Cover Page
Dec. 31, 2020
Dec. 26, 2020
Cover [Abstract]    
Document Type   8-K
Document Period End Date   Dec. 26, 2020
Entity Registrant Name   Compass Minerals International, Inc.
Entity Incorporation, State or Country Code   DE
Entity File Number   001-31921
Entity Tax Identification Number   36-3972986
Entity Address, Address Line One   9900 West 109th Street
Entity Address, Address Line Two   Suite 100
Entity Address, City or Town   Overland Park
Entity Address, State or Province   KS
Entity Address, Postal Zip Code   66210
City Area Code   913
Local Phone Number   344-9200
Written Communications   false
Soliciting Material   false
Pre-commencement Tender Offer   false
Pre-commencement Issuer Tender Offer   false
Title of 12(b) Security   Common stock, $0.01 par value
Trading Symbol   CMP
Security Exchange Name   NYSE
Entity Emerging Growth Company   false
Entity Central Index Key   0001227654
Current Fiscal Year End Date --12-31  
Amendment Flag   false