Stockholders' Equity (Changes in Non-vested Stock Options) (Details) - Stock Options [Member] - $ / shares shares in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, beginning balance	1,905	2,068
Weighted-Average Grant Date Fair Value Per Share, beginning balance	$ 25.90	$ 23.43
Options granted, Number of options	3	629
Options granted, Weighted-Average Grant Date Fair Value Per Share	$ 33.44	$ 28.57
Options vested, Number of options	(32)	(800)
Options vested, Weighted-Average Grant Date Fair Value Per Share	$ 23.79	$ 21.52
Options forfeited, Number of options	(9)	(30)
Options forfeited, Weighted-Average Grant Date Fair Value Per Share	$ 25.68	$ 25.34
Number of Options, ending balance	1,867	1,867
Weighted-Average Grant Date Fair Value Per Share, ending balance	$ 25.95	$ 25.95