Assets Held for Sale and Discontinued Operations - Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Provision for (reversal of) allowance for doubtful accounts, net	$ 1,074	$ 45	$ (720)
Gain on sale of subsidiary	1,614
Tempress and SoLayTec \| Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax	(8,297)	(1,326)	6,937
Non-cash impairment charges	0	4,759	0
Depreciation and amortization	562	801	1,120
Provision for (reversal of) allowance for doubtful accounts, net	874	(56)	(837)
Gain on sale of subsidiary	1,614	0	0
Purchases of property, plant and equipment	$ 131	$ 1,403	$ 838

Disposal group including discontinued operation impairment charges.

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- Definition

Amount of deprecation and amortization expense attributable to property, plant and equipment and intangible assets of discontinued operations.

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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- Definition

Amount after tax of income (loss) from a discontinued operation attributable to the parent. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cash outflow from the acquisition of or improvements to long-lived, physical assets used to produce goods and services and not intended for resale, classified as other.

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Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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