Other Current Liabilities - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 26, 2020	Jun. 28, 2019	Dec. 27, 2019
Accrued Liabilities, Current [Abstract]
Customer advances and deferred revenue	$ 50,300		$ 33,100
Contract with Customer, Liability, Revenue Recognized	14,200	$ 29,900
Foreign Currency Transaction Loss, before Tax	24,000
Impairment - Other Current Liabilities Narrative	$ 35,000