CyrusOne (CONE) 10-K 24 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Feb. 21, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	CONE
Entity Registrant Name	CyrusOne Inc.
Entity Central Index Key	1,553,023
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 4.4
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		83,441,227

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Investment in real estate:
Land	$ 142.7	$ 93
Buildings and improvements	1,008.9	905.3
Equipment	1,042.9	598.2
Construction in progress	407.1	231.1
Subtotal	2,601.6	1,827.6
Accumulated depreciation	(578.5)	(435.6)
Net investment in real estate	2,023.1	1,392
Cash and cash equivalents	14.6	14.3
Rent and other receivables (net of allowance for doubtful accounts of $2.1 and $1.0 as of December 31, 2016 and December 31, 2015, respectively)	83.3	76.1
Restricted cash	0	1.5
Goodwill	455.1	453.4
Intangible assets (net of accumulated amortization of $110.7 and $90.6 as of December 31, 2016 and December 31, 2015, respectively)	150.2	170.3
Other assets	126.1	88
Total assets	2,852.4	2,195.6
Liabilities and equity
Accounts payable and accrued expenses	227.1	136.6
Deferred revenue	76.7	78.7
Capital lease obligations	10.8	12.2
Long-term debt, net	1,240.1	996.5
Lease financing arrangements	135.7	150
Total liabilities	1,690.4	1,374
Commitment and contingencies
Equity
Preferred stock, $.01 par value, 100,000,000 authorized; no shares issued or outstanding	0	0
Common stock, $.01 par value, 500,000,000 shares authorized and 83,536,250 and 72,556,334 shares issued and outstanding at December 31, 2016 and December 31, 2015, respectively	0.8	0.7
Additional paid in capital	1,412.3	967.2
Accumulated deficit	(249.8)	(145.9)
Accumulated other comprehensive loss	(1.3)	(0.4)
Total shareholders’ equity	1,162	821.6
Total liabilities and equity	$ 2,852.4	$ 2,195.6

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 2.1	$ 1
Accumulated amortization of intangible assets	$ 110.7	$ 90.6
Preferred stock par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock authorized (in shares)	100,000,000	100,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	500,000,000	500,000,000
Common stock issued (in shares)	83,536,250	72,556,334
Common stock outstanding (in shares)	83,536,250	72,556,334

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue	$ 137,400,000	$ 143,800,000	$ 130,100,000	$ 117,800,000	$ 113,300,000	$ 111,200,000	$ 89,100,000	$ 85,700,000	$ 529,100,000	$ 399,300,000	$ 330,900,000
Costs and expenses:
Property operating expenses									187,500,000	148,700,000	124,500,000
Sales and marketing									16,900,000	12,100,000	12,800,000
General and administrative									60,700,000	46,600,000	34,600,000
Depreciation and amortization									183,900,000	141,500,000	118,000,000
Transaction and acquisition integration costs									4,300,000	14,100,000	1,000,000
Asset impairments and loss on disposal									5,300,000	13,500,000	0
Total costs and expenses									458,600,000	376,500,000	290,900,000
Operating income	12,700,000	18,800,000	21,100,000	17,900,000	11,100,000	7,500,000	2,600,000	1,600,000	70,500,000	22,800,000	40,000,000
Interest expense									48,800,000	41,200,000	39,500,000
Loss on extinguishment of debt									0	0	13,600,000
Net income (loss) before income taxes									21,700,000	(18,400,000)	(13,100,000)
Income tax expense									(1,800,000)	(1,800,000)	(1,400,000)
Net income (loss)	800,000	4,400,000	9,100,000	5,600,000	(1,200,000)	(5,300,000)	(6,500,000)	(7,200,000)	19,900,000	(20,200,000)	(14,500,000)
Noncontrolling interest in net loss									0	(4,800,000)	(6,700,000)
Net income (loss) attributed to common stockholders	$ 800,000	$ 4,400,000	$ 9,100,000	$ 5,600,000	$ (1,000,000)	$ (4,600,000)	$ (5,500,000)	$ (4,300,000)	$ 19,900,000	$ (15,400,000)	$ (7,800,000)
Basic weighted average common shares outstanding (in shares)									78.3	54.3	29.2
Diluted weighted average common shares outstanding (in shares)									79	54.3	29.2
Income (loss) per share - basic and diluted (in dollars per share)									$ 0.24	$ (0.30)	$ (0.30)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 19.9	$ (20.2)	$ (14.5)
Other comprehensive income (loss):
Foreign currency translation adjustments	(0.9)	(0.2)	(0.3)
Comprehensive income (loss)	19	(20.4)	(14.8)
Comprehensive loss attributable to noncontrolling interests	0	(4.8)	(6.8)
Comprehensive income (loss) attributable to CyrusOne Inc.	$ 19	$ (15.6)	$ (8)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Accumulated Deficit	Paid-In Capital	Accumulated Other Comprehensive Loss	Total Shareholder’s Equity/ Parent’s Net Investment	Non-Controlling Interest
Beginning Balance (in shares) at Dec. 31, 2013		22
Beginning Balance at Dec. 31, 2013	$ 777.6	$ 0.2	$ (18.9)	$ 340.7	$ 0	$ 322	$ 455.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(14.5)		(14.5)			(14.5)
Noncontrolling interest in net loss	(6.7)		6.7			6.7	(6.7)
Stock issuance costs	(1.3)			(1.3)		(1.3)
Foreign currency translation adjustments	(0.3)				(0.2)	(0.2)	(0.1)
Stock-based compensation (in shares)		0.7
Stock-based compensation	10.3			10.3		10.3
Issuance of common stock (in shares)		16
Issuance of common stock	356	$ 0.2		355.8		356
Redemption of noncontrolling interest	(355.9)			(189)		(189)	(166.9)
Dividends declared	(54.9)		(29.2)			(29.2)	(25.7)
Ending Balance (in shares) at Dec. 31, 2014		38.7
Ending Balance at Dec. 31, 2014	717	$ 0.4	(55.9)	516.5	(0.2)	460.8	256.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(20.2)		(20.2)			(20.2)
Noncontrolling interest in net loss	(4.8)		4.8			4.8	(4.8)
Stock issuance costs	(0.8)			(0.8)		(0.8)
Foreign currency translation adjustments	(0.2)				(0.2)	(0.2)
Stock-based compensation (in shares)		0.3
Stock-based compensation	14.4			14.4		14.4
Tax payment upon exercise of equity awards	(0.8)			(0.8)		(0.8)
Issuance of common stock (in shares)		33.6
Issuance of common stock	799.5	$ 0.3		799.2		799.5
Redemption of noncontrolling interest	(596.4)			(412.3)		(412.3)	(184.1)
Conversion of operating partnership units to common stock				51		51	(51)
Dividends declared	(90.9)		(74.6)			(74.6)	(16.3)
Ending Balance (in shares) at Dec. 31, 2015		72.6
Ending Balance at Dec. 31, 2015	821.6	$ 0.7	(145.9)	967.2	(0.4)	821.6	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	19.9		19.9			19.9
Noncontrolling interest in net loss	0
Stock issuance costs	(1.6)			(1.6)		(1.6)
Foreign currency translation adjustments	(0.9)				(0.9)	(0.9)
Stock-based compensation (in shares)		0.6
Stock-based compensation	12.3			12.3		12.3
Tax payment upon exercise of equity awards (in shares)		(0.5)
Tax payment upon exercise of equity awards	(14.2)			(14.2)		(14.2)
Issuance of common stock (in shares)		10.8
Issuance of common stock	448.7	$ 0.1		448.6		448.7
Dividends declared	(123.8)		(123.8)			(123.8)
Ending Balance (in shares) at Dec. 31, 2016		83.5
Ending Balance at Dec. 31, 2016	$ 1,162	$ 0.8	$ (249.8)	$ 1,412.3	$ (1.3)	$ 1,162	$ 0

Consolidated Statements of Equ7

Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)	$ 1.52	$ 1.26	$ 0.84

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income (loss)	$ 19,900,000	$ (20,200,000)	$ (14,500,000)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	183,900,000	141,500,000	118,000,000
Provision for bad debt	1,600,000	0	800,000
Asset impairments and loss on disposal	5,300,000	13,500,000	0
Loss on extinguishment of debt	0	0	13,600,000
Non-cash interest expense	4,800,000	3,400,000	3,400,000
Stock-based compensation expense	12,300,000	14,400,000	10,300,000
Change in operating assets and liabilities:
Rent receivables and other assets	(51,700,000)	(23,900,000)	(37,000,000)
Accounts payable and accrued expenses	7,000,000	7,000,000	6,900,000
Deferred revenues	(2,500,000)	5,400,000	9,800,000
Due to affiliates	0	(900,000)	(200,000)
Net cash provided by operating activities	180,600,000	140,200,000	111,100,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets	(131,100,000)	(17,300,000)	0
Capital expenditures – other development	(600,000,000)	(217,200,000)	(284,200,000)
Business acquisition, net of cash acquired	0	(398,400,000)	0
Changes in restricted cash	1,500,000	7,300,000	0
Net cash used in investing activities	(729,600,000)	(625,600,000)	(284,200,000)
Cash flows from financing activities:
Issuance of common stock	448,700,000	799,500,000	356,000,000
Stock issuance costs	(1,600,000)	(800,000)	(1,300,000)
Acquisition of operating partnership units	0	(596,400,000)	(355,900,000)
Dividends paid	(114,300,000)	(80,800,000)	(50,900,000)
Borrowings from credit facility	710,000,000	260,000,000	315,000,000
Payments on credit facility	(460,000,000)	(10,000,000)	(30,000,000)
Payments on senior notes	0	0	(150,200,000)
Proceeds from issuance of debt	0	103,800,000	0
Payments on capital leases and lease financing arrangements	(9,100,000)	(5,900,000)	(3,900,000)
Payment of note payable	(1,500,000)	0	0
Debt issuance costs	(8,700,000)	(5,400,000)	(5,200,000)
Payment of debt extinguishment costs	0	0	(12,800,000)
Tax payment upon exercise of equity awards	(14,200,000)	(800,000)	0
Net cash provided by financing activities	549,300,000	463,200,000	60,800,000
Net increase (decrease) in cash and cash equivalents	300,000	(22,200,000)	(112,300,000)
Cash and cash equivalents at beginning of period	14,300,000	36,500,000	148,800,000
Cash and cash equivalents at end of period	14,600,000	14,300,000	36,500,000
Supplemental disclosures
Cash paid for interest, net of amount capitalized	55,000,000	43,700,000	41,300,000
Cash paid for income taxes	1,200,000	3,400,000	400,000
Capitalized interest	10,600,000	6,100,000	4,600,000
Non-cash investing and financing activities:
Acquisition and development of properties in accounts payable and other liabilities	132,700,000	59,200,000	26,800,000
Dividends payable	$ 33,900,000	$ 23,600,000	$ 14,300,000

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business CyrusOne Inc., together with CyrusOne GP, a wholly owned subsidiary of CyrusOne Inc., through which CyrusOne Inc. wholly owns CyrusOne LP (the operating partnership) and the subsidiaries of the operating partnership (collectively, “CyrusOne”, “we”, “us”, “our”, and the “Company”) is an owner, operator and developer of enterprise-class, carrier-neutral, multi-tenant data center properties. Our customers operate in a number of industries, including information technology, financial services, energy, oil and gas, mining, medical and consumer goods and services. We currently operate 35 data centers and 2 recovery centers located in the United States, United Kingdom and Singapore.

Formation and Recent Developmen

Formation and Recent Developments	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Formation and Recent Developments	Formation and Recent Developments Formation On January 24, 2013 , CyrusOne Inc. completed its initial public offering (the IPO) of common stock. During 2014, 2015 and 2016, the Company completed public offerings of 16.0 million , 27.3 million , and 10.3 million shares of its common stock and received $355.9 million , $799.3 million and $419.8 million net proceeds, respectively, from these public offerings. On December 14, 2015, CyrusOne Inc. completed a public secondary offering of 1.4 million shares of common stock on behalf of CBI. The Company received no proceeds from the offering. On December 31, 2015, CyrusOne Inc. completed an issuance of approximately 6.3 million newly issued shares of common stock in exchange for an equal number of operating partnership units of CyrusOne LP, held by a subsidiary of CBI. As of December 31, 2015, CBI owned 9.5% of the common stock of CyrusOne Inc. As of December 31, 2016 , CBI owned less than 5.0% of the common stock of CyrusOne Inc. All of the 83.5 million outstanding operating partnership units of CyrusOne LP are owned, directly or indirectly, by CyrusOne Inc. Recent Developments On March 17, 2016 , CyrusOne LP entered into a first amended and restated credit agreement (the First Amended and Restated Credit Agreement) which amended and restated in its entirety the credit agreement governing its senior unsecured revolving credit facility (the Revolving Credit Facility) and senior unsecured term loan facility (the Initial Term Loan), originally dated as of October 9, 2014. The First Amended and Restated Credit Agreement provided for an additional $250.0 million senior unsecured term loan facility (the Additional Term Loan, and together with the Initial Term Loan, the Term Loans) in addition to the existing $300.0 million Initial Term Loan and existing $650.0 million Revolving Credit Facility. CyrusOne LP borrowed $250.0 million under the Additional Term Loan and used the proceeds to repay a portion of the amount outstanding under the Revolving Credit Facility. On November 21, 2016, CyrusOne LP entered into a second amended and restated credit agreement (the Second Amended and Restated Credit Agreement) which amended and restated in its entirety the First Amended and Restated Credit Agreement. The Second Amended and Restated Credit Agreement increased the available commitments under the Revolving Credit Facility to $1.0 billion . On March 21, 2016 , CyrusOne Inc. completed a public offering of 6.9 million shares of its common stock for $255.0 million , net of underwriting discounts of approximately $10.6 million . CyrusOne LP used the proceeds to acquire the Chicago-Aurora I data center from CME Group for $131.1 million and to fund its development pipeline. During the first quarter of 2016, the Company received $0.9 million from the exercise of stock options and $0.1 million relating to common shares purchased under the employee stock purchase plan. In total, offerings of common stock during the first quarter of 2016 resulted in $256.0 million of cash flow from financing activities on the consolidated statements of cash flows. On May 2, 2016, CyrusOne Inc. and CyrusOne GP amended and restated the Agreement of Limited Partnership of CyrusOne LP (Amended LP Agreement) to reflect that CBI and its subsidiaries have ceased to be partners or hold any partnership interests in CyrusOne LP and therefore have no rights under the Amended LP Agreement. The Amended LP Agreement also effects certain changes to clarify language, comply with or conform to Maryland and partnership tax law and make various technical corrections and ministerial changes. On May 4, 2016, CyrusOne Inc. filed a Form S-3 with the SEC as a "well-known seasoned issuer" ("WKSI") using an automatic shelf registration process. Under this process, CyrusOne Inc. or any selling security holders may sell any combination of the securities described in the registration statement from time to time in one or more offerings in amounts to be determined at the time of any offering. On July 1, 2016, the Company filed a prospectus supplement and entered into sales agreements (the Sales Agreements) with each of Raymond James & Associates, Inc., Jefferies LLC, KeyBanc Capital Markets Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and SunTrust Robinson Humphrey, Inc., as sales agents, pursuant to which CyrusOne Inc. may issue and sell from time to time shares of its common stock having an aggregate gross sales price of up to $320.0 million , pursuant to an “at the market” program. Sales of shares of CyrusOne Inc. common stock under the Sales Agreements are made by means of ordinary brokers’ transactions on the NASDAQ Global Select Market or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or, subject to specific instructions of CyrusOne Inc., at negotiated prices. During the year ended December 31, 2016, the Company sold 0.5 million shares of its common stock under this program, generating net proceeds of approximately $26.3 million after giving effect to sales agent commissions of $0.3 million . On August 15, 2016, CyrusOne Inc. completed a public offering of 3.4 million shares of its common stock for $164.8 million , net of underwriting discounts of approximately $6.9 million . CyrusOne Inc. contributed the net proceeds from the sale of its shares to its operating partnership in exchange for an equivalent number of newly issued operating partnership units (the August OP Contribution and Issuance). CyrusOne LP has used and intends to use the proceeds from the August OP Contribution and Issuance to fund growth capital expenditures related to recently signed leases, to repay borrowings under its Revolving Credit Facility, and for general corporate purposes, which may include funding future acquisitions, investments or capital expenditures. In connection with this offering, on August 10, 2016, CyrusOne Inc. entered into (a) a forward sale agreement with Goldman, Sachs & Co. (the Forward Sale Agreement) with respect to 3.4 million shares of its common stock, and (b) an additional forward sale agreement with Goldman, Sachs & Co. (the Additional Forward Sale Agreement, and together with the Forward Sale Agreement, the Forward Sale Agreements) with respect to approximately 1.0 million shares of its common stock in connection with the underwriters' exercise of their option to purchase these shares. Pursuant to the terms of the Forward Sale Agreements, and subject to CyrusOne Inc.’s right to elect cash or net share settlement under the Forward Sale Agreements, CyrusOne Inc. intends to issue and sell, upon physical settlement of such Forward Sale Agreements, approximately 4.4 million shares of its common stock to Goldman, Sachs & Co. in exchange for cash proceeds per share equal to the applicable forward sale price, which was initially $48.48 per share and is subject to certain adjustments as provided in the applicable forward sale agreement. CyrusOne Inc. expects to physically settle the Forward Sale Agreements in full, which settlement or settlements will occur on or before August 1, 2017.

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements as of December 31, 2016 and December 31, 2015 , and for the years ended December 31, 2016 , December 31, 2015 and December 31, 2014 , are prepared on a consolidated basis. In addition, the accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). All intercompany transactions and balances have been eliminated in consolidation. All prior year amounts have been presented to conform to current year's presentation. During the third quarter of 2016, the Company identified certain immaterial errors relating to prior periods where Depreciation and amortization and Interest expense were understated. In 2016, we corrected the cumulative amount of these errors which resulted in additional Depreciation and amortization of $2.6 million and related Interest expense of $1.1 million .

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Use of Estimates —Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Estimates are used in determining the fair value of leased real estate, including purchase price allocations for business combinations and asset acquisitions, the useful lives of real estate and other long-lived assets, future cash flows associated with goodwill and other long-lived asset impairment testing, deferred tax assets and liabilities and loss contingencies. Actual results may differ from these estimates and assumptions. Investment in Real Estate —Investment in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. Real estate acquired from third parties has been recorded at its acquisition cost. Additions and improvements which extend an asset’s useful life or increase its functionality are capitalized and depreciated over the asset’s remaining life. Maintenance and repairs are expensed as incurred. When we are involved in the construction of structural improvements to leased property, we are deemed the accounting owner of the leased real estate. In these instances, we bear substantially all the construction period risk, including managing or funding construction. As we have substantially all of the construction risks, we are deemed the “owner” of the asset under construction for accounting purposes during the construction period, and are therefore required to capitalize the construction costs on the accompanying consolidated balance sheets. At inception, the fair value of the building (excluding land) is recorded as an asset and the construction and modification costs to the building, that are not funded by us would be recorded as a liability. As construction progresses, the value of the asset and obligation increases by the fair value of the structural improvements. At completion of the construction, Sales-Leaseback Accounting under ASC 840-40-25 is also evaluated. Due to our continuing involvement with the lessor, Sales-Leaseback Accounting is precluded and the liability is not derecognized. When the asset is placed in service, depreciation commences, and the leased real estate is depreciated to the lesser of (i) its estimated fair value at the end of the term or (ii) the expected amount of the unamortized obligation at the end of the term. The associated obligation is presented as Lease financing arrangements in the accompanying consolidated balance sheets. When we are not deemed the accounting owner of leased real estate, we further evaluate the lease to determine whether the lease should be classified as a capital or operating lease. One of the following four characteristics must be present to classify a lease as a capital lease: (i) the lease transfers ownership of the property to the lessee by the end of the lease term, (ii) the lease contains a bargain purchase option, (iii) the lease term is equal to 75% or more of the estimated economic life of the leased property or (iv) the net present value of the lease payments is at least 90% of the fair value of the leased property. Construction in progress includes direct and indirect expenditures for the construction and expansion of our data centers and is stated at its acquisition cost. Independent contractors perform substantially all of the construction and expansion efforts of our data centers. Construction in progress includes costs incurred under construction contracts including project management services, engineering and schematic design services, design development, construction services and other construction-related fees and services. Interest, property taxes and certain labor costs are also capitalized during the construction of an asset. Capitalized interest in 2016 , 2015 , and 2014 was $10.6 million , $6.1 million , and $4.6 million , respectively. These costs are depreciated over the estimated useful life of the related assets. Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to thirty years for buildings, three to thirty years for building improvements, and two to twenty years for equipment. Leasehold improvements are amortized over the shorter of the asset’s useful life or the remaining lease term, including renewal options which are reasonably assured. Management reviews the carrying value of long-lived assets, including intangible assets with finite lives, when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Examples of such indicators may include a significant adverse change in the extent to which or manner in which the property is being used, an accumulation of costs significantly in excess of the amount originally expected for acquisition or development, or a history of operating or cash flow losses. When such indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of an asset (or group of assets) and its eventual disposition and compare such amount to its carrying amount. We consider factors such as future operating income, leasing demand, competition and other factors. If our undiscounted net cash flows indicate that we are unable to recover the carrying value of the asset, an impairment loss is recognized. An impairment loss is measured as the amount by which the asset’s carrying value exceeds its estimated fair value. For the years ended December 31, 2016 and 2015, we recognized impairments and loss on disposal of $5.3 million and $13.5 million , respectively. There were no impairments recognized for the year ended December 31, 2014. Business Combinations —The Company applies the purchase method for business combinations, where all tangible and identifiable intangible assets acquired and all liabilities assumed are recorded at fair value. Any excess purchase price is recorded as goodwill. Transaction costs associated with business combinations are expensed as incurred. Revenues and the results of operations of the acquired business are included in the accompanying consolidated financial statements commencing on the date of acquisition. Cash and Cash Equivalents —Cash and cash equivalents include all non-restricted cash held in financial institutions and other non-restricted highly liquid short-term investments with original maturities at acquisition of three months or less. Restricted Cash —Restricted cash includes cash equivalents held to collateralize standby letters of credit and/or deposited in escrow to fund construction or pending potential acquisition transactions. In addition, we may have other cash that is not immediately available for use in current operations. Goodwill —We evaluate goodwill for possible impairment at least annually or upon the occurrence of a triggering event. A triggering event is an event or circumstance that would more likely than not reduce the fair value of a reporting unit below its carrying amount, including sales of properties defined as businesses for which the relative size of the sold property is significant to the reporting unit, that could impact our goodwill impairment calculations. 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. 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. If the fair value is below the carrying value the Company estimates the fair value of all the assets and liabilities of the reporting unit and compares them to the carrying value to determine the amount of the impairment, Step two. During the fourth quarter of 2016, we applied Step zero and determined that it is more likely than not that the fair value of the reporting unit is more than the carrying amount and therefore determined that the two step method for goodwill impairment testing was not necessary. During fourth quarters of 2015 and 2014, we performed a detailed, quantitative assessment. Based on the Company's annual assessment of goodwill, no impairment has been recognized through December 31, 2016. Long-Lived and Intangible Assets —Intangible assets represent purchased assets that lack physical substance, but can be separately distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged, either on its own or in combination with a related contract, asset, or liability. Intangible assets with finite lives consist of trademarks, customer relationships, and a favorable leasehold interest. Rent and Other Receivables —Receivables consist principally of trade receivables from customers and are generally unsecured and due within 30 to 120 days . Unbilled receivables arise from services rendered but not yet billed. Expected credit losses associated with trade receivables are recorded as an allowance for doubtful accounts. 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. When internal collection efforts on accounts have been exhausted, the accounts are written-off and the associated allowance for doubtful accounts is reduced. At December 31, 2016, there were no customers with receivables that made up 10% of the Company's outstanding accounts receivable balance. The Company had receivables with one customer that made up 10% of the Company’s outstanding accounts receivable balance at December 31, 2015 . Deferred Leasing Costs —Deferred leasing costs are presented with Other assets in the accompanying consolidated balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized over the term of the customer lease. Amortization of deferred leasing costs is presented with Depreciation and amortization in the accompanying consolidated statements of operations. If a lease terminates prior to the expiration of the lease, the remaining unamortized cost is written off to amortization expense. As of December 31, 2016 and 2015 , deferred leasing costs were $23.3 million and $14.2 million , respectively. Deferred Financing Costs —Deferred financing costs include costs incurred in connection with issuance of debt, including our senior notes, term loans and revolving credit facilities. These costs include deferred financing costs associated with our revolving line of credit and are presented in the balance sheet as a direct reduction from the carrying amount of the debt liability. These financing costs are deferred and amortized to expense over the term of the instrument and are included as a component of Interest expense. Lease Financing Arrangements —Lease financing arrangements represent leases of real estate where we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our consolidated balance sheets. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. Revenue Recognition —Colocation rentals are generally billed monthly in advance, and some contracts have escalating payments over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased space or power, and the lessee takes possession of, or controls the physical use of the property (including all contractually committed power) at the beginning of the lease term, the rental payments by the lessee are recognized as revenue on a straight-line basis over the term of the lease. If rents escalate because the lessee gains access to and control over additional leased space or power, revenue is recognized in proportion to the additional space or power in the periods that the lessee has control over the use of the additional space or power. The excess of revenue recognized over amounts contractually due is recognized in Other assets in the accompanying consolidated balance sheets. As of December 31, 2016 and 2015 , straight-line rent receivable was $67.6 million and $44.7 million , respectively. Revenue is recognized for services or products that are deemed separate units of accounting. When a customer makes an advance payment or they are contractually obligated to pay any amounts in advance, which is not deemed a separate unit of accounting, Deferred revenue is recorded. This revenue is recognized ratably over the expected term of the lease, unless the pattern of service suggests otherwise. As of December 31, 2016 and 2015 , Deferred revenue was $76.7 million and $78.7 million , respectively. Some of our leases are structured on a full-service gross basis in which the customer pays a fixed amount for both colocation rent and power. Other leases provide that the customer will be billed for power based upon actual usage which is separately metered. In both cases, this revenue is presented as Revenue in the accompanying consolidated statements of operations. Power is generally billed one month in arrears, and an estimate of this revenue is accrued in the month that the associated costs are incurred. We generally are not entitled to reimbursements for real estate taxes, insurance or other operating expenses. Generally, we receive an administrative fee when we manage the meters for our customers. Certain customer leases require specified levels of service or performance. If we fail to meet these service levels, our customers may be eligible to receive credits on their contractual billings. These credits are recognized against revenue when an event occurs that gives rise to such credits. Customer credits were immaterial for each of the years presented. A provision for doubtful accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible. Sales and Marketing Expense —Sales and marketing expense is comprised of compensation and benefits associated with Sales and marketing personnel as well as advertising and marketing costs. Costs related to advertising expense were $4.1 million , $2.2 million and $2.9 million for the years ended December 31, 2016 , 2015 and 2014, respectively. Depreciation and Amortization Expense —Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal of the lease is reasonably assured. The residual value of leased real estate is estimated as the lesser of (i) the expected fair value of the asset at the end of the lease term or (ii) the expected amount of the unamortized liability at the end of the lease term. Estimated useful lives are periodically reviewed. Depreciation expense was $157.7 million , $117.8 million and $95.8 million for the years ended December 31, 2016 , 2015 and 2014, respectively. Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. Finite-lived intangibles include trademarks, customer relationships, favorable leasehold interests, trade names and deferred leasing costs. As of December 31, 2016 , the estimated remaining weighted average useful life of trademarks and customer relationships were 9 and 12 years, respectively. In addition, we have a favorable leasehold interest related to a land lease that is being amortized over the lease term of fifty-one years. The trade name is being amortized over three years. Deferred leasing costs are amortized over three to five years . Amortization expense was $26.2 million , $23.7 million and $22.2 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Transaction and Acquisition Integration Costs —Transaction costs represent incremental legal, accounting and professional fees incurred in connection with consummated and potential business combinations. Transaction costs are expensed as incurred and do not include any recurring costs from our ongoing operations. Integration costs represent incremental costs to integrate a consummated acquisition. Income Taxes —The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the Code), commencing with our initial taxable year ending December 31, 2013. Provided we continue to meet the various qualification tests mandated under the Code, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our stockholders. If we fail to qualify as a REIT in any taxable year, our taxable income will be subject to federal income tax at regular corporate rates and any applicable alternative minimum tax, and we may not be able to qualify as a REIT for four subsequent taxable years. While CyrusOne Inc. does not pay federal income taxes, we are still subject to foreign, state and local income taxes in the locations in which we conduct business. Our taxable REIT subsidiaries (each a TRS) are also subject to federal and state income taxes to the extent they earn taxable income. Deferred income taxes are recognized in certain entities. Deferred income taxes are provided for temporary differences in the basis between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various foreign, state and local jurisdictions. The Company's previous tax filings are subject to normal reviews by regulatory agencies until the related statute of limitations expires. With a few exceptions, the Company is no longer subject to U. S. federal, state or local examinations for years prior to 2012, and we have no liabilities for uncertain tax positions as of December 31, 2016 or 2015 . Foreign Currency Translation and Transactions —The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average rates of exchange during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive (loss) income. Gains or losses from foreign currency transactions are included in determining net income. Comprehensive Income (Loss) —Comprehensive income (loss) represents the change in net assets of a company from transactions and other events from non-owner sources. Comprehensive income (loss) comprises all components of net income (loss) and all components of other comprehensive income (loss). Earnings Per Share —Basic EPS includes only the weighted average number of common shares outstanding during the period. Diluted EPS includes the weighted average number of common shares and the dilutive effect of stock options, restricted stock and share unit awards outstanding during the period, when such instruments are dilutive. Diluted EPS also includes the dilutive impact of shares issuable under the forward sales agreement using the treasury stock method. All outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are treated as participating in undistributed earnings with common shareholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS is applied. The forward contract entered into in August 2016 is not a participating security. Stock-Based Compensation —In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan (LTIP), which was amended and restated by our stockholders on May 2, 2016. The LTIP is administered by the compensation committee of the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. See Note 17 for additional details relating to these awards. Share-based compensation expense is based on the estimated grant-date fair value. CyrusOne Inc. recognizes share-based compensation expense on a straight-line basis over the requisite service period for time-based awards and on a graded vesting basis for performance-based awards. We adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (Subtopic 718) in the fourth quarter of 2016 and elected to account for forfeitures as they occur. Prior to the adoption of this ASU, CyrusOne estimated forfeitures based on historical activity, expected employee turnover, and other qualitative factors which were adjusted for changes in estimates and award vesting. Expenses for an award are recognized by the time they become fully vested. CyrusOne Inc. uses the Black-Scholes-Merton option pricing model to calculate the fair value of stock options. This option valuation model requires the use of subjective assumptions, including the estimated fair value of the underlying common stock, the expected stock price volatility, and the expected term of the option. The estimated fair value of the underlying common stock is based on third-party valuations. Our volatility estimates are based on a peer group of companies. We estimate the expected term of the awards to be the weighted average mid-point between the vesting date and the end of the contractual term. For interim and annual periods, we use our year-to-date actual results, financial forecasts, and other available information to estimate the probability of the award vesting based on the performance metrics. Fair Value Measurements —Fair value measurements are utilized in accounting for business combinations and testing of goodwill and other long-lived assets for impairment and disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows: Level 1—Observable inputs for identical instruments such as quoted market prices; Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data. Business Segments —Business segments are components of an enterprise for which separate financial information is available and regularly viewed by the chief operating decision maker to assess performance and allocate resources. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis. Furthermore, our data centers have similar economic characteristics and customers across all geographic locations, and our service offerings have similar production processes, deliver services in a similar manner and use the same types of facilities and similar technologies. As a result, we have concluded that we have one reportable operating segment. As of December 31, 2016 , one customer represented approximately 10% of our revenue, with that customer representing 13% of our annualized rent.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	12 Months Ended
	Dec. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards Accounting Standards Update (ASU) No. 2014-09 (ASU 2014-09), Revenue from Contracts with Customers (Topic 606) On May 28, 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09, which supersedes the revenue recognition requirements in Topic 605, "Revenue Recognition" and most industry-specific guidance. The core principle of ASU 2014-09 is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. On July 9, 2015, the FASB deferred the effective date of ASU 2014-09. The new revenue standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017 (January 1, 2018 for CyrusOne) and allows either a full retrospective adoption to all periods presented or a modified retrospective adoption approach with the cumulative effect of initial application of the revised guidance recognized at the date of initial application. We are beginning to evaluate the adoption alternatives and the impact of ASU 2014-09 on our consolidated financial statements. Our initial evaluation is that revenue from base colocation services, which is a majority of our revenues, would not be impacted by the adoption of this standard and therefore, we are inclined to adopt the modified retrospective approach. Our initial conclusion may change when we complete our evaluation. ASU No. 2015-17 (ASU 2015-17), Income Taxes (Topic 740) In November 2015, the FASB issued guidance which amended the balance sheet classification requirements for deferred Taxes. The ASU requires an entity to classify all deferred tax liabilities and assets as noncurrent in the balance sheet. This guidance is effective for financial statements issued for annual periods beginning after December 15, 2016, including interim periods within those fiscal years. Early application is permitted. The Company adopted this standard in the fourth quarter of 2016 and applied it prospectively to all deferred tax assets and liabilities. The adoption had no effect on our consolidated financial statements because we have a full valuation allowance for our deferred tax assets. ASU No. 2016-01 (ASU 2016-01), Financial Instruments-Overall (Subtopic 825-10) In January 2016, the FASB amended its standards related to the accounting of certain financial instruments. This amendment addresses certain aspects of recognition, measurement, presentation and disclosure. The new rules will become effective for annual and interim periods beginning after December 15, 2017. Early adoption is not permitted. We are in the process of evaluating the impact the amendment will have on the consolidated financial statements. ASU No. 2016-02 (ASU 2016-02), Leases (Topic 842) On February 25, 2016, the FASB issued ASU 2016-02. Lessees will need to recognize on their balance sheet a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to current operating leases) while finance leases will result in a front-loaded expense pattern (similar to current capital leases). Classification will be based on criteria that are largely similar to those applied in current lease accounting. The standard is effective for CyrusOne beginning January 1, 2019. Early adoption is permitted. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Transition will require application of the new guidance at the beginning of the earliest comparative period presented. We are beginning to evaluate the impact of ASU 2016-02 on our consolidated financial statements and timing of adoption. ASU No. 2016-09 (ASU 2016-09), Improvements to Employee Share-Based Payment Accounting (Subtopic 718) In March 2016, the FASB issued guidance which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted. The Company adopted the guidance in the fourth quarter of 2016 with effective date of January 1, 2016 and elected the actual forfeiture rate which had an immaterial impact to our financial statements. ASU No. 2016-10 (ASU 2016-10), Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing (Topic 606) In April 2016, the FASB issued ASU 2016-10 in response to an issue communicated by the Transition Resource Group for Revenue Recognition (the TRG), a group which was formed by the FASB and the International Accounting Standards Board (IASB), (collectively, the Boards), whose objective is to inform the Boards of any issues that could arise with the implementation of a converged standard on recognition of revenue from contracts with customers. ASU 2016-10 does not change the core principal of the guidance in Topic 606, but adds clarification around identifying performance obligations and licensing. The amendments in this update affect the guidance in ASU 2014-09, Contracts with Customers (Topic 606), which is not yet effective, and therefore follow the same effective date and transition requirements. ASU 2014-09 is effective for CyrusOne on January 1, 2018 and allows either a full retrospective adoption to all periods presented or a modified retrospective adoption approach with the cumulative effect of initial application of the revised guidance recognized at the date of the initial application. We are currently evaluating the impact of ASU 2016-10 and ASU 2014-09 on the company consolidated financial statements. ASU No. 2016-12 (ASU 2016-12), Revenue from Contracts with Customers (Subtopic 606) In May 2016, the FASB issued guidance which amends certain aspects of the Board's new revenue standard, ASU 2014-09. The amendments include the collectibility of revenue, presentation of sales tax and other similar taxes collected from customers, contracts containing noncash considerations, and contract modifications and completed contracts at transition. The effective date and transition provisions are aligned with the requirements of ASU 2014-09 (as described above). We are currently evaluating the full impact of the new standard. ASU No. 2016-13 (ASU 2016-13), Measurement of Credit Losses on Financial Instruments (Subtopic 326) In June 2016, the FASB issued guidance which requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The amendments affect entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. The guidance is effective for annual periods beginning after December 15, 2019. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2016-15 (ASU 2016-15), Classification of Certain Cash Receipts and Cash Payments (Subtopic 230) In August 2016, the FASB issued guidance which addresses the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. The Company adopted the standard in the fourth quarter of 2016 with effective date of January 1, 2016. The adoption of the standard had no effect on our consolidated financial statements. ASU No. 2016-18 (ASU 2016-18), Restricted Cash (Subtopic 230) In November 2016, the FASB issued guidance which addresses the diversity in the classification and presentation of changes in restricted cash on the statement of cash flows. The amendment requires that a statement of cash flows explain the change during the period in the total of cash. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2017-01 (ASU 2017-01), Business Combinations (Topic 805) In January 2017, the FASB issued guidance which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill and consolidation. Under this new guidance, the Company expects most acquisitions of investment property will meet the definition of an asset and, thus, be accounted for as asset acquisitions. Consistent with existing guidance, transaction costs associated with asset acquisitions are capitalized while transaction costs associated with business combinations are expensed as incurred. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. We are considering the early adoption of this standard in the first quarter of 2017.

