Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Payables and Accruals [Abstract]
Federal excise and other passenger taxes and fees payable	$ 42,790	$ 26,979
Salaries and wages	30,775	26,174
Aircraft maintenance	29,738	36,165
Airport expenses	18,155	17,109
Fuel	11,799	13,819
Federal and state income tax payable	9,153	7,993
Aircraft and facility rent	5,031	794
Other	12,945	16,229
Other current liabilities	$ 160,386	$ 145,262