Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 800,849	$ 700,900
Short-term investment securities	100,937	100,155
Accounts receivable, net	49,323	41,136
Aircraft maintenance deposits, net	175,615	87,035
Income tax receivable	69,844	0
Prepaid expenses and other current assets	83,692	46,619
Total current assets	1,280,260	975,845
Property and equipment:
Flight equipment	2,291,110	1,461,525
Ground property and equipment	155,166	126,206
Less accumulated depreciation	(207,808)	(122,509)
Total property and equipment	2,238,468	1,465,222
Deposits on flight equipment purchase contracts	253,687	325,688
Long-term aircraft maintenance deposits	150,617	199,415
Deferred heavy maintenance, net	99,915	75,534
Other long-term assets	121,003	110,223
Total assets	4,143,950	3,151,927
Current liabilities:
Accounts payable	22,822	15,193
Air traffic liability	246,404	206,392
Current maturities of long-term debt	115,430	84,354
Other current liabilities	262,370	226,011
Total current liabilities	647,026	531,950
Long-term debt, less current maturities	1,387,498	897,359
Deferred income taxes	313,140	308,143
Deferred gains and other long-term liabilities	19,205	19,868
Shareholders’ equity:
Common stock: Common stock, $0.0001 par value, 240,000,000 shares authorized at December 31, 2017 and 2016, respectively; 69,770,795 and 73,549,872 issued and 68,196,964 and 69,326,202 outstanding as of December 31, 2017 and 2016, respectively	7	7
Additional paid-in-capital	360,153	551,004
Treasury stock, at cost: 1,573,831 and 4,223,670 shares as of December 31, 2017 and 2016, respectively	(65,854)	(218,692)
Retained earnings	1,484,239	1,063,633
Accumulated other comprehensive loss	(1,464)	(1,345)
Total shareholders’ equity	1,777,081	1,394,607
Total liabilities and shareholders’ equity	$ 4,143,950	$ 3,151,927