Credit Card Processing Arrangements (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012
Credit Card Processing Arrangements [Abstract]
Cash collateral required for credit card transactions as a percentage of air traffic liability, prior to amendment	100.00%
Cash holdback for credit card transactions	$ 0	$ 0
Maximum potential exposure to cash holdbacks by the credit card processors	$ 115,200,000	$ 144,800,000