CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
CURRENT ASSETS:
Cash and cash equivalents	$ 129,526	$ 112,338
Marketable securities	497,552	670,739
Restricted cash	19,434	21,775
Income tax receivable	1,568	3,356
Receivables, net	130,510	119,845
Inventories, net	115,211	106,572
Prepaid aircraft rents	285,737	256,168
Deferred tax assets	69,519	56,102
Other current assets	31,407	32,308
Total current assets	1,280,464	1,379,203
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	3,973,027	3,836,550
Deposits on aircraft		400
Buildings and ground equipment	291,294	278,665
Total property and equipment, gross	4,264,321	4,115,615
Less-accumulated depreciation and amortization	(1,380,846)	(1,172,796)
Total property and equipment, net	2,883,475	2,942,819
OTHER ASSETS
Intangible assets, net	19,497	21,747
Other assets	98,472	112,379
Total other assets	117,969	134,126
Total assets	4,281,908	4,456,148
CURRENT LIABILITIES:
Current maturities of long-term debt	208,398	159,039
Accounts payable	220,784	216,128
Accrued salaries, wages and benefits	112,987	112,728
Accrued aircraft rents	22,285	16,780
Taxes other than income taxes	21,186	25,146
Other current liabilities	38,508	42,457
Total current liabilities	624,148	572,278
OTHER LONG TERM LIABILITIES	50,194	46,325
LONG TERM DEBT, net of current maturities	1,606,993	1,738,936
DEFERRED INCOME TAXES PAYABLE	567,874	569,847
DEFERRED AIRCRAFT CREDITS	98,438	107,839
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; 75,833,696 and 75,244,553 shares issued, respectively	598,985	589,610
Retained earnings	1,104,144	1,139,739
Treasury stock, at cost, 25,221,481 and 21,071,582 shares, respectively	(370,309)	(309,628)
Accumulated other comprehensive income (Note 1)	1,441	1,202
Total stockholders' equity	1,334,261	1,420,923
Total liabilities and stockholders' equity	$ 4,281,908	$ 4,456,148