Cash And Cash Equivalents And Advertising Accounting Policies (Effect Of Reclassification Of Consolidated Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Accounts receivable and prepaid expenses	$ 7,627	$ 10,712
Net cash provided by operating activities	50,787	7,805
Net increase (decreases) in cash and cash equivalents	2,298	(9,185)
Cash and cash equivalents at beginning of year	47,917	46,818
Cash and cash equivalents at end of period	50,215	37,633
As Previously Reported [Member]
Accounts receivable and prepaid expenses		17,539
Net cash provided by operating activities		14,632
Net increase (decreases) in cash and cash equivalents		(2,358)
Cash and cash equivalents at beginning of year	21,305	14,653
Cash and cash equivalents at end of period		12,295
Reclassifications [Member]
Accounts receivable and prepaid expenses		(6,827)
Net cash provided by operating activities		(6,827)
Net increase (decreases) in cash and cash equivalents		(6,827)
Cash and cash equivalents at beginning of year	$ 26,612	32,165
Cash and cash equivalents at end of period		$ 25,338