Segment Information (Summary Of Inter-Segment Eliminations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Revenues, net	$ 601,138	$ 522,093	$ 1,269,820	$ 1,046,647
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues, net	(353)	(511)	(874)	(1,215)
Intersegment Eliminations [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net	(336)	(316)	(788)	(990)
Intersegment Eliminations [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net	$ (17)	$ (195)	$ (86)	$ (225)