CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 87,206	$ 328,384
Marketable securities	432,966	360,945
Income tax receivable	11,141	25,936
Receivables, net	82,977	64,194
Inventories, net	110,503	127,690
Prepaid aircraft rents		87,031
Other current assets	35,553	26,614
Total current assets	760,346	1,020,794
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	7,078,801	6,433,916
Deposits on aircraft	48,858	42,012
Buildings and ground equipment	265,398	291,544
Total property and equipment, gross	7,393,057	6,767,472
Less-accumulated depreciation and amortization	(1,998,376)	(1,761,728)
Total property and equipment, net	5,394,681	5,005,744
OTHER ASSETS
Operating lease right-of-use assets	336,009
Long-term prepaid assets		181,830
Other long-term assets	166,093	104,844
Total other assets	502,102	286,674
Total assets	6,657,129	6,313,212
CURRENT LIABILITIES:
Current maturities of long-term debt	364,126	350,206
Accounts payable	284,473	331,982
Accrued salaries, wages and benefits	133,856	161,606
Current maturities of operating lease liabilities	94,806
Taxes other than income taxes	15,004	16,024
Other current liabilities	32,411	65,008
Total current liabilities	924,676	924,826
LONG-TERM DEBT, net of current maturities	2,628,989	2,809,768
DEFERRED INCOME TAXES PAYABLE	623,580	518,159
DEFERRED AIRCRAFT CREDITS		29,308
NONCURRENT OPERATING LEASE LIABILITIES	259,237
OTHER LONG-TERM LIABILITIES	45,633	66,870
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; 81,742,937 and 81,239,289 shares issued, respectively	686,806	690,910
Retained earnings	2,079,179	1,776,585
Treasury stock, at cost, 31,420,179 and 29,850,999 shares, respectively	(590,971)	(503,182)
Accumulated other comprehensive loss		(32)
Total stockholders' equity	2,175,014	1,964,281
Total liabilities and stockholders' equity	$ 6,657,129	$ 6,313,212