Calculation Of Net Income Per Share (Weighted-Average Shares Used In Calculation Of Basic And Diluted EPS) (Details) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding	126,710	144,591	156,953
Conversion spread related to Convertible Debentures	13,384	10,361	5,944
Unvested restricted stock units	740	709	763
Stock options	27	92	174
Employee stock purchase plan	34	33	75
Shares used to compute diluted net income per share	140,895	155,786	163,909