Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Current Assets:
Cash and cash equivalents	$ 427,243	$ 487,884
Short-term investments	134,491	89,335
Accounts receivable, net of allowance of $1,806 and $1,820, respectively	209,402	192,623
Inventories of materials and supplies, net	96,504	104,180
Prepaid expenses and other, net	97,857	89,305
Assets held-for-sale	13,076	0
Total current assets	978,573	963,327
Investments	34,569	31,585
Property, plant and equipment, net	3,374,235	3,646,341
Other Noncurrent Assets:
Goodwill	45,653	45,653
Intangible assets, net	77,430	81,027
Operating lease right-of-use asset	56,474	44,583
Other assets, net	21,170	17,105
Total other noncurrent assets	200,727	188,368
Total assets	4,588,104	4,829,621
Current Liabilities:
Accounts payable	63,934	36,468
Dividends payable	27,327	27,226
Accrued liabilities	160,342	155,442
Total current liabilities	251,603	219,136
Noncurrent Liabilities:
Long-term debt, net	481,647	480,727
Deferred income taxes	604,536	650,675
Other	163,063	147,180
Noncurrent liabilities - discontinued operations	3,559	13,389
Total noncurrent liabilities	1,252,805	1,291,971
Commitments and Contingencies (Note 14)
Shareholders' Equity:
Common stock, $.10 par value, 160,000,000 shares authorized, 112,222,865 and 112,151,563 shares issued as of March 31, 2021 and September 30, 2020, respectively, and 107,893,998 and 107,488,242 shares outstanding as of March 31, 2021 and September 30, 2020, respectively	11,222	11,215
Preferred stock, no par value, 1,000,000 shares authorized, no shares issued	0	0
Additional paid-in capital	516,870	521,628
Retained earnings	2,762,735	3,010,012
Accumulated other comprehensive loss	(25,274)	(26,188)
Treasury stock, at cost, 4,328,867 shares and 4,663,321 shares as of March 31, 2021 and September 30, 2020, respectively	(181,857)	(198,153)
Total shareholders’ equity	3,083,696	3,318,514
Total liabilities and shareholders' equity	$ 4,588,104	$ 4,829,621