Income Taxes (Schedule Of Effective Income Tax Rates Different From Statutory Federal Income Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit	0.60%	0.10%	0.20%
Domestic production exclusion	(2.90%)	(2.30%)	(2.50%)
Other	(0.20%)	(0.20%)	(0.40%)
Effective income tax rate	32.50%	32.60%	32.30%