Nature Of Business And Significant Accounting Policies (Schedule Of Estimated Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2017
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum [Member] | Furniture And Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	10 years
Maximum [Member] | Furniture And Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years