Acquisitions and Purchase of Fi

Acquisitions and Purchase of Fixed Assets	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions and Purchase of Fixed Assets	Acquisitions and Purchase of Fixed Assets Cervalis On July 1, 2015, CyrusOne LP acquired 100% of Cervalis, a privately-held owner and operator of data centers for $398.4 million , excluding transaction-related expenses, in an all cash transaction. Cervalis has four data center facilities and two work recovery facilities serving the New York metropolitan area. CyrusOne LP financed the acquisition with proceeds of CyrusOne Inc.'s June 2015 common stock offering and CyrusOne LP and CyrusOne Finance Corp.'s July 2015 6.375% senior notes offering as well as drawing under CyrusOne Inc.'s Revolving Credit Facility. The acquisition of Cervalis enhances the geographic diversification of CyrusOne, provides access to a high quality enterprise customer base and strengthens our product portfolio. The goodwill recorded for this acquisition relates to the incremental value that Cervalis brings to the existing CyrusOne operations. The customer relationships intangible is expected to be amortized over fifteen years . This acquisition was accounted for as a business combination. For the year ended December 31, 2015, transaction and integration costs related to the Cervalis Acquisition were $12.9 million . The consolidated financial statements include the operating results of Cervalis from the date of acquisition. The following table summarizes the estimated fair values of all assets acquired and liabilities assumed at the date of acquisition: Cash $ 1.1 Rent and other receivables 10.5 Restricted cash 8.8 Net investment in real estate 197.8 Goodwill 178.9 Customer relationships 117.4 Trade name 2.3 Other long-term assets 5.6 Total assets acquired 522.4 Current liabilities 18.3 Capital lease obligations 1.7 Long-term debt 1.5 Lease financing arrangements 101.4 Total liabilities 122.9 Net assets acquired attributable to CyrusOne Inc. 399.5 Cash acquired (1.1 ) Net cash paid at acquisition 398.4 The acquisition of Cervalis in July 2015 resulted in an increase in revenue of $37.7 million for year ended December 31, 2015. The unaudited pro forma combined historical results of CyrusOne, as if Cervalis had been acquired and the financing transactions had been consummated as of January 1, 2014 are: IN MILLIONS For the year ended December 31, 2015 2014 Revenue 438.6 399.0 Net loss (10.9 ) (17.2 ) Loss per share - basic and diluted (0.16 ) (0.35 ) These amounts have been calculated after applying CyrusOne's policies and adjusting the results to reflect changes to Depreciation and amortization to property and equipment, amongst others, and amortizing intangible assets had been recorded as of January 1, 2014. These pro forma combined results of operation are presented for informative purposes only and they do not purport to be indicative of the results of operation that actually would have resulted had the acquisition occurred on the date indicated, or that may result in the future. CME On March 31, 2016 , CyrusOne LP purchased CME Group's Chicago-Aurora I data center in Aurora, Illinois for $131.1 million , including transaction related costs, in an all cash transaction. This acquisition was accounted for as an asset acquisition. CyrusOne LP financed the purchase with proceeds of CyrusOne Inc.'s March 2016 common stock offering. The purchase enhances the geographic diversification of CyrusOne, provides access to a high quality enterprise customer base and strengthens our product portfolio. The transaction adds to CyrusOne Inc.'s existing data center platform an approximately 428,000 square-foot facility data center serving the Chicago metropolitan region. In addition, CyrusOne acquired approximately 15 acres of land directly adjacent to the data center for future development. On April 1, 2016, the CME Group entered into a 15 -year lease for data center space at the Aurora facility. The agreement is expected to enhance the range of services available to the Company and CME Group's mutual customers through connectivity, hosting and data offerings. In addition, during the year ended December 31, 2016, the Company purchased four properties for development for approximately $54.5 million .

Investment in Real Estate

Investment in Real Estate	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 Land Building and Equipment Land Building and Equipment Dallas - Carrollton $ 16.1 $ 57.6 $ 154.0 $ 16.1 $ 52.7 $ 116.5 Houston - Houston West I 1.4 85.0 48.4 1.4 84.8 46.4 Dallas - Lewisville — 76.7 33.7 — 76.6 24.9 Cincinnati - 7th Street 0.9 110.6 21.0 0.9 110.6 19.6 Northern Virginia - Sterling II — 28.7 111.8 — — — Totowa - Madison — 28.3 50.8 — 28.3 48.8 Wappingers Falls I — 11.3 17.1 — 11.3 14.4 Cincinnati - North Cincinnati 4.0 77.3 9.0 4.0 77.3 7.6 Houston - Houston West II 2.8 23.1 49.0 2.0 22.6 47.1 San Antonio I 4.6 32.1 33.6 4.6 32.1 33.0 Chicago - Aurora I 2.4 28.5 99.9 — — — Phoenix - Chandler II — 16.1 38.8 — 16.0 39.5 Houston - Galleria — 68.6 16.6 — 68.6 16.0 Florence 2.2 41.9 4.9 2.2 41.5 3.3 Austin II 2.0 23.4 6.6 2.0 23.2 5.7 San Antonio II 7.0 29.0 59.4 7.0 — 0.1 Northern Virginia - Sterling I 7.0 19.7 47.2 7.0 19.2 45.2 Phoenix - Chandler I 14.8 56.8 56.5 14.8 56.7 39.8 Cincinnati - Hamilton — 50.2 5.0 — 49.2 4.4 Stamford - Riverbend — 4.3 14.5 — 4.3 13.2 Phoenix - Chandler III — 9.9 44.5 — — — London - Great Bridgewater — 25.9 0.9 — 31.2 0.8 Dallas - Midway — 2.0 0.4 — 2.0 0.4 Cincinnati - Mason — 20.2 1.4 — 20.2 1.0 Norwalk I — 19.0 26.6 — 18.3 25.4 Dallas - Marsh — 0.1 0.6 — 0.1 0.6 Chicago - Lombard 0.7 4.7 7.9 0.7 4.7 7.6 Stamford - Omega — 3.2 1.5 — 3.2 1.5 Northern Virginia - Sterling IV 4.6 11.0 33.4 — — — Cincinnati - Blue Ash — 0.6 0.1 — 0.6 0.1 Totowa - Commerce — 4.1 1.4 — 4.1 1.0 South Bend - Crescent — 1.7 0.2 — 3.3 0.4 Houston - Houston West III 18.4 9.4 13.5 18.4 4.0 0.8 Singapore - Inter Business Park — 8.2 0.1 — 8.4 0.1 South Bend - Monroe — 2.5 0.3 — 2.5 0.3 Cincinnati - Goldcoast 0.2 4.0 0.1 0.6 6.7 0.1 Austin III 3.3 9.7 31.8 3.3 7.4 31.5 Austin I — 3.5 0.2 — 13.6 1.0 Austin Land A 8.0 — 0.2 8.0 — 0.1 Chicago - Aurora Land A 2.6 — — — — — Phoenix - Chandler Land A 10.5 — — — — — Chicago - Aurora Land B 5.1 — — — — — Northern Virginia - Sterling Land A 24.1 — — — — — Total $ 142.7 $ 1,008.9 $ 1,042.9 $ 93.0 $ 905.3 $ 598.2 In addition, Construction in progress was $407.1 million and $231.1 million as of December 31, 2016 and December 31, 2015 , respectively, as we continue to build data center facilities. For the year ended December 31, 2016, our capital expenditures were $731.1 million , as shown on the statement of cash flows. This included the purchase of the Aurora Properties for $131.1 million , the purchase of four properties for development in Northern Virginia - Sterling, Chicago - Aurora and Phoenix - Chandler II for approximately $54.5 million and $545.5 million for other developments primarily in Northern Virginia - Sterling, Phoenix - Chandler II, San Antonio, Dallas - Carrollton and Houston - Houston West III. For the year ended December 31, 2016, we recognized Asset impairment and loss on disposal of $5.3 million which related primarily to two properties, South Bend-Crescent, a leased facility, and Cincinnati-Goldcoast, an owned facility. For the year ended December 31, 2015, our capital expenditures were $17.3 million for the purchase of Austin III facility and $217.2 million for other development as shown on the consolidated statements of cash flows. The significant items included the development of additional square footage and power in our Northern Virginia - Sterling, Phoenix - Chandler II, Houston - Houston West III and Dallas - Carrollton data centers, and the purchase of Austin III in February of 2015. The total purchase price of the Austin III facility was $17.3 million , of which $3.3 million was allocated to Land and the remaining amount remains in Construction in progress as of December 31, 2015. For the year ended December 31, 2015, we recognized Asset impairment and loss on disposal of $13.5 million which related primarily to the exit of Austin I, which is a leased facility, and loss on disposal of certain other assets.

Notes Receivable

Notes Receivable	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Notes Receivable	Notes Receivable The carrying amount of notes receivable was $6.6 million and $2.5 million as of December 31, 2016 and 2015, respectively, and consisted of the following: IN MILLIONS For the year ended December 31, 2016 2015 Note 1 $ 3.9 $ — Note 2 2.2 2.5 Note 3 0.5 — Total $ 6.6 $ 2.5 Each of the above notes are from different customers. Note 1 matures in February 2018, and the payments are approximately $300,000 per month. Note 2 matures in September 2021, and the payments are approximately $50,000 per month. Note 3 matures in October 2020, and the payments are approximately $12,000 per month. These notes are included in Rent and other receivables on the consolidated balance sheets.

Goodwill, Intangible and Other

Goodwill, Intangible and Other Long-Lived Assets	12 Months Ended
	Dec. 31, 2016
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 and $453.4 million as of December 31, 2016 and 2015 , respectively. As of December 31, 2015, the amounts recognized for Goodwill and Intangible assets were in connection with the acquisition of Cervalis, Cyrus Networks as well as prior acquisitions. For the year ended December 31, 2015, the additions relating to the Cervalis Acquisition were $177.2 million , $117.4 million , $2.3 million and $0.2 million for Goodwill, customer relationships, trade name and favorable leasehold interest, respectively. For the year ended December 31, 2016 , the addition to Goodwill was due to a reclassification from Other assets as a result of a measurement period adjustment relating to the Cervalis Acquisition. Summarized below are the carrying values for the major classes of intangible assets: IN MILLIONS For the year ended December 31, 2016 2015 Weighted- Gross Carrying Amount Accumulated Amortization Total Gross Carrying Amount Accumulated Amortization Total Customer relationships 12 $ 247.1 $ (106.3 ) $ 140.8 $ 247.1 $ (87.5 ) $ 159.6 Trademark 9 7.4 (3.2 ) 4.2 7.4 (2.7 ) 4.7 Favorable leasehold interest 48 4.1 (0.5 ) 3.6 4.1 (0.4 ) 3.7 Trade name 2 2.3 (0.7 ) 1.6 2.3 — 2.3 Total $ 260.9 $ (110.7 ) $ 150.2 $ 260.9 $ (90.6 ) $ 170.3 There were no goodwill or intangible asset impairments for the years ended December 31, 2016 or 2015 . Amortization expense for acquired intangible assets was $20.1 million , $18.5 million and $17.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The following table presents estimated amortization expense for each of the next five years and thereafter, commencing January 1, 2017 : IN MILLIONS 2017 $ 18.1 2018 16.2 2019 13.8 2020 12.6 2021 11.6 Thereafter 77.9 Total $ 150.2

Long-Term Debt, Capital Lease O

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements	Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements Long-term debt, Capital lease obligations and Lease financing arrangements presented in the accompanying consolidated financial statements consist of the following: IN MILLIONS For the year ended December 31, 2016 2015 Credit facilities: Revolving Credit Facility $ 235.0 $ 235.0 Term loans 550.0 300.0 6.375% senior notes due 2022, including bond premium 477.3 477.6 Notes payable — 1.5 Deferred financing costs (22.2 ) (17.6 ) Long-term debt 1,240.1 996.5 Capital lease obligations 10.8 12.2 Lease financing arrangements 135.7 150.0 Total $ 1,386.6 $ 1,158.7 Credit Facility —On October 9, 2014, CyrusOne LP entered into a credit agreement (the Credit Agreement) which provided for a $450 million senior unsecured revolving credit facility to replace CyrusOne LP's $225 million secured credit facility, and a $150 million senior unsecured term loan. On June 22, 2015, CyrusOne entered into an amendment to the Credit Agreement and other loan documents governing its revolving credit facility and term loan facility. The amendment increased the size of the Credit Agreement's accordion feature, which gave the operating partnership the ability to request an increase in the total commitment under the Credit Agreement, from $300 million to $600 million . Immediately after entering into the amendment, the operating partnership exercised $350 million of this accordion feature and obtained commitments to increase the total commitment under the Credit Agreement from $600 million to $950 million , comprised of $650 million of commitments under the revolving credit facility (the Revolving Credit Facility) and $300 million under the term loan (the Initial Term Loan). In addition, the Credit Agreement contained an accordion feature that allows CyrusOne LP to increase the aggregate commitment by up to $250 million . On March 17, 2016 , CyrusOne LP entered into a first amended and restated credit agreement (the First Amended and Restated Credit Agreement) which amended and restated in its entirety the Credit Agreement, as amended previously. The First Amended and Restated Credit Agreement provided for an additional $250.0 million senior unsecured term loan facility (the Additional Term Loan, and together with the Initial Term Loan, the Term Loans) in addition to the existing $300.0 million Initial Term Loan and the existing $650.0 million Revolving Credit Facility. The First Amended and Restated Credit Agreement had an accordion feature under which CyrusOne LP may have requested an increase in the total commitments up to an amount not to exceed $250.0 million . Deferred financing costs of $2.1 million related to this amendment were recorded. On November 21, 2016, CyrusOne LP entered into a second amended and restated credit agreement (the Second Amended and Restated Credit Agreement) which amended and restated in its entirety the First Amended and Restated Credit Agreement. The Second Amended and Restated Credit Agreement, among other things, increased the available commitments under the Revolving Credit Facility to $1.0 billion . Deferred financing costs of $6.6 million related to this amendment were recorded. The Revolving Credit Facility is scheduled to mature in November 2020 and includes a one -year extension option, which if exercised by CyrusOne LP would extend the maturity date to November 2021. The Initial Term Loan of $300 million is scheduled to mature in January 2022. The Additional Term Loan of $250 million is scheduled to mature in September 2021. The Revolving Credit Facility currently bears interest at a rate per annum equal to LIBOR plus 1.55% and the Initial Term Loan and Additional Term Loan currently bear interest at a rate per annum equal to LIBOR plus 1.50% . As of December 31, 2016, the interest rate for the Revolving Credit Facility and the Term Loans was 2.31% and 2.26% , respectively. As of December 31, 2016, there were outstanding borrowings of $235.0 million on the Revolving Credit Facility and aggregate borrowings of $550.0 million on the Term Loans. In addition, the Second Amended and Restated Credit Agreement contains an accordion feature that allows CyrusOne LP to increase the aggregate commitment by up to $300 million . We pay commitment fees for the unused amount of borrowings on the Revolving Credit Facility and letter of credit fees on any outstanding letters of credit. The commitment fees are equal to 0.25% per annum of the actual daily amount by which the aggregate revolving commitments exceed the sum of outstanding revolving loans and letter of credit obligations. Commitment fees related to the Second Amended and Restated Credit Agreement were $1.6 million and $0.9 million for the years ended December 31, 2016 and 2015 , respectively. 6.375% Senior Notes due 2022 —On November 20, 2012, CyrusOne LP and CyrusOne Finance Corp. (Issuers) issued $525.0 million of 6.375% senior notes due 2022 ( 6.375% senior notes). The 6.375% senior notes are senior unsecured obligations of the Issuers, which rank equally in right of payment with all existing and future unsecured senior debt of the Issuers. The 6.375% senior notes are effectively subordinated to all existing and future secured indebtedness of the Issuers to the extent of the value of the assets securing such indebtedness. The 6.375% senior notes are fully and unconditionally and jointly and severally guaranteed by CyrusOne Inc., CyrusOne GP, and each of CyrusOne LP’s existing and future domestic subsidiary that guarantees other indebtedness of CyrusOne LP or any guarantor, subject to certain exceptions. Each such guarantee is a senior unsecured obligation of the applicable guarantor, ranking equally with all existing and future unsecured senior debt of such guarantor and effectively subordinated to all existing and future secured indebtedness of such guarantor to the extent of the value of the assets securing that indebtedness. The 6.375% senior notes are structurally subordinated to all liabilities (including trade payables), of each subsidiary of the Issuers that does not guarantee the 6.375% senior notes. The 6.375% senior notes bear interest at a rate of 6.375% per annum, payable semi-annually on May 15 and November 15 of each year. The 6.375% senior notes will mature on November 15, 2022. However, prior to November 15, 2017, the Issuers may, at their option, redeem some or all of the 6.375% senior notes at a redemption price equal to 100% of the principal amount of the 6.375% senior notes being redeemed, together with accrued and unpaid interest, if any, to the date of redemption plus a “make-whole” premium. On or after November 15, 2017, the Issuers may, at their option, redeem some or all of the 6.375% senior notes at any time at declining redemption prices equal to (i) 103.188% beginning on November 15, 2017, (ii) 102.125% beginning on November 15, 2018, (iii) 101.063% beginning on November 15, 2019 and (iv) 100.000% beginning on November 15, 2020 and thereafter, plus, in each case, accrued and unpaid interest, if any, to the applicable redemption date. In addition, before November 15, 2015, and subject to certain conditions, the Issuers were permitted , at their option, to redeem up to 35% of the aggregate principal amount of the 6.375% senior notes with the net proceeds of certain equity offerings at a redemption price equal to 106.375% of the principal amount thereof, plus accrued and unpaid interest, if any, to the date of redemption; provided that (i) at least 65% of the aggregate principal amount of the 6.375% senior notes remained outstanding after the redemption and (ii) the redemption occurred within 90 days of the closing of any such equity offering. In November and December of 2014, we repurchased a portion of our 6.375% senior notes with an aggregate face value of $150.2 million for a purchase price of $163.0 million , including accrued and unpaid interest. This resulted in a loss on extinguishment of debt of $12.8 million . On July 1, 2015, the Issuers closed a private offering of $100.0 million aggregate principal amount of the 6.375% senior notes (New Notes) plus a premium of $3.8 million . The New Notes were issued as additional notes under the Indenture dated November 20, 2012 as supplemented by the first supplemental indenture dated July 1, 2015, and the New Notes have terms substantially identical to those of the 6.375% senior notes issued in November 2012. On December 29, 2015, all notes issued on July 1, 2015 were exchanged for registered notes that are freely tradable. As of December 31, 2016, the outstanding balance on the 6.375% senior notes was $477.3 million , including bond premium. Debt Covenants —The Second Amended and Restated Credit Agreement requires us to maintain certain financial covenants including the following, in each case on a consolidated basis: • A minimum fixed charge ratio; • Maximum total and secured leverage ratios; • A minimum consolidated tangible net worth ratio; • A maximum secured recourse indebtedness ratio; • A minimum unencumbered debt yield ratio; and • A maximum ratio of unsecured indebtedness to unencumbered asset value. Notwithstanding these limitations, we will be permitted, subject to the terms and conditions of the Second Amended and Restated Credit Agreement, to distribute to our stockholders cash dividends in an amount not to exceed 95% of our Funds From Operations (FFO), as defined in the Second Amended and Restated Credit Agreement for any period. Similarly, our indenture permits dividends and distributions necessary for us to maintain our status as a REIT. The Company’s most restrictive covenants are generally included in the Second Amended and Restated Credit Agreement. In order to continue to have access to amounts available to it under the Second Amended and Restated Credit Agreement, the Company must remain in compliance with all covenants. The indenture governing the 6.375% senior notes contains affirmative and negative covenants customarily found in indebtedness of this type, including a number of covenants that, among other things, restrict, subject to certain exceptions, the Company’s ability to: incur secured or unsecured indebtedness; pay dividends or distributions on its equity interests, or redeem or repurchase equity interests of the Company; make certain investments or other restricted payments; enter into transactions with affiliates; enter into agreements limiting the ability of the operating partnership’s subsidiaries to pay dividends or make certain transfers and other payments to the operating partnership or to other subsidiaries; sell assets; and merge, consolidate or transfer all or substantially all of the operating partnership’s assets. Notwithstanding the foregoing, the covenants contained in the indenture do not restrict the Company’s ability to pay dividends or distributions to stockholders to the extent (i) no default or event of default exists or is continuing under the indenture and (ii) the Company believes in good faith that we qualify as a REIT under the Code and the payment of such dividend or distribution is necessary either to maintain its status as a REIT or to enable it to avoid payment of any tax that could be avoided by reason of such dividend or distribution. The Company and its subsidiaries are also required to maintain total unencumbered assets of at least 150% of their unsecured debt on a consolidated basis, provided that for the purposes of such calculation their Revolving Credit Facility shall be treated as unsecured indebtedness, in each case subject to certain qualifications set forth in the indenture. As of December 31, 2016 , we believe we were in compliance with all covenants. Notes Payable —The Company's note payable for approximately $1.5 million with a third-party for installation of electrical infrastructure at one of the Company's locations was repaid in July 2016. Deferred financing costs —Deferred financing costs are costs incurred in connection with obtaining long-term financing. Deferred financing costs were incurred in connection with the issuance of the Revolving Credit Facility, the Initial Term Loan, the Additional Term Loan and 6.375% senior notes due 2022. As of December 31, 2016 , and 2015 , deferred financing costs totaled $22.2 million and $17.6 million , respectively. Amortization of deferred financing costs, included in Interest expense in the consolidated statements of operations, totaled $4.1 million , $3.4 million , and $3.4 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Capital lease obligations —We use leasing as a source of financing for certain of our data center facilities and related equipment. We currently operate eight data center facilities under leases recognized as capital leases. We have options to extend the initial lease term on all but one of these leases. Lease financing arrangements —Lease financing arrangements represent leases of real estate in which we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our balance sheet. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations. Interest expense on Capital lease obligations and Lease financing arrangements were $10.6 million , $7.8 million and $5.9 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The following table summarizes aggregate maturities of total future value and present value of the minimum payments associated with our Lease financing arrangements for the five years subsequent to December 31, 2016 , and thereafter: IN MILLIONS Future Value of Payments Interest Present Value of Payments 2017 $ 16.4 $ 7.9 $ 8.5 2018 14.3 7.5 6.8 2019 14.5 7.0 7.5 2020 25.4 6.4 19.0 2021 11.4 5.7 5.7 Thereafter 109.8 21.6 88.2 Total lease financing arrangements $ 191.8 $ 56.1 $ 135.7 The following table summarizes aggregate maturities of the Revolving Credit Facility and Term Loans, 6.375% senior notes due 2022 and capital leases for the five years subsequent to December 31, 2016 , and thereafter: IN MILLIONS Revolving Credit Facility/Term Loan 6.375% Senior Notes Capital Leases Total 2017 $ — $ — $ 3.3 $ 3.3 2018 — — 1.7 1.7 2019 — — 1.5 1.5 2020 235.0 — 1.7 236.7 2021 250.0 — 1.6 251.6 Thereafter 300.0 474.8 1.0 775.8 Total debt $ 785.0 $ 474.8 $ 10.8 $ 1,270.6 The payment of interest on capital leases over the next five years and thereafter will be $0.9 million , $0.7 million , $0.5 million , $0.4 million , $0.2 million and $0.1 million , respectively.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The fair value of Cash and cash equivalents, Restricted cash, Rent and other receivables and Accounts payable and accrued expenses approximate their carrying value because of the short-term nature of these instruments. The carrying value and fair value of other financial instruments are as follows: IN MILLIONS For the year ended December 31, 2016 2015 Carrying Value Fair Value Carrying Value Fair Value 6.375% senior notes due 2022 $ 477.3 $ 502.1 $ 477.6 $ 493.8 Revolving Credit Facility and Term Loans 785.0 785.0 535.0 535.0 Note payable — — 1.5 1.2 The fair value of our 6.375% senior notes as of December 31, 2016 and 2015 was based on the quoted market price for these notes, which is considered Level 1 of the fair value hierarchy. The carrying value of the Revolving Credit Facility, the Initial Term Loan and the Additional Term Loan approximates estimated fair value as of December 31, 2016 , due to the variability of interest rates and the stability of our credit ratings. The fair value of the note payable at December 31, 2015 , was calculated using a discounted cash flow model that incorporates current borrowing rates for obligations of similar duration. These fair value measurements are considered Level 3 of the fair value hierarchy.

Noncontrolling Interest - Opera

Noncontrolling Interest - Operating Partnership	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest - Operating Partnership	Noncontrolling Interest - Operating Partnership Prior to the IPO, the operating partnership received a contribution of interests in real estate properties and the assumption of debt and other specified liabilities from CBI in exchange for the issuance of 123.7 million operating partnership units of CyrusOne LP to CBI. Subsequent to December 31, 2012, CyrusOne LP executed a 2.8 to 1.0 reverse unit split, resulting in CBI owning 44.1 million operating partnership units. On January 24, 2013, CBI exchanged 1.5 million operating partnership units for common shares of CyrusOne Inc. After the IPO on January 24, 2013, CBI retained a noncontrolling interest in the operating partnership of 66.1% . The Company completed public offerings in 2014 and 2015 in which the proceeds were used to acquire the limited partnership interests in the operating partnership from CBI. As of December 31, 2015 , CBI owned approximately 9.5% of the Company’s common stock, and all of the operating partnership units of CyrusOne LP were owned, directly or indirectly, by the Company. CyrusOne Inc. had no noncontrolling interests as of December 31, 2016 , and CBI owned less than 5.0% of the Company's common stock. The following table shows the ownership interests as of December 31, 2015 , and the portion of net income (loss) and distributions for the year ended December 31, 2015 : For the year ended December 31, 2015 (in millions, except unit amount) The Company CBI Operating partnership units 72.6 — Ownership % 100.0 % — % Portion of net income (loss) $ (15.4 ) $ (4.8 ) Distributions $ (74.6 ) $ (16.3 )

Dividends

Dividends	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Dividends	Dividends We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2016 and 2015 as presented in the table below: Record date Payment date Cash dividend per share or operating partnership unit March 27, 2015 April 15, 2015 $0.315 June 26, 2015 July 15, 2015 $0.315 September 25, 2015 October 15, 2015 $0.315 December 24, 2015 January 8, 2016 $0.315 March 25, 2016 April 15, 2016 $0.38 June 24, 2016 July 15, 2016 $0.38 September 30, 2016 October 14, 2016 $0.38 December 30, 2016 January 13, 2017 $0.38 As of December 31, 2016 and 2015 we had a dividend payable of $33.9 million and $24.4 million , respectively. On February 23, 2017 , we announced a regular cash dividend of $0.42 per common share payable to shareholders of record as of March 31, 2017. The dividend will be paid on April 14, 2017.

Customer Leases

Customer Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Customer Leases	Customer Leases Customer lease arrangements customarily contain provisions that allow either for renewal or continuation on a month-to-month arrangement. Certain leases contain early termination rights. At lease inception, early termination is generally not deemed reasonably assured due to the significant economic penalty incurred by the lessee to exercise its termination right and to relocate its equipment. The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below: IN MILLIONS 2017 $ 404.3 2018 306.3 2019 224.5 2020 179.9 2021 141.0

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans Currently, our employees participate in health care plans sponsored by CyrusOne, which provide medical, dental, vision and prescription benefits. We incurred $4.4 million , $3.1 million and $2.1 million of expenses related to these plans for the years ended December 31, 2016 , 2015 and 2014 , respectively. CyrusOne offers a retirement savings plan to its employees. CyrusOne's matching contribution to its retirement savings plan was $1.5 million , $1.1 million and $0.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively.

