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Goodwill And Other Intangible Assets (Schedule Of Intangible Assets With Determinable Useful Lives By Major Category) (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | ---
Goodwill [Line Items] |  |  |
Gross Carrying Amount | $ 142,300 | $ 142,300 | $ 142,300
Accumulated Amortization | (39,990) | (33,414) | (19,809)
Net Carrying Amount | 102,310 | 108,886 | 122,491
Trade Name |  |  |
Goodwill [Line Items] |  |  |
Gross Carrying Amount | 22,500 | 22,500 | 22,500
Accumulated Amortization | (6,629) | (5,512) | (3,235)
Net Carrying Amount | 15,871 | 16,988 | 19,265
Technological Know-How |  |  |
Goodwill [Line Items] |  |  |
Gross Carrying Amount | 55,300 | 55,300 | 55,300
Accumulated Amortization | (20,502) | (17,265) | (10,397)
Net Carrying Amount | 34,798 | 38,035 | 44,903
Customer-Related Intangible |  |  |
Goodwill [Line Items] |  |  |
Gross Carrying Amount | 64,500 | 64,500 | 64,500
Accumulated Amortization | (12,859) | (10,637) | (6,177)
Net Carrying Amount | $ 51,641 | $ 53,863 | $ 58,323

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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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