Health Care, Pension and Other Benefits - Components of Net Periodic Benefit Costs (Credits) for Domestic Defined Benefit Pension Plans, Foreign Defined Benefit Pension Plans and Postretirement Benefits Other Than Pensions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Recognition of:
Settlement expense			$ 32,410
Postretirement Benefits Other than Pensions
Net periodic benefit cost (credit):
Service cost	362	499	1,085	1,496
Interest cost	2,800	2,545	8,401	7,634
Expected return on assets
Recognition of:
Unrecognized prior service cost (credit)	(1,249)	(1,643)	(3,748)	(4,927)
Unrecognized actuarial loss	133	581	401	1,744
Ongoing pension cost (credit)			6,139	5,947
Curtailment expense
Settlement expense
Net periodic benefit cost (credit)	2,046	1,982	6,139	5,947
Domestic Defined Benefit Pension Plans | Defined Benefit Pension Plans
Net periodic benefit cost (credit):
Service cost	759	1,158	2,624	6,673
Interest cost	1,232	8,541	3,629	25,233
Expected return on assets	(1,325)	(14,383)	(3,989)	(43,199)
Recognition of:
Unrecognized prior service cost (credit)	349	407	1,048	1,192
Unrecognized actuarial loss
Ongoing pension cost (credit)			3,312	(10,101)
Curtailment expense				825
Settlement expense			32,410
Net periodic benefit cost (credit)	1,015	(4,277)	35,722	(9,276)
Foreign Defined Benefit Pension Plans | Defined Benefit Pension Plans
Net periodic benefit cost (credit):
Service cost	1,488	2,016	4,468	6,048
Interest cost	2,387	2,352	7,099	7,055
Expected return on assets	(2,788)	(2,685)	(7,669)	(8,055)
Recognition of:
Unrecognized prior service cost (credit)
Unrecognized actuarial loss	228	383	744	1,149
Ongoing pension cost (credit)			4,642	6,197
Curtailment expense
Settlement expense
Net periodic benefit cost (credit)	$ 1,315	$ 2,066	$ 4,642	$ 6,197