Income (Loss) per Share

Income (Loss) per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Income (Loss) per Share	Income (Loss) per Share Basic income (loss) per share is calculated using the weighted average number of shares of common stock outstanding during the period. In addition, net income (loss) applicable to participating securities and the 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 and shares contingently issuable under the Forward Sales Agreement (as defined below). If there is net income during the period, the dilutive impact of common stock equivalents outstanding would also be reflected. On August 15, 2016, CyrusOne Inc. completed a public offering of 3.4 million shares of its common stock for $164.8 million , net of underwriting discounts of approximately $6.9 million . In connection with this offering, on August 10, 2016, CyrusOne Inc. entered into (a) a forward sale agreement with Goldman, Sachs & Co. (the Forward Sale Agreement) with respect to 3.4 million shares of its common stock, and (b) an additional forward sale agreement with Goldman, Sachs & Co. (the Additional Forward Sale Agreement, and together with the Forward Sale Agreement, the Forward Sale Agreements) with respect to approximately 1.0 million shares of its common stock in connection with the underwriters' exercise of their option to purchase these shares. This contract had no effect on our diluted share count at December 31, 2016. The following table reflects the computation of basic and diluted net income (loss) per share: IN MILLIONS, except per share amounts Year Ended Year Ended Period Ended For December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) attributed to common stockholders $ 19.9 $ 19.9 $ (15.4 ) $ (15.4 ) $ (7.8 ) $ (7.8 ) Less: Restricted stock dividends (0.7 ) (0.7 ) (1.0 ) (1.0 ) (0.8 ) (0.8 ) Net income (loss) available to stockholders $ 19.2 $ 19.2 $ (16.4 ) $ (16.4 ) $ (8.6 ) $ (8.6 ) Denominator: Weighted average common outstanding-basic 78.3 78.3 54.3 54.3 29.2 29.2 Performance-based restricted stock (1)(2) 0.7 — — Weighted average shares outstanding-diluted 79.0 54.3 29.2 EPS: Net income (loss) per share-basic $ 0.24 $ (0.30 ) $ (0.30 ) Effect of dilutive shares: — — — Net income (loss) per share-diluted $ 0.24 $ (0.30 ) $ (0.30 ) (1) We have excluded 1.9 million weighted average shares of restricted stock, and 13.1 million of weighted average operating partnership units which are securities convertible into common stock from our diluted earnings per share as of December 31, 2015. These amounts were deemed anti-dilutive. (2) We have excluded 0.8 million weighted average shares of restricted stock, and 34.3 million of weighted average operating partnership units which are securities convertible into common stock from our diluted earnings per share as of December 31, 2014. These amounts were deemed anti-dilutive.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans Stock-based compensation expense was as follows: For the periods ended December 31, 2016 2015 2014 Founders $ 0.3 $ 5.2 $ 5.4 2013 Grants 0.1 1.2 1.2 2014 Grants 1.2 3.0 3.7 2015 Grants 3.5 5.0 — 2016 Grants 7.2 — — Total $ 12.3 $ 14.4 $ 10.3 In conjunction with the IPO, the board of directors of CyrusOne Inc. adopted the 2012 Long-Term Incentive Plan (LTIP), which was amended and restated on May 2, 2016. The LTIP is administered by the board of directors. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. CyrusOne Inc. has reserved a total of 8.9 million shares of CyrusOne Inc. common stock for issuance pursuant to the LTIP, which may be adjusted for changes in capitalization and certain corporate transactions. To the extent that an award, if forfeitable, expires, terminates or lapses, or an award is otherwise settled in cash without the delivery of shares of common stock to the participant, then any unpaid shares subject to the award will be available for future grant or issuance under the LTIP. The payment of dividend equivalents in cash in conjunction with any outstanding awards will not be counted against the shares available for issuance under the LTIP. The related stock compensation expense incurred by CyrusOne Inc. is allocated to the operating partnership. Shares available under the LTIP at December 31, 2016 , were approximately 5.8 million . Shares vest according to each agreement and as long as the employee remains employed with the Company. The Company uses the Black-Scholes option-pricing model for time and performance-based options and a Monte Carlo simulation for market-based awards. The fair values of these awards use assumptions such as volatility, risk-free interest rate, and expected term of the awards. Compensation expense is measured based on the estimated grant-date fair value. Expense for time-based grants is recognized under a straight-line method. For market-based grants, expense is recognized under a graded expense attribution method. For performance-based grants, expense is recognized under a graded expense attribution method if it is probable that the performance targets will be achieved. 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. In March 2016, the FASB issued guidance which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The Company adopted the guidance in the fourth quarter of 2016 and elected the actual forfeiture rate, which had an immaterial impact to our financial statements. The compensation expense for the year ended December 31, 2016 includes $0.8 million due to the acceleration of equity awards of a senior executive who left the Company. The compensation expense for the year ended December 31, 2015 includes $2.4 million due to the acceleration of equity awards of two senior executives who left the Company. Founders Grants On January 24, 2013, the Company granted one million shares of time-based restricted stock, which had an aggregate value of $19.0 million on the grant date. Holders of the restricted stock have all of the rights and privileges of stockholders including but not limited to the right to vote, receive dividends and distributions upon liquidation of CyrusOne. These shares vested on January 24, 2016 . 2013 Grants On April 17, 2013, the Company issued performance and market-based awards under the LTIP in the form of stock options and restricted stock. For these awards, vesting was tied 50% to the achievement of a non-GAAP performance measure (cumulative EBITDA targets, as defined in the agreement), over the 2013-2015 performance period, and 50% market-based performance measure (the total stockholder return (TSR), as defined in the agreement) at the end of the three -year period ending December 31, 2015. The portion of the awards tied to cumulative EBITDA was eligible to vest annually over a three -year period based on the Company attaining predetermined cumulative EBITDA targets. 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 = 0% - At 90% of performance target = 50% - At 100% of performance target = 100% - At or above 115% of performance target = up to 200% The portion of the awards tied to TSR was eligible to vest at the end of three years if the TSR, during the three -year measurement period following the grant date, met or exceeded the return of the MSCI US REIT Index (Index) over the same period. The TSR targets are 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 Index = 0% - If CyrusOne's TSR is equal to or greater than the return of the Index = 100% ; up to 200% if CyrusOne's TSR exceeds the return of the Index by 2% - If CyrusOne's TSR exceeds the return of the Index, but is negative, any calculated vesting amount will be reduced by 50% The stock option awards have a contractual life of 10 years from the award date and were granted with an exercise price equal to $23.58 . In addition, during the year ended December 31, 2013, the Company also granted from time-to-time a total of 4,361 additional time-based restricted shares which had an aggregate value of $0.1 million on the grant date. A portion of these shares cliff vested one year after the grant date and a portion vested three years after the grant date. The holders of restricted stock shall have all of the rights and privileges of shareholders including the right to vote. As of December 31, 2016 , there was no unearned compensation representing the unvested portion of the awards granted during 2013. 2014 Grants On February 7, 2014, the Company issued performance and market-based awards under the LTIP in the form of restricted stock units. For these awards, vesting is tied 50% to the achievement of a non-GAAP performance measure (cumulative Adjusted EBITDA targets, as defined in the agreement) over the 2014-2016 performance period, and 50% to a market-based performance measure TSR, as defined in the agreement), as of the end of the three-year period ending December 31, 2016. The portion of the awards tied to cumulative Adjusted EBITDA vest annually over a three -year period based on the Company attaining predetermined cumulative Adjusted EBITDA targets and as long as the employee remains employed with the Company. The portion of the award tied to TSR will vest at the end of three years based on the cumulative TSR over a three -year performance period. The market and performance-based awards will vest based on the same scales as the awards granted during 2013. 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 will vest three years after the grant date. The holders of restricted stock have all of the rights and privileges of shareholders including the right to vote. As of December 31, 2016 , unearned compensation of the awards granted during 2014 totaled $0.1 million , with a weighted average vesting period of 0.1 years. 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 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 period. The first two years are capped at 100% of the target with a cumulative true-up in year three. The market and 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, for various new employee hires, the following grants were made: • 8,157 shares of time-based restricted stock which cliff vest in three years from the date of each grant. • 29,424 shares of time-based restricted stock which vest annually from the date of each grant. • 12,719 time-based options which vest annually from the date of each grant. • 11,711 shares of performance and market-based restricted stock, which vest annually based upon the achievement of certain criteria for each year of the three -year measurement period. • 55,301 shares of performance-based (separate non-GAAP measure, as defined in the award agreement) restricted stock, which cliff vests in three years from the date of grant. For the year ended December 31, 2016 , the unearned compensation of the awards granted in 2015 totaled $2.2 million and the weighted average vesting period was 1.0 years. 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 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 in year three. Certain employees were also awarded time-based restricted stock that cliff vest at the end of three years. The stock options are time-based and vest annually on a pro-rata basis over 3 years. The market and performance-based awards will vest based on the same scales as the awards granted during 2015. 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 from the date of each grant. As of December 31, 2016 , unearned compensation representing the unvested portion of the awards granted in 2016 totaled $14.5 million , with a weighted average vesting period of 2.0 years. Restricted Stock and Stock Option Activity The following table summarizes the unvested restricted stock activity and the weighted average fair value of these shares at the date of grant for the year ended December 31, 2016 : For the year ended December 31, 2016 Shares Weighted Average Grant Date Fair Value Non-vested at January 1 1,585,010 $ 22.11 Granted 641,097 35.18 Vested (839,571 ) 21.10 Forfeited (111,823 ) 26.72 Non-vested at December 31 1,274,713 $ 28.95 The non-vested shares at December 31, 2014 were 1,739,642 . The following table summarizes the stock option activity for the year ended December 31, 2016 : For the year ended December 31, 2016 Options Weighted Average Exercise Price Outstanding at January 1 334,402 $ 26.44 Granted 222,461 36.99 Exercised (70,668 ) 26.00 Forfeited or expired (51,927 ) 26.65 Outstanding at December 31 434,268 31.89 Exercisable at December 31 138,157 27.27 Vested and expected to vest 434,268 $ 31.89 The outstanding options at December 31, 2014 were 166,872 . 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 fiscal year 2016 was $1.3 million and 2015 was immaterial. There were no options exercised during 2014. The aggregate intrinsic value of options outstanding at December 31, 2016 was $5.6 million . The aggregate intrinsic value of options exercisable at December 31, 2016 was $2.4 million . Stock Option Assumptions The following table summarizes the stock option assumptions for the years ended December 31, 2016 , 2015 , and 2014 : 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 2014 $23.58 166,872 8.3 13,915 8.3 0.92% 3.4% 6.0 35% 2015 $23.58 142,556 7.3 43,460 7.3 0.92% 3.4% 6.0 35% $28.42 178,704 9.1 35,346 9.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 9.6 — 0.0 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% 2016 $23.58 67,601 6.3 67,601 6.3 0.92% 3.4% 6.0 35% $28.42 143,358 8.1 47,786 8.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 8.6 4,240 8.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 210,590 9.1 18,530 9.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0%

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions CBI Prior to November 20, 2012, CyrusOne Inc., CyrusOne GP, CyrusOne LP and its subsidiaries were operated by CBI. The consolidated financial statements reflect the following transactions with CBI and its affiliated entities, including Cincinnati Bell Telephone (CBT) and Cincinnati Bell Technology Solutions (CBTS). At December 31, 2015, CBI owned 9.5% of the outstanding common stock of CyrusOne Inc. and no operating partnership units, at which point it ceased to be a related party of CyrusOne Inc. As of December 31, 2016, CBI owned less than 5% of the outstanding common stock of CyrusOne Inc. Revenues —The Company records revenues from CBI under contractual service arrangements. These services include leasing of data center space, power and cooling in certain of our data center facilities, network interface services and office space. Operating Expenses —The Company records expenses from CBI incurred in relation to network support, services calls, monitoring and management, storage and backup, IT systems support, and connectivity services. The following related party transactions are based on agreements and arrangements that were in place during the respective periods. Revenues and expenses for the periods presented were as follows: IN MILLIONS December 31, 2015 December 31, 2014 Revenue: Data center colocation agreement provided to CBT and CBTS $ 7.8 $ 6.4 229 West 7th Street lease provided to CBT 1.9 2.0 Goldcoast Drive/Parkway (Mason) lease 0.3 0.4 Transition services provided to CBTS (network interfaces) 0.3 0.4 Data center leases provided to CBTS 12.0 13.6 Total revenue $ 22.3 $ 22.8 Operating costs and expenses: Transition services agreement by CBTS $ 0.7 $ 0.8 Charges for services provided by CBT (connectivity) 1.0 1.0 209 West 7th Street rent provided by CBT 0.2 0.2 Total operating costs and expenses $ 1.9 $ 2.0 Other Related Party Transactions Our director, Lynn A. Wentworth, is a member of the board of directors of CBI, and serves as the chair of its audit and finance committee. The spouse of one of our former directors, who served until May 2015, is a partner with Skadden, Arps, Slate, Meagher & Flom LLP (Skadden). For the years ended December 31, 2015 and 2014, CyrusOne paid Skadden an immaterial amount and $1.1 million , respectively, for services rendered. In the ordinary course of its business, CyrusOne periodically pays brokerage commissions to real estate brokerage firms in connection with property transactions and tenant leases. The spouse of one of our former directors, who served until 2014, is a principal with Jones Lang LaSalle. In 2014, CyrusOne paid $1.0 million to Jones Lang LaSalle.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CyrusOne Inc. elected to be taxed as a REIT under the Code, commencing with our taxable year ended December 31, 2013. To remain qualified as a REIT, we are required to distribute at least 90% of our taxable income to our stockholders and meet various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we continue to qualify for taxation as a REIT, we are generally not subject to corporate level federal income tax on the taxable income distributed currently to our stockholders. It is our policy and intent, subject to change, to distribute 100% of our taxable income and therefore no provision is required in the accompanying financial statements for federal income taxes with regards to activities of CyrusOne Inc. and its subsidiary pass-through entities. We have elected to designate two subsidiaries as taxable REIT subsidiaries (each a TRS). A TRS may perform services for our tenants that would otherwise be considered impermissible for REITs. The income generated from these services is taxed at federal and state corporate rates. While CyrusOne Inc. and the operating partnership do not pay federal income taxes, we are still subject to foreign, state, and local income taxes in the locations in which we conduct business. Income tax expense for the years ended December 31, 2016 , 2015 and 2014 were $1.8 million , $1.8 million and $1.4 million , respectively. For certain entities we calculate deferred tax assets and liabilities for temporary differences in the basis between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards. Deferred tax assets (net of valuation allowance) and liabilities were accrued, as necessary, for the years ended December 31, 2016 and 2015 . Historically, we have recorded a full valuation allowance on our foreign net deferred tax assets related to our foreign generated net operating losses due to the uncertainty of their realization. In 2013 and 2014, management determined it was necessary to record a full valuation allowance on all of our domestic and foreign net deferred tax assets due to the uncertainty of their realization. Accordingly, at December 31, 2016 and at December 31, 2015 , the net domestic and foreign deferred tax assets were zero . The Company adopted ASU No. 2015-17 in the fourth quarter of 2016 and applied it prospectively to all deferred tax assets and liabilities. The adoption had no effect on our consolidated financial statements. In 2016 and 2015 , we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the years ended December 31, 2016 and 2015 : For the year ended December 31, 2016 2015 Common Stock dividend per share: Ordinary income $ 0.20 $ — Return of capital 1.26 1.16 Total dividend $ 1.46 $ 1.16 Common stock dividends may be characterized for federal income tax purposes as ordinary income, qualified dividends, capital gains, non-taxable return of capital or a combination of the four. Common stock dividends that exceed our current and accumulated earnings and profits (calculated for tax purposes) constitute a return of capital rather than a dividend and generally reduce the stockholder's basis in the common stock. To the extent that a dividend exceeds both current and accumulated earnings and profits and the stockholder's basis in the common stock, it will generally be treated as gain from the sale or exchange of that stockholder's common stock. At the beginning of each year, we notify our stockholders of the taxability of the common stock dividends paid during the preceding year.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases We lease certain data center facilities and equipment from third parties. Operating lease expense was $7.5 million , $7.4 million and $6.7 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Certain of these leases provide for renewal options with fixed rent escalations beyond the initial lease term. At December 31, 2016 , future minimum lease payments required under operating leases having initial or remaining non-cancellable lease terms in excess of one year are as follows: IN MILLIONS 2017 $ 7.2 2018 4.4 2019 1.9 2020 1.4 2021 0.5 Thereafter 4.7 Total $ 20.1 Standby Letters of Credit As of December 31, 2016 , CyrusOne Inc. had outstanding letters of credit of $7.1 million as security for obligations under the terms of the lease 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, 2016 and 2015 , no accruals for performance guarantees were required. Indemnifications During the normal course of business, CyrusOne has made certain indemnities, commitments and guarantees under which it may be required to make payments in relation to certain transactions. These include (i) intellectual property indemnities to customers in connection with the use, sale, and/or license of products and services, (ii) indemnities to vendors and service providers pertaining to claims based on negligence or willful misconduct and (iii) indemnities involving the representations and warranties in certain contracts. The majority of these indemnities, commitments and guarantees do not provide for any limitation on the maximum potential for future payments that we could be obligated to make. Purchase Commitments CyrusOne has non-cancellable purchase commitments for certain services and contracts related to construction of data center facilities and equipment. These agreements range from one to two years and provide for payments for early termination or require minimum payments for the remaining term. As of December 31, 2016 , the minimum commitments for these arrangements were approximately $171.2 million . Contingencies CyrusOne is involved in legal, tax and regulatory proceedings arising from the conduct of its business activities. Liabilities are established for loss contingencies when losses associated with such claims are deemed to be probable, and the loss can be reasonably estimated. Based on information currently available and consultation with legal counsel, we believe that the outcome of all claims will not, individually or in the aggregate, have a material effect on our financial statements.

Guarantors

Guarantors	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Guarantors	Guarantors CyrusOne Inc. CyrusOne LP and CyrusOne Finance Corp., as “LP Co-issuer” and “Finance Co-issuer,” respectively (together, the Issuers), had $477.3 million aggregate principal amount of 6.375% senior notes outstanding, including bond premium, at December 31, 2016 . As of December 31, 2016 , the 6.375% senior notes are fully and unconditionally and jointly and severally guaranteed on a senior basis by CyrusOne Inc. (Parent Guarantor), CyrusOne GP (General Partner), and CyrusOne LP’s wholly owned subsidiaries, CyrusOne LLC, CyrusOne TRS Inc., CyrusOne Foreign Holdings LLC, Cervalis Holdings LLC, and Cervalis LLC (such subsidiaries, together the Guarantor Subsidiaries). None of CyrusOne LP's subsidiaries organized outside of the United States (collectively, together with CyrusOne Government Services LLC, the Non-Guarantor Subsidiaries) guarantee the 6.375% senior notes. Subject to the provisions of the indenture governing the 6.375% senior notes, in certain circumstances, a Guarantor may be released from its guarantee obligation, including: • upon the sale or other disposition (including by way of consolidation or merger) of such Guarantor or of all of the capital stock of such Guarantor such that such Guarantor is no longer a restricted subsidiary under the indenture, • upon the sale or disposition of all or substantially all of the assets of the Guarantor, • upon the LP Co-issuer designating such Guarantor as an unrestricted subsidiary under the terms of the indenture, • if such Guarantor is no longer a guarantor or other obligor of any other indebtedness of the LP Co-issuer or the Parent Guarantor, and • upon the defeasance or discharge of the 6.375% senior notes in accordance with the terms of the indenture. The entity structure of each Issuer and guarantor of the 6.375% senior notes is described below. CyrusOne Inc. – CyrusOne Inc. is the Parent Guarantor and became a separate registrant with the SEC upon completion of its IPO on January 24, 2013. CyrusOne GP – CyrusOne GP is the general partner and 1% owner of CyrusOne LP and has no other assets or operations. Issuers – The Issuers are CyrusOne LP and CyrusOne Finance Corp. CyrusOne Finance Corp., a wholly owned subsidiary of CyrusOne LP, was formed for the sole purpose of acting as co-issuer of the 6.375% senior notes and has no other assets or operations. CyrusOne LP, in addition to being the co-issuer of the 6.375% senior notes, is also the 100% owner, either directly or indirectly, of the Guarantor Subsidiaries and Non-Guarantor Subsidiaries. Guarantor Subsidiaries – The guarantors of the 6.375% senior notes include CyrusOne LLC, CyrusOne TRS Inc., CyrusOne Foreign Holdings LLC, Cervalis and Cervalis LLC (the Guarantor Subsidiaries) agreed to provide unconditional guarantees of the issuers’ obligations under the 6.375% senior notes. The guarantee of each Guarantor Subsidiary is (i) a senior unsecured obligation of such Guarantor Subsidiary, (ii) pari passu in right of payment with any existing and future unsecured senior indebtedness of such Guarantor Subsidiary, (iii) senior in right of payment to any future subordinated indebtedness of such Guarantor Subsidiary and (iv) effectively subordinated in right of payment to all existing and future secured indebtedness of such Guarantor Subsidiary, to the extent of the value of the collateral securing that indebtedness. CyrusOne LLC, together with CyrusOne Foreign Holdings LLC, directly or indirectly owns 100% of the Non-Guarantor Subsidiaries. Non-Guarantor Subsidiaries consist of wholly owned subsidiaries which conduct operations in the United Kingdom and Singapore, as well as CyrusOne Government Services LLC, a Delaware limited liability company and wholly owned subsidiary of CyrusOne LP. The following schedules present the balance sheets as of December 31, 2016 and 2015 , and the statements of operations and comprehensive income (loss) for the years ended December 31, 2016 , 2015 and 2014 , and the statements of cash flows for the years ended December 31, 2016 , 2015 and 2014 for the Parent Guarantor, General Partner, LP Co-issuer, Finance Co-issuer, Guarantor Subsidiaries, and Non-Guarantor Subsidiaries. The condensed consolidating statements of cash flows for the year ended December 31, 2015 , includes the acquisition of Cervalis in July 2015. The results for Cervalis are included in the Guarantor Subsidiaries financial statements subsequent to the acquisition. Consolidating Balance Sheets IN MILLIONS As of December 31, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 142.7 $ — $ — $ 142.7 Buildings and improvements — — — — 973.6 34.1 1.2 1,008.9 Equipment — — — — 1,036.8 1.0 5.1 1,042.9 Construction in progress — — — — 406.4 — 0.7 407.1 Subtotal — — — — 2,559.5 35.1 7.0 2,601.6 Accumulated depreciation — — — — (571.3 ) (7.2 ) — (578.5 ) Net investment in real estate — — — — 1,988.2 27.9 7.0 2,023.1 Cash and cash equivalents — — — — 13.4 1.2 — 14.6 Investment in subsidiaries 1,170.3 11.7 1,376.1 — 2.0 — (2,560.1 ) — Rent and other receivables — — — — 81.8 1.5 — 83.3 Intercompany receivable 18.6 — 1,057.7 — — 0.5 (1,076.8 ) — Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 150.2 — — 150.2 Other assets — — — — 123.4 2.7 — 126.1 Total assets $ 1,188.9 $ 11.7 $ 2,433.8 $ — $ 2,814.1 $ 33.8 $ (3,629.9 ) $ 2,852.4 Accounts payable and accrued expenses $ 33.9 $ — $ 4.8 — $ 187.7 $ 0.7 $ — $ 227.1 Deferred revenue — — — — 76.0 0.7 — 76.7 Intercompany payable — — 18.6 — 1,058.2 — (1,076.8 ) — Capital lease obligations — — — — 5.6 5.2 — 10.8 Long-term debt — — 1,240.1 — — — — 1,240.1 Lease financing arrangements — — — — 110.5 25.2 — 135.7 Total liabilities 33.9 — 1,263.5 — 1,438.0 31.8 (1,076.8 ) 1,690.4 Total stockholders' equity 1,155.0 11.7 1,170.3 — 1,376.1 2.0 (2,553.1 ) 1,162.0 Total liabilities and equity $ 1,188.9 $ 11.7 $ 2,433.8 $ — $ 2,814.1 $ 33.8 $ (3,629.9 ) $ 2,852.4 IN MILLIONS As of December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 93.0 $ — $ — $ 93.0 Buildings and improvements — — — — 865.6 39.6 0.1 905.3 Equipment — — — — 594.7 0.9 2.6 598.2 Construction in progress — — — — 229.8 0.1 1.2 231.1 Subtotal — — — — 1,783.1 40.6 3.9 1,827.6 Accumulated depreciation — — — — (426.0 ) (9.6 ) — (435.6 ) Net investment in real estate — — — — 1,357.1 31.0 3.9 1,392.0 Cash and cash equivalents — — — — 10.4 3.9 — 14.3 Investment in subsidiaries 817.7 8.2 850.6 — 0.7 — (1,677.2 ) — Restricted cash — — — — 1.5 — — 1.5 Rent and other receivables — — — — 74.8 1.3 — 76.1 Intercompany receivable — — 991.3 — — — (991.3 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 170.3 — — 170.3 Other assets — — — — 85.3 2.7 — 88.0 Total assets $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Accounts payable and accrued expenses $ — $ — $ 29.2 — $ 106.8 $ 0.6 $ — $ 136.6 Deferred revenue — — — — 78.0 0.7 — 78.7 Intercompany payable — — — — 991.3 — (991.3 ) — Capital lease obligations — — — — 6.1 6.1 — 12.2 Long-term debt — — 995.0 — 1.5 — — 996.5 Lease financing arrangements — — — — 119.2 30.8 — 150.0 Total liabilities — — 1,024.2 — 1,302.9 38.2 (991.3 ) 1,374.0 Total stockholders' equity 817.7 8.2 817.7 — 850.6 0.7 (1,673.3 ) 821.6 Total liabilities and equity $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Consolidating Statements of Operations and Comprehensive Income (Loss) IN MILLIONS Year Ended December 31, 2016 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 523.7 $ 5.4 $ — $ 529.1 Costs and expenses: Property operating expenses — — — — 185.2 2.3 — 187.5 Sales and marketing — — — — 16.9 — — 16.9 General and administrative — — — — 60.5 0.2 — 60.7 Depreciation and amortization — — — — 185.3 (1.4 ) — 183.9 Transaction and acquisition integration costs — — — — 4.3 — — 4.3 Asset impairments and loss on disposal — — — — 5.3 — — 5.3 Total costs and expenses — — — — 457.5 1.1 — 458.6 Operating income — — — — 66.2 4.3 — 70.5 Interest expense — — 49.1 — — 2.8 (3.1 ) 48.8 Income (loss) income before income taxes — — (49.1 ) — 66.2 1.5 3.1 21.7 Income tax expense — — — — (1.8 ) — — (1.8 ) Equity (loss) earnings related to investment in subsidiaries 15.9 0.2 65.0 — 0.6 — (81.7 ) — Net income (loss) 15.9 0.2 15.9 — 65.0 1.5 (78.6 ) 19.9 Net income (loss) attributed to common stockholders 15.9 0.2 15.9 — 65.0 1.5 (78.6 ) 19.9 Other comprehensive loss — — — — — (0.9 ) — (0.9 ) Comprehensive income (loss) attributable to common stockholders $ 15.9 $ 0.2 $ 15.9 $ — $ 65.0 $ 0.6 $ (78.6 ) $ 19.0 IN MILLIONS Year Ended December 31, 2015 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 393.8 $ 5.5 $ — $ 399.3 Costs and expenses: Property operating expenses — — — — 146.0 2.7 — 148.7 Sales and marketing — — — — 12.0 0.1 — 12.1 General and administrative — — — — 46.6 — — 46.6 Depreciation and amortization — — — — 138.7 2.8 — 141.5 Transaction and acquisition integration costs — — — — 14.1 — — 14.1 Asset impairments and loss on disposal — — — — 13.5 — — 13.5 Total costs and expenses — — — — 370.9 5.6 — 376.5 Operating income (loss) — — — — 22.9 (0.1 ) — 22.8 Interest expense — — 39.7 — — 3.2 (1.7 ) 41.2 Income (loss) before income taxes — — (39.7 ) — 22.9 (3.3 ) 1.7 (18.4 ) Income tax expense — — — — (1.8 ) — — (1.8 ) Equity (loss) earnings related to investment in subsidiaries (17.1 ) (0.2 ) 17.8 — (3.3 ) — 2.8 — Net income (loss) (17.1 ) (0.2 ) (21.9 ) — 17.8 (3.3 ) 4.5 (20.2 ) Noncontrolling interest in net loss — — — — — — 4.8 4.8 Net income (loss) attributed to common stockholders (17.1 ) (0.2 ) (21.9 ) — 17.8 (3.3 ) 9.3 (15.4 ) Other comprehensive loss — — — — — (0.2 ) — (0.2 ) Comprehensive income (loss) attributable to common stockholders $ (17.1 ) $ (0.2 ) $ (21.9 ) $ — $ 17.8 $ (3.5 ) $ 9.3 $ (15.6 ) IN MILLIONS Year Ended December 31, 2014 Parent (1) General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 325.1 $ 5.8 $ — $ 330.9 Costs and expenses: Property operating expenses — — — — 121.9 2.6 — 124.5 Sales and marketing — — — — 12.6 0.2 — 12.8 General and administrative — — — — 34.2 0.4 — 34.6 Depreciation and amortization — — — — 115.0 3.0 — 118.0 Transaction and acquisition integration costs — — — — 1.0 — — 1.0 Total costs and expenses — — — — 284.7 6.2 — 290.9 Operating income (loss) — — — — 40.4 (0.4 ) — 40.0 Interest expense — — 38.2 — — 3.5 (2.2 ) 39.5 Loss on extinguishment of debt — — 13.6 — — — — 13.6 (Loss) income before income taxes — — (51.8 ) — 40.4 (3.9 ) 2.2 (13.1 ) Income tax expense — — — — (1.4 ) — — (1.4 ) Equity (loss) earnings related to investment in subsidiaries (10.0 ) (0.2 ) 35.1 — (3.9 ) — (21.0 ) — Net income (loss) (10.0 ) (0.2 ) (16.7 ) — 35.1 (3.9 ) (18.8 ) (14.5 ) Noncontrolling interest in net loss — — — — — — 6.7 6.7 Net (loss) income attributed to common stockholders (10.0 ) (0.2 ) (16.7 ) — 35.1 (3.9 ) (12.1 ) (7.8 ) Other comprehensive loss — — — — — (0.3 ) — (0.3 ) Other comprehensive loss attributable to noncontrolling interests — — — — — — 0.1 0.1 Comprehensive loss attributable to common stockholders $ (10.0 ) $ (0.2 ) $ (16.7 ) $ — $ 35.1 $ (4.2 ) $ (12.0 ) $ (8.0 ) Consolidating Statements of Cash Flows IN MILLIONS Year Ended December 31, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net income (loss) $ 15.9 0.2 $ 15.9 $ — 65.0 $ 1.5 $ (78.6 ) $ 19.9 Equity earnings (loss) related to investment in subsidiaries (15.9 ) (0.2 ) (65.0 ) — (0.6 ) — 81.7 — Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 185.3 (1.4 ) — 183.9 Stock-based compensation expense — — — — 12.3 — — 12.3 Non-cash interest expense — — 3.7 — — — 1.1 4.8 Provision for bad debt — — — — 1.6 — — 1.6 Asset impairments and loss on disposal — — — — 5.3 — — 5.3 Change in operating assets and liabilities: Rent receivables and other assets — — — — (51.5 ) (0.2 ) — (51.7 ) Accounts payable and accrued expenses — — — — 6.9 0.1 — 7.0 Deferred revenues — — — — (2.5 ) — — (2.5 ) Net cash provided by (used in) operating activities — — (45.4 ) — 221.8 — 4.2 180.6 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (131.1 ) — — (131.1 ) Capital expenditures - other development — — — — (598.9 ) (1.1 ) — (600.0 ) Changes in restricted cash — — — — 1.5 — — 1.5 Investment in subsidiaries (448.2 ) (4.5 ) (448.2 ) — — — 900.9 — Return of investment 112.3 — — — — — (112.3 ) — Intercompany borrowings 15.3 — (66.3 ) — — (0.5 ) 51.5 — Net cash provided by (used in) investing activities (320.6 ) (4.5 ) (514.5 ) — (728.5 ) (1.6 ) 840.1 (729.6 ) Cash flows from financing activities: Issuance of common stock 448.7 — — — — — — 448.7 Stock issuance costs (1.6 ) — — — — — — (1.6 ) Dividends paid (112.3 ) — (114.3 ) — — — 112.3 (114.3 ) Intercompany borrowings — — (15.3 ) — 71.0 — (55.7 ) — Borrowings from credit facility — — 710.0 — — — — 710.0 Payments on credit facility — — (460.0 ) — — — — (460.0 ) Payments on capital leases and lease financing arrangements — — — — (8.0 ) (1.1 ) — (9.1 ) Tax payment upon exercise of equity awards (14.2 ) — — — — — — (14.2 ) Contributions/distributions from parent — 4.5 448.2 — 448.2 — (900.9 ) — Payment of note payable — — — — (1.5 ) — — (1.5 ) Debt issuance costs — — (8.7 ) — — — — (8.7 ) Net cash provided by (used in) financing activities 320.6 4.5 559.9 — 509.7 (1.1 ) (844.3 ) 549.3 Net increase (decrease) in cash and cash equivalents — — — — 3.0 (2.7 ) — 0.3 Cash and cash equivalents at beginning of period — — — — 10.4 3.9 — 14.3 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 13.4 $ 1.2 $ — $ 14.6 IN MILLIONS Year Ended December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net (loss) income $ (17.1 ) (0.2 ) $ (21.9 ) $ — 17.8 $ (3.3 ) $ 4.5 $ (20.2 ) Equity earnings (loss) related to investment in subsidiaries 17.1 0.2 (17.8 ) — 3.3 — (2.8 ) — Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 138.7 2.8 — 141.5 Stock-based compensation expense — — — — 14.4 — — 14.4 Non-cash interest expense — — 3.4 — — — — 3.4 Asset impairments and loss on disposal — — — — 13.5 — — 13.5 Change in operating assets and liabilities: Rent receivables and other assets — — — — (26.1 ) 2.2 — (23.9 ) Accounts payable and accrued expenses — — 16.7 — (9.8 ) 0.1 — 7.0 Deferred revenues — — — — 5.3 0.1 — 5.4 Due to affiliates — — — — (0.9 ) — — (0.9 ) Net cash (used in) provided by operating activities — — (19.6 ) — 156.2 1.9 1.7 140.2 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (17.3 ) — — (17.3 ) Capital expenditures - other development — — — — (216.7 ) (0.5 ) — (217.2 ) Business acquisition, net of cash acquired — — — — (398.4 ) — — (398.4 ) Release of restricted cash — — — — 7.3 — — 7.3 Investment in subsidiaries (203.1 ) (2.0 ) (203.1 ) — (0.4 ) — 408.6 — Return of investment 62.6 — 102.0 — (17.9 ) — (146.7 ) — Intercompany borrowings — — (348.4 ) — — — 348.4 — Net cash provided by (used in) investing activities (140.5 ) (2.0 ) (449.5 ) — (643.4 ) (0.5 ) 610.3 (625.6 ) Cash flows from financing activities: Issuance of common stock 799.5 — — — — — — 799.5 Stock issuance costs (0.8 ) — — — — — — (0.8 ) Acquisition of operating partnership units (596.4 ) — — — — — — (596.4 ) Dividends paid (61.0 ) — (80.8 ) — (80.8 ) — 141.8 (80.8 ) Intercompany borrowings — — — — 348.4 — (348.4 ) — Borrowings from credit facility — — 260.0 — — — — 260.0 Proceeds from issuance of debt — — 103.8 — — — — 103.8 Payments on credit facility — — (10.0 ) — — — — (10.0 ) Payments on capital leases and lease financing arrangements — — — — (5.0 ) (0.9 ) — (5.9 ) Tax payment upon exercise of equity awards (0.8 ) — — — — — — (0.8 ) Contributions/distributions from parent — 2.0 201.5 — 201.5 0.4 (405.4 ) — Debt issuance costs — — (5.4 ) — — — — (5.4 ) Net cash (used in) provided by financing activities 140.5 2.0 469.1 — 464.1 (0.5 ) (612.0 ) 463.2 Net (decrease) increase in cash and cash equivalents — — — — (23.1 ) 0.9 — (22.2 ) Cash and cash equivalents at beginning of period — — — — 33.5 3.0 — 36.5 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 10.4 $ 3.9 $ — $ 14.3 IN MILLIONS Year Ended December 31, 2014 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Net (loss) income $ (10.0 ) (0.2 ) $ (16.7 ) $ — 35.1 $ (3.9 ) $ (18.8 ) $ (14.5 ) Equity earnings (loss) related to investment in subsidiaries 10.0 0.2 (35.1 ) — 3.9 — 21.0 — Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 115.0 3.0 — 118.0 Stock-based compensation expense — — — — 10.3 — — 10.3 Non-cash interest expense — — 3.4 — — — — 3.4 Provision for bad debt — — — — 0.8 — — 0.8 Loss on extinguishment of debt — — 13.6 — — — — 13.6 Change in operating assets and liabilities: Rent receivables and other assets — — 0.4 — (35.3 ) (2.1 ) — (37.0 ) Accounts payable and accrued expenses — — 4.7 — 2.1 0.1 — 6.9 Due to affiliates — — — — (0.2 ) — — (0.2 ) Deferred revenues — — — — 10.0 (0.2 ) — 9.8 Net cash provided by (used in) operating activities — — (29.7 ) — 141.7 (3.1 ) 2.2 111.1 Cash flows from investing activities: Capital expenditures - other development — — — — (283.9 ) (0.3 ) — (284.2 ) Return of investment 25.2 — 97.3 — (45.4 ) — (77.1 ) — Intercompany receipts — — 180.2 — — — (180.2 ) — Intercompany borrowings — — (315.0 ) — — — 315.0 — Net cash (used in) provided by investing activities 25.2 — (37.5 ) — (329.3 ) (0.3 ) 57.7 (284.2 ) Cash flows from financing activities: Issuance of common stock 356.0 — — — — — — 356.0 Stock issuance costs (1.3 ) — — — — — — (1.3 ) Acquisition of operating partnership units (355.9 ) — — — — — — (355.9 ) Dividends paid (24.0 ) — (50.9 ) — (50.9 ) — 74.9 (50.9 ) Intercompany borrowings — — — — 315.0 — (315.0 ) — Intercompany payments — — — — (180.2 ) — 180.2 — Borrowings from credit facility — — 315.0 — — — — 315.0 Payments on credit facility — — (30.0 ) — — — — (30.0 ) Payments on senior notes — — (150.2 ) — — — — (150.2 ) Payments on capital leases obligations — — — — (2.4 ) (0.6 ) — (3.0 ) Payments on financing arrangements — — — — (0.7 ) (0.2 ) — (0.9 ) Payment of debt extinguishment costs — — (12.8 ) — — — — (12.8 ) Contributions/distributions from parent — — 1.3 — (6.5 ) 5.2 — — Debt issuance costs — — (5.2 ) — — — — (5.2 ) Net cash provided by (used in) financing activities (25.2 ) — 67.2 — 74.3 4.4 (59.9 ) 60.8 Net (decrease) increase in cash and cash equivalents — — — — (113.3 ) 1.0 — (112.3 ) Cash and cash equivalents at beginning of period — — — — 146.8 2.0 — 148.8 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 33.5 $ 3.0 $ — $ 36.5

