Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

v2.4.0.6
Long-Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended 1 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Apr. 19, 2013
Subsequent Event
Mar. 31, 2013
8.50% Senior Notes, due June 2019
Dec. 31, 2012
8.50% Senior Notes, due June 2019
Mar. 31, 2013
Credit Agreement
Mar. 31, 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.    
Annual effective interest rate       8.40% 8.40%   3.70%
Credit agreement expiration date           May 05, 2015  
Letters of credit outstanding $ 0.6 $ 0.6          
Revolving bank credit facility borrowing base 725.0   800.0        
Line of credit, borrowing capacity availability $ 581.4