricted stock. The Company granted 161,797 time-based restricted stock units that generally vest annually on a pro-rata basis over a three -year period and 17,052 shares of time-based restricted stock that generally vest over a one -year period with a grant date fair value of $51.31 , and 160,266 market-based restricted stock units, at target, with a grant date fair value of $52.53 . In addition, during the year ended December 31, 2018 the Company granted from time to time a total of 40,249 time-based restricted stock units that vest annually on a pro rata basis over a three -year period. Total awards granted in 2018 had a grant date fair value of $20.2 million . As of December 31, 2019 , unearned compensation representing the unvested portion of the awards granted in 2018 totaled $5.7 million , with a weighted average vesting period of 0.8 years. 2019 Grants On February 21, 2019, the Company issued time and market-based awards under the LTIP in the form of restricted stock units and restricted stock. The Company granted 175,073 time-based restricted stock units that generally vest annually on a pro-rata basis over a three-year period and 16,681 shares of time-based restricted stock that generally vest over a one-year period with a grant date fair value of $52.46 , and 184,145 market-based restricted stock units, at target, with a grant date fair value of $43.67 . In addition, during the year ended December 31, 2019, the Company granted from time to time a total of 42,052 time-based restricted stock units that vest annually on a pro rata basis over a three-year period. Total awards granted in 2019 had a grant date fair value of $20.5 million . As of December 31, 2019 , unearned compensation representing the unvested portion of the awards granted in 2019 totaled $11.9 million , with a weighted average vesting period of 1.6 years. Restricted Stock Units, Restricted Stock and Stock Option Activity The following tables summarize the unvested restricted stock units, restricted stock and stock options activity and the weighted average fair value of these shares at the date of grant for the year ended December 31, 2019 : Restricted Stock Units ("RSU") 2019 Restricted Stock Units Weighted Average Grant Date Fair Value Outstanding January 1, 511,409 $ 56.23 Granted 401,270 48.90 Vested (187,176 ) 43.37 Forfeited (78,884 ) 52.99 Outstanding December 31, 646,619 $ 55.80 Restricted Stock ("RS") 2019 Restricted Stock Weighted Average Grant Date Fair Value Outstanding January 1, 419,356 $ 35.73 Granted 16,681 52.46 Vested (384,753 ) 35.61 Forfeited (34,603 ) 37.09 Outstanding December 31, 16,681 $ 52.46 Stock Options 2019 Options Weighted Average Exercise Price Outstanding January 1, 401,223 $ 31.96 Granted — — Exercised (25,586 ) 36.70 Forfeited or expired (551 ) 23.58 Outstanding December 31, 375,086 31.64 Exercisable at December 31, 375,086 31.64 Vested and expected to vest 375,086 $ 31.64 The aggregate intrinsic value of options outstanding and options exercisable is based on the Company's closing stock price on the last trading day of the fiscal year for in-the-money options. The aggregate intrinsic value represents the cumulative difference between the fair market value of the underlying common stock and the option exercise prices. The total intrinsic value of options exercised during 2019 was $0.4 million , 2018 was $0.6 million and 2017 was $0.5 million . The aggregate intrinsic value of both options outstanding and options exercisable at December 31, 2019 was $13.1 million . Stock Option Assumptions The following table summarizes the stock option assumptions for the years ended December 31, 2019 , 2018 and 2017 : Options Outstanding Options Exercisable Assumption Range Exercise Prices Number of Shares Weighted Average Remaining Contractual Terms (Years) Number of Shares Weighted Average Remaining Contractual Terms (Years) Risk-Free Interest Rate Expected Annual Dividend Yield Expected Terms in Years Expected Volatility 2017 $23.58 67,322 5.3 67,322 5.3 0.92% 3.4% 6.0 35% $28.42 143,358 7.1 95,572 7.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 7.6 8,479 7.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 192,060 8.1 64,022 8.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0% 2018 $23.58 53,086 4.3 53,086 4.3 0.92% 3.4% 6.0 35% $28.42 143,358 6.1 143,358 6.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 6.6 12,719 6.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 192,060 6.8 130,425 6.7 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0% 2019 $23.58 51,985 3.3 51,985 3.3 0.92% 3.4% 6.0 35% $28.42 143,358 5.1 143,358 5.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 5.6 12,719 5.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 167,024 6.1 167,024 6.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0%

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Capitalization During the first quarter of 2018, the Company entered 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 Company entered 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. During the year ended December 31, 2019 , the Company sold approximately 6.5 million shares of its common stock under its New 2018 ATM Stock Offering Program at an average price of $55.43 , generating net proceeds of approximately $355.6 million , net of sales commissions, underwriting discounts and estimated expenses of $4.3 million . As of December 31, 2019 , there was approximately $290.1 million under the New 2018 ATM Stock Offering Program available for future offerings. During the year ended December 31, 2018, the Company sold 12.2 million common shares at an average price of $59.28 . At December 31, 2019 , the Company had approximately 114.8 million shares of common stock outstanding. On November 20, 2019, CyrusOne Inc. entered into a forward sale agreement with a financial institution acting as forward purchaser under the New 2018 ATM Stock Offering Program with respect to 1.6 million shares of its common stock at an initial forward price of $61.67 per share. The Company has twelve months to settle the forward sale agreement. The Company did not receive any proceeds from the sale of its common shares by the forward purchasers. The Company currently expects to fully physically settle the forward equity sale agreement and receive cash proceeds upon one or more settlement dates at the Company’s discretion, prior to the final settlement dates under the forward equity sale agreement in November 2020, in which case we expect to receive aggregate net cash proceeds at settlement equal to the number of shares specified in such forward equity sale agreement multiplied by the relevant forward price per share. The weighted average forward sale price that we expect to receive upon physical settlement of the agreement will be subject to adjustment for (i) a floating interest rate factor equal to a specified daily rate less a spread, (ii) the forward purchasers’ stock borrowing costs and (iii) scheduled dividends during the term of the agreement. We have not settled any portion of this forward equity sale agreement as of the date of this filing. Dividends We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2019 and 2018 as presented in the table below: Record date Payment date Cash dividend per share or operating partnership unit March 29, 2018 April 13, 2018 $0.46 June 29, 2018 July 13, 2018 $0.46 September 28, 2018 October 12, 2018 $0.46 January 2, 2019 January 11, 2019 $0.46 March 29, 2019 April 12, 2019 $0.46 June 28, 2019 July 12, 2019 $0.46 September 27, 2019 October 11, 2019 $0.50 January 2, 2020 January 10, 2020 $0.50 As of December 31, 2019 and 2018 we had a dividend payable of $58.6 million and $51.0 million , respectively. On February 19, 2020 , we announced a regular cash dividend of $0.50 per common share payable to shareholders of record as of the close of business on March 27, 2020 , payable on April 10, 2020 .

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 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 the People's Republic of 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 years ended December 31, 2019 and 2018 , the Company incurred $0.5 million and $0.9 million of commission and referral charges payable to GDS, respectively. The commission and referral charges were capitalized as deferred leasing costs and will be amortized over the terms of the respective customer leases. No significant referral expense was recognized by the Company in 2019 , 2018 or 2017 . We have not recognized any referral revenue related to the agreement with GDS in 2019 , 2018 or 2017 . See Note 9, Equity Investments, for additional information related to our GDS investment.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CyrusOne Inc. elected to be taxed as a REIT under the Code, commencing with our taxable year ended December 31, 2013. To remain qualified as a REIT, we are required to distribute at least 90% of our taxable income to our stockholders and meet various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we continue to qualify for taxation as a REIT, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our stockholders. It is our policy and intent, subject to change, to distribute 100% of our taxable income and therefore no provision is required in the accompanying financial statements for federal income taxes with regards to activities of CyrusOne Inc. and its subsidiary pass-through entities. The REIT and certain of its subsidiaries are subject to state and local income taxes, franchise taxes, and gross receipts taxes. We have elected to treat certain of our subsidiaries as taxable REIT subsidiaries (TRSs). Our TRSs are subject to U.S. federal, state and local corporate income taxes. Our foreign subsidiaries are subject to corporate income taxes in the jurisdictions in which they operate. Income tax expense (benefit) for the years ended December 31, 2019, 2018 and 2017 as reported in the accompanying Consolidated Statements of Operations was comprised of the following: Year Ended December 31, IN MILLIONS 2019 2018 2017 Current Federal $ 1.7 $ 1.0 $ 1.2 State 1.9 2.0 1.8 Foreign 0.2 — — Total current expense $ 3.8 $ 3.0 $ 3.0 Deferred: Federal — — — State — — — Foreign $ (7.5 ) $ (2.4 ) $ — Total deferred (benefit) expense (7.5 ) (2.4 ) — Total income tax (benefit) expense $ (3.7 ) $ 0.6 $ 3.0 An income tax expense reconciliation between the U.S. statutory tax rate and the effective tax rate is as follows: Year Ended December 31, IN MILLIONS 2019 2018 2017 Income tax at U.S. federal statutory income tax rate $ 7.9 $ 0.4 $ (28.2 ) State and local taxes, net of federal income tax benefit 1.7 2.0 1.8 Impact of REIT status (13.7 ) (2.1 ) 28.6 Permanent differences (0.7 ) (0.1 ) — Foreign tax rate and currency differences (1.0 ) 0.2 — Anti-hybrid disallowances 1.6 0.1 — Valuation allowance 0.5 0.1 0.8 Income tax (benefit) expense $ (3.7 ) $ 0.6 $ 3.0 The effective tax rate on income from continuing operations differs from tax at the statutory rate primarily due to our status as a REIT and taxation of our foreign subsidiaries. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. The components of the Company’s deferred tax assets and liabilities are as follows: Year Ended December 31, IN MILLIONS 2019 2018 Deferred tax assets Net operating loss carryforwards $ 16.3 $ 15.1 Accounts receivable/payable and other 8.2 7.4 Finance leases 0.9 1.8 Total gross deferred tax assets $ 25.4 $ 24.3 Valuation allowance (7.6 ) (6.9 ) Total gross deferred tax assets, net $ 17.8 $ 17.4 Deferred tax liabilities Fixed assets (67.4 ) (73.5 ) Intangibles $ (10.9 ) $ (12.8 ) Total gross deferred tax liabilities $ (78.3 ) $ (86.3 ) Total net deferred tax assets/(liabilities) $ (60.5 ) $ (68.9 ) On August 24, 2018, the Company completed the acquisition of Zenium. The Company recorded a deferred tax liability of $72.7 million in connection with the acquisition, which primarily related to differences between the carrying amounts of the assets and liabilities acquired and their tax bases in the jurisdictions in which they operate. As of December 31, 2019 , the Company’s deferred tax assets were primarily attributable to foreign NOL carryforwards that generally do not expire. A valuation allowance will be recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. As of each reporting date, the Company’s management considers new evidence, both positive and negative, that could impact management’s view with regard to future realization of deferred tax assets. The Company has recorded a valuation allowance of $7.6 million as of December 31, 2019 . The Company and its subsidiaries file tax returns in the U.S. federal jurisdiction, various state and local jurisdictions, and certain foreign jurisdictions. With few exceptions, the Company is no longer subject to examination of its U.S. federal, state and local tax returns for years prior to 2015. As of December 31, 2019 , the Company as no liability for unrecognized tax benefits. If applicable, the Company will recognize interest and penalties related to unrecognized tax benefits as a component of tax expense.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases We lease certain data center facilities and equipment from third parties. Certain of these leases provide for renewal options with fixed rent escalations beyond the initial lease term. Standby Letters of Credit As of December 31, 2019 , CyrusOne Inc. had outstanding letters of credit of $8.2 million as security for obligations under the terms of its lessee agreements. Performance Guarantees Customer contracts generally require specified levels of performance related to uninterrupted service and cooling temperatures. If these performance standards are not met, we could be obligated to issue billing credits to the customer. Management assesses the probability that a performance standard will not be achieved. As of December 31, 2019 and 2018 , no accruals for performance guarantees were required. Purchase Commitments The Company has entered into non-cancellable contracted commitments for construction of data center facilities and acquisition of equipment. As of December 31, 2019 , these commitments were approximately $217.4 million and are expected to be incurred over the next one to two years . In addition, the Company has entered into equipment and electricity 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 December 31, 2019 , the minimum commitments for these arrangements were approximately $89.9 million . The Company has entered into an Agreement to Lease contract that requires the Company to enter into a lease upon shell completion of building in London, UK totaling 70,000 square feet with annual rent totaling £1.4 million for initial lease terms of 20 years. We expect construction of the shell building to be completed in 2020. Indemnifications 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. Contingencies CyrusOne is involved in legal, tax and regulatory proceedings arising from the conduct of its business activities. Liabilities are established for loss contingencies when losses associated with such claims are deemed to be probable, and the loss can be reasonably estimated. Based on information currently available and consultation with legal counsel, we believe that the outcome of all claims will not, individually or in the aggregate, have a material effect on our financial statements.

Guarantors

Guarantors	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Guarantors	Guarantors The 2024 Notes and the 2029 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 by CyrusOne Inc. (the “Parent Guarantor”). The indentures governing the 2024 Notes and 2029 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. 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 indentures. The covenants contained in the indentures do not restrict the Company’s ability to pay dividends or distributions to stockholders. The Old 2024 Notes and the Old 2027 Notes issued by the LP Co-Issuer and the Finance Co-Issuer were fully and unconditionally and jointly and severally guaranteed on a senior unsecured basis. The indentures governing the Old 2024 Notes and Old 2027 Notes contained affirmative and negative covenants customarily found in indebtedness of this type, including covenants that restricted, 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 were 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 did not restrict the Company’s ability to pay dividends or distributions to stockholders to the extent (i) no default or event of default existed or was continuing under the indentures and (ii) the Company believed in good faith that it qualified as a REIT under the Code and the payment of such dividend or distribution was 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 Old 2024 Notes and Old 2027 Notes, in certain circumstances, a Guarantor could have been 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 was 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 was 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 Old 2024 Notes or Old 2027 Notes, as applicable, in accordance with the terms of the indentures, and • upon the Old 2024 Notes or Old 2027 Notes, as applicable, being rated investment grade by at least two rating agencies and no default or event of default having occurred and continuing. The term “Guarantor Subsidiaries” refers collectively to the Subsidiary Guarantors and the General Partner, who were guarantors of the Old 2024 Notes and Old 2027 Notes prior to May 9, 2019. The term “Non-Guarantors” refers collectively to the Company’s foreign subsidiaries and certain domestic subsidiaries, which are not, and were not, prior to May 9, 2019, guarantors of the Old 2024 Notes or Old 2027 Notes. On and after May 9, 2019, the term “Non-Guarantor Subsidiaries” refers collectively to the Subsidiary Guarantors and the Non-Guarantors. 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 following schedules present the consolidating balance sheets as of December 31, 2019 , and the consolidating statements of operations, comprehensive income (loss) and cash flows for the years ended December 31, 2019 , 2018 and 2017 for the Parent Guarantor, General Partner, each Co-Issuer and Non-Guarantor Subsidiaries. Prior to the release of the Subsidiary Guarantors on May 9, 2019, the following schedules present the consolidating balance sheets as of December 31, 2018, the consolidating statements of operations and comprehensive income (loss), and the statements of cash flows for the years ended December 31, 2018 and 2017 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). Consolidating Balance Sheets IN MILLIONS As of December 31, 2019 Parent General LP Finance Non-Guarantor Subsidiaries Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 4,640.4 $ 69.9 $ 4,710.3 Cash and cash equivalents — — 0.6 — 75.8 — 76.4 Investment in subsidiaries 2,402.2 16.8 3,569.0 — — (5,988.0 ) — Rent and other receivables, net — — — — 291.9 — 291.9 Restricted cash — — — — 1.3 — 1.3 Operating lease right-of-use assets, net — — — — 161.9 — 161.9 Intercompany receivable 21.1 — 1,753.3 — 38.8 (1,813.2 ) — Equity investments — — — — 135.1 — 135.1 Goodwill — — — — 455.1 — 455.1 Intangible assets, net — — — — 196.1 — 196.1 Other assets — — 3.5 — 110.4 — 113.9 Total assets $ 2,423.3 $ 16.8 $ 5,326.4 $ — $ 6,106.8 $ (7,731.3 ) $ 6,142.0 Debt $ — $ — $ 2,886.6 $ — $ — $ — $ 2,886.6 Intercompany payable — — 21.1 — 1,792.1 (1,813.2 ) — Finance lease liabilities — — — — 31.8 — 31.8 Operating lease liabilities — — — — 195.8 — 195.8 Construction costs payable — — — — 176.3 — 176.3 Accounts payable and accrued expenses — — 5.1 — 117.6 — 122.7 Dividends payable 58.6 — — — — — 58.6 Deferred revenue and prepaid rents — — — — 163.7 — 163.7 Deferred tax liability — — — — 60.5 — 60.5 Other liabilities — — 11.4 — — — 11.4 Total liabilities 58.6 — 2,924.2 — 2,537.8 (1,813.2 ) 3,707.4 Total stockholders' equity 2,364.7 16.8 2,402.2 — 3,569.0 (5,918.1 ) 2,434.6 Total liabilities and equity $ 2,423.3 $ 16.8 $ 5,326.4 $ — $ 6,106.8 $ (7,731.3 ) $ 6,142.0 IN MILLIONS 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, net — — — — 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) IN MILLIONS Year Ended December 31, 2019 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Non-Guarantor Subsidiaries Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 981.3 $ — $ 981.3 Total operating expenses — — — — 914.3 — 914.3 Operating income — — — — 67.0 — 67.0 Interest (expense) income, net — — (114.5 ) — (0.4 ) 32.9 (82.0 ) Gain on marketable equity investment — — — — 132.3 — 132.3 Loss on early extinguishment of debt — — (71.8 ) — — — (71.8 ) Foreign currency and derivative losses, net — — (7.5 ) — — — (7.5 ) Other expense — — — — (0.3 ) — (0.3 ) (Loss) income before income taxes — — (193.8 ) — 198.6 32.9 37.7 Income tax benefit — — — — 3.7 — 3.7 Equity earnings (loss) related to investment in subsidiaries 19.6 0.1 214.1 — — (233.8 ) — Net income (loss) 19.6 0.1 20.3 — 202.3 (200.9 ) 41.4 Other comprehensive income — — (0.7 ) — 11.8 — 11.1 Comprehensive income (loss) $ 19.6 $ 0.1 $ 19.6 $ — $ 214.1 $ (200.9 ) $ 52.5 IN MILLIONS Year Ended December 31, 2018 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 799.7 $ 21.7 $ — $ 821.4 Total operating expenses — — — — 700.2 31.5 — 731.7 Operating income (loss) — — — — 99.5 (9.8 ) — 89.7 Interest (expense) benefit, net — — (110.6 ) — — (3.3 ) 19.2 (94.7 ) Gain on marketable equity investment — — — — — 9.9 — 9.9 Loss on early extinguishment of debt — — (3.1 ) — — — — (3.1 ) (Loss) income before income taxes — — (113.7 ) — 99.5 (3.2 ) 19.2 1.8 Income tax (expense) benefit — — — — (3.0 ) 2.4 — (0.6 ) Equity (loss) earnings related to investment in subsidiaries (28.9 ) (0.3 ) 84.8 — — — (55.6 ) — Net (loss) income (28.9 ) (0.3 ) (28.9 ) — 96.5 (0.8 ) (36.4 ) 1.2 Other comprehensive loss — — — — — (10.9 ) — (10.9 ) Comprehensive (loss) income $ (28.9 ) $ (0.3 ) $ (28.9 ) $ — $ 96.5 $ (11.7 ) $ (36.4 ) $ (9.7 ) IN MILLIONS Year Ended December 31, 2017 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 666.4 $ 5.6 $ — $ 672.0 Total operating expenses — — — — 640.4 7.5 — 647.9 Operating income (loss) — — — — 26.0 (1.9 ) — 24.1 Interest (expense) benefit, net — — (76.2 ) — — (2.6 ) 10.7 (68.1 ) Loss on early extinguishment of debt — — (36.5 ) — — — — (36.5 ) (Loss) income before income taxes — — (112.7 ) — 26.0 (4.5 ) 10.7 (80.5 ) Income tax expense — — — — (3.0 ) — — (3.0 ) Equity (loss) earnings related to investment in subsidiaries (18.7 ) (0.2 ) 94.0 — (4.6 ) — (70.5 ) — Net (loss) income (18.7 ) (0.2 ) (18.7 ) — 18.4 (4.5 ) (59.8 ) (83.5 ) Other comprehensive income — — — — — 75.5 — 75.5 Comprehensive (loss) income $ (18.7 ) $ (0.2 ) $ (18.7 ) $ — $ 18.4 $ 71.0 $ (59.8 ) $ (8.0 ) Consolidating Statements of Cash Flows IN MILLIONS Year Ended December 31, 2019 Parent General LP Finance Non-Guarantor Subsidiaries Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (124.9 ) $ — $ 457.7 $ 32.9 $ 365.7 Cash flows from investing activities: Investment in real estate — — — — (843.5 ) (32.9 ) (876.4 ) Investment in subsidiaries (357.2 ) (2.5 ) (210.4 ) — — 570.1 — Equity investments — — — — (3.8 ) — (3.8 ) Proceeds from sale of equity investments — — — — 199.0 — 199.0 Proceeds from the sale of real estate assets — — — — 1.3 — 1.3 Return of investment 210.4 — — — — (210.4 ) — Intercompany borrowings 9.3 — 8.2 — 32.0 (49.5 ) — Net cash (used in) provided by investing activities (137.5 ) (2.5 ) (202.2 ) — (615.0 ) 277.3 (679.9 ) Cash flows from financing activities: Issuance of common stock, net 357.2 — — — — — 357.2 Dividends paid (210.4 ) — (210.4 ) — — 210.4 (210.4 ) Intercompany borrowings — — (9.3 ) — (40.2 ) 49.5 — Proceeds from revolving credit facility — — 656.7 — — — 656.7 Repayments of revolving credit facility — — (182.5 ) — — — (182.5 ) Repayments of unsecured term loan — — (200.0 ) — — — (200.0 ) Proceeds from senior notes — — 1,197.4 — — — 1,197.4 Repayments of senior notes — — (1,200.0 ) — — — (1,200.0 ) Payment of debt extinguishment costs — — (72.0 ) — — — (72.0 ) Payment of deferred financing costs — — (9.4 ) — — — (9.4 ) Payments on finance lease liabilities — — — — (2.9 ) — (2.9 ) Tax payment upon exercise of equity awards (9.3 ) — — — — — (9.3 ) Contributions/distributions from parent — 2.5 357.2 — 210.4 (570.1 ) — Net cash provided by (used in) financing activities 137.5 2.5 327.7 — 167.3 (310.2 ) 324.8 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — — — 2.7 — 2.7 Net increase (decrease) in cash, cash equivalents and restricted cash — — 0.6 — 12.7 — 13.3 Cash, cash equivalents and restricted cash at beginning of period — — — — 64.4 — 64.4 Cash, cash equivalents and restricted cash at end of period $ — $ — $ 0.6 $ — $ 77.1 $ — $ 77.7 IN MILLIONS Year Ended December 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (103.6 ) $ — $ 421.6 $ (27.9 ) $ 19.2 $ 309.3 Cash flows from investing activities: Asset acquisitions, primarily real estate, net of cash acquired — — — — — (462.8 ) — (462.8 ) Investment in real estate — — — — (814.6 ) (31.9 ) (19.2 ) (865.7 ) Equity investments — — — — — (12.6 ) — (12.6 ) Investment in subsidiaries (700.0 ) (7.0 ) (829.5 ) — — — 1,536.5 — Return of investment 181.1 — — — — — (181.1 ) — Intercompany borrowings 5.6 — (105.1 ) — (6.8 ) — 106.3 — Net cash (used in) provided by investing activities (513.3 ) (7.0 ) (934.6 ) — (821.4 ) (507.3 ) 1,442.5 (1,341.1 ) Cash flows from financing activities: Issuance of common stock, net 699.6 — — — — — — 699.6 Dividends paid (181.1 ) — (181.1 ) — — — 181.1 (181.1 ) Intercompany borrowings — — (5.6 ) — 105.1 6.8 (106.3 ) — Proceeds from revolving credit facility — — 658.4 — — 29.9 — 688.3 Repayments of revolving credit facility — — (532.7 ) — — (114.7 ) — (647.4 ) Proceeds from unsecured term loan — — 1,300.0 — — — — 1,300.0 Repayments of unsecured term loan — — (900.0 ) — — — — (900.0 ) Payments on finance lease liabilities — — — — (7.9 ) (1.6 ) — (9.5 ) Tax payment upon exercise of equity awards (5.2 ) — — — — — — (5.2 ) Contributions/distributions from parent — 7.0 700.0 — 178.6 650.9 (1,536.5 ) — Net cash provided by (used in) financing activities 513.3 7.0 1,039.0 — 275.8 571.3 (1,461.7 ) 944.7 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — (0.8 ) — — 0.4 — (0.4 ) Net increase (decrease) in cash, cash equivalents and restricted cash — — — — (124.0 ) 36.5 — (87.5 ) 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 $ — $ — $ — $ — $ 27.2 $ 37.2 $ — $ 64.4 IN MILLIONS Year Ended December 31, 2017 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 $ — $ — $ (60.3 ) $ — $ 339.7 $ (0.6 ) $ 10.7 $ 289.5 Cash flows from investing activities: Asset acquisitions, primarily real estate, net of cash acquired — — — — (492.3 ) — — (492.3 ) Investment in real estate — — — — (903.8 ) — (10.7 ) (914.5 ) Equity investments — — — — — (100.0 ) — (100.0 ) Investment in subsidiaries (705.3 ) (7.1 ) (705.3 ) — (0.7 ) — 1,418.4 — Return of investment 145.7 — — — — — (145.7 ) — Intercompany borrowings 6.5 — (598.8 ) — — 0.5 591.8 — Net cash (used in) provided by investing activities (553.1 ) (7.1 ) (1,304.1 ) — (1,396.8 ) (99.5 ) 1,853.8 (1,506.8 ) Cash flows from financing activities: Issuance of common stock, net 705.7 — — — — — — 705.7 Dividends paid (145.7 ) — (145.7 ) — — — 145.7 (145.7 ) Intercompany borrowings — — (6.5 ) — 598.2 — (591.7 ) — Proceeds from revolving credit facility — — 1,037.3 — — — — 1,037.3 Repayments of revolving credit facility — — (1,275.0 ) — — — — (1,275.0 ) Proceeds from unsecured term loan — — 350.0 — — — — 350.0 Proceeds from senior notes — — 1,217.8 — — — — 1,217.8 Repayments of senior notes — — (474.8 ) — — — — (474.8 ) Payment of debt extinguishment costs — — (30.0 ) — — — — (30.0 ) Payment of deferred financing costs — — (16.7 ) — — — — (16.7 ) Payments on finance lease liabilities — — — — (8.6 ) (1.2 ) — (9.8 ) Interest paid by lenders on issuance of the senior notes — — 2.7 — — — — 2.7 Tax payment upon exercise of equity awards (6.9 ) — — — — — — (6.9 ) Contributions/distributions from parent — 7.1 705.3 — 605.3 100.8 (1,418.5 ) — Net cash provided by (used in) financing activities 553.1 7.1 1,364.4 — 1,194.9 99.6 (1,864.5 ) 1,354.6 Net increase (decrease) in cash, cash equivalents and restricted cash — — — — 137.8 (0.5 ) — 137.3 Cash, cash equivalents and restricted cash at beginning of period — — — — 13.4 1.2 — 14.6 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 151.2 $ 0.7 $ — $ 151.9