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 : IN MILLIONS, except per share amounts 2016 First Quarter Second Quarter Third Quarter Fourth Total Revenue $ 117.8 $ 130.1 $ 143.8 $ 137.4 $ 529.1 Operating income 17.9 21.1 18.8 12.7 70.5 Net income 5.6 9.1 4.4 0.8 19.9 Net income attributed to common stockholders 5.6 9.1 4.4 0.8 19.9 Basic and diluted income per share $ 0.07 $ 0.11 $ 0.05 $ 0.01 $ 0.24 IN MILLIONS, except per share amounts 2015 First Second Quarter Third Quarter Fourth Quarter Total Revenue $ 85.7 $ 89.1 $ 111.2 $ 113.3 $ 399.3 Operating income 1.6 2.6 7.5 11.1 22.8 Net loss (7.2 ) (6.5 ) (5.3 ) (1.2 ) (20.2 ) Net loss attributed to common stockholders (4.3 ) (5.5 ) (4.6 ) (1.0 ) (15.4 ) Basic and diluted loss per share (a) $ (0.12 ) $ (0.11 ) $ (0.08 ) $ (0.02 ) $ (0.33 ) (a) The basic and diluted income (loss) per share for 2015 was $(0.30) compared to $(0.33) due to the impact of the 14.3 million shares of common stock issued during the secondary offering in April 2015, and the 6.0 million shares of common stock issued during the secondary offering in June 2015.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 6, 2017, CyrusOne Inc. announced the execution of a definitive agreement to purchase two data centers located in Raleigh-Durham, North Carolina and Somerset, New Jersey for a total purchase price of $490 million , excluding transaction-related costs, in an all cash transaction. The transaction is expected to close in the next 30 to 45 days, subject to the fulfillment of customary closing conditions. These facilities add more than 160,000 colocation square feet and approximately 21 megawatts of power capacity to our portfolio. This transaction is expected to provide enhanced geographic diversification, establishing a presence in the Raleigh-Durham and expanding our footprint in the Northeast. On February 22, 2017, the Company notified Goldman, Sachs & Co. that it has elected full physical settlement of the previously announced forward sale agreements entered into by the Company on August 10, 2016 relating to, in the aggregate, 4.4 million shares of the Company’s common stock. The Company expects settlement to occur on February 27, 2017. Upon settlement, the Company expects to issue and sell 4.4 million shares of its common stock to Goldman, Sachs & Co., in its capacity as forward purchaser, in exchange for net proceeds of approximately $211 million , in accordance with the provisions of the forward sales agreements.

Schedule II. Valuation and Qual

Schedule II. Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
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 2016 $ 1.0 $ 1.6 $ (0.5 ) $ 2.1 2015 1.0 — — 1.0 2014 0.5 0.8 (0.3 ) 1.0 Deferred Tax Valuation Allowance 2016 $ 6.3 $ 0.2 $ — $ 6.5 2015 5.7 0.6 — 6.3 2014 3.6 2.1 — 5.7

Schedule III. Real Estate Prope

Schedule III. Real Estate Properties and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2016
SEC Schedule III, 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, 2016 (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 Dallas - Carrollton $ 16.1 $ — $ — $ — $ 57.6 $ 154.0 $ 16.1 $ 57.6 $ 154.0 $ 54.3 2012 Houston - Houston West I 1.4 21.4 0.1 — 63.6 48.3 1.4 85.0 48.4 63.2 2010 Dallas - Lewisville — 46.2 2.2 — 30.5 31.5 — 76.7 33.7 53.4 2010 Cincinnati - 7th Street 0.9 42.2 — — 68.4 21.0 0.9 110.6 21.0 80.7 1999 Northern Virginia - Sterling II — — — — 28.7 111.8 — 28.7 111.8 6.0 2013 Totowa - Madison — 28.3 45.6 — — 5.2 — 28.3 50.8 11.7 2015 Wappingers Falls I — 9.9 13.3 — 1.4 3.8 — 11.3 17.1 5.4 2015 Cincinnati - North Cincinnati 4.0 12.3 — — 65.0 9.0 4.0 77.3 9.0 32.1 2008 Houston - Houston West II 2.0 — — 0.8 23.1 49.0 2.8 23.1 49.0 22.2 2013 San Antonio I 4.6 3.0 — — 29.1 33.6 4.6 32.1 33.6 21.4 2011 Chicago - Aurora I 2.4 26.0 97.3 — 2.5 2.6 2.4 28.5 99.9 9.4 2016 Phoenix - Chandler II — — — — 16.1 38.8 — 16.1 38.8 10.5 2014 Houston - Galleria — 56.0 2.0 — 12.6 14.6 — 68.6 16.6 43.3 2010 Florence 2.2 7.7 — — 34.2 4.9 2.2 41.9 4.9 24.9 2005 Austin II 2.0 — — — 23.4 6.6 2.0 23.4 6.6 12.1 2011 San Antonio II 6.7 — — 0.3 29.0 59.4 7.0 29.0 59.4 3.6 2013 Northern Virginia - Sterling I 6.9 — — 0.1 19.7 47.2 7.0 19.7 47.2 10.9 2013 Phoenix - Chandler I 14.8 — — — 56.8 56.5 14.8 56.8 56.5 27.0 2011 Cincinnati - Hamilton — 9.5 — — 40.7 5.0 — 50.2 5.0 32.4 2007 Stamford - Riverbend — 4.3 13.2 — — 1.3 — 4.3 14.5 3.8 2015 Phoenix - Chandler III — 0.9 2.5 — 9.0 42.0 — 9.9 44.5 1.6 2016 London - Great Bridgewater — 16.5 — — 9.4 0.9 — 25.9 0.9 2.8 2011 Dallas - Midway — 1.8 — — 0.2 0.4 — 2.0 0.4 2.3 2010 Cincinnati - Mason — — — — 20.2 1.4 — 20.2 1.4 12.8 2004 Norwalk I — 18.3 25.3 — 0.7 1.3 — 19.0 26.6 5.0 2015 Dallas - Marsh — — — — 0.1 0.6 — 0.1 0.6 0.5 2010 Chicago - Lombard 0.7 3.2 — — 1.5 7.9 0.7 4.7 7.9 4.6 2008 Stamford - Omega — 3.2 0.6 — — 0.9 — 3.2 1.5 0.5 2015 Northern Virginia - Sterling IV 4.6 9.6 0.1 — 1.4 33.3 4.6 11.0 33.4 0.3 2016 Cincinnati - Blue Ash — 2.6 — — (2.0 ) 0.1 — 0.6 0.1 0.3 2009 Totowa - Commerce — 4.1 0.8 — — 0.6 — 4.1 1.4 0.5 2015 South Bend - Crescent — 1.1 — — 0.6 0.2 — 1.7 0.2 1.8 2008 Houston - Houston West III 18.3 — — 0.1 9.4 13.5 18.4 9.4 13.5 2.1 2013 Singapore - Inter Business Park — 9.0 — — (0.8 ) 0.1 — 8.2 0.1 4.4 2011 South Bend - Monroe — — — — 2.5 0.3 — 2.5 0.3 1.4 2007 Cincinnati - Goldcoast 0.6 — — (0.4 ) 4.0 0.1 0.2 4.0 0.1 2.9 2007 Austin III 3.3 — — — 9.7 31.8 3.3 9.7 31.8 3.3 2015 Austin I — 11.9 0.2 — (8.4 ) — — 3.5 0.2 3.1 2010 Dallas - Downtown — 0.1 — — (0.1 ) — — — — — 2010 Austin Land A 7.9 — — 0.1 — 0.2 8.0 — 0.2 — 2013 Chicago - Aurora Land A 2.6 — — — — — 2.6 — — — 2016 Phoenix - Chandler Land A 10.5 — — — — — 10.5 — — — 2016 Chicago - Aurora Land B 5.1 — — — — — 5.1 — — — 2016 Northern Virginia - Sterling Land A 24.1 — — — — — 24.1 — — — 2016 $ 141.7 $ 349.1 $ 203.2 $ 1.0 $ 659.8 $ 839.7 $ 142.7 $ 1,008.9 $ 1,042.9 $ 578.5 The aggregate cost of the total properties for federal income tax purposes was $3,095.0 million at December 31, 2016 . In addition, Construction in progress was $407.1 million as we continue to build data center facilities. Historical Cost and Accumulated Depreciation and Amortization The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2016 , 2015 and 2014 . Years Ended December 31, (amounts in millions) 2016 2015 2014 Property Balance—beginning of period $ 1,827.6 $ 1,378.4 $ 1,120.5 Disposals (12.0 ) (7.0 ) (0.1 ) Impairments (4.9 ) (9.3 ) — Additions (acquisitions and improvements) 790.9 465.5 258.0 Balance, end of period $ 2,601.6 $ 1,827.6 $ 1,378.4 Accumulated Depreciation Balance—beginning of period $ 435.6 $ 327.0 $ 236.7 Disposals (7.9 ) (2.7 ) — Impairments — — — Additions (depreciation and amortization expense) 150.8 111.3 90.3 Balance, end of period $ 578.5 $ 435.6 $ 327.0

Significant Accounting Polici34

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements as of December 31, 2016 and December 31, 2015 , and for the years ended December 31, 2016 , December 31, 2015 and December 31, 2014 , are prepared on a consolidated basis. In addition, the accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). All intercompany transactions and balances have been eliminated in consolidation. All prior year amounts have been presented to conform to current year's presentation. During the third quarter of 2016, the Company identified certain immaterial errors relating to prior periods where Depreciation and amortization and Interest expense were understated. In 2016, we corrected the cumulative amount of these errors which resulted in additional Depreciation and amortization of $2.6 million and related Interest expense of $1.1 million .
Use of Estimates	Use of Estimates —Preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates and assumptions are based on management’s knowledge of current events and actions that we may undertake in the future. Estimates are used in determining the fair value of leased real estate, including purchase price allocations for business combinations and asset acquisitions, the useful lives of real estate and other long-lived assets, future cash flows associated with goodwill and other long-lived asset impairment testing, deferred tax assets and liabilities and loss contingencies. Actual results may differ from these estimates and assumptions.
Investments in Real Estate	Investment in Real Estate —Investment in real estate consist of land, buildings, improvements and integral equipment utilized in our data center operations. Real estate acquired from third parties has been recorded at its acquisition cost. Additions and improvements which extend an asset’s useful life or increase its functionality are capitalized and depreciated over the asset’s remaining life. Maintenance and repairs are expensed as incurred. When we are involved in the construction of structural improvements to leased property, we are deemed the accounting owner of the leased real estate. In these instances, we bear substantially all the construction period risk, including managing or funding construction. As we have substantially all of the construction risks, we are deemed the “owner” of the asset under construction for accounting purposes during the construction period, and are therefore required to capitalize the construction costs on the accompanying consolidated balance sheets. At inception, the fair value of the building (excluding land) is recorded as an asset and the construction and modification costs to the building, that are not funded by us would be recorded as a liability. As construction progresses, the value of the asset and obligation increases by the fair value of the structural improvements. At completion of the construction, Sales-Leaseback Accounting under ASC 840-40-25 is also evaluated. Due to our continuing involvement with the lessor, Sales-Leaseback Accounting is precluded and the liability is not derecognized. When the asset is placed in service, depreciation commences, and the leased real estate is depreciated to the lesser of (i) its estimated fair value at the end of the term or (ii) the expected amount of the unamortized obligation at the end of the term. The associated obligation is presented as Lease financing arrangements in the accompanying consolidated balance sheets. When we are not deemed the accounting owner of leased real estate, we further evaluate the lease to determine whether the lease should be classified as a capital or operating lease. One of the following four characteristics must be present to classify a lease as a capital lease: (i) the lease transfers ownership of the property to the lessee by the end of the lease term, (ii) the lease contains a bargain purchase option, (iii) the lease term is equal to 75% or more of the estimated economic life of the leased property or (iv) the net present value of the lease payments is at least 90% of the fair value of the leased property. Construction in progress includes direct and indirect expenditures for the construction and expansion of our data centers and is stated at its acquisition cost. Independent contractors perform substantially all of the construction and expansion efforts of our data centers. Construction in progress includes costs incurred under construction contracts including project management services, engineering and schematic design services, design development, construction services and other construction-related fees and services. Interest, property taxes and certain labor costs are also capitalized during the construction of an asset. Capitalized interest in 2016 , 2015 , and 2014 was $10.6 million , $6.1 million , and $4.6 million , respectively. These costs are depreciated over the estimated useful life of the related assets. Depreciation is calculated using the straight-line method over the estimated useful life of the asset. Useful lives range from nine to thirty years for buildings, three to thirty years for building improvements, and two to twenty years for equipment. Leasehold improvements are amortized over the shorter of the asset’s useful life or the remaining lease term, including renewal options which are reasonably assured. Management reviews the carrying value of long-lived assets, including intangible assets with finite lives, when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Examples of such indicators may include a significant adverse change in the extent to which or manner in which the property is being used, an accumulation of costs significantly in excess of the amount originally expected for acquisition or development, or a history of operating or cash flow losses. When such indicators exist, we review an estimate of the undiscounted future cash flows expected to result from the use of an asset (or group of assets) and its eventual disposition and compare such amount to its carrying amount. We consider factors such as future operating income, leasing demand, competition and other factors. If our undiscounted net cash flows indicate that we are unable to recover the carrying value of the asset, an impairment loss is recognized. An impairment loss is measured as the amount by which the asset’s carrying value exceeds its estimated fair value.
Business Combinations	Business Combinations —The Company applies the purchase method for business combinations, where all tangible and identifiable intangible assets acquired and all liabilities assumed are recorded at fair value. Any excess purchase price is recorded as goodwill. Transaction costs associated with business combinations are expensed as incurred. Revenues and the results of operations of the acquired business are included in the accompanying consolidated financial statements commencing on the date of acquisition.
Cash and Cash Equivalents	Cash and Cash Equivalents —Cash and cash equivalents include all non-restricted cash held in financial institutions and other non-restricted highly liquid short-term investments with original maturities at acquisition of three months or less.
Restricted Cash	Restricted Cash —Restricted cash includes cash equivalents held to collateralize standby letters of credit and/or deposited in escrow to fund construction or pending potential acquisition transactions. In addition, we may have other cash that is not immediately available for use in current operations.
Goodwill	Goodwill —We evaluate goodwill for possible impairment at least annually or upon the occurrence of a triggering event. A triggering event is an event or circumstance that would more likely than not reduce the fair value of a reporting unit below its carrying amount, including sales of properties defined as businesses for which the relative size of the sold property is significant to the reporting unit, that could impact our goodwill impairment calculations. 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. 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. If the fair value is below the carrying value the Company estimates the fair value of all the assets and liabilities of the reporting unit and compares them to the carrying value to determine the amount of the impairment, Step two. During the fourth quarter of 2016, we applied Step zero and determined that it is more likely than not that the fair value of the reporting unit is more than the carrying amount and therefore determined that the two step method for goodwill impairment testing was not necessary. During fourth quarters of 2015 and 2014, we performed a detailed, quantitative assessment. Based on the Company's annual assessment of goodwill, no impairment has been recognized through December 31, 2016.
Long-Lived and Intangible Assets	Long-Lived and Intangible Assets —Intangible assets represent purchased assets that lack physical substance, but can be separately distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged, either on its own or in combination with a related contract, asset, or liability. Intangible assets with finite lives consist of trademarks, customer relationships, and a favorable leasehold interest.
Rent and Other Receivables	Rent and Other Receivables —Receivables consist principally of trade receivables from customers and are generally unsecured and due within 30 to 120 days . Unbilled receivables arise from services rendered but not yet billed. Expected credit losses associated with trade receivables are recorded as an allowance for doubtful accounts. 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. When internal collection efforts on accounts have been exhausted, the accounts are written-off and the associated allowance for doubtful accounts is reduced.
Deferred Leasing and Financing Costs	Deferred Leasing Costs —Deferred leasing costs are presented with Other assets in the accompanying consolidated balance sheets. Leasing commissions incurred at the commencement of a new lease are capitalized and amortized over the term of the customer lease. Amortization of deferred leasing costs is presented with Depreciation and amortization in the accompanying consolidated statements of operations. If a lease terminates prior to the expiration of the lease, the remaining unamortized cost is written off to amortization expense. As of December 31, 2016 and 2015 , deferred leasing costs were $23.3 million and $14.2 million , respectively. Deferred Financing Costs —Deferred financing costs include costs incurred in connection with issuance of debt, including our senior notes, term loans and revolving credit facilities. These costs include deferred financing costs associated with our revolving line of credit and are presented in the balance sheet as a direct reduction from the carrying amount of the debt liability. These financing costs are deferred and amortized to expense over the term of the instrument and are included as a component of Interest expense.
Lease Financing Arrangements	Lease Financing Arrangements —Lease financing arrangements represent leases of real estate where we are involved in the construction of structural improvements to develop buildings into data centers. When we bear substantially all the construction period risk, such as managing or funding construction, we are deemed to be the accounting owner of the leased property and, at the lease inception date, we are required to record at fair value the property and associated liability on our consolidated balance sheets. These transactions generally do not qualify for sale-leaseback accounting due to our continued involvement in these data center operations.
Revenue Recognition	Revenue Recognition —Colocation rentals are generally billed monthly in advance, and some contracts have escalating payments over the term of the contract. If rents escalate without the lessee gaining access to or control over additional leased space or power, and the lessee takes possession of, or controls the physical use of the property (including all contractually committed power) at the beginning of the lease term, the rental payments by the lessee are recognized as revenue on a straight-line basis over the term of the lease. If rents escalate because the lessee gains access to and control over additional leased space or power, revenue is recognized in proportion to the additional space or power in the periods that the lessee has control over the use of the additional space or power. The excess of revenue recognized over amounts contractually due is recognized in Other assets in the accompanying consolidated balance sheets. As of December 31, 2016 and 2015 , straight-line rent receivable was $67.6 million and $44.7 million , respectively. Revenue is recognized for services or products that are deemed separate units of accounting. When a customer makes an advance payment or they are contractually obligated to pay any amounts in advance, which is not deemed a separate unit of accounting, Deferred revenue is recorded. This revenue is recognized ratably over the expected term of the lease, unless the pattern of service suggests otherwise. As of December 31, 2016 and 2015 , Deferred revenue was $76.7 million and $78.7 million , respectively. Some of our leases are structured on a full-service gross basis in which the customer pays a fixed amount for both colocation rent and power. Other leases provide that the customer will be billed for power based upon actual usage which is separately metered. In both cases, this revenue is presented as Revenue in the accompanying consolidated statements of operations. Power is generally billed one month in arrears, and an estimate of this revenue is accrued in the month that the associated costs are incurred. We generally are not entitled to reimbursements for real estate taxes, insurance or other operating expenses. Generally, we receive an administrative fee when we manage the meters for our customers. Certain customer leases require specified levels of service or performance. If we fail to meet these service levels, our customers may be eligible to receive credits on their contractual billings. These credits are recognized against revenue when an event occurs that gives rise to such credits. Customer credits were immaterial for each of the years presented. A provision for doubtful accounts is recognized when the collection of contractual rent, straight-line rent or customer reimbursements are deemed to be uncollectible.
Sales and Marketing Expense	Sales and Marketing Expense —Sales and marketing expense is comprised of compensation and benefits associated with Sales and marketing personnel as well as advertising and marketing costs. Costs related to advertising expense were $4.1 million , $2.2 million and $2.9 million for the years ended December 31, 2016 ,
Depreciation and Amortization Expense	Depreciation and Amortization Expense —Depreciation expense is recognized over the estimated useful lives of real estate applying the straight-line method. The useful life of leased real estate and leasehold improvements is the lesser of the economic useful life of the asset or the term of the lease, including optional renewal periods if renewal of the lease is reasonably assured. The residual value of leased real estate is estimated as the lesser of (i) the expected fair value of the asset at the end of the lease term or (ii) the expected amount of the unamortized liability at the end of the lease term. Estimated useful lives are periodically reviewed. Depreciation expense was $157.7 million , $117.8 million and $95.8 million for the years ended December 31, 2016 , 2015 and 2014, respectively. Amortization expense is recognized over the estimated useful lives of finite-lived intangibles. Finite-lived intangibles include trademarks, customer relationships, favorable leasehold interests, trade names and deferred leasing costs. As of December 31, 2016 , the estimated remaining weighted average useful life of trademarks and customer relationships were 9 and 12 years, respectively. In addition, we have a favorable leasehold interest related to a land lease that is being amortized over the lease term of fifty-one years.
Transaction and Acquisition Integration Costs	Transaction and Acquisition Integration Costs —Transaction costs represent incremental legal, accounting and professional fees incurred in connection with consummated and potential business combinations. Transaction costs are expensed as incurred and do not include any recurring costs from our ongoing operations. Integration costs represent incremental costs to integrate a consummated acquisition.
Income Taxes	Income Taxes —The income tax provision consists of an amount for taxes currently payable and an amount for tax consequences deferred to future periods. CyrusOne Inc. has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the Code), commencing with our initial taxable year ending December 31, 2013. Provided we continue to meet the various qualification tests mandated under the Code, we are generally not subject to corporate level federal income tax on the earnings distributed currently to our stockholders. If we fail to qualify as a REIT in any taxable year, our taxable income will be subject to federal income tax at regular corporate rates and any applicable alternative minimum tax, and we may not be able to qualify as a REIT for four subsequent taxable years. While CyrusOne Inc. does not pay federal income taxes, we are still subject to foreign, state and local income taxes in the locations in which we conduct business. Our taxable REIT subsidiaries (each a TRS) are also subject to federal and state income taxes to the extent they earn taxable income. Deferred income taxes are recognized in certain entities. Deferred income taxes are provided for temporary differences in the basis between financial statement and income tax assets and liabilities. Deferred income taxes are recalculated annually at rates then in effect. Valuation allowances are recorded to reduce deferred tax assets to amounts that are more likely than not to be realized. The ultimate realization of the deferred tax assets depends upon our ability to generate future taxable income during the periods in which basis differences and other deductions become deductible and prior to the expiration of the net operating loss carryforwards. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various foreign, state and local jurisdictions. The Company's previous tax filings are subject to normal reviews by regulatory agencies until the related statute of limitations expires. With a few exceptions, the Company is no longer subject to U. S. federal, state or local examinations for years prior to 2012, and we have no liabilities for uncertain tax positions as of December 31, 2016 or 2015 .
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions —The financial position of foreign subsidiaries is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average rates of exchange during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive (loss) income. Gains or losses from foreign currency transactions are included in determining net income.
Comprehensive Income (Loss)	Comprehensive Income (Loss) —Comprehensive income (loss) represents the change in net assets of a company from transactions and other events from non-owner sources. Comprehensive income (loss) comprises all components of net income (loss) and all components of other comprehensive income (loss).
Earnings Per Share	Earnings Per Share —Basic EPS includes only the weighted average number of common shares outstanding during the period. Diluted EPS includes the weighted average number of common shares and the dilutive effect of stock options, restricted stock and share unit awards outstanding during the period, when such instruments are dilutive. Diluted EPS also includes the dilutive impact of shares issuable under the forward sales agreement using the treasury stock method. All outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are treated as participating in undistributed earnings with common shareholders. Awards of this nature are considered participating securities and the two-class method of computing basic and diluted EPS is applied. The forward contract entered into in August 2016 is not a participating security.
Stock-Based Compensation	Stock-Based Compensation —In conjunction with the IPO, our board of directors adopted the 2012 Long-Term Incentive Plan (LTIP), which was amended and restated by our stockholders on May 2, 2016. The LTIP is administered by the compensation committee of the board of directors, or the plan administrator. Awards issuable under the LTIP include common stock, restricted stock, stock options and other incentive awards. See Note 17 for additional details relating to these awards. Share-based compensation expense is based on the estimated grant-date fair value. CyrusOne Inc. recognizes share-based compensation expense on a straight-line basis over the requisite service period for time-based awards and on a graded vesting basis for performance-based awards. We adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (Subtopic 718) in the fourth quarter of 2016 and elected to account for forfeitures as they occur. Prior to the adoption of this ASU, CyrusOne estimated forfeitures based on historical activity, expected employee turnover, and other qualitative factors which were adjusted for changes in estimates and award vesting. Expenses for an award are recognized by the time they become fully vested. CyrusOne Inc. uses the Black-Scholes-Merton option pricing model to calculate the fair value of stock options. This option valuation model requires the use of subjective assumptions, including the estimated fair value of the underlying common stock, the expected stock price volatility, and the expected term of the option. The estimated fair value of the underlying common stock is based on third-party valuations. Our volatility estimates are based on a peer group of companies. We estimate the expected term of the awards to be the weighted average mid-point between the vesting date and the end of the contractual term. For interim and annual periods, we use our year-to-date actual results, financial forecasts, and other available information to estimate the probability of the award vesting based on the performance metrics.
Fair Value Measurements	Fair Value Measurements —Fair value measurements are utilized in accounting for business combinations and testing of goodwill and other long-lived assets for impairment and disclosures. Fair value of financial and non-financial assets and liabilities is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs used in the methodologies of measuring fair value for asset and liabilities, is as follows: Level 1—Observable inputs for identical instruments such as quoted market prices; Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs); and Level 3—Unobservable inputs that reflect our determination of assumptions that market participants would use in pricing the asset or liability. These inputs are developed based on the best information available, including our own data.
Business Segments	Business Segments —Business segments are components of an enterprise for which separate financial information is available and regularly viewed by the chief operating decision maker to assess performance and allocate resources. Our chief operating decision maker, the Company's Chief Executive Officer, reviews our financial information on an aggregate basis. Furthermore, our data centers have similar economic characteristics and customers across all geographic locations, and our service offerings have similar production processes, deliver services in a similar manner and use the same types of facilities and similar technologies. As a result, we have concluded that we have one reportable operating segment. As of December 31, 2016 , one customer represented approximately 10% of our revenue, with that customer representing 13% of our annualized rent.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Accounting Standards Update (ASU) No. 2014-09 (ASU 2014-09), Revenue from Contracts with Customers (Topic 606) On May 28, 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09, which supersedes the revenue recognition requirements in Topic 605, "Revenue Recognition" and most industry-specific guidance. The core principle of ASU 2014-09 is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. On July 9, 2015, the FASB deferred the effective date of ASU 2014-09. The new revenue standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017 (January 1, 2018 for CyrusOne) and allows either a full retrospective adoption to all periods presented or a modified retrospective adoption approach with the cumulative effect of initial application of the revised guidance recognized at the date of initial application. We are beginning to evaluate the adoption alternatives and the impact of ASU 2014-09 on our consolidated financial statements. Our initial evaluation is that revenue from base colocation services, which is a majority of our revenues, would not be impacted by the adoption of this standard and therefore, we are inclined to adopt the modified retrospective approach. Our initial conclusion may change when we complete our evaluation. ASU No. 2015-17 (ASU 2015-17), Income Taxes (Topic 740) In November 2015, the FASB issued guidance which amended the balance sheet classification requirements for deferred Taxes. The ASU requires an entity to classify all deferred tax liabilities and assets as noncurrent in the balance sheet. This guidance is effective for financial statements issued for annual periods beginning after December 15, 2016, including interim periods within those fiscal years. Early application is permitted. The Company adopted this standard in the fourth quarter of 2016 and applied it prospectively to all deferred tax assets and liabilities. The adoption had no effect on our consolidated financial statements because we have a full valuation allowance for our deferred tax assets. ASU No. 2016-01 (ASU 2016-01), Financial Instruments-Overall (Subtopic 825-10) In January 2016, the FASB amended its standards related to the accounting of certain financial instruments. This amendment addresses certain aspects of recognition, measurement, presentation and disclosure. The new rules will become effective for annual and interim periods beginning after December 15, 2017. Early adoption is not permitted. We are in the process of evaluating the impact the amendment will have on the consolidated financial statements. ASU No. 2016-02 (ASU 2016-02), Leases (Topic 842) On February 25, 2016, the FASB issued ASU 2016-02. Lessees will need to recognize on their balance sheet a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to current operating leases) while finance leases will result in a front-loaded expense pattern (similar to current capital leases). Classification will be based on criteria that are largely similar to those applied in current lease accounting. The standard is effective for CyrusOne beginning January 1, 2019. Early adoption is permitted. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Transition will require application of the new guidance at the beginning of the earliest comparative period presented. We are beginning to evaluate the impact of ASU 2016-02 on our consolidated financial statements and timing of adoption. ASU No. 2016-09 (ASU 2016-09), Improvements to Employee Share-Based Payment Accounting (Subtopic 718) In March 2016, the FASB issued guidance which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted. The Company adopted the guidance in the fourth quarter of 2016 with effective date of January 1, 2016 and elected the actual forfeiture rate which had an immaterial impact to our financial statements. ASU No. 2016-10 (ASU 2016-10), Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing (Topic 606) In April 2016, the FASB issued ASU 2016-10 in response to an issue communicated by the Transition Resource Group for Revenue Recognition (the TRG), a group which was formed by the FASB and the International Accounting Standards Board (IASB), (collectively, the Boards), whose objective is to inform the Boards of any issues that could arise with the implementation of a converged standard on recognition of revenue from contracts with customers. ASU 2016-10 does not change the core principal of the guidance in Topic 606, but adds clarification around identifying performance obligations and licensing. The amendments in this update affect the guidance in ASU 2014-09, Contracts with Customers (Topic 606), which is not yet effective, and therefore follow the same effective date and transition requirements. ASU 2014-09 is effective for CyrusOne on January 1, 2018 and allows either a full retrospective adoption to all periods presented or a modified retrospective adoption approach with the cumulative effect of initial application of the revised guidance recognized at the date of the initial application. We are currently evaluating the impact of ASU 2016-10 and ASU 2014-09 on the company consolidated financial statements. ASU No. 2016-12 (ASU 2016-12), Revenue from Contracts with Customers (Subtopic 606) In May 2016, the FASB issued guidance which amends certain aspects of the Board's new revenue standard, ASU 2014-09. The amendments include the collectibility of revenue, presentation of sales tax and other similar taxes collected from customers, contracts containing noncash considerations, and contract modifications and completed contracts at transition. The effective date and transition provisions are aligned with the requirements of ASU 2014-09 (as described above). We are currently evaluating the full impact of the new standard. ASU No. 2016-13 (ASU 2016-13), Measurement of Credit Losses on Financial Instruments (Subtopic 326) In June 2016, the FASB issued guidance which requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The amendments affect entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. The guidance is effective for annual periods beginning after December 15, 2019. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2016-15 (ASU 2016-15), Classification of Certain Cash Receipts and Cash Payments (Subtopic 230) In August 2016, the FASB issued guidance which addresses the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. The Company adopted the standard in the fourth quarter of 2016 with effective date of January 1, 2016. The adoption of the standard had no effect on our consolidated financial statements. ASU No. 2016-18 (ASU 2016-18), Restricted Cash (Subtopic 230) In November 2016, the FASB issued guidance which addresses the diversity in the classification and presentation of changes in restricted cash on the statement of cash flows. The amendment requires that a statement of cash flows explain the change during the period in the total of cash. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. We are currently evaluating the full impact of the new standard. ASU No. 2017-01 (ASU 2017-01), Business Combinations (Topic 805) In January 2017, the FASB issued guidance which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill and consolidation. Under this new guidance, the Company expects most acquisitions of investment property will meet the definition of an asset and, thus, be accounted for as asset acquisitions. Consistent with existing guidance, transaction costs associated with asset acquisitions are capitalized while transaction costs associated with business combinations are expensed as incurred. The guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. We are considering the early adoption of this standard in the first quarter of 2017.

