Goodwill and Other Intangible Assets - Additional (Details) - KFMB - USD ($) $ in Millions		3 Months Ended
	Feb. 15, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Estimated consideration transferred	$ 328.4
Working capital adjustment		$ 2.5
Finite-lived intangible assets, remaining amortization period	10 years
Goodwill, acquired during period	$ 17.4
Increase in goodwill		$ 0.3
Licensing Agreements
Business Acquisition [Line Items]
Indefinite-lived intangible assets acquired	192.2
Retransmission And Network Affiliation Agreements
Business Acquisition [Line Items]
Finite-lived intangible assets acquired	$ 91.4