Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Allowance for doubtful accounts	$ 7.4	$ 10.9
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	52,221,054	51,953,354
Common stock, shares outstanding (in shares)	46,196,244	46,116,670
Treasury stock, shares (in shares)	6,024,810	5,836,684
Commitments and Contingencies