CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
OPERATING REVENUES:
Passenger	$ 791,341	$ 784,813	$ 1,536,752	$ 1,529,203
Ground handling and other	18,418	16,525	38,422	34,211
Total operating revenues	809,759	801,338	1,575,174	1,563,414
OPERATING EXPENSES:
Salaries, wages and benefits	295,929	304,228	595,969	609,785
Aircraft maintenance, materials and repairs	152,356	142,289	284,681	281,149
Depreciation and amortization	71,206	69,887	141,320	137,688
Aircraft rentals	55,413	72,567	113,123	139,691
Aircraft fuel	37,183	32,306	71,493	57,638
Ground handling services	15,902	16,743	35,436	37,727
Other operating expenses	75,174	79,181	150,262	153,790
Total operating expenses	703,163	717,201	1,392,284	1,417,468
OPERATING INCOME	106,596	84,137	182,890	145,946
OTHER INCOME (EXPENSE):
Interest income	1,330	485	1,990	915
Interest expense	(27,063)	(18,287)	(51,612)	(36,012)
Total other expense, net	(25,733)	(17,802)	(49,622)	(35,097)
INCOME BEFORE INCOME TAXES	80,863	66,335	133,268	110,849
PROVISION FOR INCOME TAXES	30,386	26,091	48,005	43,513
NET INCOME	$ 50,477	$ 40,244	$ 85,263	$ 67,336
BASIC EARNINGS PER SHARE (in dollars per share)	$ 0.98	$ 0.78	$ 1.65	$ 1.31
DILUTED EARNINGS PER SHARE (in dollars per share)	$ 0.95	$ 0.77	$ 1.61	$ 1.29
Weighted average common shares:
Basic (in shares)	51,751	51,418	51,785	51,318
Diluted (in shares)	52,977	52,194	53,090	52,104
COMPREHENSIVE INCOME:
Net income	$ 50,477	$ 40,244	$ 85,263	$ 67,336
Net unrealized appreciation on marketable securities, net of taxes	17	213	56	228
TOTAL COMPREHENSIVE INCOME	$ 50,494	$ 40,457	$ 85,319	$ 67,564