UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Current Assets:
Cash and cash equivalents	$ 214,104	$ 257,174
Restricted cash	65,137	59,064
Short-term investments	84,121	93,600
Accounts receivable, net of allowance of $3,948 and $2,688, respectively	435,819	404,188
Inventories of materials and supplies, net	101,419	94,227
Prepaid expenses and other, net	88,080	97,727
Assets held-for-sale	0	645
Total current assets	988,680	1,006,625
Investments	263,443	264,947
Property, plant and equipment, net	2,970,371	2,921,695
Other Noncurrent Assets:
Goodwill	45,653	45,653
Intangible assets, net	58,968	60,575
Operating lease right-of-use assets	62,254	50,400
Other assets, net	31,959	32,061
Total other noncurrent assets	198,834	188,689
Total assets	4,421,328	4,381,956
Current Liabilities:
Accounts payable	157,302	130,852
Dividends payable	41,993	25,194
Accrued liabilities	269,691	262,885
Total current liabilities	468,986	418,931
Noncurrent Liabilities:
Long-term debt, net	545,292	545,144
Deferred income taxes	510,015	517,809
Other	137,389	128,129
Total noncurrent liabilities	1,192,696	1,191,082
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 December 31, 2023 and September 30, 2023, and 98,623,747 and 99,426,526 shares outstanding as of December 31, 2023 and September 30, 2023, respectively	11,222	11,222
Preferred stock, no par value, 1,000,000 shares authorized, no shares issued	0	0
Additional paid-in capital	506,672	525,369
Retained earnings	2,743,794	2,707,715
Accumulated other comprehensive loss	(7,847)	(7,981)
Treasury stock, at cost, 13,599,118 shares and 12,796,339 shares as of December 31, 2023 and September 30, 2023, respectively	(494,195)	(464,382)
Total shareholders’ equity	2,759,646	2,771,943
Total liabilities and shareholders' equity	$ 4,421,328	$ 4,381,956