Restructuring and Other Related Charges (Restructuring and Related Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges	$ 35,068	$ 27,897	$ 45,847
Other related charges	0	13,017	0
Total restructuring and other related charges	35,068	40,914	45,847
Intersegment Eliminations [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	0	(623)	(6,502)
National Networks [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	20,553	13,453	17,160
International And Other [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	$ 14,515	$ 28,084	$ 35,189