Stockholders' Equity (Other Stock Option Information) (Details) - Stock Options [Member] - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of stock options vested	$ 17,423	$ 15,863	$ 13,944
Total intrinsic value of options exercised	50,059	70,866	16,690
Cash received from exercises of stock options	24,969	36,044	9,132
Excess tax benefit realized from exercise of stock options	$ 9,399	$ 13,416	$ 3,524

Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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-Publisher FASB
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