CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 179,979	$ 148,277
Marketable securities	641,185	686,946
Receivables, net	85,882	82,854
Inventories, net	129,866	127,114
Other current assets	32,449	86,705
Total current assets	1,069,361	1,131,896
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	8,405,513	8,323,107
Deposits on aircraft	77,282	77,282
Buildings and ground equipment	292,633	282,398
Total property and equipment, gross	8,775,428	8,682,787
Less-accumulated depreciation and amortization	(3,284,609)	(3,199,820)
Total property and equipment, net	5,490,819	5,482,967
OTHER ASSETS:
Operating lease right-of-use assets	85,905	86,727
Long-term receivables and other assets	336,658	324,703
Total other assets	422,563	411,430
Total assets	6,982,743	7,026,293
CURRENT LIABILITIES:
Current maturities of long-term debt	506,602	443,869
Accounts payable	480,654	470,251
Accrued salaries, wages and benefits	181,154	194,881
Current maturities of operating lease liabilities	19,668	19,335
Taxes other than income taxes	20,924	26,077
Other current liabilities	103,294	99,879
Total current liabilities	1,312,296	1,254,292
LONG-TERM DEBT, net of current maturities	2,389,227	2,562,183
DEFERRED INCOME TAXES PAYABLE	703,602	687,600
NONCURRENT OPERATING LEASE LIABILITIES	66,237	67,392
OTHER LONG-TERM LIABILITIES	346,478	341,324
COMMITMENTS AND CONTINGENCIES (Note 7)
STOCKHOLDERS' EQUITY:
Preferred stock, 5,000,000 shares authorized; none issued
Common stock, no par value, 120,000,000 shares authorized; 83,137,744 and 82,840,372 shares issued as of March 31, 2024, and December 31, 2023, respectively	761,318	754,362
Retained earnings	2,331,509	2,271,211
Treasury stock, at cost, 42,868,446 and 42,615,347 shares as of March 31, 2024, and December 31, 2023, respectively	(928,076)	(912,396)
Accumulated other comprehensive income	152	325
Total stockholders' equity	2,164,903	2,113,502
Total liabilities and stockholders' equity	$ 6,982,743	$ 7,026,293