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, 2015	Dec. 31, 2014	Sep. 30, 2014
Stock-Based Compensation
Options outstanding, Number of options	5,111	5,170	4,501
Options outstanding, Weighted-Average Exercise Price	$ 30.86	$ 30.83	$ 28.08
Options outstanding, Weighted-Average Remaining Life in Years	5 years 8 months 12 days
Options outstanding, Aggregate Intrinsic Value	$ 103,010
Options vested and exercisable, Number of options	3,365
Options vested and exercisable, Weighted-Average Exercise Price Per Share	$ 25.85
Options vested and exercisable, Weighted-Average Remaining Life in Years	4 years 3 months 18 days
Options vested and exercisable, Aggregate Intrinsic Value	84,647
Options vested and expected to vest, Number of options	4,982
Options vested and expected to vest, Weighted-Average Exercise Price Per Share	$ 30.54
Options vested and to expected vest, Weighted-Average Remaining Life in Years	5 years 8 months 12 days
Options vested and expected to vest, Aggregate Intrinsic Value	$ 101,963