Cash And Cash Equivalents And Advertising Accounting Policies (Effect Of Reclassification Of Consolidated Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017
Accounts receivable and prepaid expenses	$ 5,436	$ 15,371
Net cash provided by operating activities	84,227	63,262
Net increase (decreases) in cash and cash equivalents	(13,294)	(3,129)
Cash and cash equivalents at beginning of year	47,917	46,818
Cash and cash equivalents at end of period	34,623	43,689
As Previously Reported [Member]
Accounts receivable and prepaid expenses		21,429
Net cash provided by operating activities		69,320
Net increase (decreases) in cash and cash equivalents		2,929
Cash and cash equivalents at beginning of year	21,305	14,653
Cash and cash equivalents at end of period		17,582
Reclassifications [Member]
Accounts receivable and prepaid expenses		(6,058)
Net cash provided by operating activities		(6,058)
Net increase (decreases) in cash and cash equivalents		(6,058)
Cash and cash equivalents at beginning of year	$ 26,612	32,165
Cash and cash equivalents at end of period		$ 26,107