v2.4.0.8
Fair Value of Financial Instruments (Details) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Derivatives, Fair Value [Line Items]      
Percentage of fuel cost of operating expenses (in hundredths) 4.20% 3.80% 3.40%
Derivative agreements (in dollars per gallon) 3.55 3.50 2.68
Derivative Instruments, Gain (Loss) [Line Items]      
Unrealized loss on derivative instrument $ 143,000 $ 257,000 $ 800,000
Cash settlements under derivative contracts     1,131,000
Estimate of Fair Value
     
Fair value of financial instruments [Abstract]      
Long-term debt, fair value disclosure 513,436,000 406,856,000  
Carrying (Reported) Amount
     
Fair value of financial instruments [Abstract]      
Long-term debt, fair value disclosure 516,453,000 404,478,000  
Aircraft operations expense
     
Derivative Instruments, Gain (Loss) [Line Items]      
Unrealized loss on derivative instrument $ 143,000 $ 257,000 $ 800,000