Acquisitions - Narrative (Details) $ in Thousands							1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 01, 2019 USD ($)	Nov. 30, 2018 USD ($)	Oct. 27, 2018 USD ($) television_station	Oct. 02, 2017 USD ($)	Jun. 06, 2016 USD ($) show	Apr. 12, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill							$ 834,013	$ 755,949	$ 834,013	$ 575,780	$ 544,787
Triton Digital Canada, Inc.
Business Acquisition [Line Items]
Business acquisition, purchase price		$ 160,000
Cash		10,515
Revenues from acquired operations							$ 3,300
Intangible assets acquired		75,000
Goodwill		83,876
Triton Digital Canada, Inc. | Developed Technology
Business Acquisition [Line Items]
Intangible assets acquired		39,000
Triton Digital Canada, Inc. | Developed Technology | Minimum
Business Acquisition [Line Items]
Estimated useful life									8 years
Triton Digital Canada, Inc. | Developed Technology | Maximum
Business Acquisition [Line Items]
Estimated useful life									12 years
Triton Digital Canada, Inc. | Customer Relationships
Business Acquisition [Line Items]
Intangible assets acquired		$ 31,000
Estimated useful life		12 years
Triton Digital Canada, Inc. | Trade names
Business Acquisition [Line Items]
Intangible assets acquired		$ 5,000
Estimated useful life		10 years
Katz Broadcasting Group
Business Acquisition [Line Items]
Business acquisition, purchase price				$ 292,000
Cash				21,372
Intangible assets acquired				32,300
Goodwill				$ 203,760
Noncontrolling interest prior to acquisition				5.33%
Goodwill, Purchase Accounting Adjustments									$ 5,812
Increase in fair value of property and equipment									9,900
Decrease in the fair value of program assets									4,100
Increase in previously reported depreciation expense									300
Programming Expense, Purchase Accounting Adjustments									$ 300
Gain on fair value remeasurement of acquisition								$ 5,400
Katz Broadcasting Group | Trade names
Business Acquisition [Line Items]
Intangible assets acquired				$ 8,000
Estimated useful life				10 years
Katz Broadcasting Group | Advertiser relationships
Business Acquisition [Line Items]
Intangible assets acquired				$ 24,000
Estimated useful life				5 years
Stitcher acquisition
Business Acquisition [Line Items]
Business acquisition, purchase price					$ 4,500
Intangible assets acquired					$ 2,900
Number of podcast shows | show					65,000
Stitcher acquisition | Computer software
Business Acquisition [Line Items]
Estimated useful life					3 years
Cracked acquisition
Business Acquisition [Line Items]
Business acquisition, purchase price						$ 39,000
Intangible assets acquired						9,600
Goodwill						29,400
Cracked acquisition | Trade names
Business Acquisition [Line Items]
Intangible assets acquired						$ 7,600
Estimated useful life						20 years
Cracked acquisition | Media content
Business Acquisition [Line Items]
Intangible assets acquired						$ 2,000
Estimated useful life						3 years
Cordillera Communications, LLC
Business Acquisition [Line Items]
Business acquisition, purchase price			$ 521,000
Number of television stations acquired | television_station			15
Subsequent Event | Raycom Media, Inc.
Business Acquisition [Line Items]
Business acquisition, purchase price	$ 55,000