Acquisitions and Purchase of 35

Acquisitions and Purchase of Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The consolidated financial statements include the operating results of Cervalis from the date of acquisition. The following table summarizes the estimated fair values of all assets acquired and liabilities assumed at the date of acquisition: Cash $ 1.1 Rent and other receivables 10.5 Restricted cash 8.8 Net investment in real estate 197.8 Goodwill 178.9 Customer relationships 117.4 Trade name 2.3 Other long-term assets 5.6 Total assets acquired 522.4 Current liabilities 18.3 Capital lease obligations 1.7 Long-term debt 1.5 Lease financing arrangements 101.4 Total liabilities 122.9 Net assets acquired attributable to CyrusOne Inc. 399.5 Cash acquired (1.1 ) Net cash paid at acquisition 398.4
Pro Forma	The unaudited pro forma combined historical results of CyrusOne, as if Cervalis had been acquired and the financing transactions had been consummated as of January 1, 2014 are: IN MILLIONS For the year ended December 31, 2015 2014 Revenue 438.6 399.0 Net loss (10.9 ) (17.2 ) Loss per share - basic and diluted (0.16 ) (0.35 )

Investment in Real Estate (Tabl

Investment in Real Estate (Tables)	12 Months Ended
	Dec. 31, 2016
Real Estate [Abstract]
Schedule of Gross Investment in Real Estate	A schedule of our gross investment in real estate follows: IN MILLIONS As of December 31, 2016 2015 Land Building and Equipment Land Building and Equipment Dallas - Carrollton $ 16.1 $ 57.6 $ 154.0 $ 16.1 $ 52.7 $ 116.5 Houston - Houston West I 1.4 85.0 48.4 1.4 84.8 46.4 Dallas - Lewisville — 76.7 33.7 — 76.6 24.9 Cincinnati - 7th Street 0.9 110.6 21.0 0.9 110.6 19.6 Northern Virginia - Sterling II — 28.7 111.8 — — — Totowa - Madison — 28.3 50.8 — 28.3 48.8 Wappingers Falls I — 11.3 17.1 — 11.3 14.4 Cincinnati - North Cincinnati 4.0 77.3 9.0 4.0 77.3 7.6 Houston - Houston West II 2.8 23.1 49.0 2.0 22.6 47.1 San Antonio I 4.6 32.1 33.6 4.6 32.1 33.0 Chicago - Aurora I 2.4 28.5 99.9 — — — Phoenix - Chandler II — 16.1 38.8 — 16.0 39.5 Houston - Galleria — 68.6 16.6 — 68.6 16.0 Florence 2.2 41.9 4.9 2.2 41.5 3.3 Austin II 2.0 23.4 6.6 2.0 23.2 5.7 San Antonio II 7.0 29.0 59.4 7.0 — 0.1 Northern Virginia - Sterling I 7.0 19.7 47.2 7.0 19.2 45.2 Phoenix - Chandler I 14.8 56.8 56.5 14.8 56.7 39.8 Cincinnati - Hamilton — 50.2 5.0 — 49.2 4.4 Stamford - Riverbend — 4.3 14.5 — 4.3 13.2 Phoenix - Chandler III — 9.9 44.5 — — — London - Great Bridgewater — 25.9 0.9 — 31.2 0.8 Dallas - Midway — 2.0 0.4 — 2.0 0.4 Cincinnati - Mason — 20.2 1.4 — 20.2 1.0 Norwalk I — 19.0 26.6 — 18.3 25.4 Dallas - Marsh — 0.1 0.6 — 0.1 0.6 Chicago - Lombard 0.7 4.7 7.9 0.7 4.7 7.6 Stamford - Omega — 3.2 1.5 — 3.2 1.5 Northern Virginia - Sterling IV 4.6 11.0 33.4 — — — Cincinnati - Blue Ash — 0.6 0.1 — 0.6 0.1 Totowa - Commerce — 4.1 1.4 — 4.1 1.0 South Bend - Crescent — 1.7 0.2 — 3.3 0.4 Houston - Houston West III 18.4 9.4 13.5 18.4 4.0 0.8 Singapore - Inter Business Park — 8.2 0.1 — 8.4 0.1 South Bend - Monroe — 2.5 0.3 — 2.5 0.3 Cincinnati - Goldcoast 0.2 4.0 0.1 0.6 6.7 0.1 Austin III 3.3 9.7 31.8 3.3 7.4 31.5 Austin I — 3.5 0.2 — 13.6 1.0 Austin Land A 8.0 — 0.2 8.0 — 0.1 Chicago - Aurora Land A 2.6 — — — — — Phoenix - Chandler Land A 10.5 — — — — — Chicago - Aurora Land B 5.1 — — — — — Northern Virginia - Sterling Land A 24.1 — — — — — Total $ 142.7 $ 1,008.9 $ 1,042.9 $ 93.0 $ 905.3 $ 598.2

Notes Receivable (Tables)

Notes Receivable (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Schedule of notes receivable	The carrying amount of notes receivable was $6.6 million and $2.5 million as of December 31, 2016 and 2015, respectively, and consisted of the following: IN MILLIONS For the year ended December 31, 2016 2015 Note 1 $ 3.9 $ — Note 2 2.2 2.5 Note 3 0.5 — Total $ 6.6 $ 2.5

Goodwill, Intangible and Othe38

Goodwill, Intangible and Other Long-Lived Assets (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 Weighted- Gross Carrying Amount Accumulated Amortization Total Gross Carrying Amount Accumulated Amortization Total Customer relationships 12 $ 247.1 $ (106.3 ) $ 140.8 $ 247.1 $ (87.5 ) $ 159.6 Trademark 9 7.4 (3.2 ) 4.2 7.4 (2.7 ) 4.7 Favorable leasehold interest 48 4.1 (0.5 ) 3.6 4.1 (0.4 ) 3.7 Trade name 2 2.3 (0.7 ) 1.6 2.3 — 2.3 Total $ 260.9 $ (110.7 ) $ 150.2 $ 260.9 $ (90.6 ) $ 170.3
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, 2017 : IN MILLIONS 2017 $ 18.1 2018 16.2 2019 13.8 2020 12.6 2021 11.6 Thereafter 77.9 Total $ 150.2

Long-Term Debt, Capital Lease39

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-term debt, Capital lease obligations and Lease financing arrangements	Long-term debt, Capital lease obligations and Lease financing arrangements presented in the accompanying consolidated financial statements consist of the following: IN MILLIONS For the year ended December 31, 2016 2015 Credit facilities: Revolving Credit Facility $ 235.0 $ 235.0 Term loans 550.0 300.0 6.375% senior notes due 2022, including bond premium 477.3 477.6 Notes payable — 1.5 Deferred financing costs (22.2 ) (17.6 ) Long-term debt 1,240.1 996.5 Capital lease obligations 10.8 12.2 Lease financing arrangements 135.7 150.0 Total $ 1,386.6 $ 1,158.7
Annual minimum payments associated with lease financing arrangements	The following table summarizes aggregate maturities of total future value and present value of the minimum payments associated with our Lease financing arrangements for the five years subsequent to December 31, 2016 , and thereafter: IN MILLIONS Future Value of Payments Interest Present Value of Payments 2017 $ 16.4 $ 7.9 $ 8.5 2018 14.3 7.5 6.8 2019 14.5 7.0 7.5 2020 25.4 6.4 19.0 2021 11.4 5.7 5.7 Thereafter 109.8 21.6 88.2 Total lease financing arrangements $ 191.8 $ 56.1 $ 135.7
Schedule of annual principal maturities of revolving credit facility, 6.375% Senior notes and capital leases	The following table summarizes aggregate maturities of the Revolving Credit Facility and Term Loans, 6.375% senior notes due 2022 and capital leases for the five years subsequent to December 31, 2016 , and thereafter: IN MILLIONS Revolving Credit Facility/Term Loan 6.375% Senior Notes Capital Leases Total 2017 $ — $ — $ 3.3 $ 3.3 2018 — — 1.7 1.7 2019 — — 1.5 1.5 2020 235.0 — 1.7 236.7 2021 250.0 — 1.6 251.6 Thereafter 300.0 474.8 1.0 775.8 Total debt $ 785.0 $ 474.8 $ 10.8 $ 1,270.6

Fair Value of Financial Instr40

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Carrying Value and Fair Value of Other Financial Instruments	The carrying value and fair value of other financial instruments are as follows: IN MILLIONS For the year ended December 31, 2016 2015 Carrying Value Fair Value Carrying Value Fair Value 6.375% senior notes due 2022 $ 477.3 $ 502.1 $ 477.6 $ 493.8 Revolving Credit Facility and Term Loans 785.0 785.0 535.0 535.0 Note payable — — 1.5 1.2

Noncontrolling Interest - Ope41

Noncontrolling Interest - Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Schedule of Ownership Interests in Operating Partnership	The following table shows the ownership interests as of December 31, 2015 , and the portion of net income (loss) and distributions for the year ended December 31, 2015 : For the year ended December 31, 2015 (in millions, except unit amount) The Company CBI Operating partnership units 72.6 — Ownership % 100.0 % — % Portion of net income (loss) $ (15.4 ) $ (4.8 ) Distributions $ (74.6 ) $ (16.3 )

Dividends (Tables)

Dividends (Tables)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Schedule of declared cash dividends on common shares and distributions on operating partnership units	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2016 and 2015 as presented in the table below: Record date Payment date Cash dividend per share or operating partnership unit March 27, 2015 April 15, 2015 $0.315 June 26, 2015 July 15, 2015 $0.315 September 25, 2015 October 15, 2015 $0.315 December 24, 2015 January 8, 2016 $0.315 March 25, 2016 April 15, 2016 $0.38 June 24, 2016 July 15, 2016 $0.38 September 30, 2016 October 14, 2016 $0.38 December 30, 2016 January 13, 2017 $0.38 In 2016 and 2015 , we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the years ended December 31, 2016 and 2015 : For the year ended December 31, 2016 2015 Common Stock dividend per share: Ordinary income $ 0.20 $ — Return of capital 1.26 1.16 Total dividend $ 1.46 $ 1.16

Customer Leases (Tables)

Customer Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below: IN MILLIONS 2017 $ 404.3 2018 306.3 2019 224.5 2020 179.9 2021 141.0 We lease certain data center facilities and equipment from third parties. Operating lease expense was $7.5 million , $7.4 million and $6.7 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Certain of these

Income (Loss) per Share (Tables

Income (Loss) per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) Per Share	The following table reflects the computation of basic and diluted net income (loss) per share: IN MILLIONS, except per share amounts Year Ended Year Ended Period Ended For December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator: Net income (loss) attributed to common stockholders $ 19.9 $ 19.9 $ (15.4 ) $ (15.4 ) $ (7.8 ) $ (7.8 ) Less: Restricted stock dividends (0.7 ) (0.7 ) (1.0 ) (1.0 ) (0.8 ) (0.8 ) Net income (loss) available to stockholders $ 19.2 $ 19.2 $ (16.4 ) $ (16.4 ) $ (8.6 ) $ (8.6 ) Denominator: Weighted average common outstanding-basic 78.3 78.3 54.3 54.3 29.2 29.2 Performance-based restricted stock (1)(2) 0.7 — — Weighted average shares outstanding-diluted 79.0 54.3 29.2 EPS: Net income (loss) per share-basic $ 0.24 $ (0.30 ) $ (0.30 ) Effect of dilutive shares: — — — Net income (loss) per share-diluted $ 0.24 $ (0.30 ) $ (0.30 ) (1) We have excluded 1.9 million weighted average shares of restricted stock, and 13.1 million of weighted average operating partnership units which are securities convertible into common stock from our diluted earnings per share as of December 31, 2015. These amounts were deemed anti-dilutive. (2) We have excluded 0.8 million weighted average shares of restricted stock, and 34.3 million of weighted average operating partnership units which are securities convertible into common stock from our diluted earnings per share as of December 31, 2014. These amounts were deemed anti-dilutive.

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Compensation Expense	Stock-based compensation expense was as follows: For the periods ended December 31, 2016 2015 2014 Founders $ 0.3 $ 5.2 $ 5.4 2013 Grants 0.1 1.2 1.2 2014 Grants 1.2 3.0 3.7 2015 Grants 3.5 5.0 — 2016 Grants 7.2 — — Total $ 12.3 $ 14.4 $ 10.3
Schedule of Restricted Stock Awards Activity	The following table summarizes the unvested restricted stock activity and the weighted average fair value of these shares at the date of grant for the year ended December 31, 2016 : For the year ended December 31, 2016 Shares Weighted Average Grant Date Fair Value Non-vested at January 1 1,585,010 $ 22.11 Granted 641,097 35.18 Vested (839,571 ) 21.10 Forfeited (111,823 ) 26.72 Non-vested at December 31 1,274,713 $ 28.95
Schedule of Unvested Stock Options	The following table summarizes the stock option activity for the year ended December 31, 2016 : For the year ended December 31, 2016 Options Weighted Average Exercise Price Outstanding at January 1 334,402 $ 26.44 Granted 222,461 36.99 Exercised (70,668 ) 26.00 Forfeited or expired (51,927 ) 26.65 Outstanding at December 31 434,268 31.89 Exercisable at December 31 138,157 27.27 Vested and expected to vest 434,268 $ 31.89
Schedule of Option Valuation Assumptions	The following table summarizes the stock option assumptions for the years ended December 31, 2016 , 2015 , and 2014 : 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 2014 $23.58 166,872 8.3 13,915 8.3 0.92% 3.4% 6.0 35% 2015 $23.58 142,556 7.3 43,460 7.3 0.92% 3.4% 6.0 35% $28.42 178,704 9.1 35,346 9.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 9.6 — 0.0 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% 2016 $23.58 67,601 6.3 67,601 6.3 0.92% 3.4% 6.0 35% $28.42 143,358 8.1 47,786 8.1 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $30.74 12,719 8.6 4,240 8.6 1.6% - 1.75% 4.4% 5.5-6.5 32.5% - 37.5% $36.99 210,590 9.1 18,530 9.1 1.47% - 1.64% 4.1% 5.5-6.5 27.5% - 35.0%

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following related party transactions are based on agreements and arrangements that were in place during the respective periods. Revenues and expenses for the periods presented were as follows: IN MILLIONS December 31, 2015 December 31, 2014 Revenue: Data center colocation agreement provided to CBT and CBTS $ 7.8 $ 6.4 229 West 7th Street lease provided to CBT 1.9 2.0 Goldcoast Drive/Parkway (Mason) lease 0.3 0.4 Transition services provided to CBTS (network interfaces) 0.3 0.4 Data center leases provided to CBTS 12.0 13.6 Total revenue $ 22.3 $ 22.8 Operating costs and expenses: Transition services agreement by CBTS $ 0.7 $ 0.8 Charges for services provided by CBT (connectivity) 1.0 1.0 209 West 7th Street rent provided by CBT 0.2 0.2 Total operating costs and expenses $ 1.9 $ 2.0

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of taxability of common stock dividends per share	We have declared cash dividends on common shares and distributions on operating partnership units for the years ended December 31, 2016 and 2015 as presented in the table below: Record date Payment date Cash dividend per share or operating partnership unit March 27, 2015 April 15, 2015 $0.315 June 26, 2015 July 15, 2015 $0.315 September 25, 2015 October 15, 2015 $0.315 December 24, 2015 January 8, 2016 $0.315 March 25, 2016 April 15, 2016 $0.38 June 24, 2016 July 15, 2016 $0.38 September 30, 2016 October 14, 2016 $0.38 December 30, 2016 January 13, 2017 $0.38 In 2016 and 2015 , we paid all our dividends in cash. The following table summarizes the taxability of our common stock dividends per share for the years ended December 31, 2016 and 2015 : For the year ended December 31, 2016 2015 Common Stock dividend per share: Ordinary income $ 0.20 $ — Return of capital 1.26 1.16 Total dividend $ 1.46 $ 1.16

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The future minimum lease payments to be received under non-cancellable operating leases, excluding month-to-month arrangements and submetered power, for the next five years are shown below: IN MILLIONS 2017 $ 404.3 2018 306.3 2019 224.5 2020 179.9 2021 141.0 We lease certain data center facilities and equipment from third parties. Operating lease expense was $7.5 million , $7.4 million and $6.7 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Certain of these

Guarantors (Tables)

Guarantors (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Consolidating Balance Sheet	Consolidating Balance Sheets IN MILLIONS As of December 31, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 142.7 $ — $ — $ 142.7 Buildings and improvements — — — — 973.6 34.1 1.2 1,008.9 Equipment — — — — 1,036.8 1.0 5.1 1,042.9 Construction in progress — — — — 406.4 — 0.7 407.1 Subtotal — — — — 2,559.5 35.1 7.0 2,601.6 Accumulated depreciation — — — — (571.3 ) (7.2 ) — (578.5 ) Net investment in real estate — — — — 1,988.2 27.9 7.0 2,023.1 Cash and cash equivalents — — — — 13.4 1.2 — 14.6 Investment in subsidiaries 1,170.3 11.7 1,376.1 — 2.0 — (2,560.1 ) — Rent and other receivables — — — — 81.8 1.5 — 83.3 Intercompany receivable 18.6 — 1,057.7 — — 0.5 (1,076.8 ) — Goodwill — — — — 455.1 — — 455.1 Intangible assets, net — — — — 150.2 — — 150.2 Other assets — — — — 123.4 2.7 — 126.1 Total assets $ 1,188.9 $ 11.7 $ 2,433.8 $ — $ 2,814.1 $ 33.8 $ (3,629.9 ) $ 2,852.4 Accounts payable and accrued expenses $ 33.9 $ — $ 4.8 — $ 187.7 $ 0.7 $ — $ 227.1 Deferred revenue — — — — 76.0 0.7 — 76.7 Intercompany payable — — 18.6 — 1,058.2 — (1,076.8 ) — Capital lease obligations — — — — 5.6 5.2 — 10.8 Long-term debt — — 1,240.1 — — — — 1,240.1 Lease financing arrangements — — — — 110.5 25.2 — 135.7 Total liabilities 33.9 — 1,263.5 — 1,438.0 31.8 (1,076.8 ) 1,690.4 Total stockholders' equity 1,155.0 11.7 1,170.3 — 1,376.1 2.0 (2,553.1 ) 1,162.0 Total liabilities and equity $ 1,188.9 $ 11.7 $ 2,433.8 $ — $ 2,814.1 $ 33.8 $ (3,629.9 ) $ 2,852.4 IN MILLIONS As of December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Land $ — $ — $ — $ — $ 93.0 $ — $ — $ 93.0 Buildings and improvements — — — — 865.6 39.6 0.1 905.3 Equipment — — — — 594.7 0.9 2.6 598.2 Construction in progress — — — — 229.8 0.1 1.2 231.1 Subtotal — — — — 1,783.1 40.6 3.9 1,827.6 Accumulated depreciation — — — — (426.0 ) (9.6 ) — (435.6 ) Net investment in real estate — — — — 1,357.1 31.0 3.9 1,392.0 Cash and cash equivalents — — — — 10.4 3.9 — 14.3 Investment in subsidiaries 817.7 8.2 850.6 — 0.7 — (1,677.2 ) — Restricted cash — — — — 1.5 — — 1.5 Rent and other receivables — — — — 74.8 1.3 — 76.1 Intercompany receivable — — 991.3 — — — (991.3 ) — Goodwill — — — — 453.4 — — 453.4 Intangible assets, net — — — — 170.3 — — 170.3 Other assets — — — — 85.3 2.7 — 88.0 Total assets $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6 Accounts payable and accrued expenses $ — $ — $ 29.2 — $ 106.8 $ 0.6 $ — $ 136.6 Deferred revenue — — — — 78.0 0.7 — 78.7 Intercompany payable — — — — 991.3 — (991.3 ) — Capital lease obligations — — — — 6.1 6.1 — 12.2 Long-term debt — — 995.0 — 1.5 — — 996.5 Lease financing arrangements — — — — 119.2 30.8 — 150.0 Total liabilities — — 1,024.2 — 1,302.9 38.2 (991.3 ) 1,374.0 Total stockholders' equity 817.7 8.2 817.7 — 850.6 0.7 (1,673.3 ) 821.6 Total liabilities and equity $ 817.7 $ 8.2 $ 1,841.9 $ — $ 2,153.5 $ 38.9 $ (2,664.6 ) $ 2,195.6
Consolidating Statements of Operations and Comprehensive Income (Loss)	Consolidating Statements of Operations and Comprehensive Income (Loss) IN MILLIONS Year Ended December 31, 2016 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 523.7 $ 5.4 $ — $ 529.1 Costs and expenses: Property operating expenses — — — — 185.2 2.3 — 187.5 Sales and marketing — — — — 16.9 — — 16.9 General and administrative — — — — 60.5 0.2 — 60.7 Depreciation and amortization — — — — 185.3 (1.4 ) — 183.9 Transaction and acquisition integration costs — — — — 4.3 — — 4.3 Asset impairments and loss on disposal — — — — 5.3 — — 5.3 Total costs and expenses — — — — 457.5 1.1 — 458.6 Operating income — — — — 66.2 4.3 — 70.5 Interest expense — — 49.1 — — 2.8 (3.1 ) 48.8 Income (loss) income before income taxes — — (49.1 ) — 66.2 1.5 3.1 21.7 Income tax expense — — — — (1.8 ) — — (1.8 ) Equity (loss) earnings related to investment in subsidiaries 15.9 0.2 65.0 — 0.6 — (81.7 ) — Net income (loss) 15.9 0.2 15.9 — 65.0 1.5 (78.6 ) 19.9 Net income (loss) attributed to common stockholders 15.9 0.2 15.9 — 65.0 1.5 (78.6 ) 19.9 Other comprehensive loss — — — — — (0.9 ) — (0.9 ) Comprehensive income (loss) attributable to common stockholders $ 15.9 $ 0.2 $ 15.9 $ — $ 65.0 $ 0.6 $ (78.6 ) $ 19.0 IN MILLIONS Year Ended December 31, 2015 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 393.8 $ 5.5 $ — $ 399.3 Costs and expenses: Property operating expenses — — — — 146.0 2.7 — 148.7 Sales and marketing — — — — 12.0 0.1 — 12.1 General and administrative — — — — 46.6 — — 46.6 Depreciation and amortization — — — — 138.7 2.8 — 141.5 Transaction and acquisition integration costs — — — — 14.1 — — 14.1 Asset impairments and loss on disposal — — — — 13.5 — — 13.5 Total costs and expenses — — — — 370.9 5.6 — 376.5 Operating income (loss) — — — — 22.9 (0.1 ) — 22.8 Interest expense — — 39.7 — — 3.2 (1.7 ) 41.2 Income (loss) before income taxes — — (39.7 ) — 22.9 (3.3 ) 1.7 (18.4 ) Income tax expense — — — — (1.8 ) — — (1.8 ) Equity (loss) earnings related to investment in subsidiaries (17.1 ) (0.2 ) 17.8 — (3.3 ) — 2.8 — Net income (loss) (17.1 ) (0.2 ) (21.9 ) — 17.8 (3.3 ) 4.5 (20.2 ) Noncontrolling interest in net loss — — — — — — 4.8 4.8 Net income (loss) attributed to common stockholders (17.1 ) (0.2 ) (21.9 ) — 17.8 (3.3 ) 9.3 (15.4 ) Other comprehensive loss — — — — — (0.2 ) — (0.2 ) Comprehensive income (loss) attributable to common stockholders $ (17.1 ) $ (0.2 ) $ (21.9 ) $ — $ 17.8 $ (3.5 ) $ 9.3 $ (15.6 ) IN MILLIONS Year Ended December 31, 2014 Parent (1) General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Revenue $ — $ — $ — $ — $ 325.1 $ 5.8 $ — $ 330.9 Costs and expenses: Property operating expenses — — — — 121.9 2.6 — 124.5 Sales and marketing — — — — 12.6 0.2 — 12.8 General and administrative — — — — 34.2 0.4 — 34.6 Depreciation and amortization — — — — 115.0 3.0 — 118.0 Transaction and acquisition integration costs — — — — 1.0 — — 1.0 Total costs and expenses — — — — 284.7 6.2 — 290.9 Operating income (loss) — — — — 40.4 (0.4 ) — 40.0 Interest expense — — 38.2 — — 3.5 (2.2 ) 39.5 Loss on extinguishment of debt — — 13.6 — — — — 13.6 (Loss) income before income taxes — — (51.8 ) — 40.4 (3.9 ) 2.2 (13.1 ) Income tax expense — — — — (1.4 ) — — (1.4 ) Equity (loss) earnings related to investment in subsidiaries (10.0 ) (0.2 ) 35.1 — (3.9 ) — (21.0 ) — Net income (loss) (10.0 ) (0.2 ) (16.7 ) — 35.1 (3.9 ) (18.8 ) (14.5 ) Noncontrolling interest in net loss — — — — — — 6.7 6.7 Net (loss) income attributed to common stockholders (10.0 ) (0.2 ) (16.7 ) — 35.1 (3.9 ) (12.1 ) (7.8 ) Other comprehensive loss — — — — — (0.3 ) — (0.3 ) Other comprehensive loss attributable to noncontrolling interests — — — — — — 0.1 0.1 Comprehensive loss attributable to common stockholders $ (10.0 ) $ (0.2 ) $ (16.7 ) $ — $ 35.1 $ (4.2 ) $ (12.0 ) $ (8.0 )
Consolidating Statements of Cash Flows	Consolidating Statements of Cash Flows IN MILLIONS Year Ended December 31, 2016 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net income (loss) $ 15.9 0.2 $ 15.9 $ — 65.0 $ 1.5 $ (78.6 ) $ 19.9 Equity earnings (loss) related to investment in subsidiaries (15.9 ) (0.2 ) (65.0 ) — (0.6 ) — 81.7 — Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 185.3 (1.4 ) — 183.9 Stock-based compensation expense — — — — 12.3 — — 12.3 Non-cash interest expense — — 3.7 — — — 1.1 4.8 Provision for bad debt — — — — 1.6 — — 1.6 Asset impairments and loss on disposal — — — — 5.3 — — 5.3 Change in operating assets and liabilities: Rent receivables and other assets — — — — (51.5 ) (0.2 ) — (51.7 ) Accounts payable and accrued expenses — — — — 6.9 0.1 — 7.0 Deferred revenues — — — — (2.5 ) — — (2.5 ) Net cash provided by (used in) operating activities — — (45.4 ) — 221.8 — 4.2 180.6 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (131.1 ) — — (131.1 ) Capital expenditures - other development — — — — (598.9 ) (1.1 ) — (600.0 ) Changes in restricted cash — — — — 1.5 — — 1.5 Investment in subsidiaries (448.2 ) (4.5 ) (448.2 ) — — — 900.9 — Return of investment 112.3 — — — — — (112.3 ) — Intercompany borrowings 15.3 — (66.3 ) — — (0.5 ) 51.5 — Net cash provided by (used in) investing activities (320.6 ) (4.5 ) (514.5 ) — (728.5 ) (1.6 ) 840.1 (729.6 ) Cash flows from financing activities: Issuance of common stock 448.7 — — — — — — 448.7 Stock issuance costs (1.6 ) — — — — — — (1.6 ) Dividends paid (112.3 ) — (114.3 ) — — — 112.3 (114.3 ) Intercompany borrowings — — (15.3 ) — 71.0 — (55.7 ) — Borrowings from credit facility — — 710.0 — — — — 710.0 Payments on credit facility — — (460.0 ) — — — — (460.0 ) Payments on capital leases and lease financing arrangements — — — — (8.0 ) (1.1 ) — (9.1 ) Tax payment upon exercise of equity awards (14.2 ) — — — — — — (14.2 ) Contributions/distributions from parent — 4.5 448.2 — 448.2 — (900.9 ) — Payment of note payable — — — — (1.5 ) — — (1.5 ) Debt issuance costs — — (8.7 ) — — — — (8.7 ) Net cash provided by (used in) financing activities 320.6 4.5 559.9 — 509.7 (1.1 ) (844.3 ) 549.3 Net increase (decrease) in cash and cash equivalents — — — — 3.0 (2.7 ) — 0.3 Cash and cash equivalents at beginning of period — — — — 10.4 3.9 — 14.3 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 13.4 $ 1.2 $ — $ 14.6 IN MILLIONS Year Ended December 31, 2015 Parent General LP Finance Guarantor Subsidiaries Non- Eliminations/Consolidations Total Net (loss) income $ (17.1 ) (0.2 ) $ (21.9 ) $ — 17.8 $ (3.3 ) $ 4.5 $ (20.2 ) Equity earnings (loss) related to investment in subsidiaries 17.1 0.2 (17.8 ) — 3.3 — (2.8 ) — Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 138.7 2.8 — 141.5 Stock-based compensation expense — — — — 14.4 — — 14.4 Non-cash interest expense — — 3.4 — — — — 3.4 Asset impairments and loss on disposal — — — — 13.5 — — 13.5 Change in operating assets and liabilities: Rent receivables and other assets — — — — (26.1 ) 2.2 — (23.9 ) Accounts payable and accrued expenses — — 16.7 — (9.8 ) 0.1 — 7.0 Deferred revenues — — — — 5.3 0.1 — 5.4 Due to affiliates — — — — (0.9 ) — — (0.9 ) Net cash (used in) provided by operating activities — — (19.6 ) — 156.2 1.9 1.7 140.2 Cash flows from investing activities: Capital expenditures - purchase of fixed assets — — — — (17.3 ) — — (17.3 ) Capital expenditures - other development — — — — (216.7 ) (0.5 ) — (217.2 ) Business acquisition, net of cash acquired — — — — (398.4 ) — — (398.4 ) Release of restricted cash — — — — 7.3 — — 7.3 Investment in subsidiaries (203.1 ) (2.0 ) (203.1 ) — (0.4 ) — 408.6 — Return of investment 62.6 — 102.0 — (17.9 ) — (146.7 ) — Intercompany borrowings — — (348.4 ) — — — 348.4 — Net cash provided by (used in) investing activities (140.5 ) (2.0 ) (449.5 ) — (643.4 ) (0.5 ) 610.3 (625.6 ) Cash flows from financing activities: Issuance of common stock 799.5 — — — — — — 799.5 Stock issuance costs (0.8 ) — — — — — — (0.8 ) Acquisition of operating partnership units (596.4 ) — — — — — — (596.4 ) Dividends paid (61.0 ) — (80.8 ) — (80.8 ) — 141.8 (80.8 ) Intercompany borrowings — — — — 348.4 — (348.4 ) — Borrowings from credit facility — — 260.0 — — — — 260.0 Proceeds from issuance of debt — — 103.8 — — — — 103.8 Payments on credit facility — — (10.0 ) — — — — (10.0 ) Payments on capital leases and lease financing arrangements — — — — (5.0 ) (0.9 ) — (5.9 ) Tax payment upon exercise of equity awards (0.8 ) — — — — — — (0.8 ) Contributions/distributions from parent — 2.0 201.5 — 201.5 0.4 (405.4 ) — Debt issuance costs — — (5.4 ) — — — — (5.4 ) Net cash (used in) provided by financing activities 140.5 2.0 469.1 — 464.1 (0.5 ) (612.0 ) 463.2 Net (decrease) increase in cash and cash equivalents — — — — (23.1 ) 0.9 — (22.2 ) Cash and cash equivalents at beginning of period — — — — 33.5 3.0 — 36.5 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 10.4 $ 3.9 $ — $ 14.3 IN MILLIONS Year Ended December 31, 2014 Parent Guarantor General Partner LP Co-issuer Finance Co-issuer Guarantor Subsidiaries Non- Guarantors Eliminations/Consolidations Total Net (loss) income $ (10.0 ) (0.2 ) $ (16.7 ) $ — 35.1 $ (3.9 ) $ (18.8 ) $ (14.5 ) Equity earnings (loss) related to investment in subsidiaries 10.0 0.2 (35.1 ) — 3.9 — 21.0 — Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities: Depreciation and amortization — — — — 115.0 3.0 — 118.0 Stock-based compensation expense — — — — 10.3 — — 10.3 Non-cash interest expense — — 3.4 — — — — 3.4 Provision for bad debt — — — — 0.8 — — 0.8 Loss on extinguishment of debt — — 13.6 — — — — 13.6 Change in operating assets and liabilities: Rent receivables and other assets — — 0.4 — (35.3 ) (2.1 ) — (37.0 ) Accounts payable and accrued expenses — — 4.7 — 2.1 0.1 — 6.9 Due to affiliates — — — — (0.2 ) — — (0.2 ) Deferred revenues — — — — 10.0 (0.2 ) — 9.8 Net cash provided by (used in) operating activities — — (29.7 ) — 141.7 (3.1 ) 2.2 111.1 Cash flows from investing activities: Capital expenditures - other development — — — — (283.9 ) (0.3 ) — (284.2 ) Return of investment 25.2 — 97.3 — (45.4 ) — (77.1 ) — Intercompany receipts — — 180.2 — — — (180.2 ) — Intercompany borrowings — — (315.0 ) — — — 315.0 — Net cash (used in) provided by investing activities 25.2 — (37.5 ) — (329.3 ) (0.3 ) 57.7 (284.2 ) Cash flows from financing activities: Issuance of common stock 356.0 — — — — — — 356.0 Stock issuance costs (1.3 ) — — — — — — (1.3 ) Acquisition of operating partnership units (355.9 ) — — — — — — (355.9 ) Dividends paid (24.0 ) — (50.9 ) — (50.9 ) — 74.9 (50.9 ) Intercompany borrowings — — — — 315.0 — (315.0 ) — Intercompany payments — — — — (180.2 ) — 180.2 — Borrowings from credit facility — — 315.0 — — — — 315.0 Payments on credit facility — — (30.0 ) — — — — (30.0 ) Payments on senior notes — — (150.2 ) — — — — (150.2 ) Payments on capital leases obligations — — — — (2.4 ) (0.6 ) — (3.0 ) Payments on financing arrangements — — — — (0.7 ) (0.2 ) — (0.9 ) Payment of debt extinguishment costs — — (12.8 ) — — — — (12.8 ) Contributions/distributions from parent — — 1.3 — (6.5 ) 5.2 — — Debt issuance costs — — (5.2 ) — — — — (5.2 ) Net cash provided by (used in) financing activities (25.2 ) — 67.2 — 74.3 4.4 (59.9 ) 60.8 Net (decrease) increase in cash and cash equivalents — — — — (113.3 ) 1.0 — (112.3 ) Cash and cash equivalents at beginning of period — — — — 146.8 2.0 — 148.8 Cash and cash equivalents at end of period $ — $ — $ — $ — $ 33.5 $ 3.0 $ — $ 36.5

