CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts on trade receivables	$ 15.6	$ 13.5
Accumulated depreciation on property, plant and equipment	425.2	385.5
Accumulated amortization on intangible assets	$ 187.3	$ 130.9
Class A Common Stock
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, authorized (in shares)	900,000,000	900,000,000
Common Stock, issued (in shares)	55,556,466	54,556,100
Treasury stock (in shares)	1,533,320	1,114,528