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Quarterly Financial Information (Unaudited) The table below reflects the unaudited selected quarterly information for the years ended December 31, 2019 and 2018 : IN MILLIONS, except per share amounts 2019 First Quarter Second Quarter Third Quarter Fourth Total Revenue $ 225.0 $ 251.5 $ 250.9 $ 253.9 $ 981.3 Operating income 11.8 19.7 13.2 22.3 67.0 Net income (loss) 89.4 (8.5 ) 12.6 (52.1 ) 41.4 Basic income (loss) per share 0.82 (0.08 ) 0.11 (0.46 ) 0.36 Diluted income (loss) per share 0.82 (0.08 ) 0.11 (0.46 ) 0.36 IN MILLIONS, except per share amounts 2018 First Second Quarter Third Quarter Fourth Quarter Total Revenue $ 196.6 $ 196.9 $ 206.6 $ 221.3 $ 821.4 Operating income 27.7 27.0 20.2 14.8 89.7 Net income (loss) 43.5 105.9 (42.4 ) (105.8 ) 1.2 Basic income (loss) per share 0.45 1.07 (0.43 ) (1.09 ) — Diluted income (loss) per share 0.45 1.06 (0.43 ) (1.08 ) —

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On January 22, 2020, the Issuers closed their previously announced offering of €500.0 million aggregate principal amount of 1.450% Senior Notes due 2027 (the “2027 Notes”). The 2027 Notes have been registered under the Securities Act of 1933, as amended (the “Securities Act”), pursuant to a shelf registration statement on Form S- 3 (File No. 333-231203), as supplemented by the prospectus supplement dated January 15, 2020, filed with the SEC under the Securities Act. The 2027 Notes are unsecured senior obligations of the Issuers, which rank equally in right of payment with all of the Issuers’ existing and future unsecured senior debt and senior in right of payment to all of the Issuers’ future subordinated debt, if any. The 2027 Notes will be effectively subordinated to any of the Issuers’ future secured debt, if any, to the extent of the value of the assets securing such debt. The 2027 Notes will be guaranteed on a senior unsecured basis by CyrusOne Inc., the sole beneficial owner and sole trustee of CyrusOne GP, which is the sole general partner of CyrusOne LP. The guarantees will rank equally in right of payment with all of CyrusOne Inc.’s existing and future unsecured senior debt and senior in right of payment to all of CyrusOne Inc.’s future subordinated debt, if any. The guarantees will be effectively subordinated to any of CyrusOne Inc.’s future secured debt to the extent of the value of the assets securing such debt. In addition, the 2027 Notes will be structurally subordinated to the liabilities of any subsidiaries of CyrusOne LP (other than CyrusOne Finance Corp.). The guarantees will be structurally subordinated to the liabilities of any subsidiaries of CyrusOne Inc. (other than the Issuers).

Schedule II. Valuation and Qual

Schedule II. Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II. Valuation and Qualifying Accounts	Schedule II. Valuation and Qualifying Accounts Beginning Charge (Deductions)/ End (dollars in millions) of Period to Expenses Additions of Period Allowance for Doubtful Accounts 2019 $ 1.7 $ 1.7 $ (1.6 ) $ 1.8 2018 2.1 2.3 (2.7 ) 1.7 2017 2.1 0.2 (0.2 ) 2.1 Deferred Tax Valuation Allowance 2019 $ 6.9 $ 0.7 $ — $ 7.6 2018 7.2 (0.3 ) — 6.9 2017 6.5 0.7 — 7.2

Schedule III. Real Estate Prope

Schedule III. Real Estate Properties and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III. Real Estate Properties and Accumulated Depreciation	Schedule III. Real Estate Properties and Accumulated Depreciation CyrusOne Inc. As of December 31, 2019 (dollars in millions) Initial Costs Cost Capitalized Subsequent to Acquisition Gross Carrying Amount Description Land Building and Improvements Equipment Land Building and Improvements Equipment Land Building and Improvements Equipment Accumulated Depreciation Acquisition Austin II $ 2.0 $ — $ — $ — $ 23.5 $ 13.3 $ 2.0 $ 23.5 $ 13.3 $ 19.7 2011 Austin III 3.3 — — — 12.6 64.0 3.3 12.6 64.0 16.7 2015 Chicago - Aurora I 2.4 26.0 97.3 — 6.4 39.0 2.4 32.4 136.3 57.2 2016 Chicago - Aurora II 2.6 — — — 22.9 70.3 2.6 22.9 70.3 14.6 2016 Chicago - Aurora Tower — — — — 6.4 0.9 — 6.4 0.9 0.5 2018 Chicago - Lombard 0.7 3.2 — — 1.5 8.1 0.7 4.7 8.1 8.6 2008 Cincinnati - 7th Street 0.9 42.2 — — 71.9 37.2 0.9 114.1 37.2 99.5 1999 Cincinnati - Blue Ash* — 2.6 — — (1.9 ) 0.2 — 0.7 0.2 0.6 2009 Cincinnati - Hamilton — 9.5 — — 34.2 7.8 — 43.7 7.8 33.6 2007 Cincinnati - Mason — — — — 20.3 1.7 — 20.3 1.7 15.8 2004 Cincinnati - North Cincinnati 0.9 12.3 — — 65.5 16.0 0.9 77.8 16.0 47.7 2008 Dallas - Allen 6.5 — — — 15.0 39.5 6.5 15.0 39.5 2.9 2017 Dallas - Carrollton 16.1 — — — 63.8 323.3 16.1 63.8 323.3 133.6 2012 Dallas - Lewisville — 46.2 2.2 — 11.9 38.9 — 58.1 41.1 69.4 2010 Florence 2.2 7.7 — — 34.3 8.7 2.2 42.0 8.7 36.8 2005 Frankfurt I 4.0 31.0 109.7 — 5.0 13.9 4.0 36.0 123.7 13.7 2018 Frankfurt II 7.0 — 47.7 — 135.1 45.9 7.0 135.1 93.6 12.4 2018 Houston - Galleria — 56.0 2.0 — 15.0 22.4 — 71.0 24.4 60.1 2010 Houston - Houston West I 1.4 21.4 0.1 — 63.8 51.5 1.4 85.2 51.6 90.6 2010 Houston - Houston West II 2.0 — — 0.7 22.8 52.0 2.7 22.8 52.0 39.1 2013 Houston - Houston West III 7.1 — — 0.1 18.1 32.3 7.2 18.1 32.3 13.6 2013 London - Great Bridgewater — 16.5 — — (16.5 ) 1.3 — — 1.3 1.0 2011 London I — 25.3 20.5 — 19.0 25.9 — 44.3 46.4 6.5 2018 London II — 19.9 58.7 — 22.9 34.6 — 42.8 93.3 17.4 2018 Northern Virginia - Sterling I 6.9 — — — 20.2 62.2 6.9 20.2 62.2 31.1 2013 Northern Virginia - Sterling II — — — — 28.8 112.4 — 28.8 112.4 36.7 2013 Northern Virginia - Sterling III — — — — 22.3 61.8 — 22.3 61.8 18.8 2017 Northern Virginia - Sterling IV 4.6 9.6 0.1 — 10.5 78.0 4.6 20.1 78.1 20.5 2016 Northern Virginia - Sterling V 14.5 — — — 81.7 303.7 14.5 81.7 303.7 56.6 2016 Northern Virginia - Sterling VI 9.7 — — — 60.2 196.9 9.7 60.2 196.9 19.5 2018 Northern Virginia - Sterling VIII 9.1 — — — 7.0 28.0 9.1 7.0 28.0 2.0 2018 Norwalk I* — 18.3 25.3 — (16.6 ) (14.7 ) — 1.7 10.6 4.5 2015 Phoenix - Chandler I 10.5 — — — 58.3 71.5 10.5 58.3 71.5 53.5 2011 Phoenix - Chandler II — — — — 16.2 39.8 — 16.2 39.8 24.2 2014 Phoenix - Chandler III — 0.9 2.5 — 10.5 48.8 — 11.4 51.3 16.7 2016 Phoenix - Chandler IV — — — — 18.4 44.3 — 18.4 44.3 11.6 2017 Phoenix - Chandler V — — — — 12.1 54.6 — 12.1 54.6 9.3 2017 Phoenix - Chandler VI 2.3 — — 0.1 23.3 101.7 2.4 23.3 101.7 20.8 2016 Phoenix - Chandler VII 4.2 — — — 0.8 0.4 4.2 0.8 0.4 — 2016 Raleigh-Durham I 2.1 73.5 71.3 — 6.3 8.7 2.1 79.8 80.0 34.4 2017 San Antonio I 4.6 3.0 — — 28.7 36.3 4.6 31.7 36.3 35.5 2011 San Antonio II 6.7 — — 0.3 30.3 61.0 7.0 30.3 61.0 24.4 2013 San Antonio III — — — — 40.2 99.5 — 40.2 99.5 29.9 2017 San Antonio IV — — — — 56.3 50.6 — 56.3 50.6 13.6 2017 Santa Clara II — 2.7 — — — — — 2.7 — 1.1 2019 Somerset I 12.1 124.6 83.3 — 7.5 18.5 12.1 132.1 101.8 43.2 2017 South Bend - Monroe — — — — 1.9 0.3 — 1.9 0.3 2.0 2007 Stamford - Omega* — 3.2 0.6 — (3.1 ) 0.2 — 0.1 0.8 0.7 2015 Stamford - Riverbend* — 4.3 13.2 — (3.4 ) (4.6 ) — 0.9 8.6 6.9 2015 (dollars in millions) Initial Costs Cost Capitalized Subsequent to Gross Carrying Amount Description Land Building and Equipment Land Building and Equipment Land Building and Equipment Accumulated Acquisition Totowa - Commerce $ — $ 4.1 $ 0.8 $ — $ (3.7 ) $ 0.9 $ — $ 0.4 $ 1.7 $ 0.9 2015 Totowa - Madison — 28.3 45.6 — (22.2 ) 14.5 — 6.1 60.1 33.0 2015 Wappingers Falls I — 9.9 13.3 — (6.8 ) 9.9 — 3.1 23.2 16.2 2015 $ 146.4 $ 602.2 $ 594.2 $ 1.2 $ 1,159.2 $ 2,433.9 $ 147.6 $ 1,761.4 $ 3,028.2 $ 1,379.2 Land held for future development $ 206.0 $ — $ — $ — $ — $ — $ 206.0 $ — $ — $ — The aggregate cost of the total properties for federal income tax purposes was $7,088.2 million at December 31, 2019 . In addition, Construction in progress was $946.3 million as we continue to build data center facilities. * Reductions in Cost Capitalized Subsequent to Acquisition due to impairment losses recorded for the respective facility. Historical Cost and Accumulated Depreciation and Amortization The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2019 , 2018 and 2017 . Years Ended December 31, (amounts in millions) 2019 2018 2017 Property Balance—beginning of period $ 5,347.5 $ 3,840.8 $ 2,601.6 Disposals (15.8 ) (20.8 ) (3.4 ) Impairments (0.7 ) — (71.8 ) Impact of adoption of ASU 2016-02 (97.8 ) — — Additions (acquisitions and improvements) 856.3 1,527.5 1,314.4 Balance, end of period (1) $ 6,089.5 $ 5,347.5 $ 3,840.8 Accumulated Depreciation Balance—beginning of period $ 1,054.5 $ 782.4 $ 578.5 Disposals (14.0 ) (14.0 ) (1.9 ) Impairments — — (14.1 ) Impact of adoption of ASU 2016-02 (19.3 ) — — Additions (depreciation and amortization expense) 358.0 286.1 219.9 Balance, end of period $ 1,379.2 $ 1,054.5 $ 782.4 (1) - Includes construction-in-progress of $946.3 million , $744.9 million and $487.1 million for the years ended December 31, 2019, 2018 and 2017, respectively that is not included in amounts reflected above in Schedule III.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements are prepared on a consolidated basis. In addition, the accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the U.S. (GAAP) and include the accounts of the Company, as well as all wholly-owned subsidiaries and any consolidated variable interest entities. All intercompany transactions and balances have been eliminated in consolidation.
Investments 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 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 term of the loan. In a business combination, 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 4, Recently Issued Accounting Standards) to leases that have a remaining lease term of 12 months or less at the acquisition date, and accordingly, do 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
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 term of the loan.
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
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 restricted by contract or regulation, including letters of credit.
Equity Investments	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 9, Equity Investments. Our investment in GDS Holdings Limited (“GDS”) is classified as “available for sale” and is carried at fair value. Changes in the fair value are reported as a component of net income (loss) in Gain (loss) on marketable equity investments. Our other equity investment is carried at cost because we do not exercise influence over the operating and financial decisions of the venture and there is no readily determinable fair value and our investment is recorded at cost less impairment, if any. Dividends paid from operating profits are reported as a component of net income (loss), while other dividends are reported as a return of capital.
Goodwill	Goodwill We evaluate goodwill for possible impairment at least annually or upon the occurrence of events or circumstances that indicate that they would more likely than not reduce the fair value of a reporting unit below its carrying amount. For our annual impairment evaluation, we have the option of performing a qualitative or quantitative goodwill impairment analysis. A qualitative analysis, step zero, analyzes the macro-economic environment in which we operate for any significant changes such as deterioration in the market that the Company operates or overall financial performance such as declining cash flows. Also, entity specific changes are analyzed such as change in management, strategy or composition of reporting unit. This assessment of qualitative factors serves as a basis for determining whether it is necessary to perform the step one test. A quantitative analysis, step one, requires the Company to estimate the fair value of the reporting unit and compare the fair value to the carrying value to identify whether the value of the recorded goodwill is impaired. Changes in certain assumptions could have a significant impact on the impairment test for goodwill under step one. The most critical assumptions are projected future growth rates, operating margins, capital expenditures, tax rates, terminal values and discount rates. These assumptions are subject to change as our long-term plans and strategies are updated each year. During the fourth quarters of 2019, 2018 and 2017, we performed a qualitative evaluation and determined that the fair value of the reporting unit is substantially in excess of the carrying amount and therefore determined that further quantitative impairment testing was not necessary.
Rent and Other Receivables	Rent and Other Receivables Receivables consist principally of rent receivables from customers and straight-line rent receivables with estimated credit losses recorded as an allowance for doubtful accounts. Straight-line rent receivable, net was $156.8 million and $128.7 million at December 31, 2019 and 2018, respectively. The allowance for doubtful accounts is estimated based upon historic patterns of credit losses for aged receivables as well as specific provisions for certain identifiable, potentially uncollectible balances.
Deferred Revenue and Prepaid Rents	Deferred Revenue and Prepaid Rents Deferred revenue is recorded when a customer makes a contractual payment in excess of revenues recognized in accordance with GAAP. Prepaid rent liability is recorded when a customer makes an advance payment or they are contractually obligated to pay any amounts in advance of the associated lease or service period.
Finance Lease Liabilities	Finance Lease Liabilities Finance lease liabilities represent leases of land and real estate we classified as finance leases. 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. Prior to the adoption of ASC 842, the Company had lease arrangements where we were involved in the construction of structural improvements to develop buildings into data centers. We substantially bore all the construction period risk, such as managing or funding construction, we were deemed to be the accounting owner of the leased property and, we were required to record at fair value the property and associated liability on our Consolidated Balance Sheets. These transactions did not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. Following the adoption of ASC 842, these leases are classified as operating leases and the liability is included in the Consolidated Balance Sheets under Operating lease liabilities, see Note 6, Leases - As a Lessee, for further information.
Revenue Recognition	Revenue Recognition Our revenue consists of lease revenue and revenue from contracts with customers. 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 space and power. The revenue for these types of leases is recorded in colocation rent 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. 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. 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 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. Other service revenue is measured based on the consideration specified in the contract and recognized over time as we satisfy the performance obligation. We adopted the practical expedient in ASC 606 that allows the Company to not 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.
Depreciation and Amortization Expense	Depreciation and Amortization Expense Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal is reasonably certain.
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions
Stock-Based Compensation	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, market and 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 on available-for-sale securities, derivatives 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 We primarily hedge our foreign currency risk by borrowing in the currencies in which we invest. We may use derivative financial instruments, such as cross-currency swaps to manage foreign currency exchange rate risk related to both our foreign investments and the related earnings. In addition, we occasionally use interest rate swap contracts to manage interest rate risk and limit the impact of future interest rate changes on earnings and cash flows, primarily related to variable-rate debt. Derivative instruments are measured at fair value and recorded as other assets or other liabilities. The accounting for gains and losses resulting from changes in fair value is dependent on the use of the derivative and whether it is designated and qualifies for hedge accounting. Designated Derivatives. We may choose to designate our derivative financial instruments, generally cross-currency swaps as net investment hedges in foreign operations. At inception of the transaction, we designate the derivative financial instrument as a hedge of a specific underlying exposure, including the risk management objective and the strategy for undertaking the hedge transaction. We formally assess both at inception and at least quarterly thereafter, the effectiveness of our hedging transactions. Due to the high degree of effectiveness between the hedging instruments and the underlying exposures hedged, fluctuations in the value of the derivative financial instruments will generally be offset by changes in the cash flows or fair values of the underlying exposures being hedged. In addition to the net investment hedges described above, we may issue debt in a currency that is not the same functional currency of the borrowing entity to hedge our international investments. We designate the debt and related accrued interest as a net investment hedge to offset the translation and economic exposures related to our international investments. If the debt and related accrued interest exceeds the designated amount of our international investment, the foreign currency remeasurement on the unhedged portion of the debt during the period is recognized in Foreign currency and derivative losses, net. For cash flow hedges, such as interest rate swaps, we report the effective portion of the gain or loss as a component of other comprehensive income (loss) and reclassify it to the applicable line item in the Consolidated Statements of Operations, generally Interest expense, net over the corresponding period of the underlying hedged item. The ineffective portion of a derivative financial instrument’s change in fair value is recognized in earnings, generally Interest expense, net at the time the ineffectiveness occurred. To the extent the hedged debt related to our interest rate swaps and forwards is paid off early, we write off the remaining balance in other comprehensive income (loss) and recognize the amount in Interest expense, net in the Consolidated Statements of Operations. Undesignated Derivatives . Derivative instruments, such as cross-currency swaps, for which hedge accounting is not applied are recorded at fair value in other assets and other liabilities and gains and losses resulting from changes in the fair value are reported in Foreign currency and derivative losses, net in the Consolidated Statements of Operations. In addition, we may choose to not designate our interest rate swap and forward contracts. If a swap or forward contract is not designated as a hedge, the changes in fair value of these instruments is immediately recognized in earnings in Interest expense, net in the Consolidated Statements of Operations.
Segment Information	Segment Information Our data centers have similar revenues and operating expenses across all geographic locations. The service offerings and delivery of services are provided in a similar manner, using the same types of facilities and similar technologies. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis and makes decisions about the allocations of Company resources and as a result, we have one reportable business segment.
Use of Estimates	Use of Estimates Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Significant estimates include and are related to determining lease terms and revenue recognition, the fair value for purchase price allocations for business combinations and asset acquisitions, and the useful lives of real estate and other long-lived assets. Actual results may differ from these estimates and assumptions.
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, net, ( $128.7 million ) is classified within rent and other receivables, net. This item was previously included in other assets. Statement of Cash Flows for the year ended December 31, 2018 • Proceeds from revolving credit facility and proceeds from unsecured term loan are separate line items in the current presentation. These items were previously combined in proceeds from debt, net ( $1,988.3 million ) in the comparable prior year period. Repayments of revolving credit facility and repayments of unsecured term loan are separate line items in the current presentation. These items were previously combined in payments on debt ( $1,547.4 million ) in the comparable prior year period. Statement of Cash Flows for the year ended December 31, 2017 • Proceeds from revolving credit facility, proceeds from unsecured term loan, proceeds from senior notes, payment of debt extinguishment costs and payment of deferred financing costs are separate line items in the current presentation. These items were previously combined in proceeds from debt, net ( $2,558.4 million ) in the comparable prior year period. Repayments of revolving credit facility and repayments of senior notes are separate line items in the current presentation. These items were previously combined in payments on debt ( $1,749.8 million ) in the comparable prior year period.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Recently Adopted 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 recorded as an adjustment to retained earnings on the effective date. By applying the modified retrospective transition method, the presentation of financial information for periods prior to January 1, 2019 was 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) the treatment of 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 discounted based on the implicit rate or alternatively our incremental borrowing rate. The implicit rate is generally not determinable and, as a result, we use our incremental borrowing rate at the lease commencement date to determine the present value. We determine our incremental borrowing rate based on an estimate of our existing yield curve at the lease commencement. The rates are then adjusted for various factors to estimate the company’s secured rate, including the lease term and collateralization. The determination of our incremental borrowing rate requires judgment. 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 the 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 an original lease term of 12 months or less. The adoption of ASC 842 had a significant impact on our Consolidated Balance Sheets 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 Sheets as of December 31, 2019 and 2018 (in millions) related to previously reported BTS leases: Impact to the Consolidated Balance Sheets: As of December 31, 2019 As of December 31, 2018 Buildings and improvements, net of accumulated depreciation $ — $ 77.4 Operating lease right-of-use assets, net of amortization 44.9 — Finance lease liabilities — 123.3 Operating lease liabilities, net of accretion 77.9 — 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 the Consolidated Statements 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 Statements 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 costs that are not incremental are expensed as general and administrative expense in our Consolidated Statements of Operations. Prior to the adoption of the 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 a 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 components. 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. Share-based payments granted to nonemployees On January 1, 2019, 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 to how 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 . Changes in Shareholders' Equity 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) for interim periods on Form 10-Q. In accordance with the SEC's rule, the Company’s first presentation of changes in shareholders’ equity was shown in its Form 10-Q for the quarter ending March 31, 2019. New Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies various aspects related to the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. The guidance is effective for periods beginning after December 15, 2020, with early adoption permitted. The Company is evaluating the impact of the new standard. In August 2018, the FASB issued ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software, 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 and 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, Fair Value Measurement, 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 disclosures of fair value measurement by using those concepts. The guidance is effective for periods beginning after December 15, 2019 and 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 June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses, providing guidance which requires certain financial assets to be presented at the net amount expected to be collected. The FASB has subsequently issued various amendments to further clarify the scope of the initial guidance. ASU 2016-13 and its related amendments will apply to our rent 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. FASB further clarified that receivables arising from operating leases are not within the scope of this sub-topic. The guidance is effective for periods beginning after December 15, 2019 and early adoption is allowed. The Company has evaluated the impact of the new standard and does not believe the adoption will have a significant impact on the Company because the Company has limited exposure to financial instruments subject to this standard.

