Goodwill and other intangible assets - Narrative (Details) $ in Thousands		3 Months Ended	6 Months Ended
	Jan. 27, 2021 USD ($) sportLeague	Dec. 31, 2020 USD ($) station licence	Jun. 30, 2021 USD ($) station radioStation
Business Acquisition [Line Items]
Number of major professional sports leagues | sportLeague	4
Goodwill		$ 2,968,693	$ 2,981,587
Number of television stations | station		1	64
Number of radio stations		1	2
Indefinite lived intangibles with heightened risk of future impairment		$ 67,200
Number of FCC license | licence		2
Licensing Agreements, TV Station
Business Acquisition [Line Items]
Individual impairment of headroom (less than) (as a percent)		5.00%
Licensing Agreements, Radio Station
Business Acquisition [Line Items]
Individual impairment of headroom (less than) (as a percent)		5.00%
Locked On Podcast Network LLC
Business Acquisition [Line Items]
Purchase price of acquisition	$ 13,300
Base purchase price	13,800
Working capital adjustment	500
Goodwill	12,900
Trade names | Locked On Podcast Network LLC
Business Acquisition [Line Items]
Finite-lived intangible assets acquired	$ 900