Calculation Of Net Income Per Share (Weighted-Average Shares Used In Calculation Of Basic And Diluted EPS) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding	114,155	126,710	144,591
Conversion spread related to Convertible Debentures	18,047	13,384	10,361
Unvested restricted stock units	785	740	709
Stock options	44	61	125
Shares used to compute diluted net income per share	133,031	140,895	155,786