XML 64 R71.htm IDEA: XBRL DOCUMENT v2.4.0.6
Long-Term Debt and Capital Leases - Components of Long Term Debt and Capital Leases (Parenthetical) (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Apr. 30, 2013
Apr. 30, 2012
Debt Instrument [Line Items]    
Debt instrument stated percentage 6.70%  
Senior subordinated notes due 2019 notes [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Feb. 15, 2019  
Debt instrument stated percentage 7.75%  
Senior second lien notes, unamortized discount $ 1,735 $ 0
Senior secured revolving credit facility, due 2016 [Member]
   
Debt Instrument [Line Items]    
Letters of credit 227,500  
Debt instrument, due date Mar. 18, 2016  
Interest at LIBOR 3.75%  
One month LIBOR 3.95%  
Senior second lien notes, due 2014 [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Jul. 15, 2014  
Debt instrument stated percentage 11.00%  
Senior second lien notes, unamortized discount 0 2,572
Revenue Bonds Series 2005R-2, due 2025 [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Jan. 01, 2025  
Debt instrument stated percentage 6.25%  
Long-Term Revenue Bonds Series 2013 due April 1, 2036 [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Apr. 01, 2036  
Debt instrument stated percentage 4.75%  
Revenue Bonds Series 2013 due April 1, 2029 [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Apr. 01, 2029  
One month LIBOR 0.28%  
One month LIBOR 3.875%  
Revenue Bonds Series, 2005R-1, due 2025 [Member]
   
Debt Instrument [Line Items]    
Debt instrument, due date Jan. 01, 2025  
One month LIBOR 0.28%  
One month LIBOR 3.875%  
Notes payable [Member]
   
Debt Instrument [Line Items]    
Debt instrument interest rate, minimum 2.49%  
Debt instrument interest rate 6.50%  
Debt instrument lease installments 575  
Debt instrument maturity date start May 01, 2013  
Debt instrument maturity date Apr. 30, 2017  
Capital lease obligations [Member]
   
Debt Instrument [Line Items]    
Debt instrument interest rate 4.72%  
Debt instrument lease installments $ 78  
Debt instrument maturity date Jan. 31, 2015