(Loss) Earnings per Common Share - Schedule of calculations of basic and diluted earnings per common share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net (loss) income	$ (6.2)	$ 8.9
Less: earnings and dividends allocated to participating securities	0.0	0.0
(Loss) earnings available for common stockholders used in calculation of basic (loss) earnings per common share	$ (6.2)	$ 8.9
Weighted average number of common shares outstanding, basic (in shares)	46.9	49.7
Basic (loss) earnings per common share (in dollars per share)	$ (0.13)	$ 0.18
(Loss) earnings available for common stockholders used in calculation of diluted (loss) earnings per common share	$ (6.2)	$ 8.9
Effect of shares issuable under share-based compensation plans (in shares)	0.0	0.2
Weighted average number of common shares outstanding, diluted (in shares)	46.9	49.9
Diluted (loss) earnings per common share (in dollars per share)	$ (0.13)	$ 0.18