Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic and dilutive net income (loss) available to common shareholders	$ (16.0)	$ (23.6)	$ (49.1)	$ 2.9	$ 14.4	$ (14.6)	$ (88.7)	$ 2.7
Basic weighted average shares outstanding (in shares)	33,259			33,051			33,098	32,827
Effect of dilutive securities:
Unvested shares and stock units (in shares)	0			944			0	928
Dilutive weighted average shares outstanding (in shares)	33,259			33,995			33,098	33,755
Basic earnings (loss) per share (in dollars per share)	$ (0.48)			$ 0.09			$ (2.68)	$ 0.08
Diluted earnings (loss) per share (in dollars per share)	$ (0.48)			$ 0.09			$ (2.68)	$ 0.08
Antidillutive options and shares
Effect of dilutive securities:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)							319	54