v3.26.1
Retirement Plans (Components of Net Periodic Benefits Cost) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pension Benefits [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1,432 $ 1,551 $ 2,957 $ 3,151
Interest cost 6,017 6,273 12,610 12,548
Expected return on plan assets (12,070) (11,266) (24,145) (22,534)
Amortization of net (gain) or loss and prior service costs 438 1,118 640 2,258
Net periodic benefit cost (4,183) (2,324) (7,938) (4,577)
Other Post-Retirement Benefits [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 9 9 18 18
Interest cost 153 154 307 308
Amortization of net (gain) or loss and prior service costs (185) (185) (370) (370)
Net periodic benefit cost $ (23) $ (22) $ (45) $ (44)