Stock-Based Compensation (Summary Of RSUs Under The 2007 Plan) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Stock-Based Compensation [Abstract]
Restricted Stock Units outstanding, beginning balance	404
Restricted Stock Units outstanding, Weighted average price beginning	$ 47.42
Granted, Shares	196
Granted, Weighted average price	$ 57.34
Released, Shares	(91)
Released, Weighted average price	$ 49.32
Forfeited, Shares	(14)
Forfeited, Weighted average price	$ 56.30
Restricted Stock Units outstanding, ending balance	495
Restricted Stock Units outstanding, Weighted average price ending	$ 50.76
Restricted Stock Units outstanding, Weighted average remaining contractual term (years)	2.8
Restricted Stock Units outstanding, Aggregate intrinsic value	$ 29,593
Vested and expected to vest	438
Vested and expected to vest, Weighted average price	$ 50.76
Vested and expected to vest, Weighted average remaining contractual term (years)	2.4
Vested and expected to vest, Aggregate intrinsic value	$ 26,203