Summary Of Significant Accounting Policies (Schedule Of Contract Liabilities From Contract With Customers) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Summary Of Significant Accounting Policies [Abstract]
Contract liabilities at beginning of period	$ 15,055	$ 14,417
Increase due to deferral of revenue at period end	13,852	15,055
Decrease due to beginning contract liabilities recognized as revenue	(15,055)	(14,417)
Contract liabilities at end of period	$ 13,852	$ 15,055