Basis Of Presentation And Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Investment Holdings [Line Items]
Decrease in carrying value of debt					$ 50,000
Operating revenues	$ 526,113	$ 501,524	$ 1,046,628	$ 974,261
Operating profit	46,140	19,784	73,356	80,719
Dreamcatcher Stations | Variable Interest Entity, Primary Beneficiary
Investment Holdings [Line Items]
Operating revenues	18,000	17,000	35,000	32,000
Operating profit	$ 4,000	$ 5,000	$ 7,000	$ 7,000