Stockholders' Equity and Earnings per Share - Weighted Average Number of Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Equity [Abstract]
Weighted average common shares outstanding - basic (shares)	205,370	210,934	205,693	211,503
Dilutive effect of stock options, restricted stock, and restricted stock units (shares)	1,692	1,629	1,600	1,772
Weighted average common shares outstanding - diluted (shares)	207,062	212,563	207,293	213,275

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 260
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-Section 45
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