Equity Plans and Share-based Compensation (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2012 Y	Sep. 30, 2011	Sep. 30, 2010
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Common stock reserved for future grants	1,200,000
RSUs Available for Future Grant	800,000
Share-based Compensation, Capitalized Amount	$ 3,400,000	$ 1,900,000	$ 1,100,000
Proceeds from Stock Options Exercised	2,817,000	1,980,000	8,361,000
Total intrinsic value of options exercised	18,500,000	17,600,000	66,100,000
Performance Based RSUs, Granted	1,419,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	48,400,000	37,900,000	18,500,000
Total unrecognized share-based compensation costs	$ 78,300,000
Weighted average recognition period (years)	1.5
Performance shares
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Performance Based RSUs, Granted	900,000	800,000	100,000