CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
OPERATING REVENUES:
Total operating revenues	$ 350,039	$ 744,383	$ 1,079,975	$ 1,468,077
OPERATING EXPENSES:
Salaries, wages and benefits	170,218	243,766	419,379	501,354
Depreciation and amortization	131,638	90,148	243,346	180,134
CARES Act payroll support grant	(151,938)		(151,938)
Special items				21,869
Other operating expenses	38,167	61,948	107,589	125,057
Total operating expenses	354,442	600,290	1,018,057	1,227,565
OPERATING INCOME (LOSS)	(4,403)	144,093	61,918	240,512
OTHER INCOME (EXPENSE):
Interest income	1,685	3,731	4,249	7,538
Interest expense	(30,926)	(32,770)	(61,130)	(65,278)
Other income (expense), net	402	281	800	47,006
Total other income (expense), net	(28,839)	(28,758)	(56,081)	(10,734)
INCOME (LOSS) BEFORE INCOME TAXES	(33,242)	115,335	5,837	229,778
PROVISION (BENEFIT) FOR INCOME TAXES	(7,527)	27,283	1,564	53,545
NET INCOME (LOSS)	$ (25,715)	$ 88,052	$ 4,273	$ 176,233
BASIC EARNINGS (LOSS) PER SHARE (in dollars per share)	$ (0.51)	$ 1.72	$ 0.09	$ 3.44
DILUTED EARNINGS (LOSS) PER SHARE (in dollars per share)	$ (0.51)	$ 1.71	$ 0.08	$ 3.40
Weighted average common shares:
Basic (in shares)	50,140	51,145	50,208	51,293
Diluted (in shares)	50,140	51,477	50,357	51,787
COMPREHENSIVE INCOME (LOSS):
Net income (loss)	$ (25,715)	$ 88,052	$ 4,273	$ 176,233
Net unrealized depreciation on debt securities, net of taxes	307		307	32
TOTAL COMPREHENSIVE INCOME (LOSS)	(25,408)	88,052	4,580	176,265
Flying agreements
OPERATING REVENUES:
Total operating revenues	336,370	725,335	1,045,864	1,425,336
Lease, airport services and other
OPERATING REVENUES:
Total operating revenues	13,669	19,048	34,111	42,741
Aircraft maintenance, materials and repairs
OPERATING EXPENSES:
Total operating expenses	121,289	124,789	281,505	243,051
Airport related expenses
OPERATING EXPENSES:
Total operating expenses	21,550	30,782	52,190	61,429
Aircraft fuel
OPERATING EXPENSES:
Total operating expenses	6,821	30,851	32,234	56,507
Aircraft rentals
OPERATING EXPENSES:
Total operating expenses	$ 16,697	$ 18,006	$ 33,752	$ 38,164