Document and Entity Information
9 Months Ended
Sep. 30, 2018
Document And Entity Information [Abstract]  
Document Type S-4
Amendment Flag false
Document Period End Date Sep. 30, 2018
Trading Symbol apy
Entity Registrant Name Apergy Corporation
Entity Central Index Key 0001723089
Entity Filer Category Non-accelerated Filer
Entity Small Business false
Entity Emerging Growth Company true
Entity Ex Transition Period true