Income Taxes (Schedule Of Income Taxes Calculated On Income Before Income Taxes And Provision For Income Taxes) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
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	3.10%	5.00%	15.70%
Foreign taxes in excess of (less than) U.S. stautory rate	(1.20%)	(0.50%)	(9.70%)
Non-deductible operating expenses and tax-exempt income		0.10%	5.30%
Creditable foreign tax, net of foreign tax credits	0.50%	0.60%	3.80%
Non-deductible goodwill impairment, write-down of an acquisition-related receivable and purchase-price adjustment		(1.60%)	34.70%
Fuel tax credit	(0.10%)	(2.50%)	(24.50%)
IRS audit settlement		4.00%
Other, net	1.50%	0.20%	15.60%
Effective income tax rate	38.80%	40.30%	75.90%