Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Current assets:
Cash and cash equivalents	$ 41,659	$ 34,599	$ 40,048
Receivables, net	743,687	727,030	661,771
Inventories	278,239	226,583	249,870
Prepayments and other current assets	52,035	81,304	63,953
Current assets held for sale	572	479	328
Total current assets	1,116,192	1,069,995	1,015,970
Investments	140,053	137,613	131,726
Property, plant and equipment	6,975,919	6,770,829	6,591,382
Less accumulated depreciation, depletion and amortization	2,758,163	2,691,641	2,638,098
Net property, plant and equipment	4,217,756	4,079,188	3,953,284
Deferred charges and other assets:
Goodwill	642,374	631,791	631,791
Other intangible assets, net	4,190	3,837	4,785
Other	409,407	407,850	416,759
Noncurrent assets held for sale	3,998	4,392	76,183
Total deferred charges and other assets	1,059,969	1,047,870	1,129,518
Total assets	6,533,970	6,334,666	6,230,498
Current liabilities:
Long-term debt due within one year	109,199	148,499	83,499
Accounts payable	330,926	312,327	279,211
Taxes payable	47,803	42,537	55,037
Dividends payable	38,714	38,573	37,596
Accrued compensation	53,933	72,919	52,951
Other accrued liabilities	208,696	186,010	181,030
Current liabilities held for sale	11,713	11,993	4,481
Total current liabilities	800,984	812,858	693,805
Long-term debt	1,743,711	1,566,354	1,677,977
Deferred credits and other liabilities:
Deferred income taxes	362,896	347,271	668,239
Other	1,175,301	1,179,140	887,525
Total deferred credits and other liabilities	1,538,197	1,526,411	1,555,764
Commitments and contingencies
Stockholders' equity:
Authorized - 500,000,000 shares, $1.00 par value Shares issued - 196,557,245 at June 30, 2018 and 195,843,297 at June 30, 2017 and December 31, 2017	196,557	195,843	195,843
Other paid-in capital	1,245,858	1,233,412	1,231,892
Retained earnings	1,056,424	1,040,748	914,632
Accumulated other comprehensive loss	(44,135)	(37,334)	(35,789)
Treasury stock at cost - 538,921 shares	(3,626)	(3,626)	(3,626)
Total stockholders' equity	2,451,078	2,429,043	2,302,952
Total liabilities and stockholders' equity	$ 6,533,970	$ 6,334,666	$ 6,230,498