Income Taxes (Schedule Of Income Taxes Calculated On Income Before Income Taxes And Provision For Income Taxes) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Federal statutory tax rate of 35%	35.00%	35.00%	35.00%
State income tax, net of federal income tax benefit	4.70%	3.10%	5.00%
Foreign taxes less than U.S. stautory rate	(1.10%)	(1.20%)	(0.50%)
Non-deductible operating expenses and tax-exempt income	0.70%	0.00%	0.10%
Foreign taxes eligible for US foreign tax credit	0.50%	0.50%	0.60%
Write-down of an acquisition-related receivable and purchase-price adjustment	0.00%	0.00%	(1.60%)
Fuel tax credit	(4.50%)	(0.10%)	(2.50%)
IRS audit	(0.40%)	1.50%	4.00%
Other, net	0.90%	0.00%	0.20%
Effective income tax rate	35.80%	38.80%	40.30%