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Affiliated Companies (Textuals) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Schedule of Equity Method Investments [Line Items] |  |  |
Unremitted income of affiliated companies | $ 69.9 | $ 63.0 | $ 56.2
Dividends received from affiliated companies | 2.2 | 1.4 | 0.8
Purchases and royalty payments made to affiliates | 86.7 | 94.5 | 65.8
Amount due and payable to affiliates | 12.4 | 9.0 |
Sales to affiliates | 8.1 | 6.8 | 5.3
Amount receivable from affiliates | 1.3 | 0.9 |
Equity method investments | 72.4 | 69.3 |
Cost method investment | 13.4 | 13.4 |
Cost method investments, original cost | 8.4 |  |
Daikyo Seiko, Ltd. [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Equity in unrealized (gains) losses in securities available-for-sale and derivative instruments | $ (0.5) | $ (5.3) | $ (5.4)

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