Restructuring (Restructuring and Related Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 1,264	$ 19,312	$ 3,887	$ 19,666
National Networks [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(10)	8,103	(53)	8,170
International And Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 1,274	$ 11,209	$ 3,940	$ 11,496