Condensed Statements Of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net income	$ 135,004	$ 145,706
Adjustments to reconcile net income to net cash provided by operations:
Unrealized losses on open derivative contracts, net	0	4,257
Losses reclassified from other comprehensive income	178	0
Equity-based compensation	3,905	4,743
Allowance for doubtful accounts	221	8
Amortization of deferred gains and losses	2,810	397
Depreciation and amortization	48,066	32,002
Deferred income tax expense	45,810	559
Loss on disposal of assets	743	1,010
Lease termination cost	24,254	0
Changes in operating assets and liabilities:
Accounts receivable	(12,662)	(8,137)
Aircraft maintenance deposits	(29,721)	(4,621)
Prepaid income taxes	69,444	0
Long-term deposits and other assets	(22,055)	(10,930)
Accounts payable	3,024	7,856
Air traffic liability	66,531	90,056
Other liabilities	25,269	36,728
Net cash provided by operating activities	360,821	299,634
Investing activities:
Proceeds from sale of property and equipment	50	0
Capitalized interest	(4,554)	(2,763)
Pre-delivery deposits for flight equipment, net of refunds	(60,772)	(70,971)
Purchase of property and equipment	(303,175)	(308,163)
Net cash used in investing activities	(368,451)	(381,897)
Financing activities:
Proceeds from issuance of long-term debt	300,547	296,000
Proceeds from stock options exercised	92	23
Payments on debt and capital lease obligations	(19,665)	(8,940)
Sale Leaseback Transaction, Gross Proceeds, Financing Activities	0	7,300
Excess tax benefit (deficiency) from equity-based compensation	(511)	8,504
Repurchase of common stock	(62,278)	(79,415)
Debt issuance costs	(107)	(4,669)
Net cash provided by financing activities	218,078	218,803
Net increase in cash and cash equivalents	210,448	136,540
Cash and cash equivalents at beginning of period	803,632	632,784
Cash and cash equivalents at end of period	1,014,080	769,324
Cash payments for:
Interest, net of capitalized interest	21,804	1,758
Income taxes paid, net of refunds	$ (36,142)	$ 54,198