CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Assets
Cash and cash equivalents	$ 286,957	$ 258,986	$ 191,886
Restricted cash	0	9,033	0
Accounts and notes receivable
Accounts and notes receivable, gross	471,590	494,634	449,538
Less: Allowance for doubtful accounts	(2,757)	(2,813)	(5,775)
Accounts and notes receivable, net	468,833	491,821	443,763
Inventories
Finished products	306,012	293,619	288,891
Raw materials	26,213	22,648	22,160
Products in process	1,314	1,480	1,221
Operating supplies and other	29,860	27,869	25,486
Inventories	363,399	345,616	337,758
Prepaid expenses	38,573	31,726	34,096
Total current assets	1,157,762	1,137,182	1,007,503
Investments and long-term receivables	34,311	39,226	38,895
Property, plant & equipment
Property, plant & equipment, cost	7,432,388	7,185,818	6,984,417
Allowance for depreciation, depletion & amortization	(3,980,567)	(3,924,380)	(3,786,590)
Property, plant & equipment, net	3,451,821	3,261,438	3,197,827
Goodwill	3,101,241	3,094,824	3,094,824
Other intangible assets, net	829,114	769,052	753,372
Other noncurrent assets	170,075	169,753	154,604
Total assets	8,744,324	8,471,475	8,247,025
Liabilities
Current maturities of long-term debt	139	138	131
Trade payables and accruals	175,906	145,042	185,653
Other current liabilities	184,853	227,064	170,701
Total current liabilities	360,898	372,244	356,485
Long-term debt	2,329,248	1,982,751	1,981,425
Deferred income taxes, net	703,491	702,854	663,364
Deferred revenue	196,739	198,388	205,892
Other noncurrent liabilities	633,187	642,762	618,806
Total liabilities	4,223,563	3,898,999	3,825,972
Other commitments and contingencies (Note 8)
Equity
Common stock, $1 par value - Authorized 480,000 shares, Outstanding 132,222, 132,339 and 133,348 shares, respectively	132,222	132,339	133,348
Capital in excess of par value	2,792,720	2,807,995	2,801,882
Retained earnings	1,734,448	1,771,518	1,605,578
Accumulated other comprehensive loss	(138,629)	(139,376)	(119,755)
Total equity	4,520,761	4,572,476	4,421,053
Total liabilities and equity	$ 8,744,324	$ 8,471,475	$ 8,247,025