Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Payables and Accruals [Abstract]
Federal excise and other passenger taxes and fees payable	$ 24,051	$ 23,401
Aircraft maintenance	23,784	22,319
Salaries and wages	22,357	21,057
Airport expenses	16,757	16,024
Fuel	12,994	11,219
Aircraft and facility rent	6,133	8,020
Tax receivable agreement	5,643	7,987
Other	18,051	11,287
Accrued liabilities	$ 129,770	$ 121,314