Other Comprehensive Income (Loss) (Accumulated Other Comprehensive Loss In Equity) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and other revenues	$ 4,770,799		$ 3,719,247	$ 13,370,462	$ 10,258,594
Cost of products sold	3,752,234	[1]	2,888,549	10,695,275	8,283,183
Operating expenses	317,196	[1]	322,277	933,699	946,264
Interest expense	(32,399)		(28,731)	(97,446)	(85,534)
Income before income taxes	478,390		446,103	1,332,649	497,601
Income tax expense (benefit)	116,258		158,386	318,742	173,593
Net of tax and noncontrolling interest	342,466		272,014	956,064	284,313
Other comprehensive income (loss), net of tax	13,993		12,853	(3,963)	21,009
Foreign currency translation adjustment	5,563			5,563		$ 14,377
Unrealized loss on pension obligation	(692)			(692)		(654)
Unrealized gain on post-retirement benefit obligations	20,711			20,711		16,939
Unrealized loss on hedging instruments	324			324		(793)
Accumulated other comprehensive income	25,906			25,906		$ 29,869
Reclassification out of Accumulated Other Comprehensive Income [Member] | Commodity Contract [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of products sold				0	(299)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(1,631)		(5,385)	(6,038)	(5,859)
Income tax expense (benefit)	(416)		(2,100)	(1,540)	(2,312)
Net income	(1,215)		(3,285)	(4,498)	(3,547)
Noncontrolling interest	0		(41)	0	(114)
Net of tax and noncontrolling interest	(1,215)		(3,326)	(4,498)	(3,661)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and other revenues	(1,422)		(488)	(5,093)	7,937
Cost of products sold				0	(299)
Operating expenses	(209)		(4,961)	(945)	(13,676)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 0		$ 64	$ 0	$ 179

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