Stockholders' Equity (Stock Options Vested, or Expected to Vest and Exercisable) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, Number of options	4,842	5,339
Options vested and exercisable, Number of options	3,445
Options vested and expected to vest, Number of options	4,799
Options outstanding, Weighted-Average Exercise Price	$ 80.48	$ 74.40
Options vested and exercisable, Weighted-Average Exercise Price Per Share	74.91
Options vested and expected to vest, Weighted-Average Exercise Price Per Share	$ 80.37
Options outstanding, Weighted-Average Remaining Life in Years	5 years 7 months 6 days
Options vested and exercisable, Weighted-Average Remaining Life in Years	4 years 7 months 6 days
Options vested and expected to vest, Weighted-Average Remaining Life in Years	5 years 7 months 6 days
Options outstanding, Aggregate Intrinsic Value	$ 211,963
Options vested and exercisable, Aggregate Intrinsic Value	170,008
Options vested and expected to vest, Aggregate Intrinsic Value	$ 210,624