CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
OPERATING REVENUES:
Passenger	$ 784,813	$ 773,107	$ 1,529,203	$ 1,515,605
Ground handling and other	16,525	15,310	34,211	33,210
Total operating revenues	801,338	788,417	1,563,414	1,548,815
OPERATING EXPENSES:
Salaries, wages and benefits	304,228	298,573	609,785	601,418
Aircraft maintenance, materials and repairs	142,289	156,319	281,149	314,576
Aircraft rentals	72,567	68,442	139,691	138,854
Depreciation and amortization	69,887	64,659	137,688	130,350
Aircraft fuel	32,306	31,192	57,638	58,492
Ground handling services	16,743	20,117	37,727	44,089
Other, net	79,181	79,183	153,790	157,028
Total operating expenses	717,201	718,485	1,417,468	1,444,807
OPERATING INCOME	84,137	69,932	145,946	104,008
OTHER INCOME (EXPENSE):
Interest income	485	697	915	1,336
Interest expense	(18,287)	(18,081)	(36,012)	(36,546)
Total other expense, net	(17,802)	(17,384)	(35,097)	(35,210)
INCOME BEFORE INCOME TAXES	66,335	52,548	110,849	68,798
PROVISION FOR INCOME TAXES	26,091	21,073	43,513	27,703
NET INCOME	$ 40,244	$ 31,475	$ 67,336	$ 41,095
BASIC EARNINGS PER SHARE (in dollars per share)	$ 0.78	$ 0.61	$ 1.31	$ 0.80
DILUTED EARNINGS PER SHARE (in dollars per share)	$ 0.77	$ 0.61	$ 1.29	$ 0.79
Weighted average common shares:
Basic (in shares)	51,418	51,357	51,318	51,407
Diluted (in shares)	52,194	51,971	52,104	52,182
COMPREHENSIVE INCOME:
Net income	$ 40,244	$ 31,475	$ 67,336	$ 41,095
Net unrealized appreciation (depreciation) on marketable securities, net of taxes	213	(223)	228	78
TOTAL COMPREHENSIVE INCOME	$ 40,457	$ 31,252	$ 67,564	$ 41,173