Summary Of Significant Accounting Policies (Schedule Of Estimated Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2017
Trademarks And Tradenames [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	2 years
Trademarks And Tradenames [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	3 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	5 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	8 years