CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Accounts receivable, allowance for doubtful accounts	$ 4.4	$ 3.6
Shareholders' equity:
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	47,990,136	47,855,496
Common stock held in treasury, shares (in shares)	13,205,741	13,205,741