XML 16 R1.htm IDEA: XBRL DOCUMENT v3.20.4
Cover Page - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Feb. 10, 2021
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Document Annual Report true    
Document Transition Report false    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2020    
Entity File Number 1-13879    
Entity Registrant Name INNOSPEC INC.    
Entity Central Index Key 0001054905    
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   24,598,689  
Entity Address, Address Line One 8310 South Valley Highway    
Entity Address, Address Line Two Suite 350    
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    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer Yes    
Entity Public Float     $ 1,061
ICFR Auditor Attestation Flag true