Condensed Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 788,225	$ 978,957
Short-term investment securities	106,208	105,321
Accounts receivable, net	33,267	73,807
Aircraft maintenance deposits, net	90,108	102,906
Income tax receivable	104,226	21,013
Prepaid expenses and other current assets	109,131	103,439
Total current assets	1,231,165	1,385,443
Property and equipment:
Flight equipment	3,965,137	3,730,751
Ground property and equipment	305,876	291,998
Less accumulated depreciation	(537,928)	(492,447)
Total property and equipment, net	3,733,085	3,530,302
Operating lease right-of-use assets	1,425,171	1,369,555
Pre-delivery deposits on flight equipment	372,068	291,930
Long-term aircraft maintenance deposits	61,246	67,682
Deferred heavy maintenance, net	376,765	361,603
Other long-term assets	35,761	36,897
Total assets	7,235,261	7,043,412
Current liabilities:
Accounts payable	62,949	43,601
Air traffic liability	411,286	315,408
Current maturities of long-term debt and finance leases	334,931	258,852
Current maturities of operating leases	125,713	120,662
Other current liabilities	296,607	373,521
Total current liabilities	1,231,486	1,112,044
Long-term debt and finance leases, less current maturities	1,965,524	1,960,453
Operating leases, less current maturities	1,268,110	1,218,014
Deferred income taxes	505,263	469,292
Deferred gains and other long-term liabilities	30,487	22,277
Shareholders’ equity:
Common stock	7	7
Additional paid-in-capital	383,186	379,380
Treasury stock, at cost	(73,991)	(72,455)
Retained earnings	1,925,750	1,955,187
Accumulated other comprehensive income (loss)	(561)	(787)
Total shareholders’ equity	2,234,391	2,261,332
Total liabilities and shareholders’ equity	$ 7,235,261	$ 7,043,412