Income Taxes - Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Statutory U.S. federal income tax rate	21.00%	21.00%	24.50%
State and local income tax rate, net of federal tax benefit	(0.50%)	2.40%	(0.10%)
Foreign tax rate differential	1.00%	(6.70%)	(6.20%)
Litigation settlements and accruals (see Note 14)	(6.20%)	0.10%	(6.30%)
U.S. Tax reform	0	(0.036)	(0.520)
PharMEDium worthless stock deduction	12.40%	0.00%	0.00%
Swiss Tax reform	6.80%	0.00%	0.00%
CARES Act	1.20%	0.00%	0.00%
Goodwill impairment (see Note 1)	0.00%	0.00%	1.70%
Capital gain on distribution	0.00%	0.00%	3.60%
Other	0.10%	(1.50%)	(2.40%)
Effective income tax rate	35.80%	11.70%	(37.20%)

Effective Income Tax Rate Reconciliation, CARES Act, Percent

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Effective Income Tax Rate Reconciliation, Capital Gain on Distribution, Percent

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Effective Income Tax Rate Reconciliation, Deduction, Worthless Stock, Percent

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

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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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.

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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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Percentage of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to Tax Cuts and Jobs Act.

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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 income tax settlements. Including, but not limited to, domestic tax settlement, foreign tax settlement, state and local tax settlement, and other tax settlements.

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