Goodwill And Other Intangible Assets (Schedule Of Intangible Assets With Determinable Useful Lives By Major Category) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Gross Carrying Amount	$ 142,300	$ 142,300
Accumulated Amortization & Impairment	(36,703)	(33,414)
Net Carrying Amount	105,597	108,886
Trade Name
Goodwill [Line Items]
Gross Carrying Amount	22,500	22,500
Accumulated Amortization & Impairment	(6,071)	(5,512)
Net Carrying Amount	16,429	16,988
Technological Know-How
Goodwill [Line Items]
Gross Carrying Amount	55,300	55,300
Accumulated Amortization & Impairment	(18,884)	(17,265)
Net Carrying Amount	36,416	38,035
Customer-Related Intangible
Goodwill [Line Items]
Gross Carrying Amount	64,500	64,500
Accumulated Amortization & Impairment	(11,748)	(10,637)
Net Carrying Amount	$ 52,752	$ 53,863