Post-Retirement Health Care (Schedule of Cost of Retirement Plans) (Details) - Postretirement Health Coverage - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017
Change in benefit obligation
Benefit obligation at beginning of year	$ 22,933	$ 21,153
Service cost	853	741
Interest cost	789	825
Benefits paid	(1,570)	(1,003)
Actuarial (gain) loss	(3,453)	1,217
Benefit obligation at end of year	19,552	22,933
Change in plan assets
Fair value at beginning of year	0	0
Actual return on assets	0	0
Employer contribution	1,570	1,003
Transferred out	0	0
Benefits paid	(1,570)	(1,003)
Fair value at end of year	0	0
Funded Status of Plan	(19,552)	(22,933)
Amounts recognized in the Statement of Financial Position consist of:
Current liabilities	1,057	1,050
Non-current liabilities	18,495	21,883
Amounts recognized in Accumulated Other Comprehensive Income (before tax) consist of:
Actuarial (gain) loss	(14)	3,565
Change in Accumulated Other Comprehensive Income (before tax):
Amount disclosed at beginning of year	3,565	2,373
Actuarial (gain) loss	(3,453)	1,217
Amortization of transition amount	(126)	(25)
Amount disclosed at end of year	$ (14)	$ 3,565