Total Debt Outstanding (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
5.625 % Senior Notes due July 2013 [Member]
Debt Instrument [Line Items]
Debt interest rate	5.625%	5.625%
Unamortized discount		$ 0.3
12% Senior Notes due February 2014 [Member]
Debt Instrument [Line Items]
Debt interest rate	12.00%	12.00%
7.875% Senior Notes due June 2017 [Member]
Debt Instrument [Line Items]
Debt interest rate	7.875%	7.875%
Unamortized discount	5.7	6.5
8.125% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Debt interest rate	8.125%	8.125%
8.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Debt interest rate	8.375%	8.375%
6.875% Senior Notes due July 2033 [Member]
Debt Instrument [Line Items]
Debt interest rate	6.875%	6.875%
Unamortized discount	1.4	1.4
Multicurrency term A facility tranche [Member]
Debt Instrument [Line Items]
Unamortized lender fees	14.7	19.6
Multicurrency term B facility tranche [Member]
Debt Instrument [Line Items]
Unamortized discount	23.4	26.5
Unamortized lender fees	18.1	$ 21.3