XML 71 R61.htm IDEA: XBRL DOCUMENT v3.25.1
Employee benefit plans - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Pension benefits    
Defined benefit plan disclosure, net periodic benefit cost [Line Items]    
Interest cost $ 3,303 $ 3,200
Expected return on assets (3,645) (4,028)
Amortization of net actuarial gain (loss) 1,193 1,037
Net periodic benefit cost (credit) 851 209
Other postretirement benefits    
Defined benefit plan disclosure, net periodic benefit cost [Line Items]    
Service cost 99 126
Interest cost 462 459
Expected return on assets (1,292) (1,329)
Amortization of prior service credit (290) (330)
Amortization of net actuarial gain (loss) (80) (72)
Net periodic benefit credit, including amount capitalized (1,101) (1,146)
Less amount capitalized 18 22
Net periodic benefit cost (credit) $ (1,119) $ (1,168)