Financial Instruments Measured at Fair Value - AFS (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended			12 Months Ended			9 Months Ended	12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014 Marubun [Member]	Dec. 31, 2013 Marubun [Member]	Dec. 31, 2013 WPG [Member]	Sep. 27, 2014 WPG [Member]	Sep. 27, 2014 Mutual Funds [Member]	Dec. 31, 2013 Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Investment Ownership Percentage					8.40%			1.90%
Proceeds from sale of investment			$ 40,542	$ 0
Cost basis					10,016	10,016	10,798		15,780	15,614
Unrealized holding gain					5,394	2,709	24,903		6,003	5,817
Fair value					15,410	12,725	35,701		21,783	21,431
Gain on sale of investment	29,743	0	29,743	0
Gain on sale of investment, Net of Tax	$ 18,269		$ 18,269	$ 0
Gain (Loss) on investments Net of Tax Per Share Basic	$ 0.19
GaIn (Loss) on Investments Net of Tax Per Share Diluted	$ 0.18