Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Federal excise and other passenger taxes and fees payable	$ 38,254	$ 42,628
Salaries and wages	34,123	34,209
Airport obligations	30,849	21,726
Aircraft and facility lease obligations	24,014	10,089
Aircraft maintenance	21,688	16,127
Interest payable	12,355	1,708
Fuel	7,084	9,508
Other	14,362	16,926
Other current liabilities	$ 182,729	$ 152,921