Statements Of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating revenues:
Passenger	$ 1,366,034	$ 1,200,621	$ 1,169,338
Non-ticket	1,281,632	1,121,335	972,125
Total operating revenues	2,647,666	2,321,956	2,141,463
Operating expenses:
Aircraft fuel	615,581	447,553	461,447
Salaries, wages and benefits	527,959	472,471	377,508
Aircraft rent	205,852	201,675	211,531
Landing fees and other rents	180,655	151,679	131,077
Depreciation and amortization	140,152	101,136	73,908
Maintenance, materials and repairs	110,439	98,587	80,448
Distribution	113,620	96,627	86,576
Special charges	12,629	37,189	673
Loss on disposal of assets	4,168	4,187	1,604
Other operating	347,820	267,191	207,569
Total operating expenses	2,258,875	1,878,295	1,632,341
Operating income	388,791	443,661	509,122
Other (income) expense:
Interest expense	57,302	41,654	20,382
Capitalized interest	(13,793)	(12,705)	(11,553)
Interest income	(8,736)	(5,276)	(2,125)
Other expense	366	528	15
Total other (income) expense	35,139	24,201	6,719
Income before income taxes	353,652	419,460	502,403
Provision (benefit) for income taxes	(66,954)	154,581	185,183
Net income	$ 420,606	$ 264,879	$ 317,220
Basic earnings per share (in dollars per share)	$ 6.08	$ 3.77	$ 4.39
Diluted earnings per share (in dollars per share)	$ 6.06	$ 3.76	$ 4.38