Reclassifications Out of Accumulated Other Comprehensive Income (Loss) to Statements of Operations (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)		$ 229	$ 689	$ 670	$ 2,188
Retirement Plans Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	[1]	2	2	5	6
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax		$ 231	$ 691	$ 675	$ 2,194

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