v3.24.1.u1
Pension Plans and Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2024
Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 2,100 $ 2,000
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 1,997 1,879
Interest cost 11,630 11,910
Expected return on plan assets (15,499) (15,110)
Amortization of prior service cost 820 820
Net periodic benefit income (1,052) (501)
Other Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 97 85
Interest cost 505 535
Expected return on plan assets (487) (634)
Amortization of prior service cost 11 10
Net periodic benefit income $ 126 $ (4)