Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Salaries and wages	$ 45,696	$ 34,123
Salaries and wages	41,452	38,254
Aircraft maintenance	36,788	30,849
Interest payable	39,393	21,688
Fuel	14,796	12,355
Aircraft and facility lease obligations	11,225	7,084
Airport obligations	11,117	24,014
Other	17,312	14,362
Other current liabilities	$ 217,779	$ 182,729