Employee Retirement and Pension Benefits - Components of Pension Benefit/ Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Retirement Benefits [Abstract]
Service cost	$ 1,250	$ 1,250
Interest cost	3,725	3,725
Expected return on plan assets	(4,650)	(4,650)
Amortization of net actuarial pension loss	2,225	2,225
Pension benefit expense	$ 2,550	$ 2,550