CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED BALANCE SHEETS
Accounts receivable-trade, allowance for doubtful accounts	$ 8.6	$ 7.5
Preferred stock, par value (in dollars per share)		$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)		100,000,000	100,000,000
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding ( in shares)		0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	95,187,161	92,182,207
Common stock, shares outstanding ( in shares)	86,847,797	84,103,108
Common shares held in treasury, (in shares)	8,339,364	8,079,099