CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 328,384	$ 181,792
Marketable securities	360,945	503,503
Income tax receivable	25,936	5,316
Receivables, net	64,194	42,731
Inventories, net	127,690	119,755
Prepaid aircraft rents	87,031	115,098
Other current assets	26,614	26,938
Total current assets	1,020,794	995,133
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	6,433,916	5,335,870
Deposits on aircraft	42,012	49,000
Buildings and ground equipment	291,544	265,608
Total property and equipment, gross	6,767,472	5,650,478
Less-accumulated depreciation and amortization	(1,761,728)	(1,467,475)
Total property and equipment, net	5,005,744	4,183,003
OTHER ASSETS:
Long-term prepaid assets	181,830	230,923
Other long-term assets	104,844	65,341
Total other assets	286,674	296,264
Total assets	6,313,212	5,474,400
CURRENT LIABILITIES:
Current maturities of long-term debt	350,206	309,678
Accounts payable	331,982	288,904
Accrued salaries, wages and benefits	161,606	154,367
Taxes other than income taxes	16,024	19,228
Other current liabilities	65,008	48,648
Total current liabilities	924,826	820,825
OTHER LONG-TERM LIABILITIES	66,870	58,662
LONG-TERM DEBT, net of current maturities	2,809,768	2,377,346
DEFERRED INCOME TAXES PAYABLE	518,159	419,020
DEFERRED AIRCRAFT CREDITS	29,308	44,225
COMMITMENTS AND CONTINGENCIES (Note 5)
STOCKHOLDERS' EQUITY:
Preferred stock, 5,000,000 shares authorized; none issued
Common stock, no par value, 120,000,000 shares authorized; 81,239,289 and 80,398,104 shares issued, respectively	690,910	672,593
Retained earnings	1,776,585	1,516,957
Treasury stock, at cost, 29,850,999 and 28,643,535 shares, respectively	(503,182)	(435,178)
Accumulated other comprehensive loss	(32)	(50)
Total stockholders' equity	1,964,281	1,754,322
Total liabilities and stockholders' equity	$ 6,313,212	$ 5,474,400