Operating Expenses (Schedule Of Employee Compensation Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Expenses [Abstract]
Wages, salaries and other benefits	$ 139,878	$ 136,650	$ 137,346
Social security costs	10,692	11,067	10,931
Defined contribution plans	3,794	3,378	3,867
Share based payment expenses	11,006	10,846	8,266
Profit-sharing and bonuses	23,903	14,781	18,793
Termination benefits		5,533
Employee compensation expenses	$ 189,273	$ 182,255	$ 179,203