Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Current assets:
Cash and cash equivalents	$ 49,721	$ 53,948	$ 58,764
Receivables, net	722,152	722,945	664,319
Inventories	311,535	287,309	257,792
Prepayments and other current assets	151,391	119,500	59,481
Current assets held for sale	430	430	458
Total current assets	1,235,229	1,184,132	1,040,814
Investments	144,616	138,620	138,451
Property, plant and equipment	7,502,368	7,397,321	6,842,967
Less accumulated depreciation, depletion and amortization	2,858,986	2,818,644	2,725,484
Net property, plant and equipment	4,643,382	4,578,677	4,117,483
Deferred charges and other assets:
Goodwill	679,395	664,922	631,791
Other intangible assets, net	11,680	10,815	3,465
Operating lease right-of-use assets (Note 11)	107,486	0	0
Other	455,048	408,857	412,456
Noncurrent assets held for sale	2,087	2,087	4,392
Total deferred charges and other assets	1,255,696	1,086,681	1,052,104
Total assets	7,278,923	6,988,110	6,348,852
Current liabilities:
Short-term borrowings	70,000	0	0
Long-term debt due within one year	251,846	251,854	149,199
Accounts payable	352,180	358,505	267,994
Taxes payable	55,319	41,929	57,354
Dividends payable	39,875	39,695	38,573
Accrued compensation	45,383	69,007	35,087
Current operating lease liabilities (Note 11)	30,978	0	0
Other accrued liabilities	213,541	221,059	204,328
Current liabilities held for sale	3,657	4,001	11,726
Total current liabilities	1,062,779	986,050	764,261
Long-term debt	1,946,181	1,856,841	1,630,343
Deferred credits and other liabilities:
Deferred income taxes	444,965	430,085	346,218
Noncurrent operating lease liabilities (Note 11)	76,444	0	0
Other	1,142,862	1,148,359	1,181,919
Total deferred credits and other liabilities	1,664,271	1,578,444	1,528,137
Commitments and contingencies
Stockholders' equity:
Authorized - 500,000,000 shares, $1.00 par value Shares issued - 198,316,808 at March 31, 2019, 195,843,297 at March 31, 2018 and 196,564,907 at December 31, 2018	198,317	196,565	195,843
Other paid-in capital	1,284,060	1,248,576	1,227,285
Retained earnings	1,164,509	1,163,602	1,051,469
Accumulated other comprehensive loss	(37,568)	(38,342)	(44,860)
Treasury stock at cost - 538,921 shares	(3,626)	(3,626)	(3,626)
Total stockholders' equity	2,605,692	2,566,775	2,426,111
Total liabilities and stockholders' equity	$ 7,278,923	$ 6,988,110	$ 6,348,852