Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Detail) - USD ($) $ in Thousands		3 Months Ended
		Apr. 04, 2021	Mar. 29, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)		$ 444	$ 515
Retirement Plans Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	[1]	2	2
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax		$ 446	$ 517

[1] The amortization of prior service credit is included in the computation of net periodic postretirement benefit cost. See Note P: “Retirement Plans.”