Goodwill and Other Intangible Assets (Schedule Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Beginning balance	$ 798,037	$ 695,158
Additions		123,865
Impairment charge	(97,996)
Purchase accounting adjustments	(2,414)
Amortization of "second component" goodwill	(1,328)	(1,328)
Foreign currency translation	5,681	(19,658)
Ending balance	701,980	798,037
National Networks [Member]
Goodwill [Roll Forward]
Beginning balance	238,431	239,759
Additions		0
Impairment charge	0
Purchase accounting adjustments	0
Amortization of "second component" goodwill	(1,328)	(1,328)
Foreign currency translation	0	0
Ending balance	237,103	238,431
International And Other [Member]
Goodwill [Roll Forward]
Beginning balance	559,606	455,399
Additions		123,865
Impairment charge	(97,996)
Purchase accounting adjustments	(2,414)
Amortization of "second component" goodwill	0	0
Foreign currency translation	5,681	(19,658)
Ending balance	$ 464,877	$ 559,606