Condensed Statements Of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 216,386	$ 242,820
Adjustments to reconcile net income to net cash provided by operations:
Unrealized losses on open derivative contracts, net	0	2,239
Losses reclassified from other comprehensive income	267	0
Equity-based compensation	5,503	6,999
Allowance for doubtful accounts	213	7
Amortization of deferred gains and losses	3,837	730
Depreciation and amortization	73,370	51,630
Deferred income tax expense	77,627	63,960
Loss on disposal of assets	1,166	1,300
Lease termination cost	31,609	0
Changes in operating assets and liabilities:
Accounts receivable	(7,840)	(10,374)
Aircraft maintenance deposits	(38,299)	(17,488)
Prepaid income taxes	66,218	0
Long-term deposits and other assets	(43,252)	(44,294)
Accounts payable	(7,044)	2,340
Air traffic liability	21,684	56,960
Other liabilities	38,596	12,161
Net cash provided by operating activities	440,041	368,990
Investing activities:
Proceeds from sale of property and equipment	50	0
Capitalized interest	(7,032)	(2,707)
Pre-delivery deposits for flight equipment, net of refunds	(109,260)	(87,658)
Purchase of investment securities	(100,076)	0
Purchase of property and equipment	(447,455)	(451,799)
Net cash used in investing activities	(663,773)	(542,164)
Financing activities:
Proceeds from issuance of long-term debt	378,569	416,000
Proceeds from stock options exercised	92	32
Payments on debt and capital lease obligations	(29,663)	(16,609)
Proceeds from sale and leaseback transactions	0	7,300
Excess tax benefit (deficiency) from equity-based compensation	(497)	8,818
Repurchase of common stock	(102,390)	(112,162)
Debt issuance costs	(107)	(14,092)
Net cash provided by financing activities	246,004	289,287
Net increase in cash and cash equivalents	22,272	116,113
Cash and cash equivalents at beginning of period	803,632	632,784
Cash and cash equivalents at end of period	825,904	748,897
Cash payments for:
Interest, net of capitalized interest	26,025	3,851
Income taxes paid, net of refunds	$ (18,169)	$ 95,135