Reclassifications Out of Accumulated Other Comprehensive Income (Loss) to Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jul. 02, 2023	Jun. 30, 2024	Jul. 02, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)	$ 13	$ (28)	$ (92)	$ (33)
Unrealized (losses) gains, net	0	(323)	1,780	(1,524)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)	13	(28)	(92)	(33)
Reclassifications, net of tax			(92)	(33)
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	2	2	3	3
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	$ 15	$ (349)	$ 1,691	$ (1,554)