Restructuring and Other Related Charges (Summary of Restructuring and Other Related Charges by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	$ 4,406	$ 10,191	$ 13,879	$ 29,995
Operating segments | National Networks
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	5,991	6,199	8,714	6,776
Operating segments | International and Other
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	(1,585)	3,992	5,165	23,915
Inter-segment eliminations
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	$ 0	$ 0	$ 0	$ (696)