CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 290,885	$ 328,384
Marketable Securities	253,397	360,945
Income tax receivable	21,255	25,936
Receivables, net	78,370	64,194
Inventories, net	112,566	127,690
Prepaid aircraft rents		87,031
Other current assets	24,921	26,614
Total current assets	781,394	1,020,794
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	6,696,982	6,433,916
Deposits on aircraft	37,602	42,012
Buildings and ground equipment	270,665	291,544
Total property and equipment, gross	7,005,249	6,767,472
Less-accumulated depreciation and amortization	(1,730,681)	(1,761,728)
Total property and equipment, net	5,274,568	5,005,744
OTHER ASSETS:
Operating lease right-of-use assets	341,898
Long-term prepaid assets		181,830
Other assets	146,672	104,844
Total other assets	488,570	286,674
Total assets	6,544,532	6,313,212
CURRENT LIABILITIES:
Current maturities of long-term debt	362,797	350,206
Accounts payable	340,195	331,982
Accrued salaries, wages and benefits	118,074	161,606
Taxes other than income taxes	13,901	16,024
Current maturities of operating lease liabilities	73,524
Other current liabilities	36,836	65,008
Total current liabilities	945,327	924,826
LONG-TERM DEBT, net of current maturities	2,734,317	2,809,768
DEFERRED INCOME TAXES PAYABLE	541,196	518,159
DEFERRED AIRCRAFT CREDITS		29,308
NONCURRENT OPERATING LEASES	275,088
OTHER LONG-TERM LIABILITIES	48,037	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; 81,798,773 and 81,239,289 shares issued, respectively	692,593	690,910
Retained earnings	1,845,467	1,776,585
Treasury stock, at cost, 30,500,393 and 29,850,999 shares, respectively	(537,493)	(503,182)
Accumulated other comprehensive loss		(32)
Total stockholders' equity	2,000,567	1,964,281
Total liabilities and stockholders' equity	$ 6,544,532	$ 6,313,212