v2.4.0.6
Financial Instruments (Details)
Mar. 31, 2013
gal
Fuel Hedges Remaining 2013 [Member]
 
Summary of costless collar hedges outstanding  
Remaining Gallons Hedged (in gallons per year) 20,490,000
Weighted Average Contract Price per Gallon (in dollars per gallon) 3.81
Fuel Hedges Remaining 2014 [Member]
 
Summary of costless collar hedges outstanding  
Remaining Gallons Hedged (in gallons per year) 27,000,000
Weighted Average Contract Price per Gallon (in dollars per gallon) 3.81
Fuel Hedges Remaining 2015 [Member]
 
Summary of costless collar hedges outstanding  
Remaining Gallons Hedged (in gallons per year) 9,000,000
Weighted Average Contract Price per Gallon (in dollars per gallon) 3.73
Fuel Hedges Remaining 2016 [Member]
 
Summary of costless collar hedges outstanding  
Remaining Gallons Hedged (in gallons per year) 3,000,000
Weighted Average Contract Price per Gallon (in dollars per gallon) 3.70