Income Taxes (Schedule Of Effective Income Tax Rates Different From Statutory Federal Income Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit	0.30%	0.60%	0.60%
Domestic production exclusion	(2.60%)	(3.10%)	(2.90%)
Research tax credit (1)	(2.00%)	(0.40%)	0.00%
Other	(0.20%)	(0.10%)	(0.20%)
Effective income tax rate	30.50%	32.00%	32.50%
Reductions related to prior tax year amended tax filings	1.30%