Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended															12 Months Ended
	Nov. 30, 2019	Aug. 31, 2019		May 31, 2019		Feb. 28, 2019		Nov. 30, 2018		Aug. 31, 2018		May 31, 2018		Feb. 28, 2018		Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017
Earnings Per Share [Abstract]
Net income (loss)	$ (23.7)	$ 0.3	[1]	$ 5.6	[1]	$ (4.6)	[1]	$ 6.9		$ (1.9)		$ 8.4		$ 7.3		$ (22.4)	$ 20.7	$ (87.8)
Denominator for basic earnings per share - weighted average shares outstanding																44,800	44,600	44,400
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements																0	300	0
Weighted Average Number of Shares Outstanding, Diluted																44,800	44,900	44,400
Net income (loss) per share - Basic and Diluted	$ (0.54)	$ 0.01		$ 0.13		$ (0.10)		$ 0.15	[1]	$ (0.04)	[1]	$ 0.19	[1]	$ 0.16	[1]	$ (0.50)	$ 0.46	$ (1.98)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount																900		600

[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.