Fair Value Measurements (Narrative) (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 29, 2017	Sep. 29, 2017	Sep. 30, 2016	Dec. 30, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Equity method investments, carrying value	$ 19,900,000	$ 19,900,000		$ 22,800,000
Cost-method investment impairment loss	300,000	5,300,000	$ 0
Fair Value, Inputs, Level 2 [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Gain on cost method and equity method investments		(2,900,000)	$ 900,000
Chinese Venture Capital Fund [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Equity method investment	$ 12,900,000	$ 12,900,000		$ 10,700,000
Equity method investment ownership (percent)	6.80%	6.80%