Consolidated Statements of Cash Flows - USD ($)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net income (loss)		$ (447,464,000)	$ (554,150,000)	$ (472,569,000)
Adjustments to reconcile net loss to net cash provided by (used in) operations:
Losses reclassified from other comprehensive income		314,000	199,000	226,000
Share-based compensation		11,963,000	11,483,000	12,536,000
Allowance for doubtful accounts (recoveries)		159,000	(108,000)	(88,000)
Amortization of debt issuance costs		15,454,000	13,468,000	12,912,000
Depreciation and amortization		320,872,000	313,090,000	297,211,000
Accretion of convertible debt and 8.00% senior secured notes		4,210,000	1,421,000	1,272,000
Amortization of debt discount		8,145,000	13,962,000	0
Deferred income tax benefit		(119,239,000)	(148,611,000)	(49,502,000)
Fixed asset impairment charges		0	333,691,000	0
Loss on disposal of assets		33,966,000	46,624,000	3,320,000
Loss (gain) on extinguishment of debt		0	0	331,630,000
Changes in operating assets and liabilities:
Accounts receivable, net		(8,351,000)	(68,340,000)	(85,800,000)
Deposits and other assets		4,215,000	(28,883,000)	47,855,000
Prepaid income taxes		0	0	156,000
Deferred heavy maintenance		(202,926,000)	(149,287,000)	(74,083,000)
Income tax receivable		36,261,000	1,629,000	109,570,000
Accounts payable		(34,051,000)	9,032,000	13,057,000
Air traffic liability		(45,867,000)	47,301,000	(19,649,000)
Other liabilities		176,440,000	68,389,000	80,103,000
Other		(762,000)	68,000	731,000
Net cash provided by (used in) operating activities		(246,661,000)	(89,022,000)	208,888,000
Investing activities:
Purchase of available-for-sale investment securities		(127,627,000)	(110,690,000)	(105,361,000)
Proceeds from the maturity and sale of available-for-sale investment securities		125,570,000	109,500,000	104,500,000
Proceeds from sale of property and equipment		230,788,000	0	0
Pre-delivery deposits on flight equipment, net of refunds		23,156,000	(8,498,000)	(119,352,000)
Capitalized interest		(21,860,000)	(18,166,000)	(17,258,000)
Assets under construction for others		(10,972,000)	(2,000)	(1,207,000)
Purchase of property and equipment		(255,563,000)	(237,584,000)	(213,767,000)
Net cash provided by (used in) investing activities		(36,508,000)	(265,440,000)	(352,445,000)
Financing activities:
Proceeds from issuance of long-term debt		457,950,000	591,000,000	614,496,000
Proceeds from issuance of common stock and warrants		0	0	375,662,000
Payments on debt obligations		(337,475,000)	(193,033,000)	(956,788,000)
Payments for the early extinguishment of debt		(323,251,000)	0	(317,905,000)
Payments on finance lease obligations		(496,000)	(842,000)	(831,000)
Reimbursement for assets under construction for others		10,974,000	2,000	996,000
Repurchase of common stock		(2,637,000)	(2,359,000)	(1,515,000)
Debt issuance costs		(3,027,000)	(3,471,000)	(2,775,000)
Net cash provided by (used in) financing activities		(197,962,000)	391,297,000	(288,660,000)
Net increase (decrease) in cash, cash equivalents, and restricted cash		(481,131,000)	36,835,000	(432,217,000)
Cash, cash equivalents, and restricted cash at beginning of period	[1]	1,465,742,000	1,428,907,000	1,861,124,000
Cash, cash equivalents, and restricted cash at end of period	[1]	984,611,000	1,465,742,000	1,428,907,000
Cash payments for:
Interest, net of capitalized interest		138,380,000	107,443,000	135,500,000
Income taxes paid (received), net		(32,854,000)	(82,000)	(112,461,000)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases		400,999,000	295,468,000	261,435,000
Financing cash flows for finance leases		30,000	57,000	93,000
Non-cash transactions:
Capital expenditures funded by finance lease borrowings		145,000	0	538,000
Capital expenditures funded by operating lease borrowings		$ 1,076,456,000	$ 897,109,000	$ 683,333,000

[1] The sum of cash and cash equivalents and restricted cash on the consolidated balance sheets equals cash, cash equivalents, and restricted cash in the consolidated statements of cash flows.