Condensed Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 869,153	$ 700,900
Short-term investment securities	100,464	100,155
Accounts receivable, net	47,996	41,136
Aircraft maintenance deposits	155,093	87,035
Prepaid expenses and other current assets	57,798	46,619
Total current assets	1,230,504	975,845
Property and equipment:
Flight equipment	1,809,747	1,461,525
Ground property and equipment	140,954	126,206
Less accumulated depreciation	(161,191)	(122,509)
Total property and equipment	1,789,510	1,465,222
Deposits on flight equipment purchase contracts	317,867	325,688
Long-term aircraft maintenance deposits	146,162	199,415
Deferred heavy maintenance, net	75,858	75,534
Other long-term assets	114,444	110,223
Total assets	3,674,345	3,151,927
Current liabilities:
Accounts payable	33,186	15,193
Air traffic liability	312,587	206,392
Current maturities of long-term debt	95,428	84,354
Other current liabilities	244,629	226,011
Total current liabilities	685,830	531,950
Long-term debt, less current maturities	1,089,159	897,359
Deferred income taxes	372,998	308,143
Deferred gains and other long-term liabilities	18,125	19,868
Shareholders’ equity:
Common stock	7	7
Additional paid-in-capital	555,704	551,004
Treasury stock, at cost	(219,909)	(218,692)
Retained earnings	1,173,711	1,063,633
Accumulated other comprehensive loss	(1,280)	(1,345)
Total shareholders’ equity	1,508,233	1,394,607
Total liabilities and shareholders’ equity	$ 3,674,345	$ 3,151,927