Consolidated Statements of Stockholders’ Equity - USD ($) $ in Millions |
Total |
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] |
Common Stock [Member] |
Common Stock [Member]
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
|
Treasury Stock [Member] |
Treasury Stock [Member]
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
|
Additional Paid-in Capital [Member] |
Additional Paid-in Capital [Member]
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
|
Retained Earnings [Member] |
Retained Earnings [Member]
Cumulative Effect, Period of Adoption, Adjustment [Member]
|
Retained Earnings [Member]
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
|
Accumulated Other Comprehensive Loss, Net [Member] |
Accumulated Other Comprehensive Loss, Net [Member]
Cumulative Effect, Period of Adoption, Adjustment [Member]
|
Accumulated Other Comprehensive Loss, Net [Member]
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Beginning balance at Sep. 30, 2017 | $ 449.9 | $ 0.2 | $ (46.3) | $ 259.0 | $ 261.5 | $ (24.5) | ||||||||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||||||||||||
| Net income | 55.5 | 55.5 | ||||||||||||
| Other comprehensive loss | (8.6) | (8.6) | ||||||||||||
| Exercise of stock options | 1.9 | 1.9 | ||||||||||||
| Share-based compensation | 6.6 | 6.6 | ||||||||||||
| Ending balance at Sep. 30, 2018 | 505.3 | 0.2 | (46.3) | 267.5 | 317.0 | (33.1) | ||||||||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||||||||||||
| Net income | 85.1 | 85.1 | ||||||||||||
| Other comprehensive loss | (1.7) | (1.7) | ||||||||||||
| Exercise of stock options | 1.2 | 1.2 | ||||||||||||
| Share-based compensation | 8.1 | 8.1 | ||||||||||||
| Repurchase of stock | (3.8) | (3.8) | ||||||||||||
| Ending balance at Sep. 30, 2019 | $ 594.2 | $ 594.2 | 0.2 | $ 0.2 | (50.1) | $ (50.1) | 276.8 | $ 276.8 | 402.1 | $ 0.7 | $ 402.8 | (34.8) | $ (0.7) | $ (35.5) |
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||||||||||||
| Accounting Standards Update [Extensible List] | us-gaap:AccountingStandardsUpdate201802Member | |||||||||||||
| Net income | $ 169.6 | 169.6 | ||||||||||||
| Other comprehensive loss | (4.6) | (4.6) | ||||||||||||
| Exercise of stock options | 5.5 | 5.5 | ||||||||||||
| Share-based compensation | 10.3 | 10.3 | ||||||||||||
| Repurchase of stock | (7.5) | (7.5) | ||||||||||||
| Ending balance at Sep. 30, 2020 | $ 767.5 | $ 0.2 | $ (57.6) | $ 292.6 | $ 572.4 | $ (40.1) |
| X | ||||||||||
- Definition Indicates amendment to accounting standards. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Value of stock issued as a result of the exercise of stock options. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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