Long-Term Debt - Summary of Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	Nov. 30, 2013	Nov. 30, 2012	Dec. 31, 2009
Debt Instrument [Line Items]
Senior debt	$ 45.0	$ 47.5
Capital lease, payable in monthly installments, maturing in March 2017	0.8	1.0
Senior secured notes	460.0
Convertible subordinated notes	193.4	200.2
Other debt	0.8	1.0
Total debt	699.2	248.7
Total long-term debt, carrying amount	696.3	246.0
Term loan, bearing interest at variable rates (rate of 3.67% as of November 30, 2013), payable in quarterly installments of $0.6 million plus interest, maturing in November 2016	42.5	45.0
Convertible subordinated notes	193.2	200.2
Senior Secured Notes Due 2021 [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
Term Loan Due on 2016 [Member]
Debt Instrument [Line Items]
Total debt	45.0
Term loan, bearing interest at variable rates (rate of 3.67% as of November 30, 2013), payable in quarterly installments of $0.6 million plus interest, maturing in November 2016	45.0	47.5
Convertible Subordinated Debentures, Bearing Interest at 2.25% Maturing in November 2024 [Member]
Debt Instrument [Line Items]
Total debt	0.2
Convertible subordinated notes	0.2	0.2
Convertible Subordinated Debentures, Bearing Interest at 4.0625% Maturing in December 2039 [Member]
Debt Instrument [Line Items]
Convertible subordinated notes	193.2	200.0	200.0
Senior Debt [Member]
Debt Instrument [Line Items]
Less: Amounts due within one year	2.5	2.5
Other Debt [Member]
Debt Instrument [Line Items]
Total debt	0.8
Less: Amounts due within one year	$ 0.4	$ 0.2