Stock-Based Compensation Stock-Based Compensation - Weighted Average Assumptions Used to Calculate Fair Value of Stock Options Granted and Unvested Options Assumed from Acquisitions (Details)	12 Months Ended
Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	27.30%
TSRs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%

The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

No definition available.

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