Income Taxes - Unrecognized Tax Benefits - Tabular Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 3,243	$ 3,378	$ 5,427
Additions for tax positions in current year	901	874	1,869
Reduction for tax positions in prior year		(656)	(3,485)
Additions for tax positions in prior year	13,400
Reductions from lapses in statutes of limitations	(68)	(353)	(431)
Reductions from settlements with taxing authorities	(166)
Foreign exchange rate adjustment			(2)
Ending Balance	$ 17,310	$ 3,243	$ 3,378

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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Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from foreign currency translation.

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