Financial Instruments and Risk Management (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Payments for premiums on fuel option derivatives	$ 300		$ 2,500
Into-plane fuel cost	114,081	$ 171,138	349,549	$ 473,994
Realized losses (gains) related to fuel derivative contracts, net	1,736	151	8,575	151
Unrealized losses (gains) related to fuel derivative contracts, net	82	295	(1,892)	762
Aircraft fuel	$ 115,899	$ 171,584	$ 356,232	$ 474,907