CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	[1]
CURRENT ASSETS:
Cash and cash equivalents	$ 175,728	$ 181,792
Marketable securities	473,362	503,503
Income tax receivable	11,115	5,316
Receivables, net	71,240	42,731
Inventories, net	118,901	119,755
Prepaid aircraft rents	90,324	115,098
Other current assets	34,555	26,938
Total current assets	975,225	995,133
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	5,929,735	5,335,870
Deposits on aircraft	49,000	49,000
Buildings and ground equipment	285,283	265,608
Total property and equipment, gross	6,264,018	5,650,478
Less-accumulated depreciation and amortization	(1,604,814)	(1,467,475)
Total property and equipment, net	4,659,204	4,183,003
OTHER ASSETS
Long-term prepaid assets	207,470	230,923
Other assets	71,194	65,341
Total other assets	278,664	296,264
Total assets	5,913,093	5,474,400
CURRENT LIABILITIES:
Current maturities of long-term debt	353,743	309,678
Accounts payable	291,009	288,904
Accrued salaries, wages and benefits	160,428	154,367
Taxes other than income taxes	16,762	19,228
Other current liabilities	56,653	48,648
Total current liabilities	878,595	820,825
LONG TERM DEBT, net of current maturities	2,615,637	2,377,346
DEFERRED INCOME TAXES PAYABLE	459,927	419,020
DEFERRED AIRCRAFT CREDITS	36,281	44,225
OTHER LONG TERM LIABILITIES	62,001	58,662
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; 81,104,752 and 80,398,104 shares issued, respectively	682,545	672,593
Retained earnings	1,636,768	1,516,957
Treasury stock, at cost, 29,058,982 and 28,643,535 shares, respectively	(458,645)	(435,178)
Accumulated other comprehensive loss	(16)	(50)
Total stockholders' equity	1,860,652	1,754,322
Total liabilities and stockholders' equity	$ 5,913,093	$ 5,474,400

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part I, Item 1 of this report for additional information.