Summary of Significant Accounting Policies - Advertising Costs and AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Advertising Costs
Advertising costs	$ 2,700	$ 3,600	$ 5,200
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	129,654	132,636	162,611
Current-period other comprehensive (loss) income	(1,524)	(18)	2,140
Balance	116,175	129,654	132,636
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(7,585)	(6,794)	(7,345)
Current-period other comprehensive (loss) income	(984)	(791)	551
Balance	(8,569)	(7,585)	(6,794)
Net Change Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	1,136	363	(1,226)
Current-period other comprehensive (loss) income	(540)	773	1,589
Balance	596	1,136	363
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(6,449)	(6,431)	(8,571)
Balance	$ (7,973)	$ (6,449)	$ (6,431)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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