CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 70.2	$ 65.2
Property, plant and equipment, accumulated depreciation	691.1	603.2
Intangible assets, accumulated amortization	$ 473.5	$ 392.5
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	700,000
Preferred stock, outstanding (in shares)	0	700,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	90,600,000	85,500,000
Common stock, outstanding (in shares)	90,600,000	85,500,000