Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (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, net of tax		$ 247	$ 638	$ 808	$ 1,086
Prior service benefit	[1]	74	74	221	221
Total reclassifications		321	712	1,029	1,307
Interest Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains, net of tax		$ 247	$ 638	$ 808	$ 1,086

[1] The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note O: "Retirement Plans."