Propert and Equipment (Property, Plant, Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 540,180	$ 443,433
Accumulated Depreciation And Amortization	(293,918)	(259,919)
Property and equipment, net	246,262	183,514
Program, Service and Test Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	250,328	212,357
Satellite Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 46,368	46,315
Property, Plant and Equipment, Useful Life	13 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 29,421	21,067
Transmission Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 58,710	56,035
Property, Plant and Equipment, Useful Life	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 155,353	$ 107,659
Minimum [Member] | Program, Service and Test Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum [Member] | Program, Service and Test Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	8 years