Annual report pursuant to Section 13 and 15(d)

Schedule of Long-Term Debt (Parenthetical) (Detail)

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Schedule of Long-Term Debt (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified
1 Months Ended 12 Months Ended
Oct. 24, 2012
Jun. 10, 2011
Dec. 31, 2012
Dec. 31, 2011
Debt Instrument [Line Items]        
Aggregate annual maturities of long-term debt, 2013     0  
Aggregate annual maturities of long-term debt, 2014     0  
Aggregate annual maturities of long-term debt, 2015     170.0  
Aggregate annual maturities of long-term debt, 2016     0  
Aggregate annual maturities of long-term debt, thereafter     900  
8.50% Senior Notes, due June 2019
       
Debt Instrument [Line Items]        
Senior notes interest rate 8.50% 8.50% 8.50% 8.50%
Senior notes maturity date Jun. 15, 2019 Jun. 15, 2019 Jun. 15, 2019 Jun. 15, 2019
Revolving Bank Credit Facility Due May 2015
       
Debt Instrument [Line Items]        
Senior notes maturity date     May 01, 2015 May 01, 2015