Fair Value Measurements (Details 2) (USD $) In Thousands, unless otherwise specified										3 Months Ended		12 Months Ended		12 Months Ended
	Jun. 28, 2014	Dec. 31, 2013	Jun. 29, 2013	Jun. 28, 2014 Reported Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Reported Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Jun. 29, 2013 Reported Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Jun. 28, 2014 Estimate of Fair Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Estimate of Fair Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Jun. 29, 2013 Estimate of Fair Value Measurement [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Warrant [Member] Auction Rate Securities [Member]	Mar. 30, 2013 Warrant [Member] Auction Rate Securities [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2008 Warrant [Member] Auction Rate Securities [Member] Fair Value, Inputs, Level 3 [Member]	Jun. 29, 2013 Warrant [Member] Auction Rate Securities [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2008 Warrant [Member] AAA Rating [Member] Auction Rate Securities [Member] Fair Value, Inputs, Level 3 [Member]
Fair value on a recurring basis
Sale value of investment										$ 10,840
Purchase cost of investment														13,550
Other-than-temporary pre-tax impairment on investment												5,140
Carrying value of investment													10,162	8,410
Unrealized loss in other comprehensive earnings											677
Industrial revenue development bonds, carrying amount, approximates fair value	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500