Calculation Of Net Income Per Share (Weighted-Average Shares Used In Calculation Of Basic And Diluted EPS) (Details) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding	148,576	157,599	150,549	158,471
Conversion spread related to Convertible Debentures	9,391	5,636	8,647	4,089
Unvested restricted stock units	536	659	661	713
Stock options	98	189	101	195
Employee stock purchase plan	40	95	24	62
Shares used to compute diluted net income per share	158,641	164,178	159,982	163,530