Financial Instruments and Fair Value Measurements (Equity Method Investments) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Oct. 02, 2020	Sep. 27, 2019	Oct. 02, 2020	Sep. 27, 2019	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Equity method investment	$ 19,718		$ 19,718		$ 16,167
Non-marketable equity securities	6,092		6,092		6,092
Total equity investments	25,810		25,810		$ 22,259
Equity method investment income	(2,234)	$ (986)	(3,954)	$ (909)
Impairment charges	0	0	0	1,575
Total (gain) loss on equity investments, net	$ (2,234)	$ (986)	$ (3,954)	$ 666

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Amount of realized gain (loss) on investment in debt and equity securities.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Fair value portion of investments accounted under the equity method.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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