CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
REVENUES	$ 2,070,611	$ 2,045,469	$ 1,734,282
OPERATING EXPENSES
Salaries, wages and benefits	685,940	666,950	591,280
Depreciation and amortization	342,985	331,064	308,448
Maintenance, materials and repairs	212,767	162,122	173,364
Fuel	278,528	275,512	173,600
Contracted ground and aviation services	74,273	77,026	75,724
Travel	128,584	111,989	86,601
Landing and ramp	17,486	16,583	14,244
Rent	31,703	30,437	23,695
Insurance	9,790	9,666	12,588
Other operating expenses	88,723	78,637	65,179
Government grants	0	0	(111,673)
Operating expenses	1,870,779	1,759,986	1,413,050
OPERATING INCOME	199,832	285,483	321,232
OTHER INCOME (EXPENSE)
Interest income	766	415	39
Settlement charges and non-service component gains of retiree benefits	(37,017)	20,046	17,827
Debt issuance costs	(936)	0	(6,505)
Net (loss) gain on financial instruments	(962)	9,022	29,979
Loss from non-consolidated affiliates	(4,740)	(7,607)	(2,577)
Interest expense	(72,704)	(46,861)	(58,790)
Other Nonoperating Income (Expense)	(115,593)	(24,985)	(20,027)
EARNINGS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	84,239	260,498	301,205
INCOME TAX EXPENSE	(24,491)	(64,060)	(72,225)
EARNINGS FROM CONTINUING OPERATIONS	59,748	196,438	228,980
EARNINGS FROM DISCONTINUED OPERATIONS, NET OF TAXES	579	2,143	2,440
NET EARNINGS	$ 60,327	$ 198,581	$ 231,420
BASIC EARNINGS PER SHARE
Basic earnings per share from continuing operations (in dollars per share)	$ 0.87	$ 2.67	$ 3.33
Discontinued operations (in dollars per share)	0.01	0.03	0.03
TOTAL BASIC EARNINGS PER SHARE (in dollars per share)	0.88	2.70	3.36
DILUTED EARNINGS PER SHARE
Diluted earnings per share from continuing operations (in dollars per share)	0.82	2.26	2.80
Discontinued operations (in dollars per share)	0	0.02	0.03
TOTAL DILUTED NET EARNINGS PER SHARE (in dollars per share)	$ 0.82	$ 2.28	$ 2.83
WEIGHTED AVERAGE SHARES
Basic (in shares)	68,641	73,611	68,853
Diluted (in shares)	75,561	88,324	76,216