Recently Issued Accounting St_2

Recently Issued Accounting Standards (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Changes and Error Corrections [Abstract]
Impact of Adoption of the Lease Standard	The table below reflects the impact of adoption of the lease standard on our Consolidated Balance Sheets as of December 31, 2019 and 2018 (in millions) related to previously reported BTS leases: Impact to the Consolidated Balance Sheets: As of December 31, 2019 As of December 31, 2018 Buildings and improvements, net of accumulated depreciation $ — $ 77.4 Operating lease right-of-use assets, net of amortization 44.9 — Finance lease liabilities — 123.3 Operating lease liabilities, net of accretion 77.9 —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Future Minimum Lease Payments under Non-Cancellable Operating Leases	At December 31, 2019 , the future minimum lease payments to be received for the next five years under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: IN MILLIONS 2020 $ 736.2 2021 620.2 2022 528.2 2023 426.5 2024 328.7 Thereafter 973.9 Total $ 3,613.7
Future Minimum Lease Payments to be Received, Excluding Month-to-Month Arrangements and Metered Power Reimbursements	The future minimum lease payments as of December 31, 2018 to be received under non-cancellable operating leases, excluding month-to-month arrangements and metered power reimbursements are shown below: IN MILLIONS 2019 $ 647.6 2020 553.7 2021 453.0 2022 365.5 2023 284.4 Thereafter 835.9 Total $ 3,140.1
Disaggregation of Revenue	For the year ended December 31, 2019 , lease revenue disaggregated by primary revenue stream is as follows (in millions): Lease revenue Year Ended December 31, 2019 Colocation (Minimum lease payments) $ 793.5 Metered power reimbursements (Variable lease payments) 138.8 Total lease revenue $ 932.3 For the years ended December 31, 2019 and 2018 revenue from contracts with customers disaggregated by primary revenue stream is as follows (in millions): Revenue from contracts with customers Year Ended December 31, 2019 Year Ended December 31, 2018 Equipment sales and services $ 29.7 $ 15.3 Other revenue 19.3 17.4 Total revenue from contracts with customers $ 49.0 $ 32.7

Leases - As a Lessee (Tables)

Leases - As a Lessee (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease, Cost	The components of lease expense are as follows (in millions): Year Ended December 31, 2019 Operating lease cost $ 20.3 Finance lease cost: Amortization of assets 2.3 Interest on lease liabilities 1.7 Total net lease cost $ 24.3 Supplemental cash flow and other information related to leases is as follows (in millions): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 22.1 Operating cash flows from finance leases 1.7 Financing cash flows from finance leases 2.9 Non-cash right-of-use assets obtained in exchange for lease liabilities: Operating leases $ 175.1 Finance leases 0.8
Assets And Liabilities, Lessee	Supplemental balance sheet information related to leases is as follows (in millions, except lease term and discount rate): December 31, 2019 Operating leases: Operating lease right-of-use assets $ 161.9 Operating lease liabilities $ 195.8 Finance leases: Property and equipment, at cost $ 34.9 Accumulated amortization (5.0 ) Property and equipment, net $ 29.9 Finance lease liabilities $ 31.8 Weighted average remaining lease term (in years): Operating leases 15.8 Finance leases (a) 18.1 Weighted average discount rate: Operating leases 3.9 % Finance leases (a) 4.9 % (a) Excludes the 999 -year ground lease in Dublin, the Republic of Ireland.
Lessee, Operating Lease, Liability, Maturity	Maturities of lease liabilities were as follows (in millions): As of December 31, 2019 Operating Leases Finance Leases 2020 $ 22.4 $ 5.0 2021 21.0 4.1 2022 22.4 2.9 2023 18.5 1.9 2024 13.9 1.4 Thereafter 165.4 31.1 Total lease payments $ 263.6 $ 46.4 Less: Imputed interest (67.8 ) (14.6 ) Total lease obligations $ 195.8 $ 31.8
Finance Lease, Liability, Maturity	Maturities of lease liabilities were as follows (in millions): As of December 31, 2019 Operating Leases Finance Leases 2020 $ 22.4 $ 5.0 2021 21.0 4.1 2022 22.4 2.9 2023 18.5 1.9 2024 13.9 1.4 Thereafter 165.4 31.1 Total lease payments $ 263.6 $ 46.4 Less: Imputed interest (67.8 ) (14.6 ) Total lease obligations $ 195.8 $ 31.8
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): Operating Leases Capital Leases Lease Financing Arrangements 2019 $ 5.0 $ 2.7 $ 15.0 2020 4.9 2.8 27.6 2021 3.7 2.9 11.4 2022 3.7 2.0 11.6 2023 3.5 1.0 10.0 Thereafter 43.4 22.0 89.1 Total lease payments $ 64.2 $ 33.4 $ 164.7
Schedule of Future Minimum Lease Payments for Finance 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): Operating Leases Capital Leases Lease Financing Arrangements 2019 $ 5.0 $ 2.7 $ 15.0 2020 4.9 2.8 27.6 2021 3.7 2.9 11.4 2022 3.7 2.0 11.6 2023 3.5 1.0 10.0 Thereafter 43.4 22.0 89.1 Total lease payments $ 64.2 $ 33.4 $ 164.7

Acquisitions and Purchases of_2

Acquisitions and Purchases of Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The consolidated financial statements of CyrusOne Inc. include the operating results of Zenium since the acquisition date, which was August 24, 2018. The following table summarizes the estimated fair values of all assets acquired at the date of acquisition: IN MILLIONS Investment in real estate $ 597.3 Cash and cash equivalents 12.7 Rent and other receivables 9.0 Intangible assets: Trade name 1.8 Leasehold interest 1.7 In-place leases 61.5 Other assets 1.1 Accounts payable (22.3 ) Deferred revenue (3.3 ) Capital lease obligations (25.0 ) Deferred tax liability (72.7 ) Debt (86.3 ) Net assets acquired attributable to CyrusOne Inc. $ 475.5 Cash acquired (12.7 ) Net cash paid at acquisition $ 462.8
Schedule of Gross Investment in Real Estate	As of December 31, 2019 and 2018 , major components of our real estate investments and intangibles and related accumulated depreciation and amortization are as follows (in millions): December 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 $ 1,761.4 $ 3,028.2 $ 247.1 $ 137.1 $ 19.4 $ 1,677.5 $ 2,630.2 $ 247.1 $ 136.0 $ 19.5 Less: accumulated depreciation and amortization (545.1 ) (834.1 ) (151.1 ) (46.7 ) (9.7 ) (481.8 ) (572.7 ) (137.9 ) (21.1 ) (7.9 ) Net $ 1,216.3 $ 2,194.1 $ 96.0 $ 90.4 $ 9.7 $ 1,195.7 $ 2,057.5 $ 109.2 $ 114.9 $ 11.6 A schedule of our gross investment in real estate follows: IN MILLIONS As of December 31, 2019 2018 Acquisition Date Land Building and Equipment Land Building and Equipment Austin II 2011 $ 2.0 $ 23.5 $ 13.3 $ 2.0 $ 23.4 $ 8.7 Austin III 2015 3.3 12.6 64.0 3.3 11.7 47.0 Chicago - Aurora I 2016 2.4 32.4 136.3 2.4 32.4 132.9 Chicago - Aurora II 2016 2.6 22.9 70.3 2.6 22.6 68.6 Chicago - Aurora Tower 2018 — 6.4 0.9 — 4.9 0.4 Chicago - Lombard 2008 0.7 4.7 8.1 0.7 4.7 8.1 Cincinnati - 7th Street (1) 1999 0.9 114.1 37.2 0.9 114.1 37.4 Cincinnati - Blue Ash (2) 2009 — 0.7 0.2 — 0.7 0.2 Cincinnati - Goldcoast 2007 — — — 0.2 4.0 0.1 Cincinnati - Hamilton (2) 2007 — 43.7 7.8 — 43.7 7.9 Cincinnati - Mason 2004 — 20.3 1.7 — 20.3 1.7 Cincinnati - North Cincinnati 2008 0.9 77.8 16.0 0.9 77.9 12.4 Dallas - Allen 2017 6.5 15.0 39.5 — — — Dallas - Carrollton 2012 16.1 63.8 323.3 16.1 62.2 272.5 Dallas - Lewisville (2) 2010 — 58.1 41.1 — 76.8 39.6 Florence 2005 2.2 42.0 8.7 2.2 42.0 8.4 Frankfurt I 2018 4.0 36.0 123.7 4.1 35.7 124.9 Frankfurt II 2018 7.0 135.1 93.6 7.1 89.8 53.9 Houston - Galleria (3) 2010 — 71.0 24.4 — 71.0 20.2 Houston - Houston West I 2010 1.4 85.2 51.6 1.4 85.2 51.1 Houston - Houston West II 2013 2.7 22.8 52.0 2.7 22.9 50.9 Houston - Houston West III 2013 7.2 18.1 32.3 7.2 18.0 31.4 London - Great Bridgewater (4) 2011 — — 1.3 — 26.8 1.2 London I (2) 2018 — 44.3 46.4 — 34.1 26.3 London II (2) 2018 — 42.8 93.3 — 25.2 74.8 Northern Virginia - Sterling I 2013 6.9 20.2 62.2 6.9 20.2 60.4 Northern Virginia - Sterling II 2013 — 28.8 112.4 — 28.8 112.4 Northern Virginia - Sterling III 2017 — 22.3 61.8 — 22.2 61.3 Northern Virginia - Sterling IV 2016 4.6 20.1 78.1 4.6 20.0 76.0 Northern Virginia - Sterling V 2016 14.5 81.7 303.7 14.5 80.8 295.8 Northern Virginia - Sterling VI 2018 9.7 60.2 196.9 — — 77.5 Northern Virginia - Sterling VIII 2018 9.1 7.0 28.0 — — — Norwalk I (4) 2015 — 1.7 10.6 — 13.6 10.1 Phoenix - Chandler I 2011 10.5 58.3 71.5 10.5 58.3 68.7 Phoenix - Chandler II 2014 — 16.2 39.8 — 16.2 39.4 Phoenix - Chandler III 2016 — 11.4 51.3 — 11.4 50.8 Phoenix - Chandler IV 2017 — 18.4 44.3 — 18.4 43.3 Phoenix - Chandler V 2017 — 12.1 54.6 — 10.7 53.4 Phoenix - Chandler VI 2016 2.4 23.3 101.7 2.4 23.3 100.3 Phoenix - Chandler VII 2016 4.2 0.8 0.4 — — — Raleigh-Durham I 2017 2.1 79.8 80.0 2.1 79.8 75.4 San Antonio I 2011 4.6 31.7 36.3 4.6 31.7 35.3 San Antonio II 2013 7.0 30.3 61.0 7.0 30.3 60.8 San Antonio III 2017 — 40.2 99.5 — 40.2 99.0 IN MILLIONS As of December 31, 2019 2018 Land Building and Equipment Land Building and Equipment San Antonio IV 2017 $ — $ 56.3 $ 50.6 $ — $ 42.1 $ 48.2 Santa Clara II 2019 — 2.7 — — — — Singapore - Inter Business Park (4) 2011 — — — — — — Somerset I 2017 12.1 132.1 101.8 12.1 125.8 91.0 South Bend - Crescent (2) 2008 — — — — 1.7 0.2 South Bend - Monroe 2007 — 1.9 0.3 — 2.5 0.4 Stamford - Omega (4) 2015 — 0.1 0.8 — 2.6 0.7 Stamford - Riverbend (4) 2015 — 0.9 8.6 — 2.9 7.8 Totowa - Commerce (4) 2015 — 0.4 1.7 — 4.1 1.7 Totowa - Madison (4) 2015 — 6.1 60.1 — 28.5 57.7 Wappingers Falls I (4) 2015 — 3.1 23.2 — 11.3 22.0 Total $ 147.6 $ 1,761.4 $ 3,028.2 $ 118.5 $ 1,677.5 $ 2,630.2 Land held for future development $ 206.0 $ — $ — $ 176.4 $ — $ — 1) The information provided for the Cincinnati - 7th Street property includes data for two facilities, one of which we lease and one of which we own. 2) Indicates properties in which we hold a leasehold interest in the building shell and land. All data center infrastructure has been constructed by us and is owned by us. 3) Indicates properties in which we hold a leasehold interest in land. All data center infrastructure has been constructed by us and is owned by us. 4) Indicates properties in which we hold a leasehold interest in the building shell, land, and all data center infrastructure.

Investment in Real Estate (Tabl

Investment in Real Estate (Tables)	12 Months Ended
	Dec. 31, 2019
Real Estate [Abstract]
Schedule of Gross Investment in Real Estate	As of December 31, 2019 and 2018 , major components of our real estate investments and intangibles and related accumulated depreciation and amortization are as follows (in millions): December 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 $ 1,761.4 $ 3,028.2 $ 247.1 $ 137.1 $ 19.4 $ 1,677.5 $ 2,630.2 $ 247.1 $ 136.0 $ 19.5 Less: accumulated depreciation and amortization (545.1 ) (834.1 ) (151.1 ) (46.7 ) (9.7 ) (481.8 ) (572.7 ) (137.9 ) (21.1 ) (7.9 ) Net $ 1,216.3 $ 2,194.1 $ 96.0 $ 90.4 $ 9.7 $ 1,195.7 $ 2,057.5 $ 109.2 $ 114.9 $ 11.6 A schedule of our gross investment in real estate follows: IN MILLIONS As of December 31, 2019 2018 Acquisition Date Land Building and Equipment Land Building and Equipment Austin II 2011 $ 2.0 $ 23.5 $ 13.3 $ 2.0 $ 23.4 $ 8.7 Austin III 2015 3.3 12.6 64.0 3.3 11.7 47.0 Chicago - Aurora I 2016 2.4 32.4 136.3 2.4 32.4 132.9 Chicago - Aurora II 2016 2.6 22.9 70.3 2.6 22.6 68.6 Chicago - Aurora Tower 2018 — 6.4 0.9 — 4.9 0.4 Chicago - Lombard 2008 0.7 4.7 8.1 0.7 4.7 8.1 Cincinnati - 7th Street (1) 1999 0.9 114.1 37.2 0.9 114.1 37.4 Cincinnati - Blue Ash (2) 2009 — 0.7 0.2 — 0.7 0.2 Cincinnati - Goldcoast 2007 — — — 0.2 4.0 0.1 Cincinnati - Hamilton (2) 2007 — 43.7 7.8 — 43.7 7.9 Cincinnati - Mason 2004 — 20.3 1.7 — 20.3 1.7 Cincinnati - North Cincinnati 2008 0.9 77.8 16.0 0.9 77.9 12.4 Dallas - Allen 2017 6.5 15.0 39.5 — — — Dallas - Carrollton 2012 16.1 63.8 323.3 16.1 62.2 272.5 Dallas - Lewisville (2) 2010 — 58.1 41.1 — 76.8 39.6 Florence 2005 2.2 42.0 8.7 2.2 42.0 8.4 Frankfurt I 2018 4.0 36.0 123.7 4.1 35.7 124.9 Frankfurt II 2018 7.0 135.1 93.6 7.1 89.8 53.9 Houston - Galleria (3) 2010 — 71.0 24.4 — 71.0 20.2 Houston - Houston West I 2010 1.4 85.2 51.6 1.4 85.2 51.1 Houston - Houston West II 2013 2.7 22.8 52.0 2.7 22.9 50.9 Houston - Houston West III 2013 7.2 18.1 32.3 7.2 18.0 31.4 London - Great Bridgewater (4) 2011 — — 1.3 — 26.8 1.2 London I (2) 2018 — 44.3 46.4 — 34.1 26.3 London II (2) 2018 — 42.8 93.3 — 25.2 74.8 Northern Virginia - Sterling I 2013 6.9 20.2 62.2 6.9 20.2 60.4 Northern Virginia - Sterling II 2013 — 28.8 112.4 — 28.8 112.4 Northern Virginia - Sterling III 2017 — 22.3 61.8 — 22.2 61.3 Northern Virginia - Sterling IV 2016 4.6 20.1 78.1 4.6 20.0 76.0 Northern Virginia - Sterling V 2016 14.5 81.7 303.7 14.5 80.8 295.8 Northern Virginia - Sterling VI 2018 9.7 60.2 196.9 — — 77.5 Northern Virginia - Sterling VIII 2018 9.1 7.0 28.0 — — — Norwalk I (4) 2015 — 1.7 10.6 — 13.6 10.1 Phoenix - Chandler I 2011 10.5 58.3 71.5 10.5 58.3 68.7 Phoenix - Chandler II 2014 — 16.2 39.8 — 16.2 39.4 Phoenix - Chandler III 2016 — 11.4 51.3 — 11.4 50.8 Phoenix - Chandler IV 2017 — 18.4 44.3 — 18.4 43.3 Phoenix - Chandler V 2017 — 12.1 54.6 — 10.7 53.4 Phoenix - Chandler VI 2016 2.4 23.3 101.7 2.4 23.3 100.3 Phoenix - Chandler VII 2016 4.2 0.8 0.4 — — — Raleigh-Durham I 2017 2.1 79.8 80.0 2.1 79.8 75.4 San Antonio I 2011 4.6 31.7 36.3 4.6 31.7 35.3 San Antonio II 2013 7.0 30.3 61.0 7.0 30.3 60.8 San Antonio III 2017 — 40.2 99.5 — 40.2 99.0 IN MILLIONS As of December 31, 2019 2018 Land Building and Equipment Land Building and Equipment San Antonio IV 2017 $ — $ 56.3 $ 50.6 $ — $ 42.1 $ 48.2 Santa Clara II 2019 — 2.7 — — — — Singapore - Inter Business Park (4) 2011 — — — — — — Somerset I 2017 12.1 132.1 101.8 12.1 125.8 91.0 South Bend - Crescent (2) 2008 — — — — 1.7 0.2 South Bend - Monroe 2007 — 1.9 0.3 — 2.5 0.4 Stamford - Omega (4) 2015 — 0.1 0.8 — 2.6 0.7 Stamford - Riverbend (4) 2015 — 0.9 8.6 — 2.9 7.8 Totowa - Commerce (4) 2015 — 0.4 1.7 — 4.1 1.7 Totowa - Madison (4) 2015 — 6.1 60.1 — 28.5 57.7 Wappingers Falls I (4) 2015 — 3.1 23.2 — 11.3 22.0 Total $ 147.6 $ 1,761.4 $ 3,028.2 $ 118.5 $ 1,677.5 $ 2,630.2 Land held for future development $ 206.0 $ — $ — $ 176.4 $ — $ — 1) The information provided for the Cincinnati - 7th Street property includes data for two facilities, one of which we lease and one of which we own. 2) Indicates properties in which we hold a leasehold interest in the building shell and land. All data center infrastructure has been constructed by us and is owned by us. 3) Indicates properties in which we hold a leasehold interest in land. All data center infrastructure has been constructed by us and is owned by us. 4) Indicates properties in which we hold a leasehold interest in the building shell, land, and all data center infrastructure.

Equity Investments (Tables)

Equity Investments (Tables)	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Unrealized Gain (Loss) on Marketable Equity Investment	IN MILLIONS Year Ended December 31, 2019 Year Ended December 31, 2018 Net gain on marketable equity investment $ 132.3 $ 9.9 Less: Net gain recognized on marketable equity investment sold 66.7 — Unrealized gain on marketable equity investment $ 65.6 $ 9.9

Goodwill, Intangible and Othe_2

Goodwill, Intangible and Other Long-Lived Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Carrying Value of Major Classes of Intangible Assets	Summarized below are the carrying values for the major classes of intangible assets: IN MILLIONS For the year ended December 31, 2019 2018 Weighted- Gross Carrying Amount Accumulated Amortization Total Gross Carrying Amount Accumulated Amortization Total Customer relationships 10 $ 247.1 $ (151.1 ) $ 96.0 $ 247.1 $ (137.9 ) $ 109.2 Trademark/tradename 4 11.5 (7.8 ) 3.7 11.5 (6.7 ) 4.8 Favorable leasehold interest 35 5.6 (1.2 ) 4.4 5.7 (0.7 ) 5.0 In-place customer leases 5 137.1 (46.7 ) 90.4 136.0 (21.1 ) 114.9 Above and below market leases 6 2.3 (0.7 ) 1.6 2.3 (0.5 ) 1.8 Total $ 403.6 $ (207.5 ) $ 196.1 $ 402.6 $ (166.9 ) $ 235.7
Schedule of Estimated Amortization Expense for Finite-Lived Intangible Assets	The following table presents estimated amortization expense for each of the next five years and thereafter, commencing January 1, 2020 : IN MILLIONS Total 2020 $ 39.3 2021 32.0 2022 28.6 2023 20.7 2024 18.6 Thereafter 56.9 Total $ 196.1

(Tables)

(Tables)	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Assets	As of December 31, 2019 and 2018 , the components of other assets are as follows (in millions): 12/31/2019 12/31/2018 Deferred leasing and other contract costs $ 53.2 $ 43.6 Prepaid expenses 22.1 26.4 Non-real estate assets, net 16.3 18.4 Derivative assets 3.5 — Other assets 18.8 22.9 Total $ 113.9 $ 111.3

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term debt Instruments	As of December 31, 2019 and 2018 , the components of debt are as follows (unless otherwise noted, interest rate and maturity date information are as of December 31, 2019 ) (in millions): December 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 (a) $ 555.0 $ — Monthly LIBOR + 1.20% EUR Revolver 33.6 143.0 Monthly EURIBOR + 1.20% GBP Revolver (a) 26.4 — Monthly LIBOR + 1.20% 2023 Term Loan 800.0 1,000.0 Monthly LIBOR + 1.35% March 2023 2025 Term Loan 300.0 300.0 Monthly LIBOR + 1.65% March 2025 Old 2024 Notes, including bond premium of $5.5 million — 705.5 5.000 % March 2024 Old 2027 Notes, including bond premium of $9.1 million — 509.1 5.375 % March 2027 2024 Notes, including bond discount of $0.8 million 599.2 — 2.900 % November 2024 2029 Notes, including bond discount of $1.8 million 598.2 — 3.450 % November 2029 Deferred financing costs (25.8 ) (32.9 ) — — Total $ 2,886.6 $ 2,624.7 (a) - Monthly USD LIBOR and GBP LIBOR as of December 31, 2019 was 1.80% and 0.71% , respectively. (b) - The Company has an option to exercise a one -year extension option, subject to certain conditions.
Schedule of Maturities of Long-term Debt	The following table summarizes aggregate maturities of the $3.0 Billion Credit Facility and 2024 Notes and 2029 Notes for the five years subsequent to December 31, 2019 , and thereafter: IN MILLIONS $3.0 Billion Credit Facility (a) 2024 Notes and 2029 Notes Total 2020 $ — $ — $ — 2021 — — — 2022 615.0 — 615.0 2023 800.0 — 800.0 2024 — 600.0 600.0 Thereafter 300.0 600.0 900.0 Total debt $ 1,715.0 $ 1,200.0 $ 2,915.0 (a) - The Company has an option to exercise a one -year extension option on the $1.7 Billion Revolving Credit Facility, subject to certain conditions, which would extend the final maturity to March 2023.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 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): IN MILLIONS For the year ended December 31, 2019 2018 Carrying Value Fair Value Carrying Value Fair Value Old 2024 Notes - 5.000% $ — $ — $ 705.5 $ 684.1 Old 2027 Notes - 5.375% — — 509.1 488.0 2024 Notes - 2.900% 599.2 602.1 — — 2029 Notes - 3.450% 598.2 603.1 — — GDS Equity investment 118.7 118.7 185.5 185.5
Summary of Derivative Positions	The following table summarizes the Company's derivative positions as of December 31, 2019 and 2018 (in millions): December 31, 2019 December 31, 2018 Maturity Date Notional Amount Hedged Risk Asset Liability Asset Liability Undesignated derivatives Cross Currency Swaps EUR - USD 01/15/2020 $ 265.3 Foreign currency exchange $ — $ 2.1 $ — $ — EUR - USD 01/15/2020 25.6 Foreign currency exchange — 0.2 — — Designated derivatives Cross Currency Swaps EUR - USD 3/29/2023 250.0 Net investment hedge — 3.8 — — EUR - USD 3/29/2023 250.0 Net investment hedge — 3.9 — — EUR - USD 1/15/2020 155.9 Net investment hedge — 1.4 — — Interest Rate Swaps USD Libor 3/29/2023 300.0 Interest rate hedge - Float to fixed 3.5 — — — Total $ 1,246.8 $ 3.5 $ 11.4 $ — $ —
Fair Values of Qualifying Instruments	The fair values of qualifying instruments used in hedging transactions as of December 31, 2019 and 2018 are as follows (in millions): Balance Sheet Location December 31, 2019 December 31, 2018 Derivatives Designated as Hedging Instruments Assets: Interest Rate Swap Other Assets $ 3.5 $ — Total $ 3.5 $ — Liabilities: Cross-Currency Swaps Other Liabilities 9.1 — Total $ 9.1 $ —
Effect of Derivative Financial Instruments	The following table presents the effect of our derivative financial instruments on our accompanying consolidated financial statements (in millions): December 31, 2019 December 31, 2018 Derivatives in Cash Flow Hedging Relationships Cross-Currency Swaps: Amount of gain (loss) recognized in OCI for derivatives $ (0.7 ) $ — Amount of gain (loss) reclassified from accumulated OCI for derivatives $ — $ — Amount of gain (loss) recognized in earnings $ (7.5 ) $ —

