Stockholders' Equity (Changes in Non-vested Stock Options) (Details) - Stock Options [Member] - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options, beginning balance	2,078
Options granted, Number of options	773
Options vested, Number of options	(763)
Options forfeited, Number of options	(25)
Number of Options, ending balance	2,063	2,078
Weighted-Average Grant Date Fair Value Per Share, beginning balance	$ 24.69
Options granted, Weighted-Average Grant Date Fair Value Per Share	28.22	$ 25.41	$ 24.12
Options vested, Weighted-Average Grant Date Fair Value Per Share	25.31
Options forfeited, Weighted-Average Grant Date Fair Value Per Share	25.40
Weighted-Average Grant Date Fair Value Per Share, ending balance	$ 25.77	$ 24.69