Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains, tax	$ 126	$ 348	$ 335	$ 591
Prior service benefit, tax	42	42	127	127
Total reclassifications, tax	$ 168	$ 390	$ 462	$ 718