Quarterly Financial Informati50

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 : IN MILLIONS, except per share amounts 2016 First Quarter Second Quarter Third Quarter Fourth Total Revenue $ 117.8 $ 130.1 $ 143.8 $ 137.4 $ 529.1 Operating income 17.9 21.1 18.8 12.7 70.5 Net income 5.6 9.1 4.4 0.8 19.9 Net income attributed to common stockholders 5.6 9.1 4.4 0.8 19.9 Basic and diluted income per share $ 0.07 $ 0.11 $ 0.05 $ 0.01 $ 0.24 IN MILLIONS, except per share amounts 2015 First Second Quarter Third Quarter Fourth Quarter Total Revenue $ 85.7 $ 89.1 $ 111.2 $ 113.3 $ 399.3 Operating income 1.6 2.6 7.5 11.1 22.8 Net loss (7.2 ) (6.5 ) (5.3 ) (1.2 ) (20.2 ) Net loss attributed to common stockholders (4.3 ) (5.5 ) (4.6 ) (1.0 ) (15.4 ) Basic and diluted loss per share (a) $ (0.12 ) $ (0.11 ) $ (0.08 ) $ (0.02 ) $ (0.33 ) (a) The basic and diluted income (loss) per share for 2015 was $(0.30) compared to $(0.33) due to the impact of the 14.3 million shares of common stock issued during the secondary offering in April 2015, and the 6.0 million shares of common stock issued during the secondary offering in June 2015.

Description of Business - Narra

Description of Business - Narrative (Details)	12 Months Ended
	Dec. 31, 2016recovery_centerdata_center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of data operating centers | data_center	35
Number of recovery centers | recovery_center	2

Formation and Recent Developm52

Formation and Recent Developments - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions	Aug. 15, 2016	Aug. 10, 2016	Jul. 01, 2016	Mar. 31, 2016	Mar. 21, 2016	Dec. 31, 2015	Dec. 14, 2015	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 21, 2016	Mar. 17, 2016	Jun. 22, 2015	Oct. 09, 2014	Oct. 08, 2014
Business Formation [Line Items]
Proceeds from public stock offerings									$ 256,000,000	$ 448,700,000	$ 799,500,000	$ 356,000,000
Proceeds from exercise of options									900,000
Proceeds from common shares purchased under employee stock purchase plan									$ 100,000
Maximum proceeds from issuance of common stock			$ 320,000,000
Stock issuance costs										$ 1,600,000	$ 800,000	$ 1,300,000
Public stock offering
Business Formation [Line Items]
Issuance of common stock (in shares)	3.4				6.9	6.3	1.4			10.3	27.3	16
Proceeds from public stock offerings	$ 164,800,000				$ 255,000,000		$ 0			$ 419,800,000	$ 799,300,000	$ 355,900,000
Stock issuance costs	$ 6,900,000				$ 10,600,000
Sales Agreements
Business Formation [Line Items]
Issuance of common stock (in shares)								0.5
Proceeds from public stock offerings								$ 26,300,000
Stock issuance costs								$ 300,000
Stock issued upon underwriters exercising option to purchase additional shares
Business Formation [Line Items]
Issuance of common stock (in shares)		1
Cincinnati Bell Inc.
Business Formation [Line Items]
Ownership % by noncontrolling owners						9.50%		5.00%		5.00%	9.50%
Goldman, Sachs & Co. | Public stock offering
Business Formation [Line Items]
Issuance of common stock (in shares)	4.4
Stock issued price (in dollars per share)		$ 48.48
The Company
Business Formation [Line Items]
Operating partnership units (in shares)						72.6				83.5	72.6
Term loans | Credit Agreement
Business Formation [Line Items]
Optional additional borrowing capacity														$ 250,000,000
Term loans | Credit Agreement
Business Formation [Line Items]
Available commitments under revolving credit facility								$ 300,000,000						300,000,000
Revolving Credit Facility
Business Formation [Line Items]
Available commitments under revolving credit facility																$ 450,000,000	$ 225,000,000
Revolving Credit Facility | Credit Agreement
Business Formation [Line Items]
Optional additional borrowing capacity														250,000,000	$ 600,000,000
Available commitments under revolving credit facility															950,000,000
Revolving Credit Facility | Credit Agreement
Business Formation [Line Items]
Optional additional borrowing capacity															300,000,000
Available commitments under revolving credit facility								$ 650,000,000						$ 650,000,000	$ 600,000,000
Revolving Credit Facility | Second Amended and Restated Credit Agreement
Business Formation [Line Items]
Optional additional borrowing capacity													$ 300,000,000
Available commitments under revolving credit facility													$ 1,000,000,000
CME Group's data center
Business Formation [Line Items]
Proceeds used to acquire Chicago-Aurora I data center				$ 131,100,000

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization	$ 183.9	$ 141.5	$ 118
Interest expense	48.8	$ 41.2	$ 39.5
Certain immaterial errors relating to understated amounts in prior periods | Cumulative amount of errors
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization	2.6
Interest expense	$ 1.1

Significant Accounting Polici54

Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Summary Of Significant Accounting Policies [Line Items]
Percentage of lease term	75.00%
Percentage of lease payment	90.00%
Capitalized interest	$ (10,600,000)	$ (6,100,000)	$ (4,600,000)
Asset impairments and loss on disposal	5,300,000	13,500,000	0
Goodwill impairments	0	0	0
Deferred leasing costs	23,300,000	14,200,000
Straight-line rents receivable	67,600,000	44,700,000
Deferred revenue	76,700,000	78,700,000
Advertising expense	4,100,000	2,200,000	2,900,000
Depreciation expense	157,700,000	117,800,000	95,800,000
Amortization expense	26,200,000	23,700,000	$ 22,200,000
Unrecognized tax benefits	$ 0	$ 0
Number of segments | segment	1
Trademark
Summary Of Significant Accounting Policies [Line Items]
Weighted-average useful life	9 years
Customer relationships
Summary Of Significant Accounting Policies [Line Items]
Weighted-average useful life	12 years
Trade name
Summary Of Significant Accounting Policies [Line Items]
Weighted-average useful life	3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Receivables due term	30 days
Deferred leasing costs amortization term	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Receivables due term	120 days
Deferred leasing costs amortization term	5 years
Buildings | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life	9 years
Buildings | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life	30 years
Building Improvements | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life	3 years
Building Improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life	30 years
Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life	2 years
Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life	20 years
Land
Summary Of Significant Accounting Policies [Line Items]
Lease term of favorable leasehold interest which being amortized	51 years
Customer 1 | Accounts receivable | Customer concentration risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	10.00%
Customer 1 | Annualized rent revenue | Customer concentration risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	13.00%

Acquisitions and Purchase of 55

Acquisitions and Purchase of Fixed Assets - Narrative (Details) ft² in Thousands, $ in Millions	Apr. 01, 2016	Mar. 31, 2016USD ($)ft²	Jul. 01, 2015USD ($)data_centerwork_recovery	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)property	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Mar. 31, 2016a	Nov. 20, 2012
Business Acquisition [Line Items]
Purchases of properties					$ 131.1	$ 17.3	$ 0
Cervalis
Business Acquisition [Line Items]
Percent of company acquired			100.00%
Data centers acquired (in data centers) | data_center			4
Work area recovery facilities acquired | work_recovery			2
Acquisition costs						$ 12.9
Revenue of acquiree since acquisition				$ 37.7
Customer relationships
Business Acquisition [Line Items]
Weighted-average useful life					12 years
Customer relationships | Cervalis
Business Acquisition [Line Items]
Weighted-average useful life			15 years
Maximum | Cervalis
Business Acquisition [Line Items]
Total consideration for acquisition			$ 398.4
CME Group's data center
Business Acquisition [Line Items]
Payment to acquire Chicago-Aurora I data center		$ 131.1
Area of real estate acquired (in sq ft)		428						15
Lease term	15 years
Properties for development
Business Acquisition [Line Items]
Number of properties purchased | property					4
Purchases of properties					$ 54.5
6.375% senior notes due 2022, including bond premium
Business Acquisition [Line Items]
Stated interest rate				6.375%	6.375%	6.375%	6.375%
6.375% senior notes due 2022, including bond premium | 6.375% Senior Notes
Business Acquisition [Line Items]
Stated interest rate					6.375%
CyrusOne LP and CyrusOne Finance Corp | 6.375% senior notes due 2022, including bond premium | 6.375% Senior Notes
Business Acquisition [Line Items]
Stated interest rate					6.375%				6.375%

Acquisitions and Purchase of 56

Acquisitions and Purchase of Fixed Assets - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Jul. 01, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill		$ 455.1	$ 453.4
Net cash paid at acquisition		$ 0	$ 398.4	$ 0
Cervalis
Business Acquisition [Line Items]
Cash	$ 1.1
Rent and other receivables	10.5
Restricted cash	8.8
Net investment in real estate	197.8
Goodwill	178.9
Customer relationships	117.4
Trade name	2.3
Other long-term assets	5.6
Total assets acquired	522.4
Current liabilities	18.3
Capital lease obligations	1.7
Long-term debt	1.5
Lease financing arrangements	101.4
Total liabilities	122.9
Net assets acquired attributable to CyrusOne Inc.	399.5
Cash acquired	(1.1)
Net cash paid at acquisition	$ 398.4

Acquisitions and Purchase of 57

Acquisitions and Purchase of Fixed Assets - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Combinations [Abstract]
Revenue	$ 438.6	$ 399
Net loss	$ (10.9)	$ (17.2)
Loss per share - basic and diluted (in dollars per share)	$ (0.16)	$ (0.35)

Investment in Real Estate - Sch

Investment in Real Estate - Schedule of Gross Investment in Real Estate (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Land	$ 142.7	$ 93
Building and Improvements	1,008.9	905.3
Equipment	1,042.9	598.2
Dallas - Carrollton
Real Estate Properties [Line Items]
Land	16.1	16.1
Building and Improvements	57.6	52.7
Equipment	154	116.5
Houston - Houston West I
Real Estate Properties [Line Items]
Land	1.4	1.4
Building and Improvements	85	84.8
Equipment	48.4	46.4
Dallas - Lewisville
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	76.7	76.6
Equipment	33.7	24.9
Cincinnati - 7th Street
Real Estate Properties [Line Items]
Land	0.9	0.9
Building and Improvements	110.6	110.6
Equipment	21	19.6
Northern Virginia - Sterling II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	28.7	0
Equipment	111.8	0
Totowa - Madison
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	28.3	28.3
Equipment	50.8	48.8
Wappingers Falls I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	11.3	11.3
Equipment	17.1	14.4
Cincinnati - North Cincinnati
Real Estate Properties [Line Items]
Land	4	4
Building and Improvements	77.3	77.3
Equipment	9	7.6
Houston - Houston West II
Real Estate Properties [Line Items]
Land	2.8	2
Building and Improvements	23.1	22.6
Equipment	49	47.1
San Antonio I
Real Estate Properties [Line Items]
Land	4.6	4.6
Building and Improvements	32.1	32.1
Equipment	33.6	33
Chicago - Aurora I
Real Estate Properties [Line Items]
Land	2.4	0
Building and Improvements	28.5	0
Equipment	99.9	0
Phoenix - Chandler II
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	16.1	16
Equipment	38.8	39.5
Houston - Galleria
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	68.6	68.6
Equipment	16.6	16
Florence
Real Estate Properties [Line Items]
Land	2.2	2.2
Building and Improvements	41.9	41.5
Equipment	4.9	3.3
Austin II
Real Estate Properties [Line Items]
Land	2	2
Building and Improvements	23.4	23.2
Equipment	6.6	5.7
San Antonio II
Real Estate Properties [Line Items]
Land	7	7
Building and Improvements	29	0
Equipment	59.4	0.1
Northern Virginia - Sterling I
Real Estate Properties [Line Items]
Land	7	7
Building and Improvements	19.7	19.2
Equipment	47.2	45.2
Phoenix - Chandler I
Real Estate Properties [Line Items]
Land	14.8	14.8
Building and Improvements	56.8	56.7
Equipment	56.5	39.8
Cincinnati - Hamilton
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	50.2	49.2
Equipment	5	4.4
Stamford - Riverbend
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	4.3	4.3
Equipment	14.5	13.2
Phoenix - Chandler III
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	9.9	0
Equipment	44.5	0
London - Great Bridgewater
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	25.9	31.2
Equipment	0.9	0.8
Dallas - Midway
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	2	2
Equipment	0.4	0.4
Cincinnati - Mason
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	20.2	20.2
Equipment	1.4	1
Norwalk I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	19	18.3
Equipment	26.6	25.4
Dallas - Marsh
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.1	0.1
Equipment	0.6	0.6
Chicago - Lombard
Real Estate Properties [Line Items]
Land	0.7	0.7
Building and Improvements	4.7	4.7
Equipment	7.9	7.6
Stamford - Omega
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	3.2	3.2
Equipment	1.5	1.5
Northern Virginia - Sterling IV
Real Estate Properties [Line Items]
Land	4.6	0
Building and Improvements	11	0
Equipment	33.4	0
Cincinnati - Blue Ash
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	0.6	0.6
Equipment	0.1	0.1
Totowa - Commerce
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	4.1	4.1
Equipment	1.4	1
South Bend - Crescent
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	1.7	3.3
Equipment	0.2	0.4
Houston - Houston West III
Real Estate Properties [Line Items]
Land	18.4	18.4
Building and Improvements	9.4	4
Equipment	13.5	0.8
Singapore - Inter Business Park
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	8.2	8.4
Equipment	0.1	0.1
South Bend - Monroe
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	2.5	2.5
Equipment	0.3	0.3
Cincinnati - Goldcoast
Real Estate Properties [Line Items]
Land	0.2	0.6
Building and Improvements	4	6.7
Equipment	0.1	0.1
Austin III
Real Estate Properties [Line Items]
Land	3.3	3.3
Building and Improvements	9.7	7.4
Equipment	31.8	31.5
Austin I
Real Estate Properties [Line Items]
Land	0	0
Building and Improvements	3.5	13.6
Equipment	0.2	1
Austin Land A
Real Estate Properties [Line Items]
Land	8	8
Building and Improvements	0	0
Equipment	0.2	0.1
Chicago - Aurora Land A
Real Estate Properties [Line Items]
Land	2.6	0
Building and Improvements	0	0
Equipment	0	0
Phoenix - Chandler Land A
Real Estate Properties [Line Items]
Land	10.5	0
Building and Improvements	0	0
Equipment	0	0
Chicago - Aurora Land B
Real Estate Properties [Line Items]
Land	5.1	0
Building and Improvements	0	0
Equipment	0	0
Northern Virginia - Sterling Land A
Real Estate Properties [Line Items]
Land	24.1	0
Building and Improvements	0	0
Equipment	$ 0	$ 0

Investment in Real Estate - Nar

Investment in Real Estate - Narrative (Details)	12 Months Ended
	Dec. 31, 2016USD ($)property	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Real Estate Properties [Line Items]
Cost of construction in progress	$ 407,100,000	$ 231,100,000
Capital expenditures	731,100,000
Capital expenditures – other development	600,000,000	217,200,000	$ 284,200,000
Capital expenditures – purchase of fixed assets	131,100,000	17,300,000	0
Asset impairment and loss on disposal	$ 5,300,000	13,500,000	$ 0
Number of properties impaired | property	2
Aurora Properties
Real Estate Properties [Line Items]
Capital expenditures – other development	$ 131,100,000
Property for development, Northern Virginia - Sterling, Chicago - Aurora and Phoenix - Chandler II [Member]
Real Estate Properties [Line Items]
Number of properties purchased | property	4
Capital expenditures – purchase of fixed assets	$ 54,500,000
Property for development, Northern Virginia - Sterling, Phoenix - Chandler II, San Antonio, Dallas - Carrollton and Houston - Houston West III [Member]
Real Estate Properties [Line Items]
Capital expenditures – purchase of fixed assets	$ 545,500,000
Austin III facility
Real Estate Properties [Line Items]
Capital expenditures – purchase of fixed assets		17,300,000
Austin III facility | Buildings
Real Estate Properties [Line Items]
Capital expenditures – purchase of fixed assets		17,300,000
Austin III facility | Land
Real Estate Properties [Line Items]
Capital expenditures – purchase of fixed assets		3,300,000
Other properties
Real Estate Properties [Line Items]
Capital expenditures – other development		$ 217,200,000

Notes Receivable - Narrative (D

Notes Receivable - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	$ 6,600	$ 2,500
Note 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	3,900	0
Monthly payments	300
Note 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	2,200	2,500
Monthly payments	50
Note 3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	500	$ 0
Monthly payments	$ 12

Notes Receivable - Carrying amo

Notes Receivable - Carrying amounts (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	$ 6.6	$ 2.5
Note 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	3.9	0
Note 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	2.2	2.5
Note 3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount notes receivable	$ 0.5	$ 0

Goodwill, Intangible and Othe62

Goodwill, Intangible and Other Long-Lived Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 01, 2015
Business Acquisition [Line Items]
Goodwill	$ 455,100,000	$ 453,400,000
Impairment of intangible assets	0	0
Impairment of goodwill	0	0	$ 0
Amortization expense for intangible assets	$ 20,100,000	18,500,000	$ 17,000,000
Cervalis
Business Acquisition [Line Items]
Goodwill				$ 178,900,000
Goodwill acquired		177,200,000
Cervalis | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired		117,400,000
Cervalis | Trade name
Business Acquisition [Line Items]
Finite-lived intangible assets acquired		2,300,000
Cervalis | Favorable leasehold interest
Business Acquisition [Line Items]
Finite-lived intangible assets acquired		$ 200,000

Goodwill, Intangible and Othe63

Goodwill, Intangible and Other Long-Lived Assets - Carrying Value of Major Classes of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 260.9	$ 260.9
Accumulated Amortization	(110.7)	(90.6)
Total	$ 150.2	170.3
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	12 years
Gross Carrying Amount	$ 247.1	247.1
Accumulated Amortization	(106.3)	(87.5)
Total	$ 140.8	159.6
Trademark
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	9 years
Gross Carrying Amount	$ 7.4	7.4
Accumulated Amortization	(3.2)	(2.7)
Total	$ 4.2	4.7
Favorable leasehold interest
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	48 years
Gross Carrying Amount	$ 4.1	4.1
Accumulated Amortization	(0.5)	(0.4)
Total	$ 3.6	3.7
Trade name
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in years)	2 years
Gross Carrying Amount	$ 2.3	2.3
Accumulated Amortization	(0.7)	0
Total	$ 1.6	$ 2.3

Goodwill, Intangible and Othe64

Goodwill, Intangible and Other Long-Lived Assets - Estimated Amortization Expense For Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2,017	$ 18.1
2,018	16.2
2,019	13.8
2,020	12.6
2,021	11.6
Thereafter	77.9
Total	$ 150.2	$ 170.3

Long-Term Debt, Capital Lease65

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements (Details) - USD ($)	Dec. 31, 2016	Mar. 17, 2016	Dec. 31, 2015	Jun. 22, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term debt, net	$ 1,240,100,000		$ 996,500,000
Deferred financing costs	(22,200,000)		(17,600,000)
Capital lease obligations	10,800,000		12,200,000
Lease financing arrangements	135,700,000		150,000,000
Total	$ 1,386,600,000		$ 1,158,700,000
6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Stated interest rate	6.375%		6.375%		6.375%
Term loans
Debt Instrument [Line Items]
Long-term debt, net	$ 550,000,000
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Long-term debt, net	$ 477,300,000		$ 477,600,000
Stated interest rate	6.375%
Notes payable
Debt Instrument [Line Items]
Long-term debt, net	$ 0		1,500,000
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving Credit Facility	235,000,000		235,000,000	$ 650,000,000
Revolving Credit Facility | Term loans
Debt Instrument [Line Items]
Revolving Credit Facility	$ 550,000,000		$ 300,000,000
Deferred financing costs		$ (2,100,000)

Long-Term Debt, Capital Lease66

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements - Lease Financing Arrangements (Details) $ in Millions	Dec. 31, 2016USD ($)
Future Value of Payments
2,017	$ 16.4
2,018	14.3
2,019	14.5
2,020	25.4
2,021	11.4
Thereafter	109.8
Total lease financing arrangements	191.8
Interest
2,017	7.9
2,018	7.5
2,019	7
2,020	6.4
2,021	5.7
Thereafter	21.6
Total lease financing arrangements	56.1
2,017	8.5
2,018	6.8
2,019	7.5
2,020	19
2,021	5.7
Thereafter	88.2
Total lease financing arrangements	$ 135.7

Long-Term Debt, Capital Lease67

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements - Maturities of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2,017	$ 3.3
2,018	1.7
2,019	1.5
2,020	236.7
2,021	251.6
Thereafter	775.8
Long-term debt, net	1,240.1	$ 996.5
Total debt	1,270.6
Revolving Credit Facility/Term Loan
Debt Instrument [Line Items]
2,017	0
2,018	0
2,019	0
2,020	235
2,021	250
Thereafter	300
Total debt	785
6.375% Senior Notes
Debt Instrument [Line Items]
2,017	0
2,018	0
2,019	0
2,020	0
2,021	0
Thereafter	474.8
Total debt	474.8
Capital Leases
Debt Instrument [Line Items]
2,017	3.3
2,018	1.7
2,019	1.5
2,020	1.7
2,021	1.6
Thereafter	1
Total debt	$ 10.8

Long-Term Debt, Capital Lease68

Long-Term Debt, Capital Lease Obligations and Lease Financing Arrangements - Narrative (Details)	Mar. 17, 2016USD ($)	Jul. 01, 2015USD ($)	Jun. 22, 2015USD ($)	Nov. 20, 2012USD ($)	Jul. 31, 2016USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)data_center	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Nov. 21, 2016USD ($)	Sep. 30, 2016USD ($)	Oct. 09, 2014USD ($)	Oct. 08, 2014USD ($)
Debt Instrument [Line Items]
Long-term debt, net							$ 1,240,100,000	$ 996,500,000
Total unencumbered assets							150.00%
Repayment of note payable					$ 1,500,000		$ 1,500,000	0	$ 0
Deferred financing costs							22,200,000	17,600,000
Amortization of deferred financing costs							$ 4,100,000	3,400,000	3,400,000
Number of data center facilities under capital lease | data_center							8
Interest expense on capital lease obligations and lease financing arrangements							$ 10,600,000	$ 7,800,000	$ 5,900,000
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017							16,400,000
2,018							14,300,000
2,019							14,500,000
2,020							25,400,000
2,021							11,400,000
Thereafter							$ 109,800,000
6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Stated interest rate						6.375%	6.375%	6.375%	6.375%
Term loans
Debt Instrument [Line Items]
Face amount of debt			$ 300,000,000									$ 150,000,000
Remaining borrowing capacity			250,000,000
Effective interest rate							2.26%
Long-term debt, net							$ 550,000,000
Term loans | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
Term loans | Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount	$ 300,000,000										$ 300,000,000
Term loans | First Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Optional additional borrowing capacity	$ 250,000,000
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Debt Instrument [Line Items]
Long-term debt, net							$ 477,300,000	$ 477,600,000
Stated interest rate							6.375%
Repurchased face amount						$ 150,200,000			$ 150,200,000
Repurchase amount						163,000,000			$ 163,000,000
Loss on extinguishment of debt						$ 12,800,000
Proceeds from private offering		$ 100,000,000
Premium on private offering		$ 3,800,000
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium | CyrusOne LP and CyrusOne Finance Corp
Debt Instrument [Line Items]
Long-term debt, net				$ 525,000,000
Stated interest rate				6.375%			6.375%
Percentage of redemption price				100.00%
Percentage of senior notes declining redemption 1				103.188%
Percentage of senior notes declining redemption 2				102.125%
Percentage of senior notes declining redemption 3				101.063%
Percentage of senior notes declining redemption 4				100.00%
Percentage of Redemption of the aggregate principal				35.00%
Percentage of equity offering on principal amount				106.375%
Percentage of Redemption of the least aggregate principal				65.00%
Term of redemption occurs				90 days
Notes payable
Debt Instrument [Line Items]
Long-term debt, net							$ 0	1,500,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit agreement amount												$ 450,000,000	$ 225,000,000
Increase (decrease) in credit facility			350,000,000
Term of extension option							1 year
Effective interest rate							2.31%
Outstanding borrowings on revolving credit agreement			650,000,000				$ 235,000,000	235,000,000
Commitment fee percent							0.25%
Commitment fee amount							$ 1,600,000	900,000
Maximum percentage of dividends allowed to be distributed							95.00%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	1.55%
Revolving Credit Facility | Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount	$ 650,000,000		600,000,000								$ 650,000,000
Optional additional borrowing capacity			300,000,000
Revolving Credit Facility | First Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount			950,000,000
Optional additional borrowing capacity	250,000,000		$ 600,000,000
Revolving Credit Facility | Second Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Credit agreement amount										$ 1,000,000,000
Optional additional borrowing capacity										300,000,000
Revolving Credit Facility | Term loans
Debt Instrument [Line Items]
Outstanding borrowings on revolving credit agreement							$ 550,000,000	$ 300,000,000
Deferred financing costs	$ 2,100,000
Revolving Credit Facility | Term loans | Second Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Deferred financing costs										$ 6,600,000
Interest on capital leases
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017							900,000
2,018							700,000
2,019							500,000
2,020							400,000
2,021							200,000
Thereafter							$ 100,000

