XML 12 R1.htm IDEA: XBRL DOCUMENT v3.19.2
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2019
Jul. 31, 2019
Document and Entity Information [Abstract]    
Amendment Flag false  
Document Type 10-Q  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Document Quarterly Report true  
Entity Central Index Key 0001054905  
Document Transition Report false  
Current Fiscal Year End Date --12-31  
Document Period End Date Jun. 30, 2019  
Entity File Number 1-13879  
Entity Registrant Name INNOSPEC INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 98-0181725  
Entity Address, Postal Zip Code 80112  
City Area Code 303  
Local Phone Number 792 5554  
Security Exchange Name NASDAQ  
Title of 12(b) Security Common stock  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   24,486,325
Entity Address, Address Line One 8310 South Valley Highway  
Entity Address, City or Town Englewood  
Entity Address, State or Province CO  
Trading Symbol IOSP  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes