CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 98,946	$ 129,526
Marketable securities	464,918	497,552
Restricted cash	19,440	19,434
Income tax receivable	2,095	1,568
Receivables, net	146,233	130,510
Inventories, net	118,620	115,211
Prepaid aircraft rents	337,559	285,737
Deferred tax assets	74,781	69,519
Other current assets	37,418	31,407
Total current assets	1,300,010	1,280,464
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	3,986,196	3,973,027
Buildings and ground equipment	291,329	291,294
Total property and equipment, gross	4,277,525	4,264,321
Less-accumulated depreciation and amortization	(1,435,405)	(1,380,846)
Total property and equipment, net	2,842,120	2,883,475
OTHER ASSETS
Intangible assets, net	18,935	19,497
Other assets	104,592	98,472
Total other assets	123,527	117,969
Total assets	4,265,657	4,281,908
CURRENT LIABILITIES:
Current maturities of long-term debt	203,943	208,398
Accounts payable	240,098	220,784
Accrued salaries, wages and benefits	110,455	112,987
Accrued aircraft rents	18,400	22,285
Taxes other than income taxes	17,507	21,186
Other current liabilities	43,838	38,508
Total current liabilities	634,241	624,148
OTHER LONG-TERM LIABILITIES	48,820	50,194
LONG-TERM DEBT, net of current maturities	1,577,773	1,606,993
DEFERRED INCOME TAXES PAYABLE	573,499	567,874
DEFERRED AIRCRAFT CREDITS	96,916	98,438
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Preferred stock, 5,000,000 shares authorized; none issued
Common stock, no par value, 120,000,000 shares authorized; 76,224,131 and 75,833,696 shares issued, respectively	602,366	598,985
Retained earnings	1,101,425	1,104,144
Treasury stock, at cost, 25,279,790 and 25,221,481 shares, respectively	(371,206)	(370,309)
Accumulated other comprehensive income	1,823	1,441
Total stockholders' equity	1,334,408	1,334,261
Total liabilities and stockholders' equity	$ 4,265,657	$ 4,281,908