Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Current Assets:
Cash and cash equivalents	$ 228,462	$ 284,355
Short-term investments	41,072	41,461
Accounts receivable, net of allowance of $6,230 and $6,217, respectively	545,731	565,202
Inventories of materials and supplies, net	159,992	158,134
Prepaid expenses and other	67,490	66,398
Total current assets	1,042,747	1,115,550
Investments	54,731	98,696
Property, plant and equipment, net	4,900,339	4,857,382
Other Noncurrent Assets:
Goodwill	67,902	64,777
Intangible assets, net	71,969	73,207
Other assets	6,653	5,255
Total other noncurrent assets	146,524	143,239
Total assets	6,144,341	6,214,867
Current Liabilities:
Accounts payable	141,406	132,664
Accrued liabilities	244,507	244,504
Total current liabilities	385,913	377,168
Noncurrent Liabilities:
Long-term debt	490,805	493,968
Deferred income taxes	853,187	853,136
Other	84,565	93,606
Noncurrent liabilities - discontinued operations	3,633	14,254
Total noncurrent liabilities	1,432,190	1,454,964
Commitments and Contingencies (Note 14)
Shareholders' Equity:
Common stock, $.10 par value, 160,000,000 shares authorized, 112,080,262 and 112,008,961 shares issued as of December 31, 2018 and September 30, 2018, respectively, and 109,404,890 and 108,993,718 shares outstanding as of December 31, 2018 and September 30, 2018, respectively	11,208	11,201
Preferred stock, no par value, 1,000,000 shares authorized, no shares issued
Additional paid-in capital	484,122	500,393
Retained earnings	3,997,283	4,027,779
Accumulated other comprehensive income (loss)	(12,296)	16,550
Treasury stock, at cost, 2,675,372 shares and 3,015,243 shares as of December 31, 2018 and September 30, 2018, respectively	(154,079)	(173,188)
Total shareholders’ equity	4,326,238	4,382,735
Total liabilities and shareholders' equity	$ 6,144,341	$ 6,214,867