Fair Value of Financial Instruments (Details 4) - Assets and liabilities measured at fair value on recurring basis - Significant Unobservable Inputs (Level 3) - Auction rate securities - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Oct. 03, 2015	Oct. 03, 2015
Fair value assets reconciliation of changes
Balance at the beginning of the period	$ 7,179	$ 7,419
Gain (loss) included in other comprehensive income (loss)	61	(179)
Balance at the end of the period	$ 7,240	$ 7,240