Pension Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Net periodic benefit cost:
Service cost	$ 275	$ 325
Interest cost	1,275	1,623
Expected return on plan assets	(3,069)	(3,279)
Amortization of net actuarial loss	340	257
Total net periodic benefit	$ (1,179)	$ (1,074)
Weighted average assumptions used to determine net cost
Discount rate	2.20%	3.00%
Expected return on plan assets	5.75%	6.50%
Employer contributions		$ 1,500