Segment Information (Summary Of Inter-Segment Eliminations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Revenue, Net	$ 395,328	$ 332,056	$ 1,156,611	$ 985,865
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue, Net	(3,935)	(3,479)	(11,898)	(11,692)
Intersegment Eliminations [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenue, Net	0	(6)	(184)	(510)
Intersegment Eliminations [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenue, Net	$ (3,935)	$ (3,473)	$ (11,714)	$ (11,182)