Basis Of Presentation And Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 29, 2015	Dec. 31, 2015
Investment Holdings [Line Items]
NewAccountingPronouncementOrChangeInAccountingPrincipleCurrentPeriodDisclosuresDebtCarryingValueDecreaseAmount			$ 50,000
Operating revenues	$ 520,515	$ 472,737
Operating profit	27,216	60,935
Dreamcatcher Stations | Variable Interest Entity, Primary Beneficiary
Investment Holdings [Line Items]
Operating revenues	17,000	15,000
Operating profit	$ 3,000	$ 2,000