Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic and dilutive net income (loss) available to common shareholders	$ (23.6)	$ (49.1)	$ 14.4	$ (14.6)	$ (72.7)	$ (0.2)
Basic weighted average shares outstanding (in shares)	33,247		32,966		33,199	32,894
Effect of dilutive securities:
Unvested shares and stock units (in shares)	0		828		0	0
Dilutive weighted average shares outstanding (in shares)	33,247		33,794		33,199	32,894
Basic earnings (loss) per share (in dollars per share)	$ (0.71)		$ 0.44		$ (2.19)	$ 0.00
Diluted earnings (loss) per share (in dollars per share)	$ (0.71)		$ 0.43		$ (2.19)	$ 0.00
Antidillutive options and shares
Effect of dilutive securities:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)					325	57