CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CONSOLIDATED STATEMENTS OF CASH FLOWS
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 168,807	$ 32,489
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(337,375)	(112,664)
Sales of marketable securities	430,688	215,005
Proceeds from the sale of equipment	5,719	3
Acquisition of property and equipment:
Aircraft and rotable spare parts	(503,317)	(297,758)
Buildings and ground equipment	(16,842)	(11,644)
Return of deposits on aircraft	2,300
Increase in other assets	(8,325)	(13,563)
NET CASH USED IN INVESTING ACTIVITIES	(427,152)	(220,621)
CASH FLOWS PROVIDED BY FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	432,568	187,389
Principal payments on long-term debt	(114,202)	(88,236)
Tax deficiency from exercise of common stock options	(2,012)	(1,266)
Net proceeds from issuance of common stock	3,721	1,933
Purchase of treasury stock	(18,726)	(8,414)
Payment of cash dividends	(4,114)	(4,119)
NET CASH PROVIDED BY FINANCING ACTIVITIES	297,235	87,287
Increase (decrease) in cash and cash equivalents	38,890	(100,845)
Cash and cash equivalents at beginning of period	132,275	170,636
CASH AND CASH EQUIVALENTS AT END OF PERIOD	171,165	69,791
Cash paid during the year for:
Interest, net of capitalized amounts	37,530	33,103
Income taxes	$ 613	$ 382