Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Sep. 30, 2018
Current Assets:
Cash and cash equivalents	$ 334,775	$ 284,355
Short-term investments	45,748	41,461
Accounts receivable, net of allowance of $4,837 and $6,217, respectively	508,183	565,202
Inventories of materials and supplies, net	150,126	158,134
Prepaid expenses and other	77,406	66,398
Total current assets	1,116,238	1,115,550
Investments	48,291	98,696
Property, plant and equipment, net	4,583,673	4,857,382
Other Noncurrent Assets:
Goodwill	67,902	64,777
Intangible assets, net	69,093	73,207
Other assets	12,182	5,255
Total other noncurrent assets	149,177	143,239
Total assets	5,897,379	6,214,867
Current Liabilities:
Accounts payable	134,077	132,664
Accrued liabilities	256,449	244,504
Total current liabilities	390,526	377,168
Noncurrent Liabilities:
Long-term debt, net	491,651	493,968
Deferred income taxes	827,027	853,136
Other	78,490	93,606
Noncurrent liabilities - discontinued operations	14,631	14,254
Total noncurrent liabilities	1,411,799	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 June 30, 2019 and September 30, 2018, respectively, and 109,433,198 and 108,993,718 shares outstanding as of June 30, 2019 and September 30, 2018, respectively	11,208	11,201
Preferred stock, no par value, 1,000,000 shares authorized, no shares issued	0	0
Additional paid-in capital	501,585	500,393
Retained earnings	3,750,785	4,027,779
Accumulated other comprehensive income (loss)	(16,085)	16,550
Treasury stock, at cost, 2,647,064 shares and 3,015,243 shares as of June 30, 2019 and September 30, 2018, respectively	(152,439)	(173,188)
Total shareholders’ equity	4,095,054	4,382,735
Total liabilities and shareholders' equity	$ 5,897,379	$ 6,214,867

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).