Pension Plans - Pension plan net periodic benefit costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2022	Apr. 02, 2021
Qualified Pension Plan
Defined Benefit Plan Disclosure
Service cost	$ 800	$ 1,300
Interest cost on projected benefit obligation	4,250	3,525
Expected return on plan assets	(10,525)	(11,275)
Amortization of net loss	975	1,075
Net pension (income) cost	(4,500)	(5,375)
SERP
Defined Benefit Plan Disclosure
Service cost	0	0
Interest cost on projected benefit obligation	22	15
Expected return on plan assets	0	0
Amortization of net loss	15	17
Net pension (income) cost	$ 37	$ 32