Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Component of Other Income (Expense), Nonoperating [Line Items]
Other income (expense)	$ (1,584)	$ (2,107)
Gain (loss) on currency transactions
Component of Other Income (Expense), Nonoperating [Line Items]
Other income (expense)	(1,163)	(1,650)
Pension and non-pension benefits, excluding service cost
Component of Other Income (Expense), Nonoperating [Line Items]
Other income (expense)	(406)	(340)
Other Non-Operating Income (Expense)
Component of Other Income (Expense), Nonoperating [Line Items]
Other income (expense)	$ (15)	$ (117)