v3.26.1
Accumulated Other Comprehensive Loss - Schedule of Components of Accumulated Other Comprehensive Loss, Net of Related Deferred Income Taxes (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax $ (1,055,155) $ (1,025,680) $ (1,036,494) $ (1,804,310) $ (1,559,018) $ (1,604,699)
Total accumulated other comprehensive loss, net of tax            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax (66,211) $ (67,260) (66,656) $ (69,803) $ (75,318) $ (73,747)
Defined benefit pension and other postretirement benefit plans            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax (69,466)   (70,603)      
Unrealized foreign currency translation gain            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax 7,139   8,757      
Unrealized loss on interest rate swaps            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax 0   (1,721)      
Share of other comprehensive loss of equity method investments            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total accumulated other comprehensive loss, net of tax $ (3,884)   $ (3,089)