Income Taxes (Reconciliation Of The Statutory Federal Income Tax Rate To The Company's Effective Tax Rate On Earnings) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory rate (as a percent)	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit (as a percent)	1.70%	1.40%	0.80%
Foreign earnings taxed at rates other than the U.S. statutory rate (as a percent)	(4.70%)	(4.40%)	(9.90%)
Foreign currency remeasurement (as a percent)	(0.70%)	2.20%	(1.80%)
Income tax adjustments to filed returns (as a percent)	(3.00%)	0.80%	1.90%
Biodiesel credit (as a percent)	(0.00%)	(3.30%)	(1.60%)
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent	(2.20%)	(1.40%)	(1.80%)
Effective Income Tax Reconciliation, Change in Enacted Rate and Other Tax Reform Impacts	23.90%
Valuation allowance (as a percent)	0.30%	0.60%	(3.10%)
Other (as a percent)	(2.10%)	(1.60%)	(0.30%)
Effective income tax rate	0.40%	29.30%	19.20%