Benefit Plans - Assets of the Plan Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) $ in Thousands	12 Months Ended
	Dec. 29, 2018 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 186,336
Ending balance	164,603
Pension Plan [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	186,336
Ending balance	164,603
Pension Plan [Member] | Limited Partner [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Redemptions	(108)
Subscriptions	108
Net appreciation in fair value	23
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	5,005
Ending balance	5,028
Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member] | Limited Partner [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	5,005
Ending balance	$ 5,028