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Common Stock and Options - Schedule of Stock Options Using Valuation Assumptions (Details) - Options | 12 Months Ended
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Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2016
2019 Modified Option Grant |  |  |
Class of Stock [Line Items] |  |  |
Expected Volatility (as a percent) | 25.00% |  |
Expected Term (in years) | 1 year 6 months |  |
Risk Free Rate | 2.52% |  |
2019 Option Grants |  |  |
Class of Stock [Line Items] |  |  |
Expected Volatility (as a percent) | 30.00% |  |
Expected Term (in years) | 4 years 1 month 2 days |  |
Risk Free Rate | 2.95% |  |
2018 Option Grants |  |  |
Class of Stock [Line Items] |  |  |
Expected Volatility (as a percent) |  | 30.00% |
Expected Term (in years) |  | 3 years 3 months 25 days |
Risk Free Rate |  | 2.80% |
2016 Option Grants |  |  |
Class of Stock [Line Items] |  |  |
Expected Volatility (as a percent) |  |  | 32.20%
Risk Free Rate |  |  | 2.45%
2016 Option Grants | Minimum |  |  |
Class of Stock [Line Items] |  |  |
Expected Term (in years) |  |  | 2 years 7 months
2016 Option Grants | Maximum |  |  |
Class of Stock [Line Items] |  |  |
Expected Term (in years) |  |  | 4 years

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- Definition The estimated measure of the 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.D.2) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 + Details
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