Income Taxes - Effective Rate Reconciliation (Details)	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Operating Loss Carryforwards [Line Items]
Federal statutory rate effect of:	21.00%	21.00%	24.50%
U.S. State and local income taxes	1.00%	(1.50%)	0.80%
Foreign earnings and losses taxed at different rates	0.10%	0.70%	(0.80%)
U.S. permanent items	0.90%	0.10%	(0.20%)
Foreign permanent items	0.50%	0.70%	2.10%
U.S. bargain purchase gain	(8.30%)	(1.00%)	0.00%
Remeasurement of deferred tax	0.00%	0.00%	8.50%
Repatriation Transition tax	0.00%	0.00%	11.00%
GILTI	0.70%	2.20%	0.00%
Other reconciling items	0.90%	(0.40%)	0.20%
Effective rate	18.00%	23.30%	45.30%
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Change in foreign and state valuation allowance	1.00%	1.00%	(0.80%)
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Change in foreign and state valuation allowance	0.20%	0.50%	0.00%

Effective Income Tax Rate Reconciliation, Permanent Items, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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-Name Accounting Standards Codification
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
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Percentage of the difference, between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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