Earnings Per Share, Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net loss	$ 20.2	$ 24.5	$ (272.0)	$ 40.3
Denominator — Weighted-average common shares outstanding (in thousands):
Basic	17,006	17,841	17,233	17,889
Add: dilutive effect of non-vested common shares, restricted stock units and performance shares	247	112	0	133
Add: dilutive effect of warrants	939	505	0	490
Diluted	18,192	18,458	17,233	18,512
Net income (loss) per common share:
Basic	$ 1.19	$ 1.38	$ (15.78)	$ 2.25
Earnings per common share, Diluted:
Diluted	$ 1.11	$ 1.33	$ (15.78)	$ 2.18