Stock-Based Compensation (Stock Options Vested, Or Expected to Vest and Are Exercisable) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Stock-Based Compensation
Options outstanding, Number of options	4,535	4,970	4,556
Options outstanding, Weighted-Average Exercise Price	$ 24.90	$ 23.94	$ 21.79
Options outstanding, Weighted-Average Remaining Life in Years	6 years 1 month 6 days
Options outstanding, Aggregate Intrinsic Value	$ 67,478
Options vested and exercisable, Number of options	2,777
Options vested and exercisable, Weighted-Average Exercise Price Per Share	$ 21.69
Options vested and exercisable, Weighted-Average Remaining Life in Years	4 years 7 months 8 days
Options vested and exercisable, Aggregate Intrinsic Value	50,203
Options vested and expected to vest, Number of options	4,412
Options vested and expected to vest, Weighted-Average Exercise Price Per Share	$ 24.73
Options vested and to expected vest, Weighted-Average Remaining Life in Years	6 years 1 month 6 days
Options vested and expected to vest, Aggregate Intrinsic Value	$ 66,374