v3.19.2
Cover Page - shares
6 Months Ended
Jun. 30, 2019
Jul. 25, 2019
Cover page.    
Document Transition Report false  
Title of 12(b) Security Common Stock, $0.01 par value  
Document Quarterly Report true  
Entity Address, Address Line One 2101 Cedar Springs Road  
Entity Incorporation, State or Country Code MD  
Entity Registrant Name CyrusOne Inc.  
Entity Central Index Key 0001553023  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2019  
Entity File Number 001-35789  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Trading Symbol CONE  
Amendment Flag false  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Common Stock, Shares Outstanding   113,192,342
Entity Address, Address Line Two Suite 900  
Entity Address, City or Town Dallas  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 75201  
City Area Code 972  
Local Phone Number 350-0060  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Tax Identification Number 46-0691837  
Entity Shell Company false  
Security Exchange Name NASDAQ