Acquisitions - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	6 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill	$ 1,969.8	$ 1,979.4	$ 1,973.6
National Media Acquisitions
Consideration
Cash	24.2
Payment in escrow	0.9
Contingent consideration arrangement	4.1
Fair value of total consideration transferred	29.2
Recognized amounts of identifiable assets acquired and liabilities assumed
Total identifiable assets acquired	23.3
Total liabilities assumed	1.2
Total identified net assets	22.1
Goodwill	7.1
Net assets acquired	$ 29.2