Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Recent Accounting Pronouncements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Accounting Policies [Abstract]
Beginning Balance	$ 4,828	$ 4,771	$ 3,980
Accounts Receivable, Credit Loss Expense (Reversal)	647	836	1,423
Accounts Receivable, Allowance for Credit Loss, Writeoff	(2,732)	(858)	(899)
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	1,002	79	267
Ending Balance	$ 3,745	$ 4,828	$ 4,771