Income (Loss) per Share (Tables

Income (Loss) per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net (Loss) Income Per Share	The following table reflects the computation of basic and diluted net (loss) income per share: IN MILLIONS, except per share amounts Year Ended Year Ended Year Ended For December 31, 2019 2018 2017 Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) $ 41.4 $ 41.4 $ 1.2 $ 1.2 $ (83.5 ) $ (83.5 ) Less: Restricted stock dividends (0.7 ) (0.7 ) (1.1 ) (1.1 ) (0.9 ) (0.9 ) Net income (loss) available to stockholders $ 40.7 $ 40.7 $ 0.1 $ 0.1 $ (84.4 ) $ (84.4 ) Denominator: Weighted average common outstanding-basic 112.1 112.1 99.8 99.8 88.9 88.9 Performance-based restricted stock and units (1) 0.4 0.6 — Weighted average shares outstanding-diluted 112.5 100.4 88.9 EPS: Net income (loss) per share-basic $ 0.36 $ — $ (0.95 ) Effect of dilutive shares: Net income (loss) per share-diluted $ 0.36 $ — $ (0.95 ) (1) We have excluded 0.4 million weighted average shares of restricted stock, and 0.1 million of weighted average stock options which are securities convertible into common stock from our diluted earnings per share as of December 31, 2017. These amounts were deemed anti-dilutive.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Compensation Expense	Stock-based compensation expense was as follows: For the periods ended December 31, 2019 2018 2017 2014 Grants $ — $ — $ 0.1 2015 Grants — 0.4 1.8 2016 Grants 1.1 5.7 6.6 2017 Grants 3.1 4.6 6.2 2018 Grants 5.4 6.8 — 2019 Grants and ESPP expense 7.1 — — Total $ 16.7 $ 17.5 $ 14.7
Schedule of Restricted Stock Awards Activity	Restricted Stock ("RS") 2019 Restricted Stock Weighted Average Grant Date Fair Value Outstanding January 1, 419,356 $ 35.73 Granted 16,681 52.46 Vested (384,753 ) 35.61 Forfeited (34,603 ) 37.09 Outstanding December 31, 16,681 $ 52.46 The following tables summarize the unvested restricted stock units, restricted stock and stock options activity and the weighted average fair value of these shares at the date of grant for the year ended December 31, 2019 : Restricted Stock Units ("RSU") 2019 Restricted Stock Units Weighted Average Grant Date Fair Value Outstanding January 1, 511,409 $ 56.23 Granted 401,270 48.90 Vested (187,176 ) 43.37 Forfeited (78,884 ) 52.99 Outstanding December 31, 646,619 $ 55.80
Schedule of Unvested Stock Options	Stock Options 2019 Options Weighted Average Exercise Price Outstanding January 1, 401,223 $ 31.96 Granted — — Exercised (25,586 ) 36.70 Forfeited or expired (551 ) 23.58 Outstanding December 31, 375,086 31.64 Exercisable at December 31, 375,086 31.64 Vested and expected to vest 375,086 $ 31.64
Schedule of Option Valuation Assumptions	The following table summarizes the stock option assumptions for the years ended December 31, 2019 , 2018 and 2017 : Options Outstanding Options Exercisable Assumption Range Exercise Prices Number of Shares Weighted Average Remaining Contractual Terms (Years) Number of Shares Weighted Average Remaining Contractual Terms (Years) Risk-Free Interest Rate Expected Annual Dividend Yield Expected Terms in Years Expected Volatility 2017 $23.58 67,322 5.3 67,322 5.3 0.92% 3.4% 6.0 35% $28.42 143,358 7.1 95,572 7.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 7.6 8,479 7.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 192,060 8.1 64,022 8.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0% 2018 $23.58 53,086 4.3 53,086 4.3 0.92% 3.4% 6.0 35% $28.42 143,358 6.1 143,358 6.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 6.6 12,719 6.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 192,060 6.8 130,425 6.7 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0% 2019 $23.58 51,985 3.3 51,985 3.3 0.92% 3.4% 6.0 35% $28.42 143,358 5.1 143,358 5.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 5.6 12,719 5.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 167,024 6.1 167,024 6.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0%

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Declared Cash Dividends and Distributions	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2019 and 2018 as presented in the table below: Record date Payment date Cash dividend per share or operating partnership unit March 29, 2018 April 13, 2018 $0.46 June 29, 2018 July 13, 2018 $0.46 September 28, 2018 October 12, 2018 $0.46 January 2, 2019 January 11, 2019 $0.46 March 29, 2019 April 12, 2019 $0.46 June 28, 2019 July 12, 2019 $0.46 September 27, 2019 October 11, 2019 $0.50 January 2, 2020 January 10, 2020 $0.50

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense (benefit) for the years ended December 31, 2019, 2018 and 2017 as reported in the accompanying Consolidated Statements of Operations was comprised of the following: Year Ended December 31, IN MILLIONS 2019 2018 2017 Current Federal $ 1.7 $ 1.0 $ 1.2 State 1.9 2.0 1.8 Foreign 0.2 — — Total current expense $ 3.8 $ 3.0 $ 3.0 Deferred: Federal — — — State — — — Foreign $ (7.5 ) $ (2.4 ) $ — Total deferred (benefit) expense (7.5 ) (2.4 ) — Total income tax (benefit) expense $ (3.7 ) $ 0.6 $ 3.0
Schedule of Effective Income Tax Rate Reconciliation	An income tax expense reconciliation between the U.S. statutory tax rate and the effective tax rate is as follows: Year Ended December 31, IN MILLIONS 2019 2018 2017 Income tax at U.S. federal statutory income tax rate $ 7.9 $ 0.4 $ (28.2 ) State and local taxes, net of federal income tax benefit 1.7 2.0 1.8 Impact of REIT status (13.7 ) (2.1 ) 28.6 Permanent differences (0.7 ) (0.1 ) — Foreign tax rate and currency differences (1.0 ) 0.2 — Anti-hybrid disallowances 1.6 0.1 — Valuation allowance 0.5 0.1 0.8 Income tax (benefit) expense $ (3.7 ) $ 0.6 $ 3.0
Schedule of Deferred Tax Assets and Liabilities	The components of the Company’s deferred tax assets and liabilities are as follows: Year Ended December 31, IN MILLIONS 2019 2018 Deferred tax assets Net operating loss carryforwards $ 16.3 $ 15.1 Accounts receivable/payable and other 8.2 7.4 Finance leases 0.9 1.8 Total gross deferred tax assets $ 25.4 $ 24.3 Valuation allowance (7.6 ) (6.9 ) Total gross deferred tax assets, net $ 17.8 $ 17.4 Deferred tax liabilities Fixed assets (67.4 ) (73.5 ) Intangibles $ (10.9 ) $ (12.8 ) Total gross deferred tax liabilities $ (78.3 ) $ (86.3 ) Total net deferred tax assets/(liabilities) $ (60.5 ) $ (68.9 )

Guarantors (Tables)

Guarantors (Tables)	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Consolidating Balance Sheet	Consolidating Balance Sheets IN MILLIONS As of December 31, 2019 Parent General LP Finance Non-Guarantor Subsidiaries Eliminations/Consolidations Total Total investment in real estate, net $ — $ — $ — $ — $ 4,640.4 $ 69.9 $ 4,710.3 Cash and cash equivalents — — 0.6 — 75.8 — 76.4 Investment in subsidiaries 2,402.2 16.8 3,569.0 — — (5,988.0 ) — Rent and other receivables, net — — — — 291.9 — 291.9 Restricted cash — — — — 1.3 — 1.3 Operating lease right-of-use assets, net — — — — 161.9 — 161.9 Intercompany receivable 21.1 — 1,753.3 — 38.8 (1,813.2 ) — Equity investments — — — — 135.1 — 135.1 Goodwill — — — — 455.1 — 455.1 Intangible assets, net — — — — 196.1 — 196.1 Other assets — — 3.5 — 110.4 — 113.9 Total assets $ 2,423.3 $ 16.8 $ 5,326.4 $ — $ 6,106.8 $ (7,731.3 ) $ 6,142.0 Debt $ — $ — $ 2,886.6 $ — $ — $ — $ 2,886.6 Intercompany payable — — 21.1 — 1,792.1 (1,813.2 ) — Finance lease liabilities — — — — 31.8 — 31.8 Operating lease liabilities — — — — 195.8 — 195.8 Construction costs payable — — — — 176.3 — 176.3 Accounts payable and accrued expenses — — 5.1 — 117.6 — 122.7 Dividends payable 58.6 — — — — — 58.6 Deferred revenue and prepaid rents — — — — 163.7 — 163.7 Deferred tax liability — — — — 60.5 — 60.5 Other liabilities — — 11.4 — — — 11.4 Total liabilities 58.6 — 2,924.2 — 2,537.8 (1,813.2 ) 3,707.4 Total stockholders' equity 2,364.7 16.8 2,402.2 — 3,569.0 (5,918.1 ) 2,434.6 Total liabilities and equity $ 2,423.3 $ 16.8 $ 5,326.4 $ — $ 6,106.8 $ (7,731.3 ) $ 6,142.0 IN MILLIONS 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, net — — — — 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)	Consolidating Statements of Operations and Comprehensive Income (Loss) IN MILLIONS Year Ended December 31, 2019 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Non-Guarantor Subsidiaries Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 981.3 $ — $ 981.3 Total operating expenses — — — — 914.3 — 914.3 Operating income — — — — 67.0 — 67.0 Interest (expense) income, net — — (114.5 ) — (0.4 ) 32.9 (82.0 ) Gain on marketable equity investment — — — — 132.3 — 132.3 Loss on early extinguishment of debt — — (71.8 ) — — — (71.8 ) Foreign currency and derivative losses, net — — (7.5 ) — — — (7.5 ) Other expense — — — — (0.3 ) — (0.3 ) (Loss) income before income taxes — — (193.8 ) — 198.6 32.9 37.7 Income tax benefit — — — — 3.7 — 3.7 Equity earnings (loss) related to investment in subsidiaries 19.6 0.1 214.1 — — (233.8 ) — Net income (loss) 19.6 0.1 20.3 — 202.3 (200.9 ) 41.4 Other comprehensive income — — (0.7 ) — 11.8 — 11.1 Comprehensive income (loss) $ 19.6 $ 0.1 $ 19.6 $ — $ 214.1 $ (200.9 ) $ 52.5 IN MILLIONS Year Ended December 31, 2018 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 799.7 $ 21.7 $ — $ 821.4 Total operating expenses — — — — 700.2 31.5 — 731.7 Operating income (loss) — — — — 99.5 (9.8 ) — 89.7 Interest (expense) benefit, net — — (110.6 ) — — (3.3 ) 19.2 (94.7 ) Gain on marketable equity investment — — — — — 9.9 — 9.9 Loss on early extinguishment of debt — — (3.1 ) — — — — (3.1 ) (Loss) income before income taxes — — (113.7 ) — 99.5 (3.2 ) 19.2 1.8 Income tax (expense) benefit — — — — (3.0 ) 2.4 — (0.6 ) Equity (loss) earnings related to investment in subsidiaries (28.9 ) (0.3 ) 84.8 — — — (55.6 ) — Net (loss) income (28.9 ) (0.3 ) (28.9 ) — 96.5 (0.8 ) (36.4 ) 1.2 Other comprehensive loss — — — — — (10.9 ) — (10.9 ) Comprehensive (loss) income $ (28.9 ) $ (0.3 ) $ (28.9 ) $ — $ 96.5 $ (11.7 ) $ (36.4 ) $ (9.7 ) IN MILLIONS Year Ended December 31, 2017 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 666.4 $ 5.6 $ — $ 672.0 Total operating expenses — — — — 640.4 7.5 — 647.9 Operating income (loss) — — — — 26.0 (1.9 ) — 24.1 Interest (expense) benefit, net — — (76.2 ) — — (2.6 ) 10.7 (68.1 ) Loss on early extinguishment of debt — — (36.5 ) — — — — (36.5 ) (Loss) income before income taxes — — (112.7 ) — 26.0 (4.5 ) 10.7 (80.5 ) Income tax expense — — — — (3.0 ) — — (3.0 ) Equity (loss) earnings related to investment in subsidiaries (18.7 ) (0.2 ) 94.0 — (4.6 ) — (70.5 ) — Net (loss) income (18.7 ) (0.2 ) (18.7 ) — 18.4 (4.5 ) (59.8 ) (83.5 ) Other comprehensive income — — — — — 75.5 — 75.5 Comprehensive (loss) income $ (18.7 ) $ (0.2 ) $ (18.7 ) $ — $ 18.4 $ 71.0 $ (59.8 ) $ (8.0 )
Consolidating Statements of Cash Flows	Consolidating Statements of Cash Flows IN MILLIONS Year Ended December 31, 2019 Parent General LP Finance Non-Guarantor Subsidiaries Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (124.9 ) $ — $ 457.7 $ 32.9 $ 365.7 Cash flows from investing activities: Investment in real estate — — — — (843.5 ) (32.9 ) (876.4 ) Investment in subsidiaries (357.2 ) (2.5 ) (210.4 ) — — 570.1 — Equity investments — — — — (3.8 ) — (3.8 ) Proceeds from sale of equity investments — — — — 199.0 — 199.0 Proceeds from the sale of real estate assets — — — — 1.3 — 1.3 Return of investment 210.4 — — — — (210.4 ) — Intercompany borrowings 9.3 — 8.2 — 32.0 (49.5 ) — Net cash (used in) provided by investing activities (137.5 ) (2.5 ) (202.2 ) — (615.0 ) 277.3 (679.9 ) Cash flows from financing activities: Issuance of common stock, net 357.2 — — — — — 357.2 Dividends paid (210.4 ) — (210.4 ) — — 210.4 (210.4 ) Intercompany borrowings — — (9.3 ) — (40.2 ) 49.5 — Proceeds from revolving credit facility — — 656.7 — — — 656.7 Repayments of revolving credit facility — — (182.5 ) — — — (182.5 ) Repayments of unsecured term loan — — (200.0 ) — — — (200.0 ) Proceeds from senior notes — — 1,197.4 — — — 1,197.4 Repayments of senior notes — — (1,200.0 ) — — — (1,200.0 ) Payment of debt extinguishment costs — — (72.0 ) — — — (72.0 ) Payment of deferred financing costs — — (9.4 ) — — — (9.4 ) Payments on finance lease liabilities — — — — (2.9 ) — (2.9 ) Tax payment upon exercise of equity awards (9.3 ) — — — — — (9.3 ) Contributions/distributions from parent — 2.5 357.2 — 210.4 (570.1 ) — Net cash provided by (used in) financing activities 137.5 2.5 327.7 — 167.3 (310.2 ) 324.8 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — — — 2.7 — 2.7 Net increase (decrease) in cash, cash equivalents and restricted cash — — 0.6 — 12.7 — 13.3 Cash, cash equivalents and restricted cash at beginning of period — — — — 64.4 — 64.4 Cash, cash equivalents and restricted cash at end of period $ — $ — $ 0.6 $ — $ 77.1 $ — $ 77.7 IN MILLIONS Year Ended December 31, 2018 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net cash (used in) provided by operating activities $ — $ — $ (103.6 ) $ — $ 421.6 $ (27.9 ) $ 19.2 $ 309.3 Cash flows from investing activities: Asset acquisitions, primarily real estate, net of cash acquired — — — — — (462.8 ) — (462.8 ) Investment in real estate — — — — (814.6 ) (31.9 ) (19.2 ) (865.7 ) Equity investments — — — — — (12.6 ) — (12.6 ) Investment in subsidiaries (700.0 ) (7.0 ) (829.5 ) — — — 1,536.5 — Return of investment 181.1 — — — — — (181.1 ) — Intercompany borrowings 5.6 — (105.1 ) — (6.8 ) — 106.3 — Net cash (used in) provided by investing activities (513.3 ) (7.0 ) (934.6 ) — (821.4 ) (507.3 ) 1,442.5 (1,341.1 ) Cash flows from financing activities: Issuance of common stock, net 699.6 — — — — — — 699.6 Dividends paid (181.1 ) — (181.1 ) — — — 181.1 (181.1 ) Intercompany borrowings — — (5.6 ) — 105.1 6.8 (106.3 ) — Proceeds from revolving credit facility — — 658.4 — — 29.9 — 688.3 Repayments of revolving credit facility — — (532.7 ) — — (114.7 ) — (647.4 ) Proceeds from unsecured term loan — — 1,300.0 — — — — 1,300.0 Repayments of unsecured term loan — — (900.0 ) — — — — (900.0 ) Payments on finance lease liabilities — — — — (7.9 ) (1.6 ) — (9.5 ) Tax payment upon exercise of equity awards (5.2 ) — — — — — — (5.2 ) Contributions/distributions from parent — 7.0 700.0 — 178.6 650.9 (1,536.5 ) — Net cash provided by (used in) financing activities 513.3 7.0 1,039.0 — 275.8 571.3 (1,461.7 ) 944.7 Effect of exchange rate changes on cash, cash equivalents and restricted cash — — (0.8 ) — — 0.4 — (0.4 ) Net increase (decrease) in cash, cash equivalents and restricted cash — — — — (124.0 ) 36.5 — (87.5 ) 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 $ — $ — $ — $ — $ 27.2 $ 37.2 $ — $ 64.4 IN MILLIONS Year Ended December 31, 2017 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 $ — $ — $ (60.3 ) $ — $ 339.7 $ (0.6 ) $ 10.7 $ 289.5 Cash flows from investing activities: Asset acquisitions, primarily real estate, net of cash acquired — — — — (492.3 ) — — (492.3 ) Investment in real estate — — — — (903.8 ) — (10.7 ) (914.5 ) Equity investments — — — — — (100.0 ) — (100.0 ) Investment in subsidiaries (705.3 ) (7.1 ) (705.3 ) — (0.7 ) — 1,418.4 — Return of investment 145.7 — — — — — (145.7 ) — Intercompany borrowings 6.5 — (598.8 ) — — 0.5 591.8 — Net cash (used in) provided by investing activities (553.1 ) (7.1 ) (1,304.1 ) — (1,396.8 ) (99.5 ) 1,853.8 (1,506.8 ) Cash flows from financing activities: Issuance of common stock, net 705.7 — — — — — — 705.7 Dividends paid (145.7 ) — (145.7 ) — — — 145.7 (145.7 ) Intercompany borrowings — — (6.5 ) — 598.2 — (591.7 ) — Proceeds from revolving credit facility — — 1,037.3 — — — — 1,037.3 Repayments of revolving credit facility — — (1,275.0 ) — — — — (1,275.0 ) Proceeds from unsecured term loan — — 350.0 — — — — 350.0 Proceeds from senior notes — — 1,217.8 — — — — 1,217.8 Repayments of senior notes — — (474.8 ) — — — — (474.8 ) Payment of debt extinguishment costs — — (30.0 ) — — — — (30.0 ) Payment of deferred financing costs — — (16.7 ) — — — — (16.7 ) Payments on finance lease liabilities — — — — (8.6 ) (1.2 ) — (9.8 ) Interest paid by lenders on issuance of the senior notes — — 2.7 — — — — 2.7 Tax payment upon exercise of equity awards (6.9 ) — — — — — — (6.9 ) Contributions/distributions from parent — 7.1 705.3 — 605.3 100.8 (1,418.5 ) — Net cash provided by (used in) financing activities 553.1 7.1 1,364.4 — 1,194.9 99.6 (1,864.5 ) 1,354.6 Net increase (decrease) in cash, cash equivalents and restricted cash — — — — 137.8 (0.5 ) — 137.3 Cash, cash equivalents and restricted cash at beginning of period — — — — 13.4 1.2 — 14.6 Cash, cash equivalents and restricted cash at end of period $ — $ — $ — $ — $ 151.2 $ 0.7 $ — $ 151.9

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Unaudited Selected Quarterly Financial Information	The table below reflects the unaudited selected quarterly information for the years ended December 31, 2019 and 2018 : IN MILLIONS, except per share amounts 2019 First Quarter Second Quarter Third Quarter Fourth Total Revenue $ 225.0 $ 251.5 $ 250.9 $ 253.9 $ 981.3 Operating income 11.8 19.7 13.2 22.3 67.0 Net income (loss) 89.4 (8.5 ) 12.6 (52.1 ) 41.4 Basic income (loss) per share 0.82 (0.08 ) 0.11 (0.46 ) 0.36 Diluted income (loss) per share 0.82 (0.08 ) 0.11 (0.46 ) 0.36 IN MILLIONS, except per share amounts 2018 First Second Quarter Third Quarter Fourth Quarter Total Revenue $ 196.6 $ 196.9 $ 206.6 $ 221.3 $ 821.4 Operating income 27.7 27.0 20.2 14.8 89.7 Net income (loss) 43.5 105.9 (42.4 ) (105.8 ) 1.2 Basic income (loss) per share 0.45 1.07 (0.43 ) (1.09 ) — Diluted income (loss) per share 0.45 1.06 (0.43 ) (1.08 ) —

Description of Business (Detail

Description of Business (Details)	12 Months Ended
	Dec. 31, 2019recovery_centerdata_center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of data centers | data_center	49
Number of recovery centers | recovery_center	2

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment losses									$ 700,000	$ 0	$ 58,000,000
Rent and other receivables	$ 291,900,000				$ 234,900,000				$ 291,900,000	234,900,000
Number of business segments | segment									1
Revenue	253,900,000	$ 250,900,000	$ 251,500,000	$ 225,000,000	221,300,000	$ 206,600,000	$ 196,900,000	$ 196,600,000	$ 981,300,000	821,400,000	672,000,000
Net investment in real estate	4,710,300,000				4,293,000,000				4,710,300,000	4,293,000,000
Proceeds previously combined in proceeds from debt, net									0	1,300,000,000	350,000,000
Repayments of unsecured term loan									$ 200,000,000	$ 900,000,000	0
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
Customer 1 | Revenue | Customer concentration risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk (as a percent)									21.00%	18.00%
Reclassification
Summary Of Significant Accounting Policies [Line Items]
Proceeds previously combined in proceeds from debt, net										$ 1,988,300,000	2,558,400,000
Repayments of unsecured term loan										1,547,400,000	$ 1,749,800,000
Straight-line rent receivable, net
Summary Of Significant Accounting Policies [Line Items]
Rent and other receivables	$ 156,800,000				128,700,000				$ 156,800,000	128,700,000
Straight-line rent receivable, net | Reclassification
Summary Of Significant Accounting Policies [Line Items]
Rent and other receivables					$ 128,700,000					$ 128,700,000

Recently Issued Accounting St_3

Recently Issued Accounting Standards - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU assets	$ 161.9
Operating lease liabilities	$ 195.8		$ 0
ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU assets		$ 87
Operating lease liabilities		123.2
Retained earnings | ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		$ 9.5
Retained earnings | ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment				$ 75.6

Recently Issued Accounting St_4

Recently Issued Accounting Standards - Impact of Adoption of the Lease Standard (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Buildings and improvements, net of accumulated depreciation	$ 1,761.4		$ 1,677.5
Operating lease right-of-use assets, net of amortization	161.9
Finance lease liabilities			156.7
Operating lease liabilities, net of accretion	195.8		0
ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net of amortization		$ 87
Operating lease liabilities, net of accretion		$ 123.2
BTS leases
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Buildings and improvements, net of accumulated depreciation			77.4
Finance lease liabilities			$ 123.3
BTS leases | ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net of amortization	44.9
Operating lease liabilities, net of accretion	$ 77.9

