Condensed Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating revenues:
Revenues	$ 855,796	$ 704,138
Operating expenses:
Aircraft fuel	229,636	204,646
Salaries, wages and benefits	203,901	155,096
Landing fees and other rents	59,649	49,630
Aircraft rent	45,782	50,191
Depreciation and amortization	50,726	39,373
Distribution	35,719	30,631
Maintenance, materials and repairs	31,604	29,710
Special charges	0	89,168
Loss on disposal of assets	1,913	848
Other operating	109,062	93,642
Total operating expenses	767,992	742,935
Operating income (loss)	87,804	(38,797)
Other (income) expense:
Interest expense	24,971	17,849
Capitalized interest	(2,557)	(2,252)
Interest income	(6,924)	(4,066)
Other expense	233	133
Special charges, non-operating	0	9,201
Total other (income) expense	15,723	20,865
Income (loss) before income taxes	72,081	(59,662)
Provision (benefit) for income taxes	16,005	(14,740)
Net income (loss)	$ 56,076	$ (44,922)
Basic earnings (loss) per share	$ 0.82	$ (0.66)
Diluted earnings (loss) per share	$ 0.82	$ (0.66)
Passenger [Member]
Operating revenues:
Revenues	$ 838,065	$ 689,141
Other [Member]
Operating revenues:
Revenues	$ 17,731	$ 14,997