Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) segment market station	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Operating segments | segment	1
Reportable segments | segment	1
Number of television stations | station	49
Number of markets In which entity operates | market	41
Right of use asset | $	$ 72,160	$ 73,800	$ 0
Lease liability | $	$ 90,756	$ 91,800