CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 253,661	$ 328,384
Marketable Securities	295,900	360,945
Income tax receivable	23,077	25,936
Receivables, net	80,233	64,194
Inventories, net	109,844	127,690
Prepaid aircraft rents		87,031
Other current assets	17,216	26,614
Total current assets	779,931	1,020,794
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	6,817,319	6,433,916
Deposits on aircraft	50,906	42,012
Buildings and ground equipment	240,154	291,544
Total property and equipment, gross	7,108,379	6,767,472
Less-accumulated depreciation and amortization	(1,817,333)	(1,761,728)
Total property and equipment, net	5,291,046	5,005,744
OTHER ASSETS:
Operating lease right-of-use assets	336,703
Long-term prepaid assets		181,830
Other assets	172,339	104,844
Total other assets	509,042	286,674
Total assets	6,580,019	6,313,212
CURRENT LIABILITIES:
Current maturities of long-term debt	345,253	350,206
Accounts payable	321,249	331,982
Accrued salaries, wages and benefits	127,367	161,606
Current maturities of operating lease liabilities	81,796
Taxes other than income taxes	16,662	16,024
Other current liabilities	35,001	65,008
Total current liabilities	927,328	924,826
LONG-TERM DEBT, net of current maturities	2,719,041	2,809,768
DEFERRED INCOME TAXES PAYABLE	569,439	518,159
DEFERRED AIRCRAFT CREDITS		29,308
NONCURRENT OPERATING LEASE LIABILITIES	265,516
OTHER LONG-TERM LIABILITIES	46,450	66,870
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; 81,703,419 and 81,239,289 shares issued, respectively	680,802	690,910
Retained earnings	1,927,412	1,776,585
Treasury stock, at cost, 30,811,446 and 29,850,999 shares, respectively	(555,969)	(503,182)
Accumulated other comprehensive loss		(32)
Total stockholders' equity	2,052,245	1,964,281
Total liabilities and stockholders' equity	$ 6,580,019	$ 6,313,212