| transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +98 | 
            +1.39% | 
            $0.00 | 
            7.16K | 
            Mar 28, 2022 | 
            Direct | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            -1.67K | 
            -23.26% | 
            $0.00 | 
            5.5K | 
            Mar 28, 2022 | 
            Direct | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            -101 | 
            -0.41% | 
            $0.00 | 
            24.3K | 
            Nov 28, 2022 | 
            Direct | 
            F1, F2, F3, F4 | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +98 | 
            +2% | 
            $0.00 | 
            4.99K | 
            Mar 28, 2022 | 
            Shares held by reporting person's wife | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +18.67% | 
            $0.00 | 
            1.87K | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 1) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +26.09% | 
            $0.00 | 
            1.42K | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 2) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +29.52% | 
            $0.00 | 
            1.29K | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 3) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +35.99% | 
            $0.00 | 
            1.11K | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 4) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +48.84% | 
            $0.00 | 
            896 | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 5) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +75.77% | 
            $0.00 | 
            682 | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 6) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +294 | 
            +116.67% | 
            $0.00 | 
            546 | 
            Mar 28, 2022 | 
            Shares held as trustee for grandchild (trust 7) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            +303 | 
             | 
            $0.00 | 
            303 | 
            Nov 28, 2022 | 
            Shares held as trustee for grandchild (trust 8) | 
             | 
          
          
            | transaction | 
            NEU | 
            Common Stock | 
            Gift | 
            $0 | 
            -160K | 
            -77.52% | 
            $0.00 | 
            46.4K | 
            Dec 16, 2022 | 
            Shares held as co-trustee fbo (among others reporting Floyd D. Gottwald) | 
             | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            37.5K | 
            Dec 31, 2022 | 
            NewMarket Savings Plan | 
            F5 | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            6.89K | 
            Dec 31, 2022 | 
            Shares held as co-trustee fbo children dtd. 12/16/1991 | 
             | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            79.7K | 
            Dec 31, 2022 | 
            2020 GRAT | 
            F2 | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            27.6K | 
            Dec 31, 2022 | 
            2021 GRAT #1 | 
            F1 | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            35.6K | 
            Dec 31, 2022 | 
            2021 GRAT #2 | 
            F4 | 
          
          
            | holding | 
            NEU | 
            Common Stock | 
             | 
             | 
             | 
             | 
             | 
            100K | 
            Dec 31, 2022 | 
            2022 GRAT | 
            F3 |