Segment Information (Summary Of Inter-Segment Eliminations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues, net	$ 609,444	$ 519,550	$ 522,093	$ 524,554	$ 435,247	$ 395,328	$ 379,322	$ 381,961	$ 2,175,641	$ 1,591,858	$ 1,352,577
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues, net									(2,502)	(316)	(2,186)
Intersegment Eliminations [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net									(1,802)	(193)	(298)
Intersegment Eliminations [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net									$ (700)	$ (123)	$ (1,888)