CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 74,524	$ 102,984
Marketable securities	861,335	944,231
Receivables, net	101,036	100,523
Inventories, net	122,426	123,209
Other current assets	92,647	100,334
Total current assets	1,251,968	1,371,281
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	8,217,413	8,143,614
Deposits on aircraft	23,931	23,931
Buildings and ground equipment	277,910	265,019
Total property and equipment, gross	8,519,254	8,432,564
Less-accumulated depreciation and amortization	(2,957,796)	(2,884,084)
Total property and equipment, net	5,561,458	5,548,480
OTHER ASSETS:
Operating lease right-of-use assets	96,374	151,928
Long-term receivables and other assets	323,961	342,864
Total other assets	420,335	494,792
Total assets	7,233,761	7,414,553
CURRENT LIABILITIES:
Current maturities of long-term debt	443,328	438,502
Accounts payable	452,214	422,001
Accrued salaries, wages and benefits	184,223	186,285
Current maturities of operating lease liabilities	18,741	71,726
Taxes other than income taxes	20,130	20,480
Other current liabilities	33,466	33,549
Total current liabilities	1,152,102	1,172,543
LONG-TERM DEBT, net of current maturities	2,855,524	2,941,772
DEFERRED INCOME TAXES PAYABLE	681,550	687,060
NONCURRENT OPERATING LEASE LIABILITIES	76,418	88,622
OTHER LONG-TERM LIABILITIES	236,109	176,925
COMMITMENTS AND CONTINGENCIES (Note 6)
STOCKHOLDERS' EQUITY:
Preferred stock, 5,000,000 shares authorized; none issued
Common stock, no par value, 120,000,000 shares authorized; 82,800,633 and 82,592,830 shares issued as of March 31, 2023, and December 31, 2022, respectively	740,030	734,426
Retained earnings	2,214,798	2,236,869
Treasury stock, at cost, 37,093,074 and 31,994,416 shares as of March 31, 2023, and December 31, 2022, respectively	(720,448)	(619,862)
Accumulated other comprehensive loss	(2,322)	(3,802)
Total stockholders' equity	2,232,058	2,347,631
Total liabilities and stockholders' equity	$ 7,233,761	$ 7,414,553