v3.26.1
Related Party and Party-In-Interest Transactions (Tables)
 12 Months Ended
Dec. 31, 2025
EBP 002  
EBP, Related Party and Party-in-Interest Transactions [Line Items]  
Schedule of Activity in the NewMarket Common Stock Fund The table below shows the activity in the NewMarket Corporation Common Stock Fund during 2025 and 2024.
 
SharesAmount
Balance—January 1, 2024337,512 $184,224,266 
Purchases19,903 11,843,021 
Distributions and sales(40,257)(23,799,660)
Depreciation(4,697,467)
Balance—December 31, 2024317,158 167,570,160 
Purchases18,140 12,884,266 
Distributions and sales(45,362)(30,151,562)
Appreciation48,958,795 
Balance—December 31, 2025289,936 $199,261,659