Revenue Recognition - Future Mi

Revenue Recognition - Future Minimum Lease Payments under Non-Cancellable Operating Leases (Details) $ in Millions	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
2020	$ 736.2
2021	620.2
2022	528.2
2023	426.5
2024	328.7
Thereafter	973.9
Total	$ 3,613.7

Revenue Recognition - Future _2

Revenue Recognition - Future Minimum Lease Payments to be Received, Excluding Month-to-Month Arrangements and Metered Power Reimbursements (Details) $ in Millions	Dec. 31, 2018USD ($)
Revenue from Contract with Customer [Abstract]
2019	$ 647.6
2020	553.7
2021	453
2022	365.5
2023	284.4
Thereafter	835.9
Total	$ 3,140.1

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 253.9	$ 250.9	$ 251.5	$ 225	$ 221.3	$ 206.6	$ 196.9	$ 196.6	$ 981.3	$ 821.4	$ 672
Lease revenue
Disaggregation of Revenue [Line Items]
Revenue									932.3
Colocation (Minimum lease payments)
Disaggregation of Revenue [Line Items]
Revenue									793.5
Metered power reimbursements (Variable lease payments)
Disaggregation of Revenue [Line Items]
Revenue									138.8
Revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue									49	32.7
Equipment sales and services
Disaggregation of Revenue [Line Items]
Revenue									29.7	15.3
Other revenue
Disaggregation of Revenue [Line Items]
Revenue									$ 19.3	$ 17.4

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contracts with customers	$ 253.9	$ 250.9	$ 251.5	$ 225	$ 221.3	$ 206.6	$ 196.9	$ 196.6	$ 981.3	$ 821.4	$ 672
Balances from customers accounts receivables	$ 6.4				$ 9.4				6.4	9.4
Contracts with customers
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contracts with customers									$ 15.9	$ 13.5
Customer concentration risk | Revenue | Customer 1
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk (as a percent)									21.00%	18.00%
Outside of the United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contracts with customers									$ 2.9

Leases - As a Lessee - Narrativ

Leases - As a Lessee - Narrative (Details)	12 Months Ended
	Dec. 31, 2019facility	Sep. 30, 2019lease
Lessee, Lease, Description [Line Items]
Number of facilities, finance lease	5
Minimum
Lessee, Lease, Description [Line Items]
Finance lease, remaining term of contract	2 years
Operating lease, term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Finance lease, remaining term of contract	21 years
Operating lease, term of contract	25 years
Data Center
Lessee, Lease, Description [Line Items]
Number of facilities, operating lease	12
Office
Lessee, Lease, Description [Line Items]
Number of facilities, operating lease	4
Dublin, Ireland | Ground Lease 1
Lessee, Lease, Description [Line Items]
Number of leases | lease		1
Finance lease, term of contract		999 years

Leases - As a Lessee - Lease Co

Leases - As a Lessee - Lease Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 20.3
Amortization of assets	2.3
Interest on lease liabilities	1.7
Total net lease cost	$ 24.3

Leases - As a Lessee - Suppleme

Leases - As a Lessee - Supplemental Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating leases:
Operating lease right-of-use assets, net of amortization	$ 161.9
Operating lease liabilities	195.8	$ 0
Finance leases:
Property and equipment, at cost	34.9
Accumulated amortization	(5)
Property and equipment, net	29.9
Finance lease liabilities	$ 31.8
Weighted average remaining lease term (in years):
Operating leases	15 years 9 months 18 days
Finance leases	18 years 1 month 6 days
Weighted average discount rate:
Operating leases	3.90%
Finance leases	4.90%

Leases - As a Lessee - Supple_2

Leases - As a Lessee - Supplemental Cash Flow (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 22.1
Operating cash flows from finance leases	1.7
Financing cash flows from finance leases	2.9
Non-cash right-of-use assets obtained in exchange for lease liabilities:
Operating leases	175.1
Finance leases	$ 0.8

Leases - As a Lessee - Maturiti

Leases - As a Lessee - Maturities of Operating and Financing Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating Leases
2020	$ 22.4
2021	21
2022	22.4
2023	18.5
2024	13.9
Thereafter	165.4
Total lease payments	263.6
Less: Imputed interest	(67.8)
Total lease obligations	195.8	$ 0
Finance Leases
2020	5
2021	4.1
2022	2.9
2023	1.9
2024	1.4
Thereafter	31.1
Total lease payments	46.4
Less: Imputed interest	(14.6)
Total lease obligations	$ 31.8

Leases - As a Lessee - Maturi_2

Leases - As a Lessee - Maturities Prior to Adoption of New Accounting Standard (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leases
2019	$ 5
2020	4.9
2021	3.7
2022	3.7
2023	3.5
Thereafter	43.4
Total	64.2
Capital Leases
2019	2.7
2020	2.8
2021	2.9
2022	2
2023	1
Thereafter	22
Total	33.4
Lease Financing Arrangements
2019	15
2020	27.6
2021	11.4
2022	11.6
2023	10
Thereafter	89.1
Total lease payments	$ 164.7

Acquisitions and Purchases of_3

Acquisitions and Purchases of Fixed Assets - Narrative (Details) ft² in Thousands, £ in Millions	Aug. 24, 2018USD ($)data_center	Nov. 30, 2019GBP (£)ft²a	Sep. 30, 2019USD ($)aMW	Aug. 31, 2019GBP (£)ft²aMW	Dec. 31, 2019USD ($)a	Dec. 31, 2018USD ($)a	Aug. 31, 2018USD ($)	Mar. 31, 2018USD ($)	Mar. 29, 2018USD ($)
Business Acquisition [Line Items]
Number of acres purchased | a					74
Fixed lease payments					$ 20,300,000
Data Centers | Zenium Topco Ltd.
Business Acquisition [Line Items]
Number of operating data centers | data_center	4
Aggregate cash consideration after post-closing working capital adjustment	$ 462,800,000
Cash acquired	12,700,000
Outstanding indebtedness assumed	86,300,000
Payments related to post-closing working capital adjustment						$ 1,000,000
Borrowings on line of credit	174,500,000
Dublin, Ireland, San Antonio, Santa Clara and Council Bluffs | Land
Business Acquisition [Line Items]
Purchase price					54,700,000
Dallas, Frankfurt, Northern Virginia, Phoenix and Santa Clara | Land
Business Acquisition [Line Items]
Number of acres purchased | a						182
Purchase price						$ 182,300,000
Dublin, Ireland | Area leased and purchased for future development
Business Acquisition [Line Items]
Area of land leased (in acres) | a			24
Dublin, Ireland | Ground Lease 1
Business Acquisition [Line Items]
Area of land leased (in acres) | a			16
Datacenter output (MW) | MW			6
Prepaid lease payments			$ 6,300,000
Dublin, Ireland | Area purchased for future development
Business Acquisition [Line Items]
Area of land leased (in acres) | a			9
London, UK | Ground Lease 1
Business Acquisition [Line Items]
Area of land leased (in acres) | a				3
Datacenter output (MW) | MW				6
Area of building shell (in square feet) | ft²				51
Operating lease, term of contract				25 years
Operating lease, renewal term				25 years
Fixed lease payments | £				£ 0.9
London, UK | Ground Lease 2
Business Acquisition [Line Items]
Area of land leased (in acres) | a		6.5
Area of building shell (in square feet) | ft²		105
Operating lease, term of contract		20 years
Operating lease, renewal term		15 years
Fixed lease payments | £		£ 2.1
Ground Lease 1 | Dublin, Ireland
Business Acquisition [Line Items]
Finance lease, term of contract			999 years
Term Loan
Business Acquisition [Line Items]
Borrowings on line of credit							$ 174,500,000
2023 Term Loan | Term Loan
Business Acquisition [Line Items]
Proceeds from delayed draw term loan							300,000,000		$ 300,000,000
Borrowings on line of credit					800,000,000	$ 1,000,000,000		$ 700,000,000
Maximum borrowing capacity									1,000,000,000
2023 Term Loan | Term Loan | Data Centers | Zenium Topco Ltd.
Business Acquisition [Line Items]
Proceeds from delayed draw term loan	300,000,000
Revolving Credit Facility | $1.7 Billion Revolving Credit Facility
Business Acquisition [Line Items]
Borrowings on line of credit					615,000,000
Maximum borrowing capacity					$ 1,700,000,000		$ 1,700,000,000		$ 1,700,000,000
Revolving Credit Facility | $1.7 Billion Revolving Credit Facility | Data Centers | Zenium Topco Ltd.
Business Acquisition [Line Items]
Maximum borrowing capacity	$ 1,700,000,000

Acquisitions and Purchases of_4

Acquisitions and Purchases of Fixed Assets - Assets Acquired and Liabilities Assumed (Details) - Zenium $ in Millions	Aug. 24, 2018USD ($)
Business Acquisition [Line Items]
Investment in real estate	$ 597.3
Cash and cash equivalents	12.7
Rent and other receivables	9
Other assets	1.1
Accounts payable	(22.3)
Deferred revenue	(3.3)
Capital lease obligations	(25)
Deferred tax liability	(72.7)
Debt	(86.3)
Net assets acquired attributable to CyrusOne Inc.	475.5
Cash acquired	(12.7)
Net cash paid at acquisition	462.8
Trade name
Business Acquisition [Line Items]
Intangible assets	1.8
Leasehold interest
Business Acquisition [Line Items]
Intangible assets	1.7
In-place leases
Business Acquisition [Line Items]
Intangible assets	$ 61.5

Acquisitions and Purchases of_5

Acquisitions and Purchases of Fixed Assets - Gross Investment in Real Estate (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Investment in Real Estate
Building and Improvements, Cost	$ 1,761.4	$ 1,677.5
Building and Improvements, Less: accumulated depreciation and amortization	(545.1)	(481.8)
Building and Improvements, Net	1,216.3	1,195.7
Equipment, Cost	3,028.2	2,630.2
Equipment, Less: accumulated depreciation and amortization	(834.1)	(572.7)
Equipment, Net	2,194.1	2,057.5
Intangibles
Cost	403.6	402.6
Less: accumulated depreciation and amortization	(207.5)	(166.9)
Total	196.1	235.7
Customer Relationships
Intangibles
Cost	247.1	247.1
Less: accumulated depreciation and amortization	(151.1)	(137.9)
Total	96	109.2
In-Place Leases
Intangibles
Cost	137.1	136
Less: accumulated depreciation and amortization	(46.7)	(21.1)
Total	90.4	114.9
Other Contractual
Intangibles
Cost	19.4	19.5
Less: accumulated depreciation and amortization	(9.7)	(7.9)
Total	$ 9.7	$ 11.6

Investment in Real Estate - Sch

Investment in Real Estate - Schedule of Gross Investment in Real Estate (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Real Estate Properties [Line Items]
Land	$ 147.6	$ 118.5
Building and Improvements	1,761.4	1,677.5
Equipment	3,028.2	2,630.2
Land held for future development	206	176.4
Austin II
Real Estate Properties [Line Items]
Land	2	2
Building and Improvements	23.5	23.4
Equipment	13.3	8.7
Austin III
Real Estate Properties [Line Items]
Land	3.3	3.3
Building and Improvements	12.6	11.7
Equipment	64	47
Chicago - Aurora I
Real Estate Properties [Line Items]
Land	2.4	2.4
Building and Improvements	32.4	32.4
Equipment	136.3	132.9
Chicago - Aurora II
Real Estate Properties [Line Items]
Land	2.6	2.6
Building and Improvements	22.9	22.6
Equipment	70.3	68.6
Chicago - Aurora Tower
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	6.4	4.9
Equipment	0.9	0.4
Chicago - Lombard
Real Estate Properties [Line Items]
Land	0.7	0.7
Building and Improvements	4.7	4.7
Equipment	8.1	8.1
Cincinnati - 7th Street
Real Estate Properties [Line Items]
Land	0.9	0.9
Building and Improvements	114.1	114.1
Equipment	37.2	37.4
Cincinnati - Blue Ash
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.7	0.7
Equipment	0.2	0.2
Cincinnati - Goldcoast
Real Estate Properties [Line Items]
Land	0	0.2
Building and Improvements	0	4
Equipment	0	0.1
Cincinnati - Hamilton
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	43.7	43.7
Equipment	7.8	7.9
Cincinnati - Mason
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	20.3	20.3
Equipment	1.7	1.7
Cincinnati - Northern Cincinnati
Real Estate Properties [Line Items]
Land	0.9	0.9
Building and Improvements	77.8	77.9
Equipment	16	12.4
Dallas - Allen
Real Estate Properties [Line Items]
Land	6.5	0
Building and Improvements	15	0
Equipment	39.5	0
Dallas - Carrollton
Real Estate Properties [Line Items]
Land	16.1	16.1
Building and Improvements	63.8	62.2
Equipment	323.3	272.5
Dallas - Lewisville
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	58.1	76.8
Equipment	41.1	39.6
Florence
Real Estate Properties [Line Items]
Land	2.2	2.2
Building and Improvements	42	42
Equipment	8.7	8.4
Frankfurt I
Real Estate Properties [Line Items]
Land	4	4.1
Building and Improvements	36	35.7
Equipment	123.7	124.9
Frankfurt II
Real Estate Properties [Line Items]
Land	7	7.1
Building and Improvements	135.1	89.8
Equipment	93.6	53.9
Houston - Galleria
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	71	71
Equipment	24.4	20.2
Houston - Houston West I
Real Estate Properties [Line Items]
Land	1.4	1.4
Building and Improvements	85.2	85.2
Equipment	51.6	51.1
Houston - Houston West II
Real Estate Properties [Line Items]
Land	2.7	2.7
Building and Improvements	22.8	22.9
Equipment	52	50.9
Houston - Houston West III
Real Estate Properties [Line Items]
Land	7.2	7.2
Building and Improvements	18.1	18
Equipment	32.3	31.4
London - Great Bridgewater
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0	26.8
Equipment	1.3	1.2
London I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	44.3	34.1
Equipment	46.4	26.3
London II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	42.8	25.2
Equipment	93.3	74.8
Northern Virginia - Sterling I
Real Estate Properties [Line Items]
Land	6.9	6.9
Building and Improvements	20.2	20.2
Equipment	62.2	60.4
Northern Virginia - Sterling II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	28.8	28.8
Equipment	112.4	112.4
Northern Virginia - Sterling III
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	22.3	22.2
Equipment	61.8	61.3
Northern Virginia - Sterling IV
Real Estate Properties [Line Items]
Land	4.6	4.6
Building and Improvements	20.1	20
Equipment	78.1	76
Northern Virginia - Sterling V
Real Estate Properties [Line Items]
Land	14.5	14.5
Building and Improvements	81.7	80.8
Equipment	303.7	295.8
Northern Virginia - Sterling VI
Real Estate Properties [Line Items]
Land	9.7	0
Building and Improvements	60.2	0
Equipment	196.9	77.5
Northern Virginia - Sterling VIII
Real Estate Properties [Line Items]
Land	9.1	0
Building and Improvements	7	0
Equipment	28	0
Norwalk I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	1.7	13.6
Equipment	10.6	10.1
Phoenix - Chandler I
Real Estate Properties [Line Items]
Land	10.5	10.5
Building and Improvements	58.3	58.3
Equipment	71.5	68.7
Phoenix - Chandler II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	16.2	16.2
Equipment	39.8	39.4
Phoenix - Chandler III
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	11.4	11.4
Equipment	51.3	50.8
Phoenix - Chandler IV
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	18.4	18.4
Equipment	44.3	43.3
Phoenix - Chandler V
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	12.1	10.7
Equipment	54.6	53.4
Phoenix - Chandler VI
Real Estate Properties [Line Items]
Land	2.4	2.4
Building and Improvements	23.3	23.3
Equipment	101.7	100.3
Phoenix - Chandler VII
Real Estate Properties [Line Items]
Land	4.2	0
Building and Improvements	0.8	0
Equipment	0.4	0
Raleigh-Durham I
Real Estate Properties [Line Items]
Land	2.1	2.1
Building and Improvements	79.8	79.8
Equipment	80	75.4
San Antonio I
Real Estate Properties [Line Items]
Land	4.6	4.6
Building and Improvements	31.7	31.7
Equipment	36.3	35.3
San Antonio II
Real Estate Properties [Line Items]
Land	7	7
Building and Improvements	30.3	30.3
Equipment	61	60.8
San Antonio III
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	40.2	40.2
Equipment	99.5	99
San Antonio IV
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	56.3	42.1
Equipment	50.6	48.2
Santa Clara II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	2.7	0
Equipment	0	0
Singapore - Inter Business Park
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0	0
Equipment	0	0
Somerset I
Real Estate Properties [Line Items]
Land	12.1	12.1
Building and Improvements	132.1	125.8
Equipment	101.8	91
South Bend - Crescent
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0	1.7
Equipment	0	0.2
South Bend - Monroe
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	1.9	2.5
Equipment	0.3	0.4
Stamford - Omega
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.1	2.6
Equipment	0.8	0.7
Stamford - Riverbend
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.9	2.9
Equipment	8.6	7.8
Totowa - Commerce
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.4	4.1
Equipment	1.7	1.7
Totowa - Madison
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	6.1	28.5
Equipment	60.1	57.7
Wappinger Falls I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	3.1	11.3
Equipment	$ 23.2	$ 22

Investment in Real Estate - Nar

Investment in Real Estate - Narrative (Details) - USD ($)	Aug. 24, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Real Estate Properties [Line Items]
Construction in progress, land under active development		$ 61,800,000	$ 69,100,000
Cost of construction in progress		946,300,000	744,900,000	$ 487,100,000
Capital expenditures		876,400,000	1,328,500,000
Impairment losses		700,000	0	$ 58,000,000
Other developments primarily in Chicago, Cincinnati, Dallas, Northern Virginia, Phoenix and San Antonio
Real Estate Properties [Line Items]
Payments for other developments			$ 865,700,000
Dublin, Ireland, San Antonio, Santa Clara and Council Bluffs | Land
Real Estate Properties [Line Items]
Land purchases included in capital expenditures		$ 54,700,000
Zenium Topco Ltd. | Data Centers
Real Estate Properties [Line Items]
Payments for other developments	$ 462,800,000

Equity Investments - Narrative

Equity Investments - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 18, 2017	Apr. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 30, 2018	Oct. 08, 2018
Schedule of Equity Method Investments [Line Items]
Value of investment			$ 135.1	$ 198.1
Sales price			$ 199	$ 0	$ 0
GDS
Schedule of Equity Method Investments [Line Items]
Newly issued American depository shares (in shares)	8,000,000
Price per ordinary share (in dollars per share)	$ 12.45		$ 51.58
Discount rate	4.00%
Value of investment	$ 100		$ 118.7
American depository shares equivalent (in shares)	8		2,300,000
Number of GDS ADSs sold (in shares)		5,700,000
Sales price		$ 199
Affiliated Entity | ODATA
Schedule of Equity Method Investments [Line Items]
Payments for investments							$ 11.9
Equity interest (as a percent)							10.00%
Additional investments			$ 3.8
Affiliated Entity | ODATA Colombia
Schedule of Equity Method Investments [Line Items]
Payments for investments						$ 0.7

Equity Investments - Unrealized

Equity Investments - Unrealized Gain (Loss) on Marketable Equity Investment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Net gain on marketable equity investment	$ 132.3	$ 9.9	$ 0
Less: Net gain recognized on marketable equity investment sold	66.7	0	0
Unrealized gain on marketable equity investment	$ 65.6	$ 9.9	$ 0

Goodwill, Intangible and Othe_3

Goodwill, Intangible and Other Long-Lived Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 455,100,000	$ 455,100,000
Impairment of goodwill	0	0
Impairment of intangible assets	0	0
Amortization expense for acquired intangible assets	$ 39,900,000	$ 30,600,000	$ 25,100,000

Goodwill, Intangible and Othe_4

Goodwill, Intangible and Other Long-Lived Assets - Carrying Value of Major Classes of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 403.6	$ 402.6
Accumulated Amortization	(207.5)	(166.9)
Total	$ 196.1	235.7
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	10 years
Gross Carrying Amount	$ 247.1	247.1
Accumulated Amortization	(151.1)	(137.9)
Total	$ 96	109.2
Trademark/tradename
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	4 years
Gross Carrying Amount	$ 11.5	11.5
Accumulated Amortization	(7.8)	(6.7)
Total	$ 3.7	4.8
Favorable leasehold interest
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	35 years
Gross Carrying Amount	$ 5.6	5.7
Accumulated Amortization	(1.2)	(0.7)
Total	$ 4.4	5
In-place customer leases
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	5 years
Gross Carrying Amount	$ 137.1	136
Accumulated Amortization	(46.7)	(21.1)
Total	$ 90.4	114.9
Above and below market leases
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	6 years
Gross Carrying Amount	$ 2.3	2.3
Accumulated Amortization	(0.7)	(0.5)
Total	$ 1.6	$ 1.8

Goodwill, Intangible and Othe_5

Goodwill, Intangible and Other Long-Lived Assets - Estimated Amortization Expense For Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 39.3
2021	32
2022	28.6
2023	20.7
2024	18.6
Thereafter	56.9
Total	$ 196.1	$ 235.7

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing and other contract costs	$ 53.2	$ 43.6
Prepaid expenses	22.1	26.4
Non-real estate assets, net	16.3	18.4
Derivative assets	3.5	0
Other assets	18.8	22.9
Total	$ 113.9	$ 111.3

Debt - Components of Debt (Deta

Debt - Components of Debt (Details) - USD ($)	Mar. 29, 2018	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Deferred financing costs			$ (25,800,000)	$ (32,900,000)
Total			2,886,600,000	2,624,700,000
US Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facilities			555,000,000	0
EUR Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facilities			33,600,000	143,000,000
GBP Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facilities			26,400,000	0
$1.7 Billion Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facilities			615,000,000
Maximum borrowing capacity	$ 1,700,000,000		1,700,000,000		$ 1,700,000,000
Option to extend maturity of debt, period	1 year	1 year
Term Loan
Debt Instrument [Line Items]
Credit facilities					$ 174,500,000
Term Loan | 2023 Term Loan
Debt Instrument [Line Items]
Credit facilities			800,000,000	1,000,000,000		$ 700,000,000
Maximum borrowing capacity	$ 1,000,000,000
Term Loan | 2025 Term Loan
Debt Instrument [Line Items]
Credit facilities			300,000,000	300,000,000
Maximum borrowing capacity	$ 300,000,000
Senior Notes | Old 2024 Notes, including bond premium of $5.5 million
Debt Instrument [Line Items]
Long-term debt, gross			$ 0	705,500,000
Interest Rate			5.00%
Bond premium			$ 5,500,000
Senior Notes | Old 2027 Notes, including bond premium of $9.1 million
Debt Instrument [Line Items]
Long-term debt, gross			$ 0	509,100,000
Interest Rate			5.375%
Bond premium			$ 9,100,000
Senior Notes | 2024 Notes, including bond discount of $0.8 million
Debt Instrument [Line Items]
Long-term debt, gross			$ 599,200,000	0
Interest Rate			2.90%
Bond discount			$ 800,000
Senior Notes | 2029 Notes, including bond discount of $1.8 million
Debt Instrument [Line Items]
Long-term debt, gross			$ 598,200,000	$ 0
Interest Rate			3.45%
Bond discount			$ 1,800,000
LIBOR | US Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
LIBOR | GBP Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
LIBOR | Term Loan | 2023 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate			1.35%
LIBOR | Term Loan | 2025 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate			1.65%
EURIBOR | EUR Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
USD | LIBOR
Debt Instrument [Line Items]
Interest Rate			1.80%
GBP | LIBOR
Debt Instrument [Line Items]
Interest Rate			0.71%

