Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Current assets:
Cash and cash equivalents	$ 180,398	$ 99,395
Restricted cash	3,352	3,446
Receivables, net	4,947	13,712
Expendable parts and supplies, net	24,707	22,971
Prepaid expenses and other current assets	8,956	16,067
Total current assets	222,360	155,591
Property and equipment, net	1,164,193	1,212,415
Intangible assets, net	7,102	8,032
Lease and equipment deposits	8,149	1,899
Operating lease right-of-use assets	97,894	123,251
Other assets	25,315	742
Total assets	1,525,013	1,501,930
Current liabilities:
Current portion of long-term debt and finance leases	107,728	189,268
Current portion of deferred revenue	6,486	9,389
Current maturities of operating leases	37,058	43,932
Accounts payable	52,835	53,229
Accrued compensation	12,432	12,030
Other accrued expenses	59,452	45,478
Total current liabilities	275,991	353,326
Noncurrent liabilities:
Long-term debt and finance leases, excluding current portion	585,761	542,456
Noncurrent operating lease liabilities	35,007	62,531
Deferred credits	4,147	5,705
Deferred income taxes	72,305	64,275
Deferred revenue, net of current portion	29,265	14,369
Other noncurrent liabilities	27,870	1,409
Total noncurrent liabilities	754,355	690,745
Total liabilities	1,030,346	1,044,071
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock of no par value, 5,000,000 shares authorized; no shares issued and outstanding
Common stock of no par value and additional paid-in capital, 125,000,000 shares authorized; 35,891,029 (2021) and 35,526,918 (2020) shares issued and outstanding, 4,899,497 (2021) and 0 (2020) warrants issued and outstanding	255,497	242,772
Retained earnings	239,170	215,087
Total stockholders' equity	494,667	457,859
Total liabilities and stockholders' equity	$ 1,525,013	$ 1,501,930