v3.26.3
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Beginning balance     $ 941,170  
Change in accumulated other comprehensive income (loss) before reclassifications $ (70,784) $ 14,398 (91,279) $ 42,077
Reclassification adjustments from accumulated other comprehensive income (loss) (19) 320 520 1,707
Ending balance 938,894 898,711 938,894 898,711
Total        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Beginning balance (25,019) (25,715) (5,063) (54,781)
Ending balance (95,822) (10,997) (95,822) (10,997)
Net unrealized gain (loss) on investments        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Beginning balance (43,668) (44,737) (25,268) (72,241)
Change in accumulated other comprehensive income (loss) before reclassifications (70,236) 15,903 (89,175) 42,020
Reclassification adjustments from accumulated other comprehensive income (loss) (19) 320 520 1,707
Ending balance (113,923) (28,514) (113,923) (28,514)
Net benefit plan assets and obligations        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Beginning balance 17,415 16,516 18,559 17,660
Change in accumulated other comprehensive income (loss) before reclassifications (572) (572) (1,716) (1,716)
Reclassification adjustments from accumulated other comprehensive income (loss) 0 0 0 0
Ending balance 16,843 15,944 16,843 15,944
Foreign currency translation adjustment        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Beginning balance 1,234 2,506 1,646 (200)
Change in accumulated other comprehensive income (loss) before reclassifications 24 (933) (388) 1,773
Reclassification adjustments from accumulated other comprehensive income (loss) 0 0 0 0
Ending balance $ 1,258 $ 1,573 $ 1,258 $ 1,573