Restatement - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	May. 31, 2015	May. 31, 2014	Aug. 31, 2015	Aug. 31, 2014	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2013
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net (loss) income	$ 7.7	$ (37.9)	$ 17.3	$ (3.3)	$ 11.9	$ (10.5)	$ (49.2)	$ (2.2)	$ 14.0	$ (51.4)	$ (23.9)	$ (61.9)	$ (16.2)	$ (50.0)	$ 162.9
Net (loss) income per share (in USD per share)		$ (0.61)				$ (0.19)	$ (0.85)	$ (0.04)		$ (0.87)	$ (0.39)	$ (1.06)		$ (0.86)
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net (loss) income		$ 0.2	$ (1.1)	$ 0.6	$ 1.8	$ (0.6)	$ 1.7	$ 0.1	$ (0.5)	$ 1.8	$ (0.3)	$ 1.2		$ 3.0	$ (5.0)
Net (loss) income per share (in USD per share)		$ 0.01				$ (0.01)	$ 0.03	$ 0.00		$ 0.04	$ 0.00	$ 0.02		$ 0.06	$ 0.06