Employee Benefit Plans (Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets, Other Postretirement Benefit Plans) (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 16,279	$ 17,374
Realized gains (losses)	1,776	(1,621)	$ 741
Fair value of plan assets at end of year	19,216	16,279	17,374
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	1,176
Fair value of plan assets at end of year	130	1,176
Multi-strategy hedge funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	1,176
Fair value of plan assets at end of year	130	1,176
Multi-strategy hedge funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement	1,074		562
Fair value of plan assets at beginning of year	1,176	1,151	1,508
Realized gains (losses)	315		229
Unrealized gains (losses)	(287)	25	(24)
Fair value of plan assets at end of year	$ 130	$ 1,176	$ 1,151