Retirement Plans and Other Postretirement Benefits - Schedule of Net Benefit Cost (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
Amortization of: | ||||
Portion of cost (credit) charged to expense | $ (6,374) | $ (12,006) | $ (11,488) | $ (24,865) |
Pension Benefits | ||||
Retirement Plans and Other Benefits | ||||
Service cost — benefits earned during the period | 12,408 | 14,121 | 24,951 | 28,334 |
Interest cost on benefit obligation | 34,069 | 31,338 | 68,421 | 62,345 |
Expected return on plan assets | (43,049) | (45,759) | (85,942) | (91,426) |
Amortization of: | ||||
Prior service credit | 0 | 0 | 0 | 0 |
Net actuarial loss | 10,053 | 8,259 | 21,292 | 16,041 |
Net periodic benefit cost (credit) | 13,481 | 7,959 | 28,722 | 15,294 |
Portion of cost (credit) charged to expense | 7,000 | 2,769 | 15,244 | 5,011 |
Other Benefits | ||||
Retirement Plans and Other Benefits | ||||
Service cost — benefits earned during the period | 4,470 | 5,445 | 9,184 | 10,550 |
Interest cost on benefit obligation | 7,421 | 6,973 | 14,947 | 14,074 |
Expected return on plan assets | (9,603) | (10,520) | (19,206) | (21,041) |
Amortization of: | ||||
Prior service credit | (9,455) | (9,461) | (18,910) | (18,921) |
Net actuarial loss | 0 | 0 | 0 | 0 |
Net periodic benefit cost (credit) | (7,167) | (7,563) | (13,985) | (15,338) |
Portion of cost (credit) charged to expense | $ (5,063) | $ (5,119) | $ (9,880) | $ (10,724) |