XML 12 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document And Entity Information - shares
9 Months Ended
Sep. 30, 2018
Oct. 26, 2018
Document and Entity Information [Abstract]    
Entity Registrant Name AdvanSix Inc.  
Document Type 10-Q  
Current Fiscal Year End Date --12-31  
Entity Common Stock, Shares Outstanding   29,802,868
Amendment Flag false  
Entity Central Index Key 0001673985  
Entity Filer Category Large Accelerated Filer  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Entity Emerging Growth Company false  
Entity Small Business false