Condensed Statements Of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net income	$ 61,920	$ 69,002
Adjustments to reconcile net income to net cash provided by operations:
Unrealized losses on open derivative contracts, net	0	3,783
Losses reclassified from other comprehensive income	90	0
Equity-based compensation	1,790	1,985
Allowance for doubtful accounts (recoveries)	25	31
Amortization of deferred gains and losses	1,968	164
Depreciation and amortization	23,109	14,863
Deferred income tax expense (benefit)	21,066	(5,560)
Loss on disposal of assets	214	595
Lease termination cost	16,202	0
Changes in operating assets and liabilities:
Accounts receivable	(4,229)	(5,444)
Aircraft maintenance deposits	(12,311)	(12,317)
Prepaid Income Taxes	72,278	0
Long-term deposits and other assets	(8,495)	(6,160)
Accounts payable	4,703	433
Air traffic liability	46,473	79,350
Other liabilities	33,296	28,810
Net cash provided by operating activities	258,099	169,535
Investing activities:
Pre-delivery deposits for flight equipment, net of refunds	(50,358)	(50,388)
Capitalized interest	(2,575)	(1,700)
Purchase of property and equipment	(159,829)	(184,609)
Net cash used in investing activities	(212,762)	(236,697)
Financing activities:
Proceeds from issuance of long-term debt	73,914	185,000
Proceeds from stock options exercised	88	15
Payments on debt and capital lease obligations	(9,749)	(2,968)
Excess tax benefit (deficiency) from equity-based compensation	(778)	7,877
Repurchase of common stock	(9,601)	(10,943)
Debt issuance costs	(34)	(2,976)
Net cash provided by financing activities	53,840	176,005
Net increase in cash and cash equivalents	99,177	108,843
Cash and cash equivalents at beginning of period	803,632	632,784
Cash and cash equivalents at end of period	902,809	741,627
Cash payments for:
Interest, net of capitalized interest	3,430	11
Income taxes paid, net of refunds	$ (64,158)	$ 9,883