Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

v2.4.0.8
Long-Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
9 Months Ended 12 Months Ended 1 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Sep. 30, 2013
Senior Notes
Dec. 31, 2012
Senior Notes
May 15, 2012
Credit Agreement
Sep. 30, 2013
Revolving Credit Facility
Debt Instrument [Line Items]            
Senior notes interest rate 8.50% 8.50%        
Senior notes payment terms Interest on the 8.50% Senior Notes is payable semi-annually in arrears on June 15 and December 15. Interest on the 8.50% Senior Notes is payable semi-annually in arrears on June 15 and December 15.        
Effective interest rate     8.40% 8.40%   3.90%
Senior notes maturity date Jun. 15, 2019          
Credit agreement expiration date         May 05, 2015  
Letters of credit outstanding $ 0.1 $ 0.1        
Revolving bank credit facility borrowing base 800.0          
Line of credit, borrowing availability $ 662.9