Assets Held for Sale and Discontinued Operations - Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax	$ 1,154	$ (8)	$ (8,113)	$ 6,517
Provision for (reversal of) allowance for doubtful accounts, net			1,104	64
Gain on sale of subsidiary			1,614	0
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	$ 1,154	$ (8)	(8,113)	6,517
Depreciation and amortization			426	561
Provision for (reversal of) allowance for doubtful accounts, net			887	(9)
Gain on sale of subsidiary			1,614	0
Purchases of