UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Current Assets:
Cash and cash equivalents	$ 159,672	$ 232,131
Restricted cash	53,231	36,246
Short-term investments	85,090	117,101
Accounts receivable, net of allowance of $6,096 and $2,975, respectively	525,611	458,713
Inventories of materials and supplies, net	99,408	87,957
Prepaid expenses and other, net	80,090	66,463
Assets held-for-sale	1,349	4,333
Total current assets	1,004,451	1,002,944
Investments	261,960	218,981
Property, plant and equipment, net	2,931,301	2,960,809
Other Noncurrent Assets:
Goodwill	45,653	45,653
Intangible assets, net	63,790	67,154
Operating lease right-of-use assets	37,150	39,064
Other assets, net	21,428	20,926
Total other noncurrent assets	168,021	172,797
Total assets	4,365,733	4,355,531
Current Liabilities:
Accounts payable	160,101	126,966
Dividends payable	50,409	26,693
Accrued liabilities	203,211	241,151
Total current liabilities	413,721	394,810
Noncurrent Liabilities:
Long-term debt, net	542,734	542,610
Deferred income taxes	540,316	537,712
Other	113,156	114,927
Total noncurrent liabilities	1,196,206	1,195,249
Commitments and Contingencies (Note 12)
Shareholders' Equity:
Common stock, $0.10 par value, 160,000,000 shares authorized, 112,222,865 shares issued as of March 31, 2023 and September 30, 2022, and 102,584,517 and 105,293,662 shares outstanding as of March 31, 2023 and September 30, 2022, respectively	11,222	11,222
Preferred stock, no par value, 1,000,000 shares authorized, no shares issued	0	0
Additional paid-in capital	509,205	528,278
Retained earnings	2,608,100	2,473,572
Accumulated other comprehensive loss	(11,560)	(12,072)
Treasury stock, at cost, 9,638,348 shares and 6,929,203 shares as of March 31, 2023 and September 30, 2022, respectively	(361,161)	(235,528)
Total shareholders’ equity	2,755,806	2,765,472
Total liabilities and shareholders' equity	$ 4,365,733	$ 4,355,531