Asset Write-Downs and Other Charges and Credits - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs				$ 8,911	$ 4,422	$ 0
Acquisition and related integration costs				4,124	0	578
Impairment of programming assets				8,920	$ 0	$ 0
Impairment charge		$ 29,400
Impairment of intangible assets		$ 6,300
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Newspaper Syndication
Restructuring Cost and Reserve [Line Items]
Gain on disposal			$ 3,000
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring costs				3,500
2015 Midroll acquisition
Restructuring Cost and Reserve [Line Items]
Earn out provision adjustment				$ 3,200
Katz Broadcasting Group
Restructuring Cost and Reserve [Line Items]
Gain recorded on investments	$ 5,400