Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic and dilutive net income (loss) available to common shareholders	$ 3.0	$ 13.9	$ (3.3)	$ 29.0
Basic weighted average shares outstanding (in shares)	32,723	32,466	32,550	32,398
Unvested shares and stock units (in shares)	869	728	0	517
Dilutive weighted average shares outstanding (in shares)	33,592	33,194	32,550	32,915
Basic earnings (loss) per share (in dollars per share)	$ 0.09	$ 0.43	$ (0.10)	$ 0.89
Diluted earnings (loss) per share (in dollars per share)	$ 0.09	$ 0.42	$ (0.10)	$ 0.88
Antidillutive options and shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share			80	213