v3.26.1
Segment Information (Schedule Of Net Sales And Operating Profit By Segment) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Information [Line Items]        
Net sales $ 747,094 $ 698,509 $ 1,416,811 $ 1,399,455
Cost of goods sold 504,665 477,555 953,503 942,478
Research, development, and testing expenses 30,388 32,374 62,024 65,550
Segment operating profit 163,665 143,152 306,894 303,021
Corporate, general, and administrative expenses (48,376) (45,428) (94,390) (88,406)
Interest and financing expenses, net (8,818) (10,735) (17,589) (21,435)
Other income (expense), net 15,491 15,271 32,687 30,215
Income before income tax expense 170,338 147,688 321,992 311,801
Operating Segments [Member]        
Segment Information [Line Items]        
Segment operating profit 171,716 150,382 319,137 315,676
Operating Segments [Member] | Petroleum Additives [Member]        
Segment Information [Line Items]        
Net sales 675,573 653,875 1,285,391 1,299,429
Cost of goods sold (463,188) (448,474) (872,626) (886,220)
Research, development, and testing expenses (30,388) (32,374) (62,024) (65,550)
Other segment items (32,627) (33,192) (66,372) (65,717)
Segment operating profit 149,370 139,835 284,369 281,942
Operating Segments [Member] | All Other [Member]        
Segment Information [Line Items]        
Net sales 4,356 2,597 6,114 4,268
Segment operating profit (212) (1,171) (1,322) (1,652)
Operating Segments [Member] | Specialty Materials [Member]        
Segment Information [Line Items]        
Net sales 67,165 42,037 125,306 95,758
Other segment items (44,819) (31,490) (90,538) (62,024)
Segment operating profit 22,346 10,547 34,768 33,734
Operating Segments [Member] | Lubricant additives [Member] | Petroleum Additives [Member]        
Segment Information [Line Items]        
Net sales 584,024 556,479 1,105,193 1,115,657
Operating Segments [Member] | Fuel additives [Member] | Petroleum Additives [Member]        
Segment Information [Line Items]        
Net sales 91,549 97,396 180,198 183,772
Corporate, Non-Segment [Member]        
Segment Information [Line Items]        
Corporate, general, and administrative expenses (7,816) (6,414) (10,869) (11,300)
Interest and financing expenses, net (8,818) (10,735) (17,589) (21,435)
Other income (expense), net $ 15,468 $ 15,626 $ 32,635 $ 30,512