CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 51,157	$ (27,335)	$ 96,350
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	251,958	254,182	236,499
Stock based compensation expense	4,693	5,365	6,428
Loss (gain) on sale of property and equipment	621	(29)	(16)
Undistributed losses (earnings) of other companies	10,199	13,273	(635)
Capitalized Brasilia engine overhauls	(25,742)	(17,792)	(19,050)
Purchase accounting gain (adjustment)		5,711	(15,586)
Net increase (decrease) in deferred income taxes	34,800	(21,537)	58,525
Changes in operating assets and liabilities:
Decrease (increase) in restricted cash	(119)	2,341	4,971
Decrease (increase) in receivables	408	(10,665)	2,818
Decrease in income tax receivable	1,568	1,788	9,746
Decrease (increase) in inventories	1,630	(8,639)	(2,071)
Increase in other current assets and prepaid aircraft rents	(39,451)	(28,668)	(19,532)
Decrease in deferred aircraft credits	(7,112)	(8,586)	(8,756)
Increase (decrease) in accounts payable and accrued aircraft rents	(7,653)	10,161	6,289
Increase (decrease) in other current liabilities	11,867	(7,444)	(8,891)
NET CASH PROVIDED BY OPERATING ACTIVITIES	288,824	162,126	347,089
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(736,330)	(683,396)	(1,073,479)
Sales of marketable securities	677,798	857,031	1,047,553
Purchase of ExpressJet, net of cash acquired			(54,018)
Payments received on note receivable from United Air Lines			79,333
Proceeds from the sale of property and equipment	15,265	193	147
Proceeds from installment payment of equity shares of TRIP	8,064
Acquisition of property and equipment:
Aircraft and rotable spare parts	(57,277)	(158,942)	(141,474)
Deposits on aircraft		(13,500)	(400)
Buildings and ground equipment	(7,662)	(13,756)	(9,391)
Decrease (increase) in other assets	(8,218)	817	(25,647)
NET CASH USED IN INVESTING ACTIVITIES	(108,360)	(11,553)	(177,376)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	44,900	76,454	81,698
Principal payments on long-term debt	(218,270)	(159,038)	(185,632)
Return of deposits on aircraft and rotable spare parts		13,900	4,247
Net proceeds from issuance of common stock	6,231	4,446	4,907
Purchase of treasury stock	(902)	(60,681)	(30,009)
Payment of cash dividends	(8,177)	(8,466)	(9,000)
NET CASH USED IN FINANCING ACTIVITIES	(176,218)	(133,385)	(133,789)
Increase in cash and cash equivalents	4,246	17,188	35,924
Cash and cash equivalents at beginning of year	129,526	112,338	76,414
CASH AND CASH EQUIVALENTS AT END OF YEAR	133,772	129,526	112,338
Cash paid (received) during the year for:
Interest, net of capitalized amounts	78,407	81,187	85,931
Income taxes	$ (1,354)	$ (2,198)	$ (16,895)