Restructuring and Other Related Charges (Summary of Restructuring and Other Related Charges by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	$ 5,966	$ 2,642
Operating segments | National Networks
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	1,509	303
Operating segments | International & Other
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	4,457	3,035
Inter-segment eliminations
Restructuring Cost and Reserve [Line Items]
Total restructuring and other related charges	$ 0	$ (696)