Goodwill and Other Intangible Assets - Goodwill by business segment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of activity related to goodwill by business segment
Gross balance		$ 854,694	$ 823,701	$ 321,675	$ 243,380
Accumulated impairment losses		(237,914)	(237,914)	(215,414)	(215,414)
Goodwill [Roll Forward]
Balance, beginning of period		585,787	106,261	27,966
Reassignment of goodwill for change in segments			0
2015 Impairment charge			(22,500)
Balance, end of period		616,780	585,787	106,261
Television
Summary of activity related to goodwill by business segment
Gross balance		681,535	681,535	288,095	243,380
Accumulated impairment losses		(215,414)	(215,414)	(215,414)	(215,414)
Goodwill [Roll Forward]
Balance, beginning of period		466,121	72,681	27,966
Reassignment of goodwill for change in segments			(2,000)
Balance, end of period		466,121	466,121	72,681
Radio
Summary of activity related to goodwill by business segment
Gross balance		41,000	41,000	0	0
Accumulated impairment losses		0	0	0	0
Goodwill [Roll Forward]
Balance, beginning of period		41,000	0	0
Reassignment of goodwill for change in segments			0
Balance, end of period		41,000	41,000	0
Digital
Summary of activity related to goodwill by business segment
Gross balance		132,159	101,166	33,580	0
Accumulated impairment losses		(22,500)	(22,500)	0	$ 0
Goodwill [Roll Forward]
Balance, beginning of period		78,666	33,580	0
Reassignment of goodwill for change in segments			2,000
2015 Impairment charge			(22,500)
Balance, end of period		109,659	78,666	33,580
2014 Newsy acquisition
Goodwill [Roll Forward]
Acquisitions				28,983
2015 Impairment charge	$ (21,000)
2014 Newsy acquisition | Digital
Goodwill [Roll Forward]
Acquisitions				28,983
2014 Granite stations acquisitions
Goodwill [Roll Forward]
Acquisitions				44,715
2014 Granite stations acquisitions | Television
Goodwill [Roll Forward]
Acquisitions				44,715
2014 WeatherSphere acquisition
Goodwill [Roll Forward]
Acquisitions				4,597
2014 WeatherSphere acquisition | Digital
Goodwill [Roll Forward]
Acquisitions				$ 4,597
2015 Journal acquisition
Goodwill [Roll Forward]
Acquisitions			456,440
2015 Journal acquisition | Television
Goodwill [Roll Forward]
Acquisitions			395,000
2015 Journal acquisition | Radio
Goodwill [Roll Forward]
Acquisitions			41,000
2015 Journal acquisition | Digital
Goodwill [Roll Forward]
Acquisitions			20,000
2015 Midroll acquisition
Goodwill [Roll Forward]
Acquisitions			45,586
2015 Midroll acquisition | Digital
Goodwill [Roll Forward]
Acquisitions			$ 45,586
2016 Cracked acquisition
Goodwill [Roll Forward]
Acquisitions		29,403
2016 Cracked acquisition | Television
Goodwill [Roll Forward]
Acquisitions		0
2016 Cracked acquisition | Radio
Goodwill [Roll Forward]
Acquisitions		0
2016 Cracked acquisition | Digital
Goodwill [Roll Forward]
Acquisitions		29,403
2016 Stitcher acquisition
Goodwill [Roll Forward]
Acquisitions		1,590
2016 Stitcher acquisition | Television
Goodwill [Roll Forward]
Acquisitions		0
2016 Stitcher acquisition | Radio
Goodwill [Roll Forward]
Acquisitions		0
2016 Stitcher acquisition | Digital
Goodwill [Roll Forward]
Acquisitions		$ 1,590