Long-term Debt - Summary of Long-term Debt (Detail) (USD $) In Millions, unless otherwise specified	Feb. 28, 2014	Nov. 30, 2013
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 3.66% as of February 28, 2014), payable in quarterly installments of $0.6 million plus interest, maturing in November 2016	$ 41.9	$ 42.5
Total senior debt	44.4	45.0
Total senior secured notes	460.0	460.0
Convertible subordinated debentures, bearing interest at 4.0625% per annum, interest payments due in June and December, maturing in December 2034	188.7	193.2
Total convertible subordinated notes	188.9	193.4
Capital lease, payable in monthly installments, maturing in March 2017	0.8	0.8
Total other debt	0.8	0.8
Total debt	694.1	699.2
Less: Amounts due within one year	(3.0)	(2.9)
Total long-term debt	691.1	696.3
Term Loan Due on 2016 [Member]
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 3.66% as of February 28, 2014), payable in quarterly installments of $0.6 million plus interest, maturing in November 2016	44.4	45.0
Senior subordinated notes [Member]
Debt Instrument [Line Items]
Total senior secured notes	460.0	460.0
Convertible Subordinated Debentures, Bearing Interest at 2.25% Maturing in November 2024 [Member]
Debt Instrument [Line Items]
Convertible subordinated debentures, bearing interest at 2.25% per annum, interest payments due in May and November, maturing in November 2024	0.2	0.2
Convertible Subordinated Debentures, Bearing Interest at 4.0625% Maturing in December 2034 [Member]
Debt Instrument [Line Items]
Convertible subordinated debentures, bearing interest at 4.0625% per annum, interest payments due in June and December, maturing in December 2034	$ 188.7	$ 193.2