Net Loss Per Share and Shareholders' Equity - Reconciliation of Numerator and Denominator of the Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net (loss) earnings	$ (24.6)	$ 9.8
Denominator:
Denominator for basic EPS–weighted-average common shares (in shares)	68,260,015	67,179,348
Dilutive effect of stock-based compensation arrangements (in shares)	0	2,496,120
Denominator for diluted EPS–adjusted weighted-average common shares (in shares)	68,260,015	69,675,468
Basic EPS (in dollars per share)	$ (0.36)	$ 0.15
Diluted EPS (in dollars per share)	$ (0.36)	$ 0.14