CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
REVENUES	$ 501,095	$ 485,860
OPERATING EXPENSES
Salaries, wages and benefits	176,715	161,762
Depreciation and amortization	84,728	82,071
Maintenance, materials and repairs	43,833	35,709
Fuel	66,755	60,358
Contracted ground and aviation services	17,788	18,331
Travel	29,553	24,199
Landing and ramp	4,124	4,578
Rent	8,112	6,663
Insurance	2,548	2,552
Other operating expenses	19,516	19,843
Operating expenses	453,672	416,066
OPERATING INCOME	47,423	69,794
OTHER INCOME (EXPENSE)
Interest income	215	9
Non-service component of retiree benefit (loss) gains	(3,218)	5,388
Net (loss) gain on financial instruments	(1,740)	2,696
Loss from non-consolidated affiliate	(406)	(1,403)
Interest expense	(15,705)	(11,399)
Other Nonoperating Income (Expense)	(20,854)	(4,709)
EARNINGS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	26,569	65,085
INCOME TAX EXPENSE	(6,428)	(15,289)
EARNINGS FROM CONTINUING OPERATIONS	20,141	49,796
EARNINGS FROM DISCONTINUED OPERATIONS, NET OF TAXES	0	0
NET EARNINGS	$ 20,141	$ 49,796
BASIC EARNINGS PER SHARE
Basic earnings per share from continuing operations (in dollars per share)	$ 0.28	$ 0.67
Discontinued operations (in dollars per share)	0	0
TOTAL BASIC EARNINGS PER SHARE (in dollars per share)	0.28	0.67
DILUTED EARNINGS PER SHARE
Diluted earnings per share from continuing operations (in dollars per share)	0.25	0.57
Discontinued operations (in dollars per share)	0	0
TOTAL DILUTED NET EARNINGS PER SHARE (in dollars per share)	$ 0.25	$ 0.57
WEIGHTED AVERAGE SHARES
Basic (in shares)	71,802	73,888
Diluted (in shares)	83,057	88,744