CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
REVENUES	$ 2,045,469	$ 1,734,282	$ 1,570,575
OPERATING EXPENSES
Salaries, wages and benefits	666,950	591,280	518,961
Depreciation and amortization	331,064	308,448	278,067
Maintenance, materials and repairs	162,122	173,364	179,315
Fuel	275,512	173,600	148,383
Contracted ground and aviation services	77,026	75,724	63,564
Travel	111,989	86,601	77,382
Landing and ramp	16,583	14,244	12,468
Rent	30,437	23,695	19,299
Insurance	9,666	12,588	9,903
Other operating expenses	78,637	65,179	64,999
Government grants	0	(111,673)	(47,231)
Impairment of aircraft and related assets	0	0	39,075
Operating expenses	1,759,986	1,413,050	1,364,185
OPERATING INCOME	285,483	321,232	206,390
OTHER INCOME (EXPENSE)
Interest income	415	39	222
Non-service component of retiree benefit gains	20,046	17,827	12,032
Debt issuance costs	0	(6,505)	0
Net gain (loss) on financial instruments	9,022	29,979	(100,771)
Loss from non-consolidated affiliate	(7,607)	(2,577)	(13,587)
Interest expense	(46,861)	(58,790)	(62,893)
Other Nonoperating Income (Expense)	(24,985)	(20,027)	(164,997)
EARNINGS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	260,498	301,205	41,393
INCOME TAX EXPENSE	(64,060)	(72,225)	(16,314)
EARNINGS FROM CONTINUING OPERATIONS	196,438	228,980	25,079
EARNINGS FROM DISCONTINUED OPERATIONS, NET OF TAXES	2,143	2,440	7,036
NET EARNINGS	$ 198,581	$ 231,420	$ 32,115
BASIC EARNINGS PER SHARE
Basic earnings per share from continuing operations (in dollars per share)	$ 2.67	$ 3.33	$ 0.42
Discontinued operations (in dollars per share)	0.03	0.03	0.12
TOTAL BASIC EARNINGS PER SHARE (in dollars per share)	2.70	3.36	0.54
DILUTED EARNINGS PER SHARE
Diluted earnings per share from continuing operations (in dollars per share)	2.26	2.80	0.42
Discontinued operations (in dollars per share)	0.02	0.03	0.12
TOTAL DILUTED NET EARNINGS PER SHARE (in dollars per share)	$ 2.28	$ 2.83	$ 0.54
WEIGHTED AVERAGE SHARES
Basic (in shares)	73,611	68,853	59,128
Diluted (in shares)	88,324	76,216	59,931