Fair Value of Financial Instr69

Fair Value of Financial Instruments - Carrying and Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	$ 1,240.1	$ 996.5
6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	6.375%	6.375%	6.375%
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	$ 477.3	$ 477.6
Stated interest rate	6.375%
6.375% Senior Notes | Carrying Value | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	$ 477.3	477.6
6.375% Senior Notes | Fair Value | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	502.1	493.8
Line of Credit | Carrying Value | Revolving Credit Facility/Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	785	535
Line of Credit | Fair Value | Revolving Credit Facility/Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	785	535
Notes payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	0	1.5
Notes payable | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	0	1.5
Notes payable | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net	$ 0	$ 1.2

Noncontrolling Interest - Ope70

Noncontrolling Interest - Operating Partnership - Schedule of Noncontrolling Interest (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Portion of net income (loss)	$ 0.8	$ 4.4	$ 9.1	$ 5.6	$ (1)	$ (4.6)	$ (5.5)	$ (4.3)	$ 19.9	$ (15.4)	$ (7.8)
Portion of net income (loss)									0	(4.8)	(6.7)
Distributions									$ (123.8)	$ (90.9)	(54.9)
The Company
Noncontrolling Interest [Line Items]
Operating partnership units (in shares)	83.5				72.6				83.5	72.6
Ownership %					100.00%					100.00%
Portion of net income (loss)										$ (15.4)
Portion of net income (loss)										4.8	6.7
Distributions									$ (123.8)	$ (74.6)	(29.2)
CBI
Noncontrolling Interest [Line Items]
Operating partnership units (in shares)					0					0
Ownership %	0.00%				0.00%				0.00%	0.00%
Portion of net income (loss)										$ (4.8)	(6.7)
Distributions										$ (16.3)	$ (25.7)

Noncontrolling Interest - Ope71

Noncontrolling Interest - Operating Partnership - Narrative (Details) shares in Millions	Jan. 24, 2013shares	Jan. 23, 2013shares	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Partners' capital units converted (in shares)	1.5
Cincinnati Bell Inc.
Noncontrolling Interest [Line Items]
Remaining combined interest held	66.10%
Ownership %			5.00%	5.00%	9.50%
CyrusOne L.P.
Noncontrolling Interest [Line Items]
Issuance of partnership units (in shares)		123.7
Partnership reverse unit split, conversion ratio	2.8
Operating partnership units owned (in shares)	44.1
Non-Controlling Interest
Noncontrolling Interest [Line Items]
Ownership %			0.00%		0.00%

Dividends (Details)

Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 23, 2017	Jan. 13, 2017	Oct. 14, 2016	Jul. 15, 2016	Apr. 15, 2016	Jan. 08, 2016	Oct. 15, 2015	Jul. 15, 2015	Apr. 15, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Dividends Payable [Line Items]
Cash dividend per share or operating partnership unit (in dollars per share)			$ 0.38	$ 0.38	$ 0.38	$ 0.315	$ 0.315	$ 0.315	$ 0.315	$ 1.46	$ 1.16
Dividends payable										$ (33.9)	$ (24.4)
Dividends declared per share (in dollars per share)										$ 1.52	$ 1.26	$ 0.84
Subsequent event
Dividends Payable [Line Items]
Cash dividend per share or operating partnership unit (in dollars per share)		$ 0.38
Dividends declared per share (in dollars per share)	$ 0.42

Customer Leases - Narrative (De

Customer Leases - Narrative (Details) $ in Millions	Dec. 31, 2016USD ($)
Leases [Abstract]
2,017	$ 404.3
2,018	306.3
2,019	224.5
2,020	179.9
2,021	$ 141

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CyrusOne health care plan
Defined Contribution Plan [Line Items]
Health care plans expenses	$ 4.4	$ 3.1	$ 2.1
Retirement savings plan
Defined Contribution Plan [Line Items]
Retirement savings plan matching contributions	$ 1.5	$ 1.1	$ 0.8

Income (Loss) per Share - Narra

Income (Loss) per Share - Narrative (Details) - USD ($) shares in Millions	Aug. 15, 2016	Aug. 10, 2016	Mar. 21, 2016	Dec. 31, 2015	Dec. 14, 2015	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Formation [Line Items]
Proceeds from public stock offerings						$ 256,000,000	$ 448,700,000	$ 799,500,000	$ 356,000,000
Stock issuance costs							$ 1,600,000	$ 800,000	$ 1,300,000
Public stock offering
Business Formation [Line Items]
Issuance of common stock (in shares)	3.4		6.9	6.3	1.4		10.3	27.3	16
Proceeds from public stock offerings	$ 164,800,000		$ 255,000,000		$ 0		$ 419,800,000	$ 799,300,000	$ 355,900,000
Stock issuance costs	$ 6,900,000		$ 10,600,000
Stock issued upon underwriters exercising option to purchase additional shares
Business Formation [Line Items]
Issuance of common stock (in shares)		1

Income (Loss) per Share - Compu

Income (Loss) per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income (loss) attributed to common stockholders	$ 0.8	$ 4.4	$ 9.1	$ 5.6	$ (1)	$ (4.6)	$ (5.5)	$ (4.3)	$ 19.9	$ (15.4)	$ (7.8)
Less: Restricted stock dividends, Basic									(0.7)	(1)	(0.8)
Less: Restricted stock dividends, Diluted									(0.7)	(1)	(0.8)
Net income (loss) available to stockholders, Basic									19.2	(16.4)	(8.6)
Net income (loss) available to stockholders, Diluted									$ 19.2	$ (16.4)	$ (8.6)
Denominator:
Weighted average common outstanding - basic (in shares)									78.3	54.3	29.2
Performance-based restricted stock (in shares)									0.7	0	0
Weighted average shares outstanding- diluted (in shares)									79	54.3	29.2
EPS:
Net income (loss) per share- basic (in dollars per share)									$ 0.24	$ (0.30)	$ (0.30)
Effect of dilutive shares (in dollars per share)									0	0	0
Net income (loss) per share - diluted (in dollars per share)									$ 0.24	$ (0.30)	$ (0.30)
Restricted Stock
EPS:
Anti-dilutive securities excluded from diluted earnings per share (in shares)										1.9	0.8
Operating Partnership Units
EPS:
Anti-dilutive securities excluded from diluted earnings per share (in shares)										13.1	34.3

Stock-Based Compensation Plan77

Stock-Based Compensation Plans - Allocated Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$ 12.3	$ 14.4	$ 10.3
Founders
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	0.3	5.2	5.4
2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	0.1	1.2	1.2
2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	1.2	3	3.7
2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	3.5	5	0
2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total compensation expense	$ 7.2	$ 0	$ 0

Stock-Based Compensation Plan78

Stock-Based Compensation Plans - Other Than Options (Details) - Restricted Stock - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Shares
Non-vested beginning balance (in shares)	1,585,010	1,739,642
Granted (in shares)	641,097
Vested (in shares)	(839,571)
Forfeited (in shares)	(111,823)
Non-vested ending balance (in shares)	1,274,713	1,585,010
Weighted Average Grant Date Fair Value
Non-vested beginning balance (in dollars per share)	$ 22.11
Granted (in dollars per share)	35.18
Vested (in dollars per share)	21.10
Forfeited (in dollars per share)	26.72
Non-vested ending balance (in dollars per share)	$ 28.95	$ 22.11

Stock-Based Compensation Plan79

Stock-Based Compensation Plans - Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Options
Beginning balance (in shares)	334,402	166,872
Granted (in shares)	222,461
Exercised (in shares)	(70,668)		0
Forfeited or expired (in shares)	(51,927)
Ending balance (in shares)	434,268	334,402	166,872
Exercisable (in shares)	138,157
Vested and expected to vest (in shares)	434,268
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 26.44
Granted (in dollars per share)	36.99
Exercised (in dollars per share)	26
Forfeited or expired (in dollars per share)	26.65
Ending balance (in dollars per share)	31.89	$ 26.44
Exercisable (in dollars per share)	27.27
Vested and expected to vest (in dollars per share)	$ 31.89

Stock-Based Compensation Plan80

Stock-Based Compensation Plans - Option Valuation Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares (in shares)	434,268	334,402	166,872
Exercisable (in shares)	138,157
$ 23.58
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)			$ 23.58
Number of shares (in shares)			166,872
Weighted average outstanding contractual term (in years)			8 years 3 months 18 days
Exercisable (in shares)			13,915
Weighted average exercisable contractual term (in years)			8 years 3 months 18 days
Risk-free rate			0.92%
Expected annual dividend			3.40%
Expected term (in years)			6 years
Expected volatility			35.00%
$ 23.58
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)		$ 23.58
Number of shares (in shares)		142,556
Weighted average outstanding contractual term (in years)		7 years 3 months 18 days
Exercisable (in shares)		43,460
Weighted average exercisable contractual term (in years)		7 years 3 months 18 days
Risk-free rate		0.92%
Expected annual dividend		3.40%
Expected term (in years)		6 years
Expected volatility		35.00%
$ 28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)		$ 28.42
Number of shares (in shares)		178,704
Weighted average outstanding contractual term (in years)		9 years 1 month 6 days
Exercisable (in shares)		35,346
Weighted average exercisable contractual term (in years)		9 years 1 month 6 days
Expected annual dividend		4.40%
$ 30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)		$ 30.74
Number of shares (in shares)		12,719
Weighted average outstanding contractual term (in years)		9 years 7 months 6 days
Exercisable (in shares)		0
Weighted average exercisable contractual term (in years)		0 years
Expected annual dividend		4.40%
$ 23.58
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)	$ 23.58
Number of shares (in shares)	67,601
Weighted average outstanding contractual term (in years)	6 years 3 months 18 days
Exercisable (in shares)	67,601
Weighted average exercisable contractual term (in years)	6 years 3 months 18 days
Risk-free rate	0.92%
Expected annual dividend	3.40%
Expected term (in years)	6 years
Expected volatility	35.00%
$ 28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)	$ 28.42
Number of shares (in shares)	143,358
Weighted average outstanding contractual term (in years)	8 years 1 month 6 days
Exercisable (in shares)	47,786
Weighted average exercisable contractual term (in years)	8 years 1 month 6 days
Expected annual dividend	4.40%
$ 30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)	$ 30.74
Number of shares (in shares)	12,719
Weighted average outstanding contractual term (in years)	8 years 7 months 6 days
Exercisable (in shares)	4,240
Weighted average exercisable contractual term (in years)	8 years 7 months 6 days
Expected annual dividend	4.40%
$ 36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)	$ 36.99
Number of shares (in shares)	210,590
Weighted average outstanding contractual term (in years)	9 years 1 month 6 days
Exercisable (in shares)	18,530
Weighted average exercisable contractual term (in years)	9 years 1 month 6 days
Expected annual dividend	4.10%
Minimum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate		1.60%
Expected term (in years)		5 years 6 months
Expected volatility		32.50%
Minimum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate		1.60%
Expected term (in years)		5 years 6 months
Expected volatility		32.50%
Minimum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.60%
Expected term (in years)	5 years 6 months
Expected volatility	32.50%
Minimum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.60%
Expected term (in years)	5 years 6 months
Expected volatility	32.50%
Minimum | $36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.47%
Expected term (in years)	5 years 6 months
Expected volatility	27.50%
Maximum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate		1.75%
Expected term (in years)		6 years 6 months
Expected volatility		37.50%
Maximum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate		1.75%
Expected term (in years)		6 years 6 months
Expected volatility		37.50%
Maximum | $28.42
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.75%
Expected term (in years)	6 years 6 months
Expected volatility	37.50%
Maximum | $30.74
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.75%
Expected term (in years)	6 years 6 months
Expected volatility	37.50%
Maximum | $36.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	1.64%
Expected term (in years)	6 years 6 months
Expected volatility	35.00%

Stock-Based Compensation Plan81

Stock-Based Compensation Plans - Narrative (Details)	Feb. 01, 2016$ / sharesshares	Feb. 10, 2015	Feb. 07, 2014	Apr. 17, 2013$ / shares	Jan. 24, 2013USD ($)shares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)executiveshares	Dec. 31, 2014USD ($)shares	Dec. 31, 2013USD ($)shares	Sep. 30, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)						8,900,000
Granted (in shares)						222,461
Grant date fair value (in dollars per share) | $ / shares						$ 36.99
Number of shares (in shares)						434,268	334,402	166,872
Intrinsic vale of options exercised | $						$ 1,300,000
Exercised (in dollars per share)						70,668		0
Intrinsic value of options outstanding | $						$ 5,600,000
Intrinsic value of options exercisable | $						2,400,000
2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for options granted (in dollars per share) | $ / shares				$ 23.58
Unrecognized compensation expense, other than options | $										$ 0
2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options | $						$ 2,200,000
Unrecognized compensation expense, period for recognition						12 months 6 days
2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, other than options | $						$ 14,500,000
Unrecognized compensation expense, period for recognition						2 years 18 days
Time, performance, and market-based awards | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)	641,097
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)						641,097
Non-vested balance (in shares)						1,274,713	1,585,010	1,739,642
Restricted stock | 2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)									4,361
Other than options grant date value | $									$ 100,000
Award vesting period									3 years
Restricted stock | 2013 Grants | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period									1 year
Restricted stock | 2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)								46,313
Other than options grant date value | $								$ 1,000,000
Award vesting period								3 years
Unrecognized compensation expense, other than options | $						$ 100,000
Unrecognized compensation expense, period for recognition						1 month 6 days
Restricted stock | 2014 Grants | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period								1 year
Restricted stock | 2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)							29,424
Award vesting rights percentage		20.00%
Award vesting period		3 years
Restricted stock | 2015 Grants | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)							8,157
Award vesting period							3 years
Restricted stock | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Restricted stock | 2016 Grants | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)						5,894
Award vesting period	3 years					3 years
Performance and market-based awards | 2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)							11,711
Award vesting rights percentage		80.00%
Performance period							3 years
Performance and market-based awards | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Cap on award vesting	100.00%
Performance awards | 2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				50.00%
Award vesting period				3 years
Performance awards | 2013 Grants | Below 90% of EBITDA Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				0.00%
Performance awards | 2013 Grants | At 90% of EBITDA Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				50.00%
Performance awards | 2013 Grants | At 100% of EBITDA Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				100.00%
Performance awards | 2013 Grants | At or above 115% of EBITDA Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				200.00%
Performance awards | 2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage			50.00%
Award vesting period			3 years
Performance period			3 years
Performance awards | 2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period		3 years
Cap on award vesting		100.00%
Performance awards | 2015 Grants | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)							55,301
Performance period							3 years
Market-based restricted stock | 2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage				50.00%
Award vesting period				3 years
Measurement period				3 years
Market-based restricted stock | 2013 Grants | 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]
Award vesting rights percentage				0.00%
Market-based restricted stock | 2013 Grants | 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]
Award vesting rights percentage				100.00%
Market-based restricted stock | 2013 Grants | 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]
Award vesting rights percentage				200.00%
Market-based restricted stock | 2013 Grants | 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]
Award vesting rights percentage				50.00%
Market-based restricted stock | 2014 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage			50.00%
Award vesting period			3 years
Market-based restricted stock | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for options granted (in dollars per share) | $ / shares	$ 43.66
Time and performance awards | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price for options granted (in dollars per share) | $ / shares	$ 36.99
Stock options | 2013 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period for award				10 years
Stock options | 2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Granted (in shares)							12,719
Stock options | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)	222,461
Award vesting period	3 years
Expiration period for award	10 years
Weighted average exercise price for options granted (in dollars per share) | $ / shares	$ 36.99
Granted (in shares)						47,667
Grant date fair value (in dollars per share) | $ / shares	$ 6.99
Senior executives | 2015 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated compensation cost | $							$ 2,400,000
Number of individuals with accelerated vesting | executive							2
Senior executives | 2016 Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated compensation cost | $						$ 800,000
Founders | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options issued (in shares)					1,000,000
Other than options grant date value | $					$ 19,000,000
2012 LTIP Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)						5,800,000

Related Party Transactions - Sc

Related Party Transactions - Schedule of Related Party Revenue and Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Total revenue	$ 22.3	$ 22.8
Operating costs and expenses:
Total operating costs and expenses	1.9	2
Data center colocation agreement provided to CBT and CBTS
Revenue:
Total revenue	7.8	6.4
229 West 7th Street lease provided to CBT
Revenue:
Total revenue	1.9	2
Goldcoast Drive/Parkway (Mason) lease
Revenue:
Total revenue	0.3	0.4
Transition services provided to CBTS (network interfaces)
Revenue:
Total revenue	0.3	0.4
Data center leases provided to CBTS
Revenue:
Total revenue	12	13.6
Transition services agreement by CBTS
Operating costs and expenses:
Total operating costs and expenses	0.7	0.8
Charges for services provided by CBT (connectivity)
Operating costs and expenses:
Total operating costs and expenses	1	1
209 West 7th Street rent provided by CBT
Operating costs and expenses:
Total operating costs and expenses	$ 0.2	$ 0.2

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Sep. 30, 2016
Related Party Transaction [Line Items]
Expenses to related party	$ 1.9	$ 2
Skadden
Related Party Transaction [Line Items]
Expenses to related party		1.1
Jones Lang LaSalle
Related Party Transaction [Line Items]
Expenses to related party		$ 1
Cincinnati Bell Inc.
Related Party Transaction [Line Items]
Ownership % by noncontrolling owners	9.50%		5.00%	5.00%

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	12 Months Ended
	Dec. 31, 2016USD ($)Subsidiary	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Income Taxes [Line Items]
Number of subsidiaries as taxable REIT | Subsidiary	2
Income tax expense	$ 1,800,000	$ 1,800,000	$ 1,400,000
Net deferred tax assets	$ 0	$ 0
Minimum
Income Taxes [Line Items]
Percentage of distributed taxable income to qualify as a REIT	90.00%
Maximum
Income Taxes [Line Items]
Percentage of distributed taxable income to qualify as a REIT	100.00%

Income Taxes - Dividends Paid (

Income Taxes - Dividends Paid (Details) - $ / shares	Oct. 14, 2016	Jul. 15, 2016	Apr. 15, 2016	Jan. 08, 2016	Oct. 15, 2015	Jul. 15, 2015	Apr. 15, 2015	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Ordinary income (in dollars per share)								$ 0.2	$ 0
Return of capital (in dollars per share)								1.26	1.16
Total dividend (in dollars per share)	$ 0.38	$ 0.38	$ 0.38	$ 0.315	$ 0.315	$ 0.315	$ 0.315	$ 1.46	$ 1.16

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 7,500,000	$ 7,400,000	$ 6,700,000
Letters of credit outstanding	7,100,000
Performance Guarantee
Loss Contingencies [Line Items]
Loss contingency accrual	0	$ 0
Services
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Amount of minimum purchase commitment	$ 171,200,000
Services | Minimum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	1 year
Services | Maximum
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Term of purchase commitment	2 years

Commitments and Contingencies87

Commitments and Contingencies - Operating Leases (Details) $ in Millions	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,017	$ 7.2
2,018	4.4
2,019	1.9
2,020	1.4
2,021	0.5
Thereafter	4.7
Total	$ 20.1

Guarantors - Narrative (Details

Guarantors - Narrative (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 20, 2012
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net	$ 1,240,100,000	$ 996,500,000
CyrusOne GP
Condensed Financial Statements, Captions [Line Items]
Combined interest held on completion of transactions	1.00%
Non- Guarantors
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net	$ 0	$ 0
Parent company's ownership percentage	100.00%
6.375% senior notes due 2022, including bond premium
Condensed Financial Statements, Captions [Line Items]
Stated interest rate	6.375%	6.375%	6.375%
6.375% senior notes due 2022, including bond premium | CyrusOne GP
Condensed Financial Statements, Captions [Line Items]
Ownership percentage of senior notes	100.00%
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net	$ 477,300,000	$ 477,600,000
Stated interest rate	6.375%
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium | CyrusOne LP and CyrusOne Finance Corp
Condensed Financial Statements, Captions [Line Items]
Long-term debt, net				$ 525,000,000
Stated interest rate	6.375%			6.375%

Guarantors - Consolidating Bala

Guarantors - Consolidating Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Consolidating Balance Sheets
Land	$ 142.7	$ 93
Buildings and improvements	1,008.9	905.3
Equipment	1,042.9	598.2
Construction in progress	407.1	231.1
Subtotal	2,601.6	1,827.6
Accumulated depreciation	(578.5)	(435.6)
Net investment in real estate	2,023.1	1,392
Cash and cash equivalents	14.6	14.3	$ 36.5	$ 148.8
Investment in subsidiaries	0	0
Restricted cash	0	1.5
Rent and other receivables	83.3	76.1
Intercompany receivable	0	0
Goodwill	455.1	453.4
Intangible assets, net	150.2	170.3
Other assets	126.1	88
Total assets	2,852.4	2,195.6
Accounts payable and accrued expenses	227.1	136.6
Deferred revenue	76.7	78.7
Intercompany payable	0	0
Capital lease obligations	10.8	12.2
Long-term debt, net	1,240.1	996.5
Lease financing arrangements	135.7	150
Total liabilities	1,690.4	1,374
Total shareholders’ equity	1,162	821.6
Total liabilities and equity	2,852.4	2,195.6
Eliminations/Consolidations
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	1.2	0.1
Equipment	5.1	2.6
Construction in progress	0.7	1.2
Subtotal	7	3.9
Accumulated depreciation	0	0
Net investment in real estate	7	3.9
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	(2,560.1)	(1,677.2)
Restricted cash		0
Rent and other receivables	0	0
Intercompany receivable	(1,076.8)	(991.3)
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	(3,629.9)	(2,664.6)
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	(1,076.8)	(991.3)
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	(1,076.8)	(991.3)
Total shareholders’ equity	(2,553.1)	(1,673.3)
Total liabilities and equity	(3,629.9)	(2,664.6)
Parent Guarantor
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	1,170.3	817.7
Restricted cash		0
Rent and other receivables	0	0
Intercompany receivable	18.6	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	1,188.9	817.7
Accounts payable and accrued expenses	33.9	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	33.9	0
Total shareholders’ equity	1,155	817.7
Total liabilities and equity	1,188.9	817.7
LP Co-issuer
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	1,376.1	850.6
Restricted cash		0
Rent and other receivables	0	0
Intercompany receivable	1,057.7	991.3
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	2,433.8	1,841.9
Accounts payable and accrued expenses	4.8	29.2
Deferred revenue	0	0
Intercompany payable	18.6	0
Capital lease obligations	0	0
Long-term debt, net	1,240.1	995
Lease financing arrangements	0	0
Total liabilities	1,263.5	1,024.2
Total shareholders’ equity	1,170.3	817.7
Total liabilities and equity	2,433.8	1,841.9
Finance Co-issuer
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	0	0
Investment in subsidiaries	0	0
Restricted cash		0
Rent and other receivables	0	0
Intercompany receivable	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	0	0
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	0	0
Total shareholders’ equity	0	0
Total liabilities and equity	0	0
Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Land	142.7	93
Buildings and improvements	973.6	865.6
Equipment	1,036.8	594.7
Construction in progress	406.4	229.8
Subtotal	2,559.5	1,783.1
Accumulated depreciation	(571.3)	(426)
Net investment in real estate	1,988.2	1,357.1
Cash and cash equivalents	13.4	10.4	33.5	146.8
Investment in subsidiaries	2	0.7
Restricted cash		1.5
Rent and other receivables	81.8	74.8
Intercompany receivable	0	0
Goodwill	455.1	453.4
Intangible assets, net	150.2	170.3
Other assets	123.4	85.3
Total assets	2,814.1	2,153.5
Accounts payable and accrued expenses	187.7	106.8
Deferred revenue	76	78
Intercompany payable	1,058.2	991.3
Capital lease obligations	5.6	6.1
Long-term debt, net	0	1.5
Lease financing arrangements	110.5	119.2
Total liabilities	1,438	1,302.9
Total shareholders’ equity	1,376.1	850.6
Total liabilities and equity	2,814.1	2,153.5
Non- Guarantors
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	34.1	39.6
Equipment	1	0.9
Construction in progress	0	0.1
Subtotal	35.1	40.6
Accumulated depreciation	(7.2)	(9.6)
Net investment in real estate	27.9	31
Cash and cash equivalents	1.2	3.9	3	2
Investment in subsidiaries	0	0
Restricted cash		0
Rent and other receivables	1.5	1.3
Intercompany receivable	0.5	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	2.7	2.7
Total assets	33.8	38.9
Accounts payable and accrued expenses	0.7	0.6
Deferred revenue	0.7	0.7
Intercompany payable	0	0
Capital lease obligations	5.2	6.1
Long-term debt, net	0	0
Lease financing arrangements	25.2	30.8
Total liabilities	31.8	38.2
Total shareholders’ equity	2	0.7
Total liabilities and equity	33.8	38.9
General Partner
Condensed Consolidating Balance Sheets
Land	0	0
Buildings and improvements	0	0
Equipment	0	0
Construction in progress	0	0
Subtotal	0	0
Accumulated depreciation	0	0
Net investment in real estate	0	0
Cash and cash equivalents	0	0	$ 0	$ 0
Investment in subsidiaries	11.7	8.2
Restricted cash		0
Rent and other receivables	0	0
Intercompany receivable	0	0
Goodwill	0	0
Intangible assets, net	0	0
Other assets	0	0
Total assets	11.7	8.2
Accounts payable and accrued expenses	0	0
Deferred revenue	0	0
Intercompany payable	0	0
Capital lease obligations	0	0
Long-term debt, net	0	0
Lease financing arrangements	0	0
Total liabilities	0	0
Total shareholders’ equity	11.7	8.2
Total liabilities and equity	$ 11.7	$ 8.2

Guarantors - Consolidating Stat

Guarantors - Consolidating Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Consolidating Statements of Operations
Revenue	$ 137,400,000	$ 143,800,000	$ 130,100,000	$ 117,800,000	$ 113,300,000	$ 111,200,000	$ 89,100,000	$ 85,700,000	$ 529,100,000	$ 399,300,000	$ 330,900,000
Costs and expenses:
Property operating expenses									187,500,000	148,700,000	124,500,000
Sales and marketing									16,900,000	12,100,000	12,800,000
General and administrative									60,700,000	46,600,000	34,600,000
Depreciation and amortization									183,900,000	141,500,000	118,000,000
Transaction and acquisition integration costs									4,300,000	14,100,000	1,000,000
Asset impairments and loss on disposal									5,300,000	13,500,000	0
Total costs and expenses									458,600,000	376,500,000	290,900,000
Operating income	12,700,000	18,800,000	21,100,000	17,900,000	11,100,000	7,500,000	2,600,000	1,600,000	70,500,000	22,800,000	40,000,000
Interest expense									48,800,000	41,200,000	39,500,000
Loss on extinguishment of debt									0	0	13,600,000
Net income (loss) before income taxes									21,700,000	(18,400,000)	(13,100,000)
Income tax expense									(1,800,000)	(1,800,000)	(1,400,000)
Equity (loss) earnings related to investment in subsidiaries									0	0	0
Net income (loss)	800,000	4,400,000	9,100,000	5,600,000	(1,200,000)	(5,300,000)	(6,500,000)	(7,200,000)	19,900,000	(20,200,000)	(14,500,000)
Noncontrolling interest in net loss									0	4,800,000	6,700,000
Net income (loss) attributed to common stockholders	$ 800,000	$ 4,400,000	$ 9,100,000	$ 5,600,000	$ (1,000,000)	$ (4,600,000)	$ (5,500,000)	$ (4,300,000)	19,900,000	(15,400,000)	(7,800,000)
Other comprehensive loss									(900,000)	(200,000)	(300,000)
Other comprehensive loss attributable to noncontrolling interests											100,000
Comprehensive income (loss) attributable to CyrusOne Inc.									19,000,000	(15,600,000)	(8,000,000)
Eliminations/Consolidations
Condensed Consolidating Statements of Operations
Revenue									0	0	0
Costs and expenses:
Property operating expenses									0	0	0
Sales and marketing									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									(3,100,000)	(1,700,000)	(2,200,000)
Loss on extinguishment of debt											0
Net income (loss) before income taxes									3,100,000	1,700,000	2,200,000
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									(81,700,000)	2,800,000	(21,000,000)
Net income (loss)									(78,600,000)	4,500,000	(18,800,000)
Noncontrolling interest in net loss										4,800,000	6,700,000
Net income (loss) attributed to common stockholders									(78,600,000)	9,300,000	(12,100,000)
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											100,000
Comprehensive income (loss) attributable to CyrusOne Inc.									(78,600,000)	9,300,000	(12,000,000)
Parent Guarantor
Condensed Consolidating Statements of Operations
Revenue									0	0	0
Costs and expenses:
Property operating expenses									0	0	0
Sales and marketing									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									0	0	0
Loss on extinguishment of debt											0
Net income (loss) before income taxes									0	0	0
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									15,900,000	(17,100,000)	(10,000,000)
Net income (loss)									15,900,000	(17,100,000)	(10,000,000)
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									15,900,000	(17,100,000)	(10,000,000)
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									15,900,000	(17,100,000)	(10,000,000)
LP Co-issuer
Condensed Consolidating Statements of Operations
Revenue									0	0	0
Costs and expenses:
Property operating expenses									0	0	0
Sales and marketing									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									49,100,000	39,700,000	38,200,000
Loss on extinguishment of debt											13,600,000
Net income (loss) before income taxes									(49,100,000)	(39,700,000)	(51,800,000)
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									65,000,000	17,800,000	35,100,000
Net income (loss)									15,900,000	(21,900,000)	(16,700,000)
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									15,900,000	(21,900,000)	(16,700,000)
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									15,900,000	(21,900,000)	(16,700,000)
Finance Co-issuer
Condensed Consolidating Statements of Operations
Revenue									0	0	0
Costs and expenses:
Property operating expenses									0	0	0
Sales and marketing									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									0	0	0
Loss on extinguishment of debt											0
Net income (loss) before income taxes									0	0	0
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									0	0	0
Net income (loss)									0	0	0
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									0	0	0
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									0	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Operations
Revenue									523,700,000	393,800,000	325,100,000
Costs and expenses:
Property operating expenses									185,200,000	146,000,000	121,900,000
Sales and marketing									16,900,000	12,000,000	12,600,000
General and administrative									60,500,000	46,600,000	34,200,000
Depreciation and amortization									185,300,000	138,700,000	115,000,000
Transaction and acquisition integration costs									4,300,000	14,100,000	1,000,000
Asset impairments and loss on disposal									5,300,000	13,500,000
Total costs and expenses									457,500,000	370,900,000	284,700,000
Operating income									66,200,000	22,900,000	40,400,000
Interest expense									0	0	0
Loss on extinguishment of debt											0
Net income (loss) before income taxes									66,200,000	22,900,000	40,400,000
Income tax expense									(1,800,000)	(1,800,000)	(1,400,000)
Equity (loss) earnings related to investment in subsidiaries									600,000	(3,300,000)	(3,900,000)
Net income (loss)									65,000,000	17,800,000	35,100,000
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									65,000,000	17,800,000	35,100,000
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									65,000,000	17,800,000	35,100,000
Non- Guarantors
Condensed Consolidating Statements of Operations
Revenue									5,400,000	5,500,000	5,800,000
Costs and expenses:
Property operating expenses									2,300,000	2,700,000	2,600,000
Sales and marketing									0	100,000	200,000
General and administrative									200,000	0	400,000
Depreciation and amortization									(1,400,000)	2,800,000	3,000,000
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									1,100,000	5,600,000	6,200,000
Operating income									4,300,000	(100,000)	(400,000)
Interest expense									2,800,000	3,200,000	3,500,000
Loss on extinguishment of debt											0
Net income (loss) before income taxes									1,500,000	(3,300,000)	(3,900,000)
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									0	0	0
Net income (loss)									1,500,000	(3,300,000)	(3,900,000)
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									1,500,000	(3,300,000)	(3,900,000)
Other comprehensive loss									(900,000)	(200,000)	(300,000)
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									600,000	(3,500,000)	(4,200,000)
General Partner
Condensed Consolidating Statements of Operations
Revenue									0	0	0
Costs and expenses:
Property operating expenses									0	0	0
Sales and marketing									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction and acquisition integration costs									0	0	0
Asset impairments and loss on disposal									0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									0	0	0
Loss on extinguishment of debt											0
Net income (loss) before income taxes									0	0	0
Income tax expense									0	0	0
Equity (loss) earnings related to investment in subsidiaries									200,000	(200,000)	(200,000)
Net income (loss)									200,000	(200,000)	(200,000)
Noncontrolling interest in net loss										0	0
Net income (loss) attributed to common stockholders									200,000	(200,000)	(200,000)
Other comprehensive loss									0	0	0
Other comprehensive loss attributable to noncontrolling interests											0
Comprehensive income (loss) attributable to CyrusOne Inc.									$ 200,000	$ (200,000)	$ (200,000)

