Earnings Per Share Earnings Per Share (Computation of Earnings Per Common Share and Fully Diluted Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended															6 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2016	Aug. 31, 2016		May 31, 2016		Feb. 29, 2016		Nov. 30, 2015		Aug. 31, 2015		May 31, 2015		Feb. 28, 2015		May 31, 2015	[1]	Aug. 31, 2015	[1]	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Discontinued operations, loss from operations net of tax																				$ 0.0	$ 0.9	$ (0.6)
Effect of dilutive securities																				$ 0.0	0.4	0.8
Gain from discontinued operations								$ 0.0		$ 0.0		$ 0.9		$ 0.0							$ 0.9	$ (0.6)
Denominator for dilutive earnings per share - adjusted weighted average shares and assumed conversions																				44.0	45.7	47.1
Income (loss) from discontinued operations, net of tax																				$ 0.00	$ 0.02	$ (0.01)
Net income (loss) per share - Basic (in dollars per share)	$ (0.25)	$ 0.11	[1]	$ 0.16	[1]	$ (0.03)	[1]	$ (0.43)	[1]					$ (0.07)	[1]	$ 0.09		$ 0.01		$ (0.01)	$ (0.39)	$ 0.25
Options to purchase common stock and restricted shares that were excluded from computation of diluted earnings per share because they were anti-dilutive																				1.0	0.9	0.1
Basic Earnings Per Share:
(Loss) income from continuing operations								$ (18.9)		0.4		3.0		$ (3.2)						$ (0.4)	$ (18.7)	$ 12.1
Net (loss) income	$ (11.3)	$ 4.7		$ 7.2		$ (1.1)		$ (18.9)		$ 0.4		$ 3.9		$ (3.2)						$ (0.4)	$ (17.8)	$ 11.5
Weighted-average common shares outstanding – basic (in shares)																				44.0	45.3	46.3
Income from continuing operations income per common share - basic (in dollars per share)								$ (0.43)	[1]	$ 0.01	[1]	$ 0.07	[1]	$ (0.07)	[1]					$ (0.01)	$ (0.41)	$ 0.26
Diluted Earnings Per Share:
(Loss) income from continuing operations								$ (18.9)		$ 0.4		$ 3.0		$ (3.2)						$ (0.4)	$ (18.7)	$ 12.1
Net (loss) income	$ (11.3)	$ 4.7		$ 7.2		$ (1.1)		$ (18.9)		$ 0.4		$ 3.9		$ (3.2)						$ (0.4)	$ (17.8)	$ 11.5
Weighted-average common shares outstanding – basic (in shares)																				44.0	45.3	46.3
Retained Earnings [Member]
Basic Earnings Per Share:
Net (loss) income																				$ (0.4)	$ (17.8)	$ 11.5
Diluted Earnings Per Share:
Net (loss) income																				$ (0.4)	$ (17.8)	$ 11.5

[1] The sum of the quarterly earnings per share amounts may not equal the annual amount due to changes in the number of shares outstanding during the year.