Concentrations Of Risk (Schedule Of Major Customers, By Revenue Concentration) (Detail) (Segment, Continuing Operations [Member], Customer Concentration Risk [Member], Ten Largest Customers [Member])	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment, Continuing Operations [Member] | Customer Concentration Risk [Member] | Ten Largest Customers [Member]
Concentration Risk [Line Items]
Revenues as a percent of total	69.00%	71.00%