Stock Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years
Stock Plans [Abstract]
Vesting period for grants (years)	four
Term of options outstanding (years)	10
Unrecognized compensation cost expected to be recognized over the period (years)	4
Outstanding closing stock price per share	$ 28.46
Total number of available shares to grant	7,400,000
Options outstanding	4,450,000
Weighted average of grant date fair value, granted	$ 21.85