Long-term Debt - Summary of Long-term Debt (Detail) (USD $) In Millions, unless otherwise specified	Aug. 31, 2014	Nov. 30, 2013
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 2.74% as of August 31, 2014), payable in quarterly installments of $1.3 million plus interest, maturing in May 2019	$ 100.0	$ 45.0
Total senior debt	100.0	45.0
Senior secured notes, bearing interest at 7.125% per annum, interest payments due in March and September, maturing in March 2021	460.0	460.0
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 2039	133.6	193.2
Total convertible subordinated notes	133.8	193.4
Capital lease, payable in monthly installments, maturing in March 2017	0.7	0.8
Total other debt	89.7	0.8
Total debt	783.5	699.2
Less: Amounts due within one year	(5.5)	(2.9)
Total long-term debt	778.0	696.3
Term Loan [Member]
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 2.74% as of August 31, 2014), payable in quarterly installments of $1.3 million plus interest, maturing in May 2019	100.0	45.0
Total senior debt	100.0	45.0
7.125% Second-Priority Senior Secured Notes [Member]
Debt Instrument [Line Items]
Senior secured notes, bearing interest at 7.125% per annum, interest payments due in March and September, maturing in March 2021	460.0	460.0
Total senior secured notes	460.0	460.0
2.25% Convertible Subordinated Debentures [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
4.0625% Convertible Subordinated Debentures [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 2039	133.6	193.2
Delayed Draw Term Loan [Member]
Debt Instrument [Line Items]
Delayed draw term loan, bearing interest at variable rates (rate of 9.50% as of August 31, 2014), maturing in April 2022	$ 89.0	$ 0