Concentrations Of Risk (Schedule Of Major Customers, By Revenue Concentration) (Detail) (Segment, Continuing Operations [Member], Customer Concentration Risk [Member], Ten Largest Customers [Member])	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment, Continuing Operations [Member] | Customer Concentration Risk [Member] | Ten Largest Customers [Member]
Concentration Risk [Line Items]
Revenues as a percent of total	64.00%	71.00%	72.00%