Income Taxes (Summary Of Income Tax Returns Subject To Examination) (Detail)	12 Months Ended
	Dec. 31, 2012
Minimum [Member] | United States Federal [Member]
Income Tax Examination [Line Items]
Tax years	2010
Minimum [Member] | States [Member]
Income Tax Examination [Line Items]
Tax years	2004
Maximum [Member] | United States Federal [Member]
Income Tax Examination [Line Items]
Tax years	2012
Maximum [Member] | States [Member]
Income Tax Examination [Line Items]
Tax years	2012