Schedule II Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Year	$ 16,800	$ 14,900	$ 15,900
Expense (Benefit)	9,571	19,500	2,400
Other Additions	0	0	0
Write-Offs and Other	(2,485)	(17,600)	(3,400)
Balance at End of Year	$ 23,886	$ 16,800	$ 14,900