Debt - Credit facilities (Detai

Debt - Credit facilities (Details)	Mar. 29, 2018USD ($)tranche	Apr. 30, 2019USD ($)	Aug. 31, 2018USD ($)	Sep. 30, 2019	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Aug. 31, 2018EUR (€)	Mar. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Loss on early extinguishment of debt					$ 71,800,000	$ 3,100,000	$ 36,500,000
Letters of credit outstanding					8,200,000
$3 Billion Credit Facility
Line of Credit Facility [Line Items]
Credit facility, available capacity under accordion feature	$ 3,800,000,000
$3 Billion Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	3,000,000,000				3,000,000,000
Borrowings used to retire debt	1,000,000,000
Remaining borrowing capacity					1,100,000,000
$1.7 Billion Revolving Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	1,700,000,000		$ 1,700,000,000		1,700,000,000
Multicurrency borrowing sublimit	$ 750,000,000
Borrowings on line of credit					$ 615,000,000
Option to extend maturity of debt, period	1 year			1 year
Commitment fee (as a percent)					0.25%
Commitment fee upon greater utilization (as a percent)					0.25%
2023 Term Loan
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
2025 Term Loan
Line of Credit Facility [Line Items]
Debt instrument, term	7 years
$2 Billion Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity							2,000,000,000
$2 Billion Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Borrowings on 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]
Maximum borrowing capacity					$ 1,100,000,000		$ 1,100,000,000
2021 Term Loan
Line of Credit Facility [Line Items]
Debt instrument, term							5 years
2022 Term Loan
Line of Credit Facility [Line Items]
Debt instrument, term							7 years
Construction facility
Line of Credit Facility [Line Items]
Debt instrument, term			6 years
Debt principal amount | €								€ 100,000,000
Second Amended and Restated Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Facility fee					2,600,000	3,800,000	$ 1,900,000
Term Loan
Line of Credit Facility [Line Items]
Borrowings on line of credit			$ 174,500,000
Term Loan | 2023 Term Loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,000,000,000
Borrowings on line of credit					800,000,000	1,000,000,000			$ 700,000,000
Proceeds from delayed draw term loan	$ 300,000,000		$ 300,000,000
Delayed draw feature, number of tranches | tranche	3
Delayed draw feature, period	6 months
Proceeds from sale of GDS shares used to pay down term loan		$ 200,000,000
Term Loan | 2025 Term Loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 300,000,000
Borrowings on line of credit					300,000,000	$ 300,000,000
Remaining borrowing capacity					$ 0
Term Loan | 2021 Term Loan
Line of Credit Facility [Line Items]
Borrowings on line of credit							250,000,000
Term Loan | 2022 Term Loan
Line of Credit Facility [Line Items]
Borrowings on line of credit							$ 650,000,000

Debt - Senior notes (Details)

Debt - Senior notes (Details) - USD ($)	Dec. 05, 2019	Nov. 03, 2017	Mar. 17, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2018	Mar. 29, 2018	Nov. 20, 2012
Debt Instrument [Line Items]
Long-term debt					$ 2,886,600,000	$ 2,624,700,000
Total consideration, including accrued and unpaid interest					$ 1,197,400,000	0	$ 1,217,800,000
Senior Notes | 2.900% Senior Notes Due 2024
Debt Instrument [Line Items]
Stated interest rate					2.90%
Senior Notes | 3.450% Senior Notes Due 2029
Debt Instrument [Line Items]
Stated interest rate					3.45%
Senior Notes | 2.900% Senior Notes Due 2024 and 3.450% Senior Notes Due 2029
Debt Instrument [Line Items]
Debt proceeds, net of underwriting costs	$ 1,197,400,000
Senior Notes | 5.000% Senior Notes Due 2024 and 5.375% Senior Notes Due 2027
Debt Instrument [Line Items]
Debt proceeds, net of underwriting costs		$ 416,100,000	$ 791,200,000
Debt underwriting costs		4,400,000
Senior Notes | Old 2024 Notes - 5.000%
Debt Instrument [Line Items]
Stated interest rate					5.00%
Senior Notes | Old 2027 Notes - 5.375%
Debt Instrument [Line Items]
Stated interest rate					5.375%
Senior Notes | 6.375% senior notes due 2022
Debt Instrument [Line Items]
Loss on early extinguishment of debt	71,800,000
Revolving Credit Facility | $1.7 Billion Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 1,700,000,000			$ 1,700,000,000	$ 1,700,000,000
Revolving Credit Facility | $3 Billion Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity					3,000,000,000				$ 3,000,000,000
CyrusOne LP and CyrusOne Finance Corp | Senior Notes | 2.900% Senior Notes Due 2024
Debt Instrument [Line Items]
Debt principal amount	$ 600,000,000
Stated interest rate	2.90%
CyrusOne LP and CyrusOne Finance Corp | Senior Notes | 3.450% Senior Notes Due 2029
Debt Instrument [Line Items]
Debt principal amount	$ 600,000,000
Stated interest rate	3.45%
CyrusOne LP and CyrusOne Finance Corp | Senior Notes | Old 2024 Notes - 5.000%
Debt Instrument [Line Items]
Debt principal amount		$ 200,000,000	$ 500,000,000
Stated interest rate		5.00%	5.00%
CyrusOne LP and CyrusOne Finance Corp | Senior Notes | Old 2027 Notes - 5.375%
Debt Instrument [Line Items]
Debt principal amount		$ 200,000,000	$ 300,000,000
Stated interest rate		5.375%	5.375%
CyrusOne LP and CyrusOne Finance Corp | Senior Notes | 6.375% senior notes due 2022
Debt Instrument [Line Items]
Debt principal amount										$ 525,000,000
Stated interest rate				6.375%						6.375%
Loss on early extinguishment of debt				$ 36,500,000
Total consideration, including accrued and unpaid interest				515,100,000
Accrued and unpaid interest				10,300,000
Fair Value | Senior Notes | 2.900% Senior Notes Due 2024
Debt Instrument [Line Items]
Long-term debt					602,100,000	0
Fair Value | Senior Notes | 3.450% Senior Notes Due 2029
Debt Instrument [Line Items]
Long-term debt					603,100,000	0
Fair Value | Senior Notes | Old 2024 Notes - 5.000%
Debt Instrument [Line Items]
Long-term debt					0	684,100,000
Fair Value | Senior Notes | Old 2027 Notes - 5.375%
Debt Instrument [Line Items]
Long-term debt					0	488,000,000
Fair Value | Senior Notes | 6.375% senior notes due 2022
Debt Instrument [Line Items]
Long-term debt				474,800,000
Carrying Value | Senior Notes | 2.900% Senior Notes Due 2024
Debt Instrument [Line Items]
Long-term debt					599,200,000	0
Carrying Value | Senior Notes | 3.450% Senior Notes Due 2029
Debt Instrument [Line Items]
Long-term debt					598,200,000	0
Carrying Value | Senior Notes | Old 2024 Notes - 5.000%
Debt Instrument [Line Items]
Long-term debt					0	705,500,000
Carrying Value | Senior Notes | Old 2027 Notes - 5.375%
Debt Instrument [Line Items]
Long-term debt					$ 0	$ 509,100,000
Carrying Value | Senior Notes | 6.375% senior notes due 2022
Debt Instrument [Line Items]
Long-term debt				$ 469,000,000

Debt - Financial debt covenants

Debt - Financial debt covenants (Details) - USD ($)	Dec. 31, 2019	Mar. 29, 2018
Revolving Credit Facility | $3 Billion Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 3,000,000,000	$ 3,000,000,000

Debt - Maturities of Debt (Deta

Debt - Maturities of Debt (Details) - USD ($)	Dec. 31, 2019	Mar. 29, 2018
Debt Instrument [Line Items]
2020	$ 0
2021	0
2022	615,000,000
2023	800,000,000
2024	600,000,000
Thereafter	900,000,000
Total debt	2,915,000,000
$3.0 Billion Credit Facility(a)
Debt Instrument [Line Items]
2020	0
2021	0
2022	615,000,000
2023	800,000,000
2024	0
Thereafter	300,000,000
Total debt	1,715,000,000
2024 Notes and 2029 Notes
Debt Instrument [Line Items]
2020	0
2021	0
2022	0
2023	0
2024	600,000,000
Thereafter	600,000,000
Total debt	1,200,000,000
$3 Billion Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 3,000,000,000	$ 3,000,000,000

Fair Value of Financial Instr_3

Fair Value of Financial Instruments and Hedging Activities - Carrying and Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Oct. 18, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	$ 2,886.6	$ 2,624.7
GDS Equity investment	135.1	198.1
GDS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
GDS Equity investment	$ 118.7		$ 100
Senior Notes | Old 2024 Notes - 5.000%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.00%
Senior Notes | Old 2027 Notes - 5.375%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.375%
Senior Notes | 2024 Notes - 2.900%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	2.90%
Senior Notes | 2029 Notes - 3.450%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	3.45%
Carrying Value | GDS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
GDS Equity investment	$ 118.7	185.5
Carrying Value | Senior Notes | Old 2024 Notes - 5.000%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	0	705.5
Carrying Value | Senior Notes | Old 2027 Notes - 5.375%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	0	509.1
Carrying Value | Senior Notes | 2024 Notes - 2.900%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	599.2	0
Carrying Value | Senior Notes | 2029 Notes - 3.450%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	598.2	0
Fair Value | GDS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
GDS Equity investment	118.7	185.5
Fair Value | Senior Notes | Old 2024 Notes - 5.000%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	0	684.1
Fair Value | Senior Notes | Old 2027 Notes - 5.375%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	0	488
Fair Value | Senior Notes | 2024 Notes - 2.900%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	602.1	0
Fair Value | Senior Notes | 2029 Notes - 3.450%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	$ 603.1	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments and Hedging Activities - Narrative (Details) € in Millions	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2019EUR (€)	Sep. 03, 2019USD ($)	Aug. 31, 2018USD ($)	Mar. 29, 2018USD ($)
Debt Instrument [Line Items]
Impairment losses	$ 700,000	$ 0	$ 58,000,000
Loss on cross-currency contracts	7,500,000
Derivative liabilities	11,400,000	0
Derivative assets	3,500,000	0
$1.7 Billion Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	1,700,000,000					$ 1,700,000,000	$ 1,700,000,000
Cross-Currency Swaps
Debt Instrument [Line Items]
Loss on cross-currency contracts	7,500,000	$ 0
Term Loan | Interest Rate Swaps
Debt Instrument [Line Items]
Derivative contracts					$ 300,000,000
Fixed interest rate					1.19%
Maturing January 2020 | Term Loan | Cross-Currency Swaps
Debt Instrument [Line Items]
Derivative contracts	446,800,000			€ 401.1
Fair value liability	3,700,000
Maturing March 2023 | Term Loan | Cross-Currency Swaps
Debt Instrument [Line Items]
Derivative contracts	500,000,000			€ 450.7
Fair value liability	$ 7,700,000

Fair Value of Financial Instr_5

Fair Value of Financial Instruments and Hedging Activities - Summary of Derivative Positions (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 1,246.8
Asset	3.5	$ 0
Liability	11.4	0
Undesignated derivatives | 01/15/2020 | Cross Currency Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	265.3
Asset	0	0
Liability	2.1	0
Undesignated derivatives | 01/15/2020 | Cross Currency Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	25.6
Asset	0	0
Liability	0.2	0
Net investment hedge | Designated derivatives | 3/29/2023 | Cross Currency Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	250
Asset	0	0
Liability	3.8	0
Net investment hedge | Designated derivatives | 3/29/2023 | Cross Currency Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	250
Asset	0	0
Liability	3.9	0
Net investment hedge | Designated derivatives | 1/15/2020 | Cross Currency Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	155.9
Asset	0	0
Liability	1.4	0
Interest rate hedge - Float to fixed | Designated derivatives | 3/29/2023 | Interest Rate Swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	300
Asset	3.5	0
Liability	$ 0	$ 0

Fair Value of Financial Instr_6

Fair Value of Financial Instruments and Hedging Activities - Fair Values of Qualifying Instruments (Details) - Derivatives Designated as Hedging Instruments - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 3.5	$ 0
Other Assets | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	3.5	0
Other Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	9.1	0
Other Liabilities | Cross-Currency Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	$ 9.1	$ 0

Fair Value of Financial Instr_7

Fair Value of Financial Instruments and Hedging Activities - Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Amount of gain (loss) recognized in OCI for derivatives	$ (0.7)	$ 0	$ 0
Amount of gain (loss) recognized in earnings	(7.5)
Cross-Currency Swaps
Derivative [Line Items]
Amount of gain (loss) recognized in OCI for derivatives	(0.7)	0
Amount of gain (loss) reclassified from accumulated OCI for derivatives	0	0
Amount of gain (loss) recognized in earnings	$ (7.5)	$ 0

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Health care plan expenses	$ 3.9	$ 3.3	$ 2.7
Retirement savings plan matching contributions	$ 1.9	$ 1.8	$ 1.5

Income (Loss) per Share - Narra

Income (Loss) per Share - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Nov. 20, 2019	Dec. 28, 2018	Sep. 28, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Formation [Line Items]
Proceeds from sale of stock				$ 357.2	$ 699.6	$ 705.7
Forward sale agreement with Jefferies LLC
Business Formation [Line Items]
Issuance of common stock (in shares)	1.6
Price per share (in dollars per share)	$ 61.67
Public stock offering
Business Formation [Line Items]
Issuance of common stock (in shares)			6.7
Proceeds from sale of stock			$ 397.3
Underwriting discounts and expenses			$ 18.1
Stock issued upon underwriters exercising option to purchase additional shares
Business Formation [Line Items]
Issuance of common stock (in shares)			2.5
Morgan Stanley & Co, LLC | Stock issued upon underwriters exercising option to purchase additional shares
Business Formation [Line Items]
Proceeds from sale of stock		$ 148.2

Income (Loss) per Share - Compu

Income (Loss) per Share - Computation of Basic and Diluted Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income (loss)	$ (52.1)	$ 12.6	$ (8.5)	$ 89.4	$ (105.8)	$ (42.4)	$ 105.9	$ 43.5	$ 41.4	$ 1.2	$ (83.5)
Less: Restricted stock dividends, Basic									(0.7)	(1.1)	(0.9)
Less: Restricted stock dividends, Diluted									(0.7)	(1.1)	(0.9)
Net income (loss) available to stockholders, Basic									40.7	0.1	(84.4)
Net (loss) income available to stockholders, Diluted									$ 40.7	$ 0.1	$ (84.4)
Denominator:
Weighted average common outstanding - basic (in shares)									112.1	99.8	88.9
Performance-based restricted stock and units (in shares)									0.4	0.6	0
Weighted average shares outstanding- diluted (in shares)									112.5	100.4	88.9
EPS:
Net income (loss) per share-basic (in dollars per share)	$ (0.46)	$ 0.11	$ (0.08)	$ 0.82	$ (1.09)	$ (0.43)	$ 1.07	$ 0.45	$ 0.36	$ 0	$ (0.95)
Effect of dilutive shares:
Net income (loss) per share-diluted (in dollars per share)	$ (0.46)	$ 0.11	$ (0.08)	$ 0.82	$ (1.08)	$ (0.43)	$ 1.06	$ 0.45	$ 0.36	$ 0	$ (0.95)
Restricted stock
Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share (in shares)											0.4
Stock options
Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share (in shares)											0.1

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)

Feb. 21, 2019

Feb. 26, 2018

Feb. 13, 2017

Feb. 01, 2016

Feb. 10, 2015

Feb. 07, 2014

Apr. 17, 2013

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of options (in dollars per share)

$ 0

Total intrinsic value of options exercised

$ 400,000

$ 600,000

$ 500,000

Aggregate intrinsic value of options outstanding and exercisable

$ 13,100,000

LTIP

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares reserved for issuance

8,900,000

Number of shares available for grant

4,600,000

2014 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value

$ 12,900,000

Unearned compensation related to awards granted

$ 0

2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value

$ 13,800,000

Unearned compensation related to awards granted

0

2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value

$ 22,600,000

Unearned compensation related to awards granted

$ 0

2017 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Cap on vesting (as a percent)

100.00%

Grant date fair value

$ 15,900,000

Unearned compensation related to awards granted

$ 500,000

Weighted average vesting period

1 month 6 days

2018 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value

$ 20,200,000

Unearned compensation related to awards granted

$ 5,700,000

Weighted average vesting period

9 months 18 days

2019 Grants and ESPP expense

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value

$ 20,500,000

Unearned compensation related to awards granted

$ 11,900,000

Weighted average vesting period

1 year 7 months 6 days

Market-based awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period when vesting is limited to 100%

2 years

Vesting period

3 years

Market-based awards | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

REIT index causing awards to vest (as a percent)

2.00%

Market-based awards | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

REIT index causing awards to vest (as a percent)

200.00%

Market-based awards | If CyrusOne's total stockholder return is less than the return of the Index

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

0.00%

Market-based awards | If CyrusOne's total stockholder return is equal to or greater than the return of the Index

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

100.00%

Market-based awards | if CyrusOne's total stockholder return exceeds the return of the Index by 2%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

200.00%

Market-based awards | If CyrusOne's total stockholder return exceeds the return of the Index, but is negative

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

50.00%

Market-based awards | 2014 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

50.00%

Vesting period

3 years

Market-based awards | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of non-option awards (in dollars per share)

$ 43.66

Market-based awards | 2017 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

129,146

Grant date fair value of non-option awards (in dollars per share)

$ 63.23

Market-based awards | 2018 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

160,266

Grant date fair value of non-option awards (in dollars per share)

$ 52.53

Market-based awards | 2019 Grants and ESPP expense

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

184,145

Grant date fair value of non-option awards (in dollars per share)

$ 43.67

Time-based restricted stock units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Term of right to receive dividends payable

10 days

Time-based restricted stock units | 2016 Grants | Cliff Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

3 years

Time-based restricted stock units | 2017 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

119,218

20,852

Vesting period

3 years

3 years

Time-based restricted stock units | 2018 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

161,797

40,249

Vesting period

3 years

3 years

Time-based restricted stock units | 2019 Grants and ESPP expense

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

175,073

42,052

Vesting period

3 years

Time-based restricted stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

16,681

Grant date fair value of non-option awards (in dollars per share)

$ 52.46

Non-option awards outstanding (in shares)

16,681

419,356

Time-based restricted stock | 2014 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

46,313

Aggregate fair value

$ 1,000,000

Vesting period

3 years

Time-based restricted stock | 2014 Grants | Cliff Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

1 year

Time-based restricted stock | 2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

20.00%

Granted (in shares)

50,300

Time-based restricted stock | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

47,667

Vesting period

3 years

3 years

Time-based restricted stock | 2016 Grants | Cliff Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

5,894

Vesting period

3 years

Time-based restricted stock | 2017 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

18,179

Vesting period

1 year

Time-based restricted stock | 2018 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

17,052

Vesting period

1 year

Time-based restricted stock | 2019 Grants and ESPP expense

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

16,681

Vesting period

1 year

Performance-based awards | 2013 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

3 years

Performance-based awards | 2014 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

50.00%

Performance-based awards | 2014 Grants | Below 90% of EBITDA Target

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

0.00%

Performance-based awards | 2014 Grants | At 90% of EBITDA Target

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

50.00%

Performance-based awards | 2014 Grants | At 100% of EBITDA Target

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

100.00%

Performance-based awards | 2014 Grants | At or above 115% of EBITDA Target

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights (as a percent)

200.00%

Performance-based awards | 2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

67,012

Performance-based awards | 2015 Grants | Cliff Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

3 years

Stock options | 2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

3 years

Stock options | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

222,461

Contractual life

10 years

Exercise price (in dollars per share)

$ 36.99

Grant date fair value of options (in dollars per share)

$ 6.99

Performance-based and market-based awards | 2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period when vesting is limited to 100%

2 years

Cap on vesting (as a percent)

100.00%

Vesting rights (as a percent)

80.00%

Vesting period

3 years

Cumulative true-up maximum (as a percent)

200.00%

Performance-based and market-based awards | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period when vesting is limited to 100%

2 years

Cap on vesting (as a percent)

100.00%

Vesting period

3 years

Cumulative true-up maximum (as a percent)

200.00%

Time-based restricted stock units and restricted stock | 2015 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

3 years

Time-based restricted stock units and restricted stock | 2017 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of non-option awards (in dollars per share)

$ 48.13

Time-based restricted stock units and restricted stock | 2018 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of non-option awards (in dollars per share)

$ 51.31

Time-based restricted stock units and restricted stock | 2019 Grants and ESPP expense

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of non-option awards (in dollars per share)

$ 52.46

Time, performance and market-based awards | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

641,097

Time and performance-based awards | 2016 Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant date fair value of non-option awards (in dollars per share)

$ 36.99

Restricted stock units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Granted (in shares)

401,270

Grant date fair value of non-option awards (in dollars per share)

$ 48.90

Non-option awards outstanding (in shares)

646,619

511,409

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($)	Feb. 19, 2020	Nov. 20, 2019	Dec. 28, 2018	Sep. 28, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Subsidiary or Equity Method Investee [Line Items]
Issuance of common stock (in shares)					6,500,000	12,200,000
Average price per share (in dollars per share)					$ 55.43	$ 59.28
Proceeds from sale of stock					$ 357,200,000	$ 699,600,000	$ 705,700,000
Common stock, shares outstanding (in shares)					114,808,898	108,329,314
Dividends payable					$ 58,600,000	$ 51,000,000	$ 41,800,000
Dividends declared (in dollars per share)					$ 1.92	$ 1.84	$ 1.68
2018 ATM Stock Offering Program
Subsidiary or Equity Method Investee [Line Items]
Aggregate sales price (up to)								$ 500,000,000
New 2018 ATM Stock Offering Program
Subsidiary or Equity Method Investee [Line Items]
Aggregate sales price (up to)						$ 750,000,000
Proceeds from sale of stock					$ 355,600,000
Stock issuance costs					4,300,000
Value of shares available for future offerings					$ 290,100,000
Forward sale agreement
Subsidiary or Equity Method Investee [Line Items]
Issuance of common stock (in shares)		1,600,000
Initial forward price (in dollars per share)		$ 61.67
Public stock offering
Subsidiary or Equity Method Investee [Line Items]
Proceeds from sale of stock				$ 397,300,000
Stock issuance costs				$ 18,100,000
Issuance of common stock (in shares)				6,700,000
Over-allotment option
Subsidiary or Equity Method Investee [Line Items]
Issuance of common stock (in shares)				2,500,000
Morgan Stanley & Co, LLC | Over-allotment option
Subsidiary or Equity Method Investee [Line Items]
Proceeds from sale of stock			$ 148,200,000
Forecast
Subsidiary or Equity Method Investee [Line Items]
Dividends declared (in dollars per share)	$ 0.50

Stock-Based Compensation - Comp

Stock-Based Compensation - Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	$ 16.7	$ 17.5	$ 14.7
2014 Grants
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	0	0	0.1
2015 Grants
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	0	0.4	1.8
2016 Grants
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	1.1	5.7	6.6
2017 Grants
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	3.1	4.6	6.2
2018 Grants
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	5.4	6.8	0
2019 Grants and ESPP expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total compensation expense	$ 7.1	$ 0	$ 0

Stockholders' Equity - Declared

Stockholders' Equity - Declared Cash Dividends and Distributions (Details) - $ / shares	Jan. 10, 2020	Oct. 11, 2019	Jul. 12, 2019	Apr. 12, 2019	Jan. 11, 2019	Oct. 12, 2018	Jul. 13, 2018	Apr. 13, 2018
Class of Stock [Line Items]
Declared cash dividends and distributions (in dollars per share)		$ 0.50	$ 0.46	$ 0.46	$ 0.46	$ 0.46	$ 0.46	$ 0.46
Subsequent Event
Class of Stock [Line Items]
Declared cash dividends and distributions (in dollars per share)	$ 0.50

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards Activity (Details)	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Restricted Stock Units
Shares
Non-vested beginning balance (in shares) | shares	511,409
Granted (in shares) | shares	401,270
Vested (in shares) | shares	(187,176)
Forfeited (in shares) | shares	(78,884)
Non-vested ending balance (in shares) | shares	646,619
Weighted Average Grant Date Fair Value
Non-vested beginning balance (in dollars per share) | $ / shares	$ 56.23
Granted (in dollars per share) | $ / shares	48.90
Vested (in dollars per share) | $ / shares	43.37
Forfeited (in dollars per share) | $ / shares	52.99
Non-vested ending balance (in dollars per share) | $ / shares	$ 55.80
Restricted Stock
Shares
Non-vested beginning balance (in shares) | shares	419,356
Granted (in shares) | shares	16,681
Vested (in shares) | shares	(384,753)
Forfeited (in shares) | shares	(34,603)
Non-vested ending balance (in shares) | shares	16,681
Weighted Average Grant Date Fair Value
Non-vested beginning balance (in dollars per share) | $ / shares	$ 35.73
Granted (in dollars per share) | $ / shares	52.46
Vested (in dollars per share) | $ / shares	35.61
Forfeited (in dollars per share) | $ / shares	37.09
Non-vested ending balance (in dollars per share) | $ / shares	$ 52.46

Stock-Based Compensation - Unve

Stock-Based Compensation - Unvested Stock Options (Details)	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Options
Beginning balance (in shares) | shares	401,223
Granted (in shares) | shares	0
Exercised (in shares) | shares	(25,586)
Forfeited or expired (in shares) | shares	(551)
Ending balance (in shares) | shares	375,086
Exercisable (in shares) | shares	375,086
Vested and expected to vest (in shares) | shares	375,086
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 31.96
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	36.70
Forfeited or expired (in dollars per share) | $ / shares	23.58
Ending balance (in dollars per share) | $ / shares	31.64
Exercisable (in dollars per share) | $ / shares	31.64
Vested and expected to vest (in dollars per share) | $ / shares	$ 31.64

Stock-Based Compensation - Opti

Stock-Based Compensation - Option Valuation Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Number of Shares (in shares)	375,086	401,223
Options Exercisable, Number of Shares (in shares)	375,086
$23.58
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Prices (in dollars per share)	$ 23.58	$ 23.58	$ 23.58
Options Outstanding, Number of Shares (in shares)	51,985	53,086	67,322
Options Outstanding, Weighted Average Remaining Contractual Terms (Years)	3 years 3 months 18 days	4 years 3 months 18 days	5 years 3 months 18 days
Options Exercisable, Number of Shares (in shares)	51,985	53,086	67,322
Options Exercisable, Weighted Average Remaining Contractual Terms (Years)	3 years 3 months 18 days	4 years 3 months 18 days	5 years 3 months 18 days
Risk-Free Interest Rate (as a percent)	0.92%	0.92%	0.92%
Expected Annual Dividend Yield (as a percent)	3.40%	3.40%	3.40%
Expected Terms in Years	6 years	6 years	6 years
Expected Volatility (as a percent)	35.00%	35.00%	35.00%
$28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Prices (in dollars per share)	$ 28.42	$ 28.42	$ 28.42
Options Outstanding, Number of Shares (in shares)	143,358	143,358	143,358
Options Outstanding, Weighted Average Remaining Contractual Terms (Years)	5 years 1 month 6 days	6 years 1 month 6 days	7 years 1 month 6 days
Options Exercisable, Number of Shares (in shares)	143,358	143,358	95,572
Options Exercisable, Weighted Average Remaining Contractual Terms (Years)	5 years 1 month 6 days	6 years 1 month 6 days	7 years 1 month 6 days
Expected Annual Dividend Yield (as a percent)	4.40%	4.40%	4.40%
$30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Prices (in dollars per share)	$ 30.74	$ 30.74	$ 30.74
Options Outstanding, Number of Shares (in shares)	12,719	12,719	12,719
Options Outstanding, Weighted Average Remaining Contractual Terms (Years)	5 years 7 months 6 days	6 years 7 months 6 days	7 years 7 months 6 days
Options Exercisable, Number of Shares (in shares)	12,719	12,719	8,479
Options Exercisable, Weighted Average Remaining Contractual Terms (Years)	5 years 7 months 6 days	6 years 7 months 6 days	7 years 7 months 6 days
Expected Annual Dividend Yield (as a percent)	4.40%	4.40%	4.40%
$36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Prices (in dollars per share)	$ 36.99	$ 36.99	$ 36.99
Options Outstanding, Number of Shares (in shares)	167,024	192,060	192,060
Options Outstanding, Weighted Average Remaining Contractual Terms (Years)	6 years 1 month 6 days	6 years 9 months 18 days	8 years 1 month 6 days
Options Exercisable, Number of Shares (in shares)	167,024	130,425	64,022
Options Exercisable, Weighted Average Remaining Contractual Terms (Years)	6 years 1 month 6 days	6 years 8 months 12 days	8 years 1 month 6 days
Expected Annual Dividend Yield (as a percent)	4.10%	4.10%	4.10%
Minimum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.60%	1.60%	1.60%
Expected Terms in Years	5 years 6 months	5 years 6 months	5 years 6 months
Expected Volatility (as a percent)	32.50%	32.50%	32.50%
Minimum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.60%	1.60%	1.60%
Expected Terms in Years	5 years 6 months	5 years 6 months	5 years 6 months
Expected Volatility (as a percent)	32.50%	32.50%	32.50%
Minimum | $36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.47%	1.47%	1.47%
Expected Terms in Years	5 years 6 months	5 years 6 months	5 years 6 months
Expected Volatility (as a percent)	27.50%	27.50%	27.50%
Maximum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.75%	1.75%	1.75%
Expected Terms in Years	6 years 6 months	6 years 6 months	6 years 6 months
Expected Volatility (as a percent)	37.50%	37.50%	37.50%
Maximum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.75%	1.75%	1.75%
Expected Terms in Years	6 years 6 months	6 years 6 months	6 years 6 months
Expected Volatility (as a percent)	37.50%	37.50%	37.50%
Maximum | $36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate (as a percent)	1.64%	1.64%	1.64%
Expected Terms in Years	6 years 6 months	6 years 6 months	6 years 6 months
Expected Volatility (as a percent)	35.00%	35.00%	35.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
GDS Holdings Limited | Investee
Related Party Transaction [Line Items]
Commission and referral charges payable	$ 0.5	$ 0.9

Income Taxes - Component of Inc

Income Taxes - Component of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Federal	$ 1.7	$ 1	$ 1.2
State	1.9	2	1.8
Foreign	0.2	0	0
Total current tax expense (benefit)	3.8	3	3
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	(7.5)	(2.4)	0
Total deferred tax expense (benefit)	(7.5)	(2.4)	0
Income tax (benefit) expense	$ (3.7)	$ 0.6	$ 3

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax at U.S. federal statutory income tax rate	$ 7.9	$ 0.4	$ (28.2)
State and local taxes, net of federal income tax benefit	1.7	2	1.8
Impact of REIT status	(13.7)	(2.1)	28.6
Permanent differences	(0.7)	(0.1)	0
Foreign tax rate and currency differences	(1)	0.2	0
Anti-hybrid disallowances	1.6	0.1	0
Valuation allowance	0.5	0.1	0.8
Income tax (benefit) expense	$ (3.7)	$ 0.6	$ 3

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and LIabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Net operating loss carryforwards	$ 16.3	$ 15.1
Accounts receivable/payable and other	8.2	7.4
Finance leases	0.9	1.8
Total gross deferred tax assets	25.4	24.3
Valuation allowance	(7.6)	(6.9)
Total gross deferred tax assets, net	17.8	17.4
Deferred tax liabilities
Fixed assets	(67.4)	(73.5)
Intangibles	(10.9)	(12.8)
Total gross deferred tax liabilities	(78.3)	(86.3)
Total net deferred tax assets/(liabilities)	$ (60.5)	$ (68.9)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Aug. 24, 2018
Income Taxes [Line Items]
Deferred tax liability	$ 60,500,000	$ 68,900,000
Valuation allowance	7,600,000	$ 6,900,000
Liability for unrecognized tax benefit	$ 0
Zenium Data Centers
Income Taxes [Line Items]
Deferred tax liability			$ 72,700,000

Commitments and Contingencies (

Commitments and Contingencies (Details) ft² in Thousands, £ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2019GBP (£)ft²	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)
Loss Contingencies [Line Items]
Outstanding letters of credit			$ 8,200,000
Annual rent				$ 64,200,000
Minimum
Loss Contingencies [Line Items]
Initial lease term		1 year	1 year
Maximum
Loss Contingencies [Line Items]
Initial lease term		25 years	25 years
Performance Guarantee
Loss Contingencies [Line Items]
Accruals for performance guarantees			$ 0	$ 0
Data Center Facilities and Equipment
Loss Contingencies [Line Items]
Commitments expected to be incurred	$ 217,400,000
Data Center Facilities and Equipment | Minimum
Loss Contingencies [Line Items]
Commitment term	1 year
Data Center Facilities and Equipment | Maximum
Loss Contingencies [Line Items]
Commitment term	2 years
Services
Loss Contingencies [Line Items]
Commitments expected to be incurred	$ 89,900,000
Services | Minimum
Loss Contingencies [Line Items]
Commitment term	1 year
Services | Maximum
Loss Contingencies [Line Items]
Commitment term	2 years
London, UK
Loss Contingencies [Line Items]
Area leased (in square feet) | ft²		70	70
Annual rent | £		£ 1.4
Land | London, UK
Loss Contingencies [Line Items]
Initial lease term		20 years	20 years

Guarantors - Narrative (Details

Guarantors - Narrative (Details)	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Minimum unencumbered asset value percentage of unsecured debt (as a percent)	150.00%

Guarantors - Consolidating Bala

Guarantors - Consolidating Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	$ 4,710.3	$ 4,293
Cash and cash equivalents	76.4	64.4
Investment in subsidiaries	0	0
Rent and other receivables, net	291.9	234.9
Restricted cash	1.3	0
Operating lease right-of-use assets, net	161.9
Intercompany receivable	0	0
Equity investments	135.1	198.1
Goodwill	455.1	455.1
Intangible assets, net	196.1	235.7
Other assets	113.9	111.3
Total assets	6,142	5,592.5
Debt	2,886.6	2,624.7
Intercompany payable	0	0
Finance lease liabilities	31.8
Finance lease liabilities		156.7
Operating lease liabilities	195.8	0
Accounts payable and accrued expenses	122.7	121.3
Construction costs payable	176.3	195.3	$ 115.5
Dividends payable	58.6	51	$ 41.8
Deferred revenue and prepaid rents	163.7	148.6
Deferred tax liability	60.5	68.9
Other liabilities	11.4	0
Total liabilities	3,707.4	3,366.5
Total stockholders’ equity	2,434.6	2,226
Total liabilities and equity	6,142	5,592.5
Eliminations/Consolidations
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	69.9	36.9
Cash and cash equivalents	0	0
Investment in subsidiaries	(5,988)	(5,361.6)
Rent and other receivables, net	0	0
Restricted cash	0
Operating lease right-of-use assets, net	0
Intercompany receivable	(1,813.2)	(1,791.5)
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	(7,731.3)	(7,116.2)
Debt	0	0
Intercompany payable	(1,813.2)	(1,791.5)
Finance lease liabilities	0
Finance lease liabilities		0
Operating lease liabilities	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
Other liabilities	0
Total liabilities	(1,813.2)	(1,791.5)
Total stockholders’ equity	(5,918.1)	(5,324.7)
Total liabilities and equity	(7,731.3)	(7,116.2)
General Partner
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	16.8	22.2
Rent and other receivables, net	0	0
Restricted cash	0
Operating lease right-of-use assets, net	0
Intercompany receivable	0	0
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	16.8	22.2
Debt	0	0
Intercompany payable	0	0
Finance lease liabilities	0
Finance lease liabilities		0
Operating lease liabilities	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
Other liabilities	0
Total liabilities	0	0
Total stockholders’ equity	16.8	22.2
Total liabilities and equity	16.8	22.2
Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	2,402.2	2,216.9
Rent and other receivables, net	0	0
Restricted cash	0
Operating lease right-of-use assets, net	0
Intercompany receivable	21.1	23.2
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	2,423.3	2,240.1
Debt	0	0
Intercompany payable	0	0
Finance lease liabilities	0
Finance lease liabilities		0
Operating lease liabilities	0
Accounts payable and accrued expenses	0	0
Construction costs payable	0	0
Dividends payable	58.6	51
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Other liabilities	0
Total liabilities	58.6	51
Total stockholders’ equity	2,364.7	2,189.1
Total liabilities and equity	2,423.3	2,240.1
LP Co-issuer
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	0	0
Cash and cash equivalents	0.6	0
Investment in subsidiaries	3,569	3,122.5
Rent and other receivables, net	0	0
Restricted cash	0
Operating lease right-of-use assets, net	0
Intercompany receivable	1,753.3	1,761.5
Equity investments	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	3.5	0.5
Total assets	5,326.4	4,884.5
Debt	2,886.6	2,624.7
Intercompany payable	21.1	23.2
Finance lease liabilities	0
Finance lease liabilities		0
Operating lease liabilities	0
Accounts payable and accrued expenses	5.1	19.7
Construction costs payable	0	0
Dividends payable	0	0
Deferred revenue and prepaid rents	0	0
Deferred tax liability	0	0
Other liabilities	11.4
Total liabilities	2,924.2	2,667.6
Total stockholders’ equity	2,402.2	2,216.9
Total liabilities and equity	5,326.4	4,884.5
Finance Co-issuer
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	0	0
Cash and cash equivalents	0	0
Investment in subsidiaries	0	0
Rent and other receivables, net	0	0
Restricted cash	0
Operating lease right-of-use assets, net	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
Intercompany payable	0	0
Finance lease liabilities	0
Finance lease liabilities		0
Operating lease liabilities	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
Other liabilities	0
Total liabilities	0	0
Total stockholders’ equity	0	0
Total liabilities and equity	0	0
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net	4,640.4
Cash and cash equivalents	75.8
Investment in subsidiaries	0
Rent and other receivables, net	291.9
Restricted cash	1.3
Operating lease right-of-use assets, net	161.9
Intercompany receivable	38.8
Equity investments	135.1
Goodwill	455.1
Intangible assets, net	196.1
Other assets	110.4
Total assets	6,106.8
Debt	0
Intercompany payable	1,792.1
Finance lease liabilities	31.8
Operating lease liabilities	195.8
Accounts payable and accrued expenses	117.6
Construction costs payable	176.3
Dividends payable	0
Deferred revenue and prepaid rents	163.7
Deferred tax liability	60.5
Other liabilities	0
Total liabilities	2,537.8
Total stockholders’ equity	3,569
Total liabilities and equity	$ 6,106.8
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net		3,611.2
Cash and cash equivalents		27.2
Investment in subsidiaries		0
Rent and other receivables, net		218.7
Intercompany receivable		6.8
Equity investments		0
Goodwill		455.1
Intangible assets, net		178.1
Other assets		94.4
Total assets		4,591.5
Debt		0
Intercompany payable		1,761.5
Finance lease liabilities		104
Accounts payable and accrued expenses		95.9
Construction costs payable		175.6
Dividends payable		0
Deferred revenue and prepaid rents		144.9
Deferred tax liability		0
Total liabilities		2,281.9
Total stockholders’ equity		2,309.6
Total liabilities and equity		4,591.5
Non- Guarantors
Condensed Financial Statements, Captions [Line Items]
Total investment in real estate, net		644.9
Cash and cash equivalents		37.2
Investment in subsidiaries		0
Rent and other receivables, net		16.2
Intercompany receivable		0
Equity investments		198.1
Goodwill		0
Intangible assets, net		57.6
Other assets		16.4
Total assets		970.4
Debt		0
Intercompany payable		6.8
Finance lease liabilities		52.7
Accounts payable and accrued expenses		5.7
Construction costs payable		19.7
Dividends payable		0
Deferred revenue and prepaid rents		3.7
Deferred tax liability		68.9
Total liabilities		157.5
Total stockholders’ equity		812.9
Total liabilities and equity		$ 970.4

Guarantors - Consolidating Stat

Guarantors - Consolidating Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Income Statements, Captions [Line Items]
Revenue	$ 253,900,000	$ 250,900,000	$ 251,500,000	$ 225,000,000	$ 221,300,000	$ 206,600,000	$ 196,900,000	$ 196,600,000	$ 981,300,000	$ 821,400,000	$ 672,000,000
Total operating expenses									914,300,000	731,700,000	647,900,000
Operating income	22,300,000	13,200,000	19,700,000	11,800,000	14,800,000	20,200,000	27,000,000	27,700,000	67,000,000	89,700,000	24,100,000
Interest (expense) income, net									(82,000,000)	(94,700,000)	(68,100,000)
Gain on marketable equity investment									132,300,000	9,900,000	0
Loss on early extinguishment of debt									700,000	0	58,000,000
Foreign currency and derivative losses, net									(7,500,000)	0	0
Other expense									(300,000)	0	0
Loss on early extinguishment of debt									(71,800,000)	(3,100,000)	(36,500,000)
Net income (loss) before income taxes									37,700,000	1,800,000	(80,500,000)
Income tax benefit									3,700,000	(600,000)	(3,000,000)
Equity earnings (loss) related to investment in subsidiaries									0	0	0
Net income (loss)	$ (52,100,000)	$ 12,600,000	$ (8,500,000)	$ 89,400,000	$ (105,800,000)	$ (42,400,000)	$ 105,900,000	$ 43,500,000	41,400,000	1,200,000	(83,500,000)
Other comprehensive income (loss)									11,100,000	(10,900,000)	75,500,000
Comprehensive income (loss)									52,500,000	(9,700,000)	(8,000,000)
Eliminations/Consolidations
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Total operating expenses									0	0	0
Operating income									0	0	0
Interest (expense) income, net									32,900,000	19,200,000	10,700,000
Gain on marketable equity investment									0	0
Foreign currency and derivative losses, net									0
Other expense									0
Loss on early extinguishment of debt									0	0	0
Net income (loss) before income taxes									32,900,000	19,200,000	10,700,000
Income tax benefit									0	0	0
Equity earnings (loss) related to investment in subsidiaries									(233,800,000)	(55,600,000)	(70,500,000)
Net income (loss)									(200,900,000)	(36,400,000)	(59,800,000)
Other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									(200,900,000)	(36,400,000)	(59,800,000)
Parent Guarantor
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Total operating expenses									0	0	0
Operating income									0	0	0
Interest (expense) income, net									0	0	0
Gain on marketable equity investment									0	0
Foreign currency and derivative losses, net									0
Other expense									0
Loss on early extinguishment of debt									0	0	0
Net income (loss) before income taxes									0	0	0
Income tax benefit									0	0	0
Equity earnings (loss) related to investment in subsidiaries									19,600,000	(28,900,000)	(18,700,000)
Net income (loss)									19,600,000	(28,900,000)	(18,700,000)
Other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									19,600,000	(28,900,000)	(18,700,000)
LP Co-issuer
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Total operating expenses									0	0	0
Operating income									0	0	0
Interest (expense) income, net									(114,500,000)	(110,600,000)	(76,200,000)
Gain on marketable equity investment									0	0
Foreign currency and derivative losses, net									(7,500,000)
Other expense									0
Loss on early extinguishment of debt									(71,800,000)	(3,100,000)	(36,500,000)
Net income (loss) before income taxes									(193,800,000)	(113,700,000)	(112,700,000)
Income tax benefit									0	0	0
Equity earnings (loss) related to investment in subsidiaries									214,100,000	84,800,000	94,000,000
Net income (loss)									20,300,000	(28,900,000)	(18,700,000)
Other comprehensive income (loss)									(700,000)	0	0
Comprehensive income (loss)									19,600,000	(28,900,000)	(18,700,000)
Finance Co-issuer
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Total operating expenses									0	0	0
Operating income									0	0	0
Interest (expense) income, net									0	0	0
Gain on marketable equity investment									0	0
Foreign currency and derivative losses, net									0
Other expense									0
Loss on early extinguishment of debt									0	0	0
Net income (loss) before income taxes									0	0	0
Income tax benefit									0	0	0
Equity earnings (loss) related to investment in subsidiaries									0	0	0
Net income (loss)									0	0	0
Other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									0	0	0
Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenue									981,300,000	799,700,000	666,400,000
Total operating expenses									914,300,000	700,200,000	640,400,000
Operating income									67,000,000	99,500,000	26,000,000
Interest (expense) income, net									(400,000)	0	0
Gain on marketable equity investment									132,300,000	0
Foreign currency and derivative losses, net									0
Other expense									(300,000)
Loss on early extinguishment of debt									0	0	0
Net income (loss) before income taxes									198,600,000	99,500,000	26,000,000
Income tax benefit									3,700,000	(3,000,000)	(3,000,000)
Equity earnings (loss) related to investment in subsidiaries									0	0	(4,600,000)
Net income (loss)									202,300,000	96,500,000	18,400,000
Other comprehensive income (loss)									11,800,000	0	0
Comprehensive income (loss)									214,100,000	96,500,000	18,400,000
Non- Guarantors
Condensed Income Statements, Captions [Line Items]
Revenue										21,700,000	5,600,000
Total operating expenses										31,500,000	7,500,000
Operating income										(9,800,000)	(1,900,000)
Interest (expense) income, net										(3,300,000)	(2,600,000)
Gain on marketable equity investment										9,900,000
Loss on early extinguishment of debt										0	0
Net income (loss) before income taxes										(3,200,000)	(4,500,000)
Income tax benefit										2,400,000	0
Equity earnings (loss) related to investment in subsidiaries										0	0
Net income (loss)										(800,000)	(4,500,000)
Other comprehensive income (loss)										(10,900,000)	75,500,000
Comprehensive income (loss)										(11,700,000)	71,000,000
General Partner
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Total operating expenses									0	0	0
Operating income									0	0	0
Interest (expense) income, net									0	0	0
Gain on marketable equity investment									0	0
Foreign currency and derivative losses, net									0
Other expense									0
Loss on early extinguishment of debt									0	0	0
Net income (loss) before income taxes									0	0	0
Income tax benefit									0	0	0
Equity earnings (loss) related to investment in subsidiaries									100,000	(300,000)	(200,000)
Net income (loss)									100,000	(300,000)	(200,000)
Other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									$ 100,000	$ (300,000)	$ (200,000)

Guarantors - Consolidating St_2

Guarantors - Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ 365.7	$ 309.3	$ 289.5
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired	0	(462.8)	(492.3)
Investment in real estate	(876.4)	(865.7)	(914.5)
Investment in subsidiaries	0	0	0
Equity investments	(3.8)	(12.6)	(100)
Proceeds from sale of equity investments	199	0	0
Proceeds from the sale of real estate assets	1.3	0	0
Return of investment	0	0	0
Intercompany borrowings	0	0	0
Net cash used in investing activities	(679.9)	(1,341.1)	(1,506.8)
Cash flows from financing activities:
Issuance of common stock, net	357.2	699.6	705.7
Dividends paid	(210.4)	(181.1)	(145.7)
Intercompany borrowings	0	0	0
Proceeds from revolving credit facility	656.7	688.3	1,037.3
Repayments of revolving credit facility	(182.5)	(647.4)	(1,275)
Proceeds from unsecured term loan	0	1,300	350
Repayments of unsecured term loan	(200)	(900)	0
Proceeds from senior notes	1,197.4	0	1,217.8
Repayments of senior notes	(1,200)	0	(474.8)
Payment of debt extinguishment costs	(72)	0	(30)
Payment of deferred financing costs	(9.4)	0	(16.7)
Payments on finance lease liabilities	(2.9)	(9.5)	(9.8)
Interest paid by lenders on issuance of the senior notes	0	0	2.7
Tax payment upon exercise of equity awards	(9.3)	(5.2)	(6.9)
Contributions/distributions from parent	0	0	0
Net cash provided by financing activities	324.8	944.7	1,354.6
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2.7	(0.4)	0
Net increase (decrease) in cash, cash equivalents and restricted cash	13.3	(87.5)	137.3
Cash, cash equivalents and restricted cash at beginning of period	64.4	151.9	14.6
Cash, cash equivalents and restricted cash at end of period	77.7	64.4	151.9
General Partner
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	0	0	0
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	0
Investment in real estate	0	0	0
Investment in subsidiaries	(2.5)	(7)	(7.1)
Equity investments	0	0	0
Proceeds from sale of equity investments	0
Proceeds from the sale of real estate assets	0
Return of investment	0	0	0
Intercompany borrowings	0	0	0
Net cash used in investing activities	(2.5)	(7)	(7.1)
Cash flows from financing activities:
Issuance of common stock, net	0	0	0
Dividends paid	0	0	0
Intercompany borrowings	0	0	0
Proceeds from revolving credit facility	0	0	0
Repayments of revolving credit facility	0	0	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan	0	0
Proceeds from senior notes	0		0
Repayments of senior notes	0		0
Payment of debt extinguishment costs	0		0
Payment of deferred financing costs	0		0
Payments on finance lease liabilities	0	0	0
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards	0	0	0
Contributions/distributions from parent	2.5	7	7.1
Net cash provided by financing activities	2.5	7	7.1
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0
Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	0	0	0
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	0
Investment in real estate	0	0	0
Investment in subsidiaries	(357.2)	(700)	(705.3)
Equity investments	0	0	0
Proceeds from sale of equity investments	0
Proceeds from the sale of real estate assets	0
Return of investment	210.4	181.1	145.7
Intercompany borrowings	9.3	5.6	6.5
Net cash used in investing activities	(137.5)	(513.3)	(553.1)
Cash flows from financing activities:
Issuance of common stock, net	357.2	699.6	705.7
Dividends paid	(210.4)	(181.1)	(145.7)
Intercompany borrowings	0	0	0
Proceeds from revolving credit facility	0	0	0
Repayments of revolving credit facility	0	0	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan	0	0
Proceeds from senior notes	0		0
Repayments of senior notes	0		0
Payment of debt extinguishment costs	0		0
Payment of deferred financing costs	0		0
Payments on finance lease liabilities	0	0	0
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards	(9.3)	(5.2)	(6.9)
Contributions/distributions from parent	0	0	0
Net cash provided by financing activities	137.5	513.3	553.1
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0
LP Co-issuer
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(124.9)	(103.6)	(60.3)
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	0
Investment in real estate	0	0	0
Investment in subsidiaries	(210.4)	(829.5)	(705.3)
Equity investments	0	0	0
Proceeds from sale of equity investments	0
Proceeds from the sale of real estate assets	0
Return of investment	0	0	0
Intercompany borrowings	8.2	(105.1)	(598.8)
Net cash used in investing activities	(202.2)	(934.6)	(1,304.1)
Cash flows from financing activities:
Issuance of common stock, net	0	0	0
Dividends paid	(210.4)	(181.1)	(145.7)
Intercompany borrowings	(9.3)	(5.6)	(6.5)
Proceeds from revolving credit facility	656.7	658.4	1,037.3
Repayments of revolving credit facility	(182.5)	(532.7)	(1,275)
Proceeds from unsecured term loan		1,300	350
Repayments of unsecured term loan	(200)	(900)
Proceeds from senior notes	1,197.4		1,217.8
Repayments of senior notes	(1,200)		(474.8)
Payment of debt extinguishment costs	(72)		(30)
Payment of deferred financing costs	(9.4)		(16.7)
Payments on finance lease liabilities	0	0	0
Interest paid by lenders on issuance of the senior notes			2.7
Tax payment upon exercise of equity awards	0	0	0
Contributions/distributions from parent	357.2	700	705.3
Net cash provided by financing activities	327.7	1,039	1,364.4
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	(0.8)
Net increase (decrease) in cash, cash equivalents and restricted cash	0.6	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0	0
Cash, cash equivalents and restricted cash at end of period	0.6	0	0
Finance Co-issuer
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	0	0	0
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	0
Investment in real estate	0	0	0
Investment in subsidiaries	0	0	0
Equity investments	0	0	0
Proceeds from sale of equity investments	0
Proceeds from the sale of real estate assets	0
Return of investment	0	0	0
Intercompany borrowings	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Issuance of common stock, net	0	0	0
Dividends paid	0	0	0
Intercompany borrowings	0	0	0
Proceeds from revolving credit facility	0	0	0
Repayments of revolving credit facility	0	0	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan	0	0
Proceeds from senior notes	0		0
Repayments of senior notes	0		0
Payment of debt extinguishment costs	0		0
Payment of deferred financing costs	0		0
Payments on finance lease liabilities	0	0	0
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards	0	0	0
Contributions/distributions from parent	0	0	0
Net cash provided by financing activities	0	0	0
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0	0
Cash, cash equivalents and restricted cash at end of period	0	0	0
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	457.7
Cash flows from investing activities:
Investment in real estate	(843.5)
Investment in subsidiaries	0
Equity investments	(3.8)
Proceeds from sale of equity investments	199
Proceeds from the sale of real estate assets	1.3
Return of investment	0
Intercompany borrowings	32
Net cash used in investing activities	(615)
Cash flows from financing activities:
Issuance of common stock, net	0
Dividends paid	0
Intercompany borrowings	(40.2)
Proceeds from revolving credit facility	0
Repayments of revolving credit facility	0
Repayments of unsecured term loan	0
Proceeds from senior notes	0
Repayments of senior notes	0
Payment of debt extinguishment costs	0
Payment of deferred financing costs	0
Payments on finance lease liabilities	(2.9)
Tax payment upon exercise of equity awards	0
Contributions/distributions from parent	210.4
Net cash provided by financing activities	167.3
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2.7
Net increase (decrease) in cash, cash equivalents and restricted cash	12.7
Cash, cash equivalents and restricted cash at beginning of period	64.4
Cash, cash equivalents and restricted cash at end of period	77.1	64.4
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities		421.6	339.7
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	(492.3)
Investment in real estate		(814.6)	(903.8)
Investment in subsidiaries		0	(0.7)
Equity investments		0	0
Return of investment		0	0
Intercompany borrowings		(6.8)	0
Net cash used in investing activities		(821.4)	(1,396.8)
Cash flows from financing activities:
Issuance of common stock, net		0	0
Dividends paid		0	0
Intercompany borrowings		105.1	598.2
Proceeds from revolving credit facility		0	0
Repayments of revolving credit facility		0	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan		0
Proceeds from senior notes			0
Repayments of senior notes			0
Payment of debt extinguishment costs			0
Payment of deferred financing costs			0
Payments on finance lease liabilities		(7.9)	(8.6)
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards		0	0
Contributions/distributions from parent		178.6	605.3
Net cash provided by financing activities		275.8	1,194.9
Effect of exchange rate changes on cash, cash equivalents and restricted cash		0
Net increase (decrease) in cash, cash equivalents and restricted cash		(124)	137.8
Cash, cash equivalents and restricted cash at beginning of period	27.2	151.2	13.4
Cash, cash equivalents and restricted cash at end of period		27.2	151.2
Non- Guarantors
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities		(27.9)	(0.6)
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		(462.8)	0
Investment in real estate		(31.9)	0
Investment in subsidiaries		0	0
Equity investments		(12.6)	(100)
Return of investment		0	0
Intercompany borrowings		0	0.5
Net cash used in investing activities		(507.3)	(99.5)
Cash flows from financing activities:
Issuance of common stock, net		0	0
Dividends paid		0	0
Intercompany borrowings		6.8	0
Proceeds from revolving credit facility		29.9	0
Repayments of revolving credit facility		(114.7)	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan		0
Proceeds from senior notes			0
Repayments of senior notes			0
Payment of debt extinguishment costs			0
Payment of deferred financing costs			0
Payments on finance lease liabilities		(1.6)	(1.2)
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards		0	0
Contributions/distributions from parent		650.9	100.8
Net cash provided by financing activities		571.3	99.6
Effect of exchange rate changes on cash, cash equivalents and restricted cash		0.4
Net increase (decrease) in cash, cash equivalents and restricted cash		36.5	(0.5)
Cash, cash equivalents and restricted cash at beginning of period	37.2	0.7	1.2
Cash, cash equivalents and restricted cash at end of period		37.2	0.7
Eliminations/Consolidations
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	32.9	19.2	10.7
Cash flows from investing activities:
Asset acquisitions, primarily real estate, net of cash acquired		0	0
Investment in real estate	(32.9)	(19.2)	(10.7)
Investment in subsidiaries	570.1	1,536.5	1,418.4
Equity investments	0	0	0
Proceeds from sale of equity investments	0
Proceeds from the sale of real estate assets	0
Return of investment	(210.4)	(181.1)	(145.7)
Intercompany borrowings	(49.5)	106.3	591.8
Net cash used in investing activities	277.3	1,442.5	1,853.8
Cash flows from financing activities:
Issuance of common stock, net	0	0	0
Dividends paid	210.4	181.1	145.7
Intercompany borrowings	49.5	(106.3)	(591.7)
Proceeds from revolving credit facility	0	0	0
Repayments of revolving credit facility	0	0	0
Proceeds from unsecured term loan		0	0
Repayments of unsecured term loan	0	0
Proceeds from senior notes	0		0
Repayments of senior notes	0		0
Payment of debt extinguishment costs	0		0
Payment of deferred financing costs	0		0
Payments on finance lease liabilities	0	0	0
Interest paid by lenders on issuance of the senior notes			0
Tax payment upon exercise of equity awards	0	0	0
Contributions/distributions from parent	(570.1)	(1,536.5)	(1,418.5)
Net cash provided by financing activities	(310.2)	(1,461.7)	(1,864.5)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0	0
Cash, cash equivalents and restricted cash at end of period	$ 0	$ 0	$ 0

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 253.9	$ 250.9	$ 251.5	$ 225	$ 221.3	$ 206.6	$ 196.9	$ 196.6	$ 981.3	$ 821.4	$ 672
Operating income	22.3	13.2	19.7	11.8	14.8	20.2	27	27.7	67	89.7	24.1
Net income (loss)	$ (52.1)	$ 12.6	$ (8.5)	$ 89.4	$ (105.8)	$ (42.4)	$ 105.9	$ 43.5	$ 41.4	$ 1.2	$ (83.5)
Basic income (loss) per share (in dollars per share)	$ (0.46)	$ 0.11	$ (0.08)	$ 0.82	$ (1.09)	$ (0.43)	$ 1.07	$ 0.45	$ 0.36	$ 0	$ (0.95)
Diluted income (loss) per share (in dollars per share)	$ (0.46)	$ 0.11	$ (0.08)	$ 0.82	$ (1.08)	$ (0.43)	$ 1.06	$ 0.45	$ 0.36	$ 0	$ (0.95)

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event - 2027 Notes - Senior Notes	Jan. 22, 2020EUR (€)
Debt Instrument [Line Items]
Debt offering	€ 500,000,000
Stated interest rate	1.45%

Schedule II. Valuation and Qu_2

Schedule II. Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	$ 1.7	$ 2.1	$ 2.1
Charge to Expenses	1.7	2.3	0.2
(Deductions)/Additions	(1.6)	(2.7)	(0.2)
End of Period	1.8	1.7	2.1
Deferred Tax Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	6.9	7.2	6.5
Charge to Expenses	0.7	(0.3)	0.7
(Deductions)/Additions	0	0	0
End of Period	$ 7.6	$ 6.9	$ 7.2

Schedule III. Real Estate Pro_2

Schedule III. Real Estate Properties and Accumulated Depreciation - Schedule of Real Estate Properties (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Initial Costs
Land	$ 146.4
Building and Improvements	602.2
Equipment	594.2
Cost Capitalized Subsequent to Acquisition
Land	1.2
Building and Improvements	1,159.2
Equipment	2,433.9
Gross Carrying Amount
Land	147.6	$ 118.5
Building and Improvements	1,761.4	1,677.5
Equipment	3,028.2	2,630.2
Accumulated Depreciation	1,379.2	1,054.5	$ 782.4	$ 578.5
Land held for future development	206	176.4
Aggregate cost of the total properties for federal income tax purposes	7,088.2
Construction in progress, including land under development	946.3	744.9	$ 487.1
Austin II
Initial Costs
Land	2
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	23.5
Equipment	13.3
Gross Carrying Amount
Land	2	2
Building and Improvements	23.5	23.4
Equipment	13.3	8.7
Accumulated Depreciation	19.7
Austin III
Initial Costs
Land	3.3
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	12.6
Equipment	64
Gross Carrying Amount
Land	3.3	3.3
Building and Improvements	12.6	11.7
Equipment	64	47
Accumulated Depreciation	16.7
Chicago - Aurora I
Initial Costs
Land	2.4
Building and Improvements	26
Equipment	97.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	6.4
Equipment	39
Gross Carrying Amount
Land	2.4	2.4
Building and Improvements	32.4	32.4
Equipment	136.3	132.9
Accumulated Depreciation	57.2
Chicago - Aurora II
Initial Costs
Land	2.6
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	22.9
Equipment	70.3
Gross Carrying Amount
Land	2.6	2.6
Building and Improvements	22.9	22.6
Equipment	70.3	68.6
Accumulated Depreciation	14.6
Chicago - Aurora Tower
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	6.4
Equipment	0.9
Gross Carrying Amount
Land	0	0
Building and Improvements	6.4	4.9
Equipment	0.9	0.4
Accumulated Depreciation	0.5
Chicago - Lombard
Initial Costs
Land	0.7
Building and Improvements	3.2
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	1.5
Equipment	8.1
Gross Carrying Amount
Land	0.7	0.7
Building and Improvements	4.7	4.7
Equipment	8.1	8.1
Accumulated Depreciation	8.6
Cincinnati - 7th Street
Initial Costs
Land	0.9
Building and Improvements	42.2
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	71.9
Equipment	37.2
Gross Carrying Amount
Land	0.9	0.9
Building and Improvements	114.1	114.1
Equipment	37.2	37.4
Accumulated Depreciation	99.5
Cincinnati - Blue Ash
Initial Costs
Land	0
Building and Improvements	2.6
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(1.9)
Equipment	0.2
Gross Carrying Amount
Land	0	0
Building and Improvements	0.7	0.7
Equipment	0.2	0.2
Accumulated Depreciation	0.6
Cincinnati - Hamilton
Initial Costs
Land	0
Building and Improvements	9.5
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	34.2
Equipment	7.8
Gross Carrying Amount
Land	0	0
Building and Improvements	43.7	43.7
Equipment	7.8	7.9
Accumulated Depreciation	33.6
Cincinnati - Mason
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	20.3
Equipment	1.7
Gross Carrying Amount
Land	0	0
Building and Improvements	20.3	20.3
Equipment	1.7	1.7
Accumulated Depreciation	15.8
Cincinnati - Northern Cincinnati
Initial Costs
Land	0.9
Building and Improvements	12.3
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	65.5
Equipment	16
Gross Carrying Amount
Land	0.9	0.9
Building and Improvements	77.8	77.9
Equipment	16	12.4
Accumulated Depreciation	47.7
Dallas - Allen
Initial Costs
Land	6.5
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	15
Equipment	39.5
Gross Carrying Amount
Land	6.5	0
Building and Improvements	15	0
Equipment	39.5	0
Accumulated Depreciation	2.9
Dallas - Carrollton
Initial Costs
Land	16.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	63.8
Equipment	323.3
Gross Carrying Amount
Land	16.1	16.1
Building and Improvements	63.8	62.2
Equipment	323.3	272.5
Accumulated Depreciation	133.6
Dallas - Lewisville
Initial Costs
Land	0
Building and Improvements	46.2
Equipment	2.2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	11.9
Equipment	38.9
Gross Carrying Amount
Land	0	0
Building and Improvements	58.1	76.8
Equipment	41.1	39.6
Accumulated Depreciation	69.4
Florence
Initial Costs
Land	2.2
Building and Improvements	7.7
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	34.3
Equipment	8.7
Gross Carrying Amount
Land	2.2	2.2
Building and Improvements	42	42
Equipment	8.7	8.4
Accumulated Depreciation	36.8
Frankfurt I
Initial Costs
Land	4
Building and Improvements	31
Equipment	109.7
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	5
Equipment	13.9
Gross Carrying Amount
Land	4	4.1
Building and Improvements	36	35.7
Equipment	123.7	124.9
Accumulated Depreciation	13.7
Frankfurt II
Initial Costs
Land	7
Building and Improvements	0
Equipment	47.7
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	135.1
Equipment	45.9
Gross Carrying Amount
Land	7	7.1
Building and Improvements	135.1	89.8
Equipment	93.6	53.9
Accumulated Depreciation	12.4
Houston - Galleria
Initial Costs
Land	0
Building and Improvements	56
Equipment	2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	15
Equipment	22.4
Gross Carrying Amount
Land	0	0
Building and Improvements	71	71
Equipment	24.4	20.2
Accumulated Depreciation	60.1
Houston - Houston West I
Initial Costs
Land	1.4
Building and Improvements	21.4
Equipment	0.1
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	63.8
Equipment	51.5
Gross Carrying Amount
Land	1.4	1.4
Building and Improvements	85.2	85.2
Equipment	51.6	51.1
Accumulated Depreciation	90.6
Houston - Houston West II
Initial Costs
Land	2
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.7
Building and Improvements	22.8
Equipment	52
Gross Carrying Amount
Land	2.7	2.7
Building and Improvements	22.8	22.9
Equipment	52	50.9
Accumulated Depreciation	39.1
Houston - Houston West III
Initial Costs
Land	7.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.1
Building and Improvements	18.1
Equipment	32.3
Gross Carrying Amount
Land	7.2	7.2
Building and Improvements	18.1	18
Equipment	32.3	31.4
Accumulated Depreciation	13.6
London - Great Bridgewater
Initial Costs
Land	0
Building and Improvements	16.5
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(16.5)
Equipment	1.3
Gross Carrying Amount
Land	0	0
Building and Improvements	0	26.8
Equipment	1.3	1.2
Accumulated Depreciation	1
London I
Initial Costs
Land	0
Building and Improvements	25.3
Equipment	20.5
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	19
Equipment	25.9
Gross Carrying Amount
Land	0	0
Building and Improvements	44.3	34.1
Equipment	46.4	26.3
Accumulated Depreciation	6.5
London II
Initial Costs
Land	0
Building and Improvements	19.9
Equipment	58.7
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	22.9
Equipment	34.6
Gross Carrying Amount
Land	0	0
Building and Improvements	42.8	25.2
Equipment	93.3	74.8
Accumulated Depreciation	17.4
Northern Virginia - Sterling I
Initial Costs
Land	6.9
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	20.2
Equipment	62.2
Gross Carrying Amount
Land	6.9	6.9
Building and Improvements	20.2	20.2
Equipment	62.2	60.4
Accumulated Depreciation	31.1
Northern Virginia - Sterling II
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	28.8
Equipment	112.4
Gross Carrying Amount
Land	0	0
Building and Improvements	28.8	28.8
Equipment	112.4	112.4
Accumulated Depreciation	36.7
Northern Virginia - Sterling III
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	22.3
Equipment	61.8
Gross Carrying Amount
Land	0	0
Building and Improvements	22.3	22.2
Equipment	61.8	61.3
Accumulated Depreciation	18.8
Northern Virginia - Sterling IV
Initial Costs
Land	4.6
Building and Improvements	9.6
Equipment	0.1
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	10.5
Equipment	78
Gross Carrying Amount
Land	4.6	4.6
Building and Improvements	20.1	20
Equipment	78.1	76
Accumulated Depreciation	20.5
Northern Virginia - Sterling V
Initial Costs
Land	14.5
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	81.7
Equipment	303.7
Gross Carrying Amount
Land	14.5	14.5
Building and Improvements	81.7	80.8
Equipment	303.7	295.8
Accumulated Depreciation	56.6
Northern Virginia - Sterling VI
Initial Costs
Land	9.7
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	60.2
Equipment	196.9
Gross Carrying Amount
Land	9.7	0
Building and Improvements	60.2	0
Equipment	196.9	77.5
Accumulated Depreciation	19.5
Northern Virginia - Sterling VIII
Initial Costs
Land	9.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	7
Equipment	28
Gross Carrying Amount
Land	9.1	0
Building and Improvements	7	0
Equipment	28	0
Accumulated Depreciation	2
Norwalk I
Initial Costs
Land	0
Building and Improvements	18.3
Equipment	25.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(16.6)
Equipment	(14.7)
Gross Carrying Amount
Land	0	0
Building and Improvements	1.7	13.6
Equipment	10.6	10.1
Accumulated Depreciation	4.5
Phoenix - Chandler I
Initial Costs
Land	10.5
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	58.3
Equipment	71.5
Gross Carrying Amount
Land	10.5	10.5
Building and Improvements	58.3	58.3
Equipment	71.5	68.7
Accumulated Depreciation	53.5
Phoenix - Chandler II
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	16.2
Equipment	39.8
Gross Carrying Amount
Land	0	0
Building and Improvements	16.2	16.2
Equipment	39.8	39.4
Accumulated Depreciation	24.2
Phoenix - Chandler III
Initial Costs
Land	0
Building and Improvements	0.9
Equipment	2.5
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	10.5
Equipment	48.8
Gross Carrying Amount
Land	0	0
Building and Improvements	11.4	11.4
Equipment	51.3	50.8
Accumulated Depreciation	16.7
Phoenix - Chandler IV
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	18.4
Equipment	44.3
Gross Carrying Amount
Land	0	0
Building and Improvements	18.4	18.4
Equipment	44.3	43.3
Accumulated Depreciation	11.6
Phoenix - Chandler V
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	12.1
Equipment	54.6
Gross Carrying Amount
Land	0	0
Building and Improvements	12.1	10.7
Equipment	54.6	53.4
Accumulated Depreciation	9.3
Phoenix - Chandler VI
Initial Costs
Land	2.3
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.1
Building and Improvements	23.3
Equipment	101.7
Gross Carrying Amount
Land	2.4	2.4
Building and Improvements	23.3	23.3
Equipment	101.7	100.3
Accumulated Depreciation	20.8
Phoenix - Chandler VII
Initial Costs
Land	4.2
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0.8
Equipment	0.4
Gross Carrying Amount
Land	4.2	0
Building and Improvements	0.8	0
Equipment	0.4	0
Accumulated Depreciation	0
Raleigh-Durham I
Initial Costs
Land	2.1
Building and Improvements	73.5
Equipment	71.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	6.3
Equipment	8.7
Gross Carrying Amount
Land	2.1	2.1
Building and Improvements	79.8	79.8
Equipment	80	75.4
Accumulated Depreciation	34.4
San Antonio I
Initial Costs
Land	4.6
Building and Improvements	3
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	28.7
Equipment	36.3
Gross Carrying Amount
Land	4.6	4.6
Building and Improvements	31.7	31.7
Equipment	36.3	35.3
Accumulated Depreciation	35.5
San Antonio II
Initial Costs
Land	6.7
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.3
Building and Improvements	30.3
Equipment	61
Gross Carrying Amount
Land	7	7
Building and Improvements	30.3	30.3
Equipment	61	60.8
Accumulated Depreciation	24.4
San Antonio III
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	40.2
Equipment	99.5
Gross Carrying Amount
Land	0	0
Building and Improvements	40.2	40.2
Equipment	99.5	99
Accumulated Depreciation	29.9
San Antonio IV
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	56.3
Equipment	50.6
Gross Carrying Amount
Land	0	0
Building and Improvements	56.3	42.1
Equipment	50.6	48.2
Accumulated Depreciation	13.6
Santa Clara II
Initial Costs
Land	0
Building and Improvements	2.7
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0
Gross Carrying Amount
Land	0	0
Building and Improvements	2.7	0
Equipment	0	0
Accumulated Depreciation	1.1
Somerset I
Initial Costs
Land	12.1
Building and Improvements	124.6
Equipment	83.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	7.5
Equipment	18.5
Gross Carrying Amount
Land	12.1	12.1
Building and Improvements	132.1	125.8
Equipment	101.8	91
Accumulated Depreciation	43.2
South Bend - Monroe
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	1.9
Equipment	0.3
Gross Carrying Amount
Land	0	0
Building and Improvements	1.9	2.5
Equipment	0.3	0.4
Accumulated Depreciation	2
Stamford - Omega
Initial Costs
Land	0
Building and Improvements	3.2
Equipment	0.6
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(3.1)
Equipment	0.2
Gross Carrying Amount
Land	0	0
Building and Improvements	0.1	2.6
Equipment	0.8	0.7
Accumulated Depreciation	0.7
Stamford - Riverbend
Initial Costs
Land	0
Building and Improvements	4.3
Equipment	13.2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(3.4)
Equipment	(4.6)
Gross Carrying Amount
Land	0	0
Building and Improvements	0.9	2.9
Equipment	8.6	7.8
Accumulated Depreciation	6.9
Totowa - Commerce
Initial Costs
Land	0
Building and Improvements	4.1
Equipment	0.8
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(3.7)
Equipment	0.9
Gross Carrying Amount
Land	0	0
Building and Improvements	0.4	4.1
Equipment	1.7	1.7
Accumulated Depreciation	0.9
Totowa - Madison
Initial Costs
Land	0
Building and Improvements	28.3
Equipment	45.6
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(22.2)
Equipment	14.5
Gross Carrying Amount
Land	0	0
Building and Improvements	6.1	28.5
Equipment	60.1	57.7
Accumulated Depreciation	33
Wappinger Falls I
Initial Costs
Land	0
Building and Improvements	9.9
Equipment	13.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(6.8)
Equipment	9.9
Gross Carrying Amount
Land	0	0
Building and Improvements	3.1	11.3
Equipment	23.2	$ 22
Accumulated Depreciation	$ 16.2

Schedule III. Real Estate Pro_3

Schedule III. Real Estate Properties and Accumulated Depreciation - Historical Cost and Accumulated Depreciation and Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property
Balance—beginning of period	$ 5,347.5	$ 3,840.8	$ 2,601.6
Disposals	(15.8)	(20.8)	(3.4)
Impairments	(0.7)	0	(71.8)
Impact of adoption of ASU 2016-02	(97.8)	0	0
Additions (acquisitions and improvements)	856.3	1,527.5	1,314.4
Balance, end of period(1)	6,089.5	5,347.5	3,840.8
Accumulated Depreciation
Balance—beginning of period	1,054.5	782.4	578.5
Disposals	(14)	(14)	(1.9)
Impairments	0	0	(14.1)
Impact of adoption of ASU 2016-02	(19.3)	0	0
Additions (depreciation and amortization expense)	358	286.1	219.9
Balance, end of period	1,379.2	1,054.5	782.4
Construction in progress, including land under development	$ 946.3	$ 744.9	$ 487.1

Uncategorized Items - cone-2019

Label	Element	Value
Accounting Standards Update 2016-02 [Member] | Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 9,500,000
Accounting Standards Update 2014-09 [Member] | Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	300,000
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	300,000
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)
Accounting Standards Update 2016-01 [Member] | Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 0