Pension Plans and Other Postretirement Benefits - Domestic and Foreign Pension and Postretirement Defined Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Total net pension and postretirement benefits cost (credit)	$ 586	$ (915)	$ 1,641	$ (2,708)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,118	1,238	3,371	3,765
Interest cost	8,314	7,967	24,854	24,010
Expected return on assets	(9,414)	(10,703)	(28,311)	(32,227)
Amortization of prior service benefit	(5)	25	7	71
Total net pension and postretirement benefits cost (credit)	13	(1,473)	(79)	(4,381)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	24	29	73	88
Interest cost	549	542	1,647	1,626
Expected return on assets	0	(1)	0	(5)
Amortization of prior service benefit	0	(12)	0	(36)
Total net pension and postretirement benefits cost (credit)	$ 573	$ 558	$ 1,720	$ 1,673