Retirement Plans and Postretirement Medical Benefits (Other Changes in Plan Assets and Benefit Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Nonpension postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ (11,837)	$ 5,134
Amortization of net actuarial loss	(3,048)	(3,600)
Amortization of prior service credit	(304)	(297)
Settlement/Curtailment	(246)	0
Total recognized in other comprehensive income	(15,435)	1,237
United States
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	50,534	(9,304)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	0
Amortization of net actuarial loss	(31,298)	(28,954)
Amortization of prior service credit	60	60
Net transition asset	0	0
Settlement/Curtailment	(44,665)	0
Total recognized in other comprehensive income	(25,369)	(38,198)
Foreign
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	3,824	(12,202)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	9,009	0
Amortization of net actuarial loss	(7,264)	(8,052)
Amortization of prior service credit	71	71
Net transition asset	7	8
Settlement/Curtailment	13	0
Total recognized in other comprehensive income	$ 5,660	$ (20,175)