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Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 4.1		$ 4.1		$ 5.0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	3.50%	3.20%	3.50%	3.20%
Tax credits	(1.80%)	(3.50%)	(1.80%)	(2.80%)
Other	0.90%	0.20%	0.90%	1.30%
Other Expense
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Indemnification Asset, Expense	$ 0.0		$ 1.6
Income Tax Information [Line Items]
Unrecognized Tax Benefits, Income Tax Indemnification Asset, Expense	$ 0.0		$ 1.6

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

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Percentage of reported income tax benefit (expense) from difference to income tax expense (benefit) computed by applying statutory federal (national) income tax rate to pretax income (loss) from continuing operation, attributable to other reconciling items. Excludes state and local income tax expense (benefit), federal tax expense (benefit), statutory income tax expense (benefit) outside of country of domicile, tax credit, nondeductible expense, deduction, income tax settlement, income tax contingency, and cross-border tax law.

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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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Amount of unrecognized tax benefits.

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