Guarantors - Consolidating St91

Guarantors - Consolidating Statements of Cash Flows (Details) - USD ($)	1 Months Ended	3 Months Ended								12 Months Ended
	Jul. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Consolidating Statements of Cash Flows
Net income (loss)		$ 800,000	$ 4,400,000	$ 9,100,000	$ 5,600,000	$ (1,200,000)	$ (5,300,000)	$ (6,500,000)	$ (7,200,000)	$ 19,900,000	$ (20,200,000)	$ (14,500,000)
Equity earnings (loss) related to investment in subsidiaries										0	0	0
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										183,900,000	141,500,000	118,000,000
Stock-based compensation expense										12,300,000	14,400,000	10,300,000
Non-cash interest expense										4,800,000	3,400,000	3,400,000
Provision for bad debt										1,600,000	0	800,000
Loss on extinguishment of debt										0	0	13,600,000
Asset impairments and loss on disposal										5,300,000	13,500,000	0
Change in operating assets and liabilities:
Rent receivables and other assets										(51,700,000)	(23,900,000)	(37,000,000)
Accounts payable and accrued expenses										7,000,000	7,000,000	6,900,000
Deferred revenues										(2,500,000)	5,400,000	9,800,000
Due to affiliates										0	(900,000)	(200,000)
Net cash provided by operating activities										180,600,000	140,200,000	111,100,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										(131,100,000)	(17,300,000)	0
Capital expenditures – other development										(600,000,000)	(217,200,000)	(284,200,000)
Business acquisition, net of cash acquired										0	(398,400,000)	0
Changes in restricted cash										1,500,000	7,300,000	0
Investment in subsidiaries										0	0
Return of investment										0	0	0
Intercompany receipts												0
Intercompany borrowings										0	0	0
Net cash used in investing activities										(729,600,000)	(625,600,000)	(284,200,000)
Cash flows from financing activities:
Issuance of common stock					256,000,000					448,700,000	799,500,000	356,000,000
Stock issuance costs										(1,600,000)	(800,000)	(1,300,000)
Acquisition of operating partnership units										0	(596,400,000)	(355,900,000)
Dividends paid										(114,300,000)	(80,800,000)	(50,900,000)
Intercompany borrowings										0	0	0
Intercompany payments												0
Borrowings from credit facility										710,000,000	260,000,000	315,000,000
Proceeds from issuance of debt										0	103,800,000	0
Payments on credit facility										(460,000,000)	(10,000,000)	(30,000,000)
Payments on senior notes										0	0	(150,200,000)
Payments on capital leases and lease financing arrangements										(9,100,000)	(5,900,000)	(3,900,000)
Payments on capital leases obligations												(3,000,000)
Payments on financing arrangements												(900,000)
Payment of debt extinguishment costs										0	0	(12,800,000)
Tax payment upon exercise of equity awards										(14,200,000)	(800,000)	0
Contributions/distributions from parent										0	0	0
Payment of note payable	$ (1,500,000)									(1,500,000)	0	0
Debt issuance costs										(8,700,000)	(5,400,000)	(5,200,000)
Net cash provided by financing activities										549,300,000	463,200,000	60,800,000
Net increase (decrease) in cash and cash equivalents										300,000	(22,200,000)	(112,300,000)
Cash and cash equivalents at beginning of period					14,300,000				36,500,000	14,300,000	36,500,000	148,800,000
Cash and cash equivalents at end of period		14,600,000				14,300,000				14,600,000	14,300,000	36,500,000
General Partner
Condensed Consolidating Statements of Cash Flows
Net income (loss)										200,000	(200,000)	(200,000)
Equity earnings (loss) related to investment in subsidiaries										(200,000)	200,000	200,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										0	0	0
Stock-based compensation expense										0	0	0
Non-cash interest expense										0	0	0
Provision for bad debt										0		0
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										0	0	0
Accounts payable and accrued expenses										0	0	0
Deferred revenues										0	0	0
Due to affiliates											0	0
Net cash provided by operating activities										0	0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										0	0	0
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										(4,500,000)	(2,000,000)
Return of investment										0	0	0
Intercompany receipts												0
Intercompany borrowings										0	0	0
Net cash used in investing activities										(4,500,000)	(2,000,000)	0
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										0	0	0
Intercompany borrowings										0	0	0
Intercompany payments												0
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										0	0
Payments on capital leases obligations												0
Payments on financing arrangements												0
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										4,500,000	2,000,000	0
Payment of note payable										0
Debt issuance costs										0	0	0
Net cash provided by financing activities										4,500,000	2,000,000	0
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					0				0	0	0	0
Cash and cash equivalents at end of period		0				0				0	0	0
Parent Guarantor
Condensed Consolidating Statements of Cash Flows
Net income (loss)										15,900,000	(17,100,000)	(10,000,000)
Equity earnings (loss) related to investment in subsidiaries										(15,900,000)	17,100,000	10,000,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										0	0	0
Stock-based compensation expense										0	0	0
Non-cash interest expense										0	0	0
Provision for bad debt										0		0
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										0	0	0
Accounts payable and accrued expenses										0	0	0
Deferred revenues										0	0	0
Due to affiliates											0	0
Net cash provided by operating activities										0	0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										0	0	0
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										(448,200,000)	(203,100,000)
Return of investment										112,300,000	62,600,000	25,200,000
Intercompany receipts												0
Intercompany borrowings										15,300,000	0	0
Net cash used in investing activities										(320,600,000)	(140,500,000)	25,200,000
Cash flows from financing activities:
Issuance of common stock										448,700,000	799,500,000	356,000,000
Stock issuance costs										(1,600,000)	(800,000)	(1,300,000)
Acquisition of operating partnership units											(596,400,000)	(355,900,000)
Dividends paid										(112,300,000)	(61,000,000)	(24,000,000)
Intercompany borrowings										0	0	0
Intercompany payments												0
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										0	0
Payments on capital leases obligations												0
Payments on financing arrangements												0
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										(14,200,000)	(800,000)
Contributions/distributions from parent										0	0	0
Payment of note payable										0
Debt issuance costs										0	0	0
Net cash provided by financing activities										320,600,000	140,500,000	(25,200,000)
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					0				0	0	0	0
Cash and cash equivalents at end of period		0				0				0	0	0
LP Co-issuer
Condensed Consolidating Statements of Cash Flows
Net income (loss)										15,900,000	(21,900,000)	(16,700,000)
Equity earnings (loss) related to investment in subsidiaries										(65,000,000)	(17,800,000)	(35,100,000)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										0	0	0
Stock-based compensation expense										0	0	0
Non-cash interest expense										3,700,000	3,400,000	3,400,000
Provision for bad debt										0		0
Loss on extinguishment of debt												13,600,000
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										0	0	400,000
Accounts payable and accrued expenses										0	16,700,000	4,700,000
Deferred revenues										0	0	0
Due to affiliates											0	0
Net cash provided by operating activities										(45,400,000)	(19,600,000)	(29,700,000)
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										0	0	0
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										(448,200,000)	(203,100,000)
Return of investment										0	102,000,000	97,300,000
Intercompany receipts												180,200,000
Intercompany borrowings										(66,300,000)	(348,400,000)	(315,000,000)
Net cash used in investing activities										(514,500,000)	(449,500,000)	(37,500,000)
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										(114,300,000)	(80,800,000)	(50,900,000)
Intercompany borrowings										(15,300,000)	0	0
Intercompany payments												0
Borrowings from credit facility										710,000,000	260,000,000	315,000,000
Proceeds from issuance of debt											103,800,000
Payments on credit facility										(460,000,000)	(10,000,000)	(30,000,000)
Payments on senior notes												(150,200,000)
Payments on capital leases and lease financing arrangements										0	0
Payments on capital leases obligations												0
Payments on financing arrangements												0
Payment of debt extinguishment costs												(12,800,000)
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										448,200,000	201,500,000	1,300,000
Payment of note payable										0
Debt issuance costs										(8,700,000)	(5,400,000)	(5,200,000)
Net cash provided by financing activities										559,900,000	469,100,000	67,200,000
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					0				0	0	0	0
Cash and cash equivalents at end of period		0				0				0	0	0
Finance Co-issuer
Condensed Consolidating Statements of Cash Flows
Net income (loss)										0	0	0
Equity earnings (loss) related to investment in subsidiaries										0	0	0
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										0	0	0
Stock-based compensation expense										0	0	0
Non-cash interest expense										0	0	0
Provision for bad debt										0		0
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										0	0	0
Accounts payable and accrued expenses										0	0	0
Deferred revenues										0	0	0
Due to affiliates											0	0
Net cash provided by operating activities										0	0	0
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										0	0	0
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										0	0
Return of investment										0	0	0
Intercompany receipts												0
Intercompany borrowings										0	0	0
Net cash used in investing activities										0	0	0
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										0	0	0
Intercompany borrowings										0	0	0
Intercompany payments												0
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										0	0
Payments on capital leases obligations												0
Payments on financing arrangements												0
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										0	0	0
Payment of note payable										0
Debt issuance costs										0	0	0
Net cash provided by financing activities										0	0	0
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					0				0	0	0	0
Cash and cash equivalents at end of period		0				0				0	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net income (loss)										65,000,000	17,800,000	35,100,000
Equity earnings (loss) related to investment in subsidiaries										(600,000)	3,300,000	3,900,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										185,300,000	138,700,000	115,000,000
Stock-based compensation expense										12,300,000	14,400,000	10,300,000
Non-cash interest expense										0	0	0
Provision for bad debt										1,600,000		800,000
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										5,300,000	13,500,000
Change in operating assets and liabilities:
Rent receivables and other assets										(51,500,000)	(26,100,000)	(35,300,000)
Accounts payable and accrued expenses										6,900,000	(9,800,000)	2,100,000
Deferred revenues										(2,500,000)	5,300,000	10,000,000
Due to affiliates											(900,000)	(200,000)
Net cash provided by operating activities										221,800,000	156,200,000	141,700,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										(131,100,000)	(17,300,000)
Capital expenditures – other development										(598,900,000)	(216,700,000)	(283,900,000)
Business acquisition, net of cash acquired											(398,400,000)
Changes in restricted cash										1,500,000	7,300,000
Investment in subsidiaries										0	(400,000)
Return of investment										0	(17,900,000)	(45,400,000)
Intercompany receipts												0
Intercompany borrowings										0	0	0
Net cash used in investing activities										(728,500,000)	(643,400,000)	(329,300,000)
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										0	(80,800,000)	(50,900,000)
Intercompany borrowings										71,000,000	348,400,000	315,000,000
Intercompany payments												(180,200,000)
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										(8,000,000)	(5,000,000)
Payments on capital leases obligations												(2,400,000)
Payments on financing arrangements												(700,000)
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										448,200,000	201,500,000	(6,500,000)
Payment of note payable										(1,500,000)
Debt issuance costs										0	0	0
Net cash provided by financing activities										509,700,000	464,100,000	74,300,000
Net increase (decrease) in cash and cash equivalents										3,000,000	(23,100,000)	(113,300,000)
Cash and cash equivalents at beginning of period					10,400,000				33,500,000	10,400,000	33,500,000	146,800,000
Cash and cash equivalents at end of period		13,400,000				10,400,000				13,400,000	10,400,000	33,500,000
Non- Guarantors
Condensed Consolidating Statements of Cash Flows
Net income (loss)										1,500,000	(3,300,000)	(3,900,000)
Equity earnings (loss) related to investment in subsidiaries										0	0	0
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										(1,400,000)	2,800,000	3,000,000
Stock-based compensation expense										0	0	0
Non-cash interest expense										0	0	0
Provision for bad debt										0		0
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										(200,000)	2,200,000	(2,100,000)
Accounts payable and accrued expenses										100,000	100,000	100,000
Deferred revenues										0	100,000	(200,000)
Due to affiliates											0	0
Net cash provided by operating activities										0	1,900,000	(3,100,000)
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										(1,100,000)	(500,000)	(300,000)
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										0	0
Return of investment										0	0	0
Intercompany receipts												0
Intercompany borrowings										(500,000)	0	0
Net cash used in investing activities										(1,600,000)	(500,000)	(300,000)
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										0	0	0
Intercompany borrowings										0	0	0
Intercompany payments												0
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										(1,100,000)	(900,000)
Payments on capital leases obligations												(600,000)
Payments on financing arrangements												(200,000)
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										0	400,000	5,200,000
Payment of note payable										0
Debt issuance costs										0	0	0
Net cash provided by financing activities										(1,100,000)	(500,000)	4,400,000
Net increase (decrease) in cash and cash equivalents										(2,700,000)	900,000	1,000,000
Cash and cash equivalents at beginning of period					3,900,000				3,000,000	3,900,000	3,000,000	2,000,000
Cash and cash equivalents at end of period		1,200,000				3,900,000				1,200,000	3,900,000	3,000,000
Eliminations/Consolidations
Condensed Consolidating Statements of Cash Flows
Net income (loss)										(78,600,000)	4,500,000	(18,800,000)
Equity earnings (loss) related to investment in subsidiaries										81,700,000	(2,800,000)	21,000,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization										0	0	0
Stock-based compensation expense										0	0	0
Non-cash interest expense										1,100,000	0	0
Provision for bad debt										0		0
Loss on extinguishment of debt												0
Asset impairments and loss on disposal										0	0
Change in operating assets and liabilities:
Rent receivables and other assets										0	0	0
Accounts payable and accrued expenses										0	0	0
Deferred revenues										0	0	0
Due to affiliates											0	0
Net cash provided by operating activities										4,200,000	1,700,000	2,200,000
Cash flows from investing activities:
Capital expenditures – purchase of fixed assets										0	0
Capital expenditures – other development										0	0	0
Business acquisition, net of cash acquired											0
Changes in restricted cash										0	0
Investment in subsidiaries										900,900,000	408,600,000
Return of investment										(112,300,000)	(146,700,000)	(77,100,000)
Intercompany receipts												(180,200,000)
Intercompany borrowings										51,500,000	348,400,000	315,000,000
Net cash used in investing activities										840,100,000	610,300,000	57,700,000
Cash flows from financing activities:
Issuance of common stock										0	0	0
Stock issuance costs										0	0	0
Acquisition of operating partnership units											0	0
Dividends paid										112,300,000	141,800,000	74,900,000
Intercompany borrowings										(55,700,000)	(348,400,000)	(315,000,000)
Intercompany payments												180,200,000
Borrowings from credit facility										0	0	0
Proceeds from issuance of debt											0
Payments on credit facility										0	0	0
Payments on senior notes												0
Payments on capital leases and lease financing arrangements										0	0
Payments on capital leases obligations												0
Payments on financing arrangements												0
Payment of debt extinguishment costs												0
Tax payment upon exercise of equity awards										0	0
Contributions/distributions from parent										(900,900,000)	(405,400,000)	0
Payment of note payable										0
Debt issuance costs										0	0	0
Net cash provided by financing activities										(844,300,000)	(612,000,000)	(59,900,000)
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					$ 0				$ 0	0	0	0
Cash and cash equivalents at end of period		$ 0				$ 0				$ 0	$ 0	$ 0

Quarterly Financial Informati92

Quarterly Financial Information (Unaudited) - Schedule of Quarterly Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		3 Months Ended								12 Months Ended
	Jun. 30, 2015	Apr. 30, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Revenue			$ 137.4	$ 143.8	$ 130.1	$ 117.8	$ 113.3	$ 111.2	$ 89.1	$ 85.7	$ 529.1	$ 399.3	$ 330.9
Operating income			12.7	18.8	21.1	17.9	11.1	7.5	2.6	1.6	70.5	22.8	40
Net income (loss)			0.8	4.4	9.1	5.6	(1.2)	(5.3)	(6.5)	(7.2)	19.9	(20.2)	(14.5)
Net income (loss) attributed to common stockholders			$ 0.8	$ 4.4	$ 9.1	$ 5.6	$ (1)	$ (4.6)	$ (5.5)	$ (4.3)	$ 19.9	$ (15.4)	$ (7.8)
Basic and diluted income (loss) per share, including anti-dilutive securities (in dollars per share)			$ 0.01	$ 0.05	$ 0.11	$ 0.07	$ (0.02)	$ (0.08)	$ (0.11)	$ (0.12)	$ 0.24	$ (0.33)
Basic and diluted income (loss) per share (in dollars per share)											$ 0.24	$ (0.30)	$ (0.30)
Public stock offering
Class of Stock [Line Items]
Anti-dilutive securities excluded from diluted earnings per share (in shares)	6	14.3

Subsequent Event (Details)

Subsequent Event (Details) ft² in Thousands, shares in Millions	Feb. 22, 2017USD ($)shares	Feb. 06, 2017USD ($)ft²data_centerMW	Aug. 15, 2016USD ($)shares	Mar. 21, 2016USD ($)shares	Dec. 31, 2015shares	Dec. 14, 2015USD ($)shares	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares
Subsequent Event [Line Items]
Proceeds from public stock offerings							$ 256,000,000	$ 448,700,000	$ 799,500,000	$ 356,000,000
Raleigh-Durham, North Carolina and Somerset, New Jersey data centers | Subsequent event
Subsequent Event [Line Items]
Data centers purchased (in data centers) | data_center		2
Total purchase price excluding transaction related costs		$ 490,000,000
Raleigh-Durham, North Carolina and Somerset, New Jersey data centers | Data centers | Subsequent event
Subsequent Event [Line Items]
Area of real estate acquired (in sq ft) | ft²		160
Amount of power capacity added (in megawatts) | MW		21
Public stock offering
Subsequent Event [Line Items]
Issuance of common stock upon full physical settlement of forward contract (in shares) | shares			3.4	6.9	6.3	1.4		10.3	27.3	16
Proceeds from public stock offerings			$ 164,800,000	$ 255,000,000		$ 0		$ 419,800,000	$ 799,300,000	$ 355,900,000
Public stock offering | Goldman, Sachs & Co., forward contract
Subsequent Event [Line Items]
Issuance of common stock upon full physical settlement of forward contract (in shares) | shares			4.4
Public stock offering | Goldman, Sachs & Co., forward contract | Subsequent event
Subsequent Event [Line Items]
Issuance of common stock upon full physical settlement of forward contract (in shares) | shares	4.4
Proceeds from public stock offerings	$ 211,000,000

Schedule II. Valuation and Qu94

Schedule II. Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	$ 1	$ 1	$ 0.5
Charge to Expenses	1.6	0	0.8
(Deductions)/Additions	(0.5)	0	(0.3)
End of Period	2.1	1	1
Deferred Tax Valuation Allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of Period	6.3	5.7	3.6
Charge to Expenses	0.2	0.6	2.1
(Deductions)/Additions	0	0	0
End of Period	$ 6.5	$ 6.3	$ 5.7

Schedule III. Real Estate Pro95

Schedule III. Real Estate Properties and Accumulated Depreciation - Schedule of Real Estate Properties (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Initial Costs
Land	$ 141.7
Building and Improvements	349.1
Equipment	203.2
Cost Capitalized Subsequent to Acquisition
Land	1
Building and Improvements	659.8
Equipment	839.7
Gross Carrying Amount
Land	142.7	$ 93
Building and Improvements	1,008.9	905.3
Equipment	1,042.9	598.2
Accumulated Depreciation	578.5	435.6	$ 327	$ 236.7
Aggregate cost of the total properties for federal income tax purposes	3,095
Construction in progress	407.1	231.1
Dallas - Carrollton
Initial Costs
Land	16.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	57.6
Equipment	154
Gross Carrying Amount
Land	16.1	16.1
Building and Improvements	57.6	52.7
Equipment	154	116.5
Accumulated Depreciation	54.3
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	63.6
Equipment	48.3
Gross Carrying Amount
Land	1.4	1.4
Building and Improvements	85	84.8
Equipment	48.4	46.4
Accumulated Depreciation	63.2
Dallas - Lewisville
Initial Costs
Land	0
Building and Improvements	46.2
Equipment	2.2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	30.5
Equipment	31.5
Gross Carrying Amount
Land	0	0
Building and Improvements	76.7	76.6
Equipment	33.7	24.9
Accumulated Depreciation	53.4
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	68.4
Equipment	21
Gross Carrying Amount
Land	0.9	0.9
Building and Improvements	110.6	110.6
Equipment	21	19.6
Accumulated Depreciation	80.7
Northern Virginia - Sterling II
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	28.7
Equipment	111.8
Gross Carrying Amount
Land	0	0
Building and Improvements	28.7	0
Equipment	111.8	0
Accumulated Depreciation	6
Totowa - Madison
Initial Costs
Land	0
Building and Improvements	28.3
Equipment	45.6
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	5.2
Gross Carrying Amount
Land	0	0
Building and Improvements	28.3	28.3
Equipment	50.8	48.8
Accumulated Depreciation	11.7
Wappingers Falls I
Initial Costs
Land	0
Building and Improvements	9.9
Equipment	13.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	1.4
Equipment	3.8
Gross Carrying Amount
Land	0	0
Building and Improvements	11.3	11.3
Equipment	17.1	14.4
Accumulated Depreciation	5.4
Cincinnati - North Cincinnati
Initial Costs
Land	4
Building and Improvements	12.3
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	65
Equipment	9
Gross Carrying Amount
Land	4	4
Building and Improvements	77.3	77.3
Equipment	9	7.6
Accumulated Depreciation	32.1
Houston - Houston West II
Initial Costs
Land	2
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.8
Building and Improvements	23.1
Equipment	49
Gross Carrying Amount
Land	2.8	2
Building and Improvements	23.1	22.6
Equipment	49	47.1
Accumulated Depreciation	22.2
San Antonio I
Initial Costs
Land	4.6
Building and Improvements	3
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	29.1
Equipment	33.6
Gross Carrying Amount
Land	4.6	4.6
Building and Improvements	32.1	32.1
Equipment	33.6	33
Accumulated Depreciation	21.4
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	2.5
Equipment	2.6
Gross Carrying Amount
Land	2.4	0
Building and Improvements	28.5	0
Equipment	99.9	0
Accumulated Depreciation	9.4
Phoenix - Chandler II
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	16.1
Equipment	38.8
Gross Carrying Amount
Land	0	0
Building and Improvements	16.1	16
Equipment	38.8	39.5
Accumulated Depreciation	10.5
Houston - Galleria
Initial Costs
Land	0
Building and Improvements	56
Equipment	2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	12.6
Equipment	14.6
Gross Carrying Amount
Land	0	0
Building and Improvements	68.6	68.6
Equipment	16.6	16
Accumulated Depreciation	43.3
Florence
Initial Costs
Land	2.2
Building and Improvements	7.7
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	34.2
Equipment	4.9
Gross Carrying Amount
Land	2.2	2.2
Building and Improvements	41.9	41.5
Equipment	4.9	3.3
Accumulated Depreciation	24.9
Austin II
Initial Costs
Land	2
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	23.4
Equipment	6.6
Gross Carrying Amount
Land	2	2
Building and Improvements	23.4	23.2
Equipment	6.6	5.7
Accumulated Depreciation	12.1
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	29
Equipment	59.4
Gross Carrying Amount
Land	7	7
Building and Improvements	29	0
Equipment	59.4	0.1
Accumulated Depreciation	3.6
Northern Virginia - Sterling I
Initial Costs
Land	6.9
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.1
Building and Improvements	19.7
Equipment	47.2
Gross Carrying Amount
Land	7	7
Building and Improvements	19.7	19.2
Equipment	47.2	45.2
Accumulated Depreciation	10.9
Phoenix - Chandler I
Initial Costs
Land	14.8
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	56.8
Equipment	56.5
Gross Carrying Amount
Land	14.8	14.8
Building and Improvements	56.8	56.7
Equipment	56.5	39.8
Accumulated Depreciation	27
Cincinnati - Hamilton
Initial Costs
Land	0
Building and Improvements	9.5
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	40.7
Equipment	5
Gross Carrying Amount
Land	0	0
Building and Improvements	50.2	49.2
Equipment	5	4.4
Accumulated Depreciation	32.4
Stamford - Riverbend
Initial Costs
Land	0
Building and Improvements	4.3
Equipment	13.2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	1.3
Gross Carrying Amount
Land	0	0
Building and Improvements	4.3	4.3
Equipment	14.5	13.2
Accumulated Depreciation	3.8
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	9
Equipment	42
Gross Carrying Amount
Land	0	0
Building and Improvements	9.9	0
Equipment	44.5	0
Accumulated Depreciation	1.6
London - Great Bridgewater
Initial Costs
Land	0
Building and Improvements	16.5
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	9.4
Equipment	0.9
Gross Carrying Amount
Land	0	0
Building and Improvements	25.9	31.2
Equipment	0.9	0.8
Accumulated Depreciation	2.8
Dallas - Midway
Initial Costs
Land	0
Building and Improvements	1.8
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0.2
Equipment	0.4
Gross Carrying Amount
Land	0	0
Building and Improvements	2	2
Equipment	0.4	0.4
Accumulated Depreciation	2.3
Cincinnati - Mason
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	20.2
Equipment	1.4
Gross Carrying Amount
Land	0	0
Building and Improvements	20.2	20.2
Equipment	1.4	1
Accumulated Depreciation	12.8
Norwalk I
Initial Costs
Land	0
Building and Improvements	18.3
Equipment	25.3
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0.7
Equipment	1.3
Gross Carrying Amount
Land	0	0
Building and Improvements	19	18.3
Equipment	26.6	25.4
Accumulated Depreciation	5
Dallas - Marsh
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0.1
Equipment	0.6
Gross Carrying Amount
Land	0	0
Building and Improvements	0.1	0.1
Equipment	0.6	0.6
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	7.9
Gross Carrying Amount
Land	0.7	0.7
Building and Improvements	4.7	4.7
Equipment	7.9	7.6
Accumulated Depreciation	4.6
Stamford - Omega
Initial Costs
Land	0
Building and Improvements	3.2
Equipment	0.6
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0.9
Gross Carrying Amount
Land	0	0
Building and Improvements	3.2	3.2
Equipment	1.5	1.5
Accumulated Depreciation	0.5
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	1.4
Equipment	33.3
Gross Carrying Amount
Land	4.6	0
Building and Improvements	11	0
Equipment	33.4	0
Accumulated Depreciation	0.3
Cincinnati - Blue Ash
Initial Costs
Land	0
Building and Improvements	2.6
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(2)
Equipment	0.1
Gross Carrying Amount
Land	0	0
Building and Improvements	0.6	0.6
Equipment	0.1	0.1
Accumulated Depreciation	0.3
Totowa - Commerce
Initial Costs
Land	0
Building and Improvements	4.1
Equipment	0.8
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0.6
Gross Carrying Amount
Land	0	0
Building and Improvements	4.1	4.1
Equipment	1.4	1
Accumulated Depreciation	0.5
South Bend - Crescent
Initial Costs
Land	0
Building and Improvements	1.1
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0.6
Equipment	0.2
Gross Carrying Amount
Land	0	0
Building and Improvements	1.7	3.3
Equipment	0.2	0.4
Accumulated Depreciation	1.8
Houston - Houston West III
Initial Costs
Land	18.3
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.1
Building and Improvements	9.4
Equipment	13.5
Gross Carrying Amount
Land	18.4	18.4
Building and Improvements	9.4	4
Equipment	13.5	0.8
Accumulated Depreciation	2.1
Singapore - Inter Business Park
Initial Costs
Land	0
Building and Improvements	9
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(0.8)
Equipment	0.1
Gross Carrying Amount
Land	0	0
Building and Improvements	8.2	8.4
Equipment	0.1	0.1
Accumulated Depreciation	4.4
South Bend - Monroe
Initial Costs
Land	0
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	2.5
Equipment	0.3
Gross Carrying Amount
Land	0	0
Building and Improvements	2.5	2.5
Equipment	0.3	0.3
Accumulated Depreciation	1.4
Cincinnati - Goldcoast
Initial Costs
Land	0.6
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	(0.4)
Building and Improvements	4
Equipment	0.1
Gross Carrying Amount
Land	0.2	0.6
Building and Improvements	4	6.7
Equipment	0.1	0.1
Accumulated Depreciation	2.9
Austin III
Initial Costs
Land	3.3
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	9.7
Equipment	31.8
Gross Carrying Amount
Land	3.3	3.3
Building and Improvements	9.7	7.4
Equipment	31.8	31.5
Accumulated Depreciation	3.3
Austin I
Initial Costs
Land	0
Building and Improvements	11.9
Equipment	0.2
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(8.4)
Equipment	0
Gross Carrying Amount
Land	0	0
Building and Improvements	3.5	13.6
Equipment	0.2	1
Accumulated Depreciation	3.1
Dallas - Downtown
Initial Costs
Land	0
Building and Improvements	0.1
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	(0.1)
Equipment	0
Gross Carrying Amount
Land	0
Building and Improvements	0
Equipment	0
Accumulated Depreciation	0
Austin Land A
Initial Costs
Land	7.9
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0.1
Building and Improvements	0
Equipment	0.2
Gross Carrying Amount
Land	8	8
Building and Improvements	0	0
Equipment	0.2	0.1
Accumulated Depreciation	0
Chicago - Aurora Land A
Initial Costs
Land	2.6
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0
Gross Carrying Amount
Land	2.6	0
Building and Improvements	0	0
Equipment	0	0
Accumulated Depreciation	0
Phoenix - Chandler Land A
Initial Costs
Land	10.5
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0
Gross Carrying Amount
Land	10.5	0
Building and Improvements	0	0
Equipment	0	0
Accumulated Depreciation	0
Chicago - Aurora Land B
Initial Costs
Land	5.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0
Gross Carrying Amount
Land	5.1	0
Building and Improvements	0	0
Equipment	0	0
Accumulated Depreciation	0
Northern Virginia - Sterling Land A
Initial Costs
Land	24.1
Building and Improvements	0
Equipment	0
Cost Capitalized Subsequent to Acquisition
Land	0
Building and Improvements	0
Equipment	0
Gross Carrying Amount
Land	24.1	0
Building and Improvements	0	0
Equipment	0	$ 0
Accumulated Depreciation	$ 0

Schedule III. Real Estate Pro96

Schedule III. Real Estate Properties and Accumulated Depreciation - Historical Cost and Accumulated Depreciation and Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property
Balance—beginning of period	$ 1,827.6	$ 1,378.4	$ 1,120.5
Disposals	(12)	(7)	(0.1)
Impairments	(4.9)	(9.3)	0
Additions (acquisitions and improvements)	790.9	465.5	258
Balance, end of period	2,601.6	1,827.6	1,378.4
Accumulated Depreciation
Balance—beginning of period	435.6	327	236.7
Disposals	(7.9)	(2.7)	0
Impairments	0	0	0
Additions (depreciation and amortization expense)	150.8	111.3	90.3
Balance, end of period	$ 578.5	$ 435.6	$ 327