Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Allowance for losses on accounts receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	$ 1,310	$ 1,062	$ 1,172
Charged to Costs and Expenses	1,170	410	319
Deductions	(329)	(172)	(557)
Other	(751)	10	128
Balance at End of Year	1,400	1,310	1,062
Reserves for sales discounts and allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	40,733	34,976	26,344
Charged to Costs and Expenses	113,709	133,434	124,638
Deductions	(112,401)	(127,330)	(118,438)
Other	1,796	(347)	2,432
Balance at End of Year	$ 43,837	$ 40,733	$ 34,976