Description of Business and Basis of Presentation (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) segment network	Mar. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease asset	$ 174,563			$ 0
Lease liabilities	$ 230,968
Number of operating segments | segment	2
Number of national programming networks | network	5
Program rights write-offs	$ 3,300	$ 5,200
ASU No. 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease asset			$ 180,000
Historical deferred rent liability			57,000
Lease liabilities			$ 237,000