Cash and Cash Equivalents and Advertising Accounting Policies, and Prior Year Reclassifications (Effect Of Reclassification Of Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Cost of sales, including advertising, warehousing and distribution expenses									$ 2,574,269	$ 2,554,284	$ 2,273,182
Gross profit on sales	$ 227,459	$ 232,340	$ 240,295	$ 234,907	$ 230,120	$ 219,609	$ 233,758	$ 229,036	935,001	912,523	863,538
Operating, general and administrative expenses									$ 851,411	836,098	765,213
As Previously Reported [Member]
Cost of sales, including advertising, warehousing and distribution expenses										2,540,348	2,264,565
Gross profit on sales										926,459	872,155
Operating, general and administrative expenses										850,034	773,830
Reclassifications [Member]
Cost of sales, including advertising, warehousing and distribution expenses										13,936	8,617
Gross profit on sales										(13,936)	(8,617)
Operating, general and administrative expenses										$ (13,936)	$ (8,617)