Calculation Of Net Income Per Share (Weighted-Average Shares Used In Calculation Of Basic And Diluted EPS) (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding	112,955	124,109	115,235	128,924
Conversion spread related to Convertible Debentures	18,024	13,228	16,936	12,935
Unvested restricted stock units	722	730	724	670
Employee stock purchase plan	20	45	30	55
Shares used to compute diluted net income per share	131,721	138,112	132,925	142,584