Income Taxes - Components of Net Deferred Tax Asset and Liability Accounts (Parenthetical) (Details) $ in Thousands	12 Months Ended
Sep. 30, 2018 USD ($)
Income Tax Disclosure [Abstract]
Decrease in tax provision due to revaluation of net deferred tax liability	$ (43,429)

Amount of income tax benefit for remeasurement of deferred tax liability from change in tax rate pursuant to Tax Cuts and Jobs Act.

No definition available.

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