Business Segment Information - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) market station	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) market station	Jun. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Operating income	$ 150,080	$ 159,736	$ 273,191	$ 312,038
Accounting Standards Update 2017-06 | Effect of Accounting Change | Operating Segments
Segment Reporting Information [Line Items]
Operating income	$ 1,900	2,600	$ 3,300	4,000
Media
Segment Reporting Information [Line Items]
Number of television stations | station	46		46
Number of markets In which entity operates | market	38		38
Media | Operating Segments
Segment Reporting Information [Line Items]
Operating income	$ 164,576	$ 179,238	$ 303,291	$ 348,397