Other (Income) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	$ (342)	$ 3,669	$ 1,069
Other Income [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	(630)	493	(521)
gain loss on sale of asset [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	(618)	(408)	(764)
Investment Income [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	(506)	(383)	(364)
Interest Income [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	0	(56)	(403)
Foreign Currency Gain (Loss) [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	1,832	4,507	4,230
Rents And Royalties Income Loss [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	(420)	(484)	(817)
gain loss on insurance recovery [Member]
Other operating expenses [Line Items]
Other Nonoperating Income (Expense)	$ 0	$ 0	$ (292)