XML 98 R85.htm IDEA: XBRL DOCUMENT v3.22.0.1
Employee benefit plans - Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Retirement Plans      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 3,916 $ 3,969 $ 3,968
Interest cost 24,186 51,297 57,348
Expected return on plan assets (22,888) (50,733) (65,143)
Amortization of prior service cost / (credit) 900 1,006 1,022
Amortization of net actuarial gain (loss) 16,503 28,833 30,681
Effect of settlement loss 550,706 854 2,377
Effect of curtailment loss 0 32 0
Net periodic benefit cost (income) 573,323 35,258 30,253
Retiree Health and Life Insurance Plans      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 374 358 308
Interest cost 197 336 467
Expected return on plan assets (444) (371) (718)
Amortization of prior service cost / (credit) 0 (279) (498)
Amortization of net actuarial gain (loss) (744) (834) (823)
Net periodic benefit cost (income) $ (617) $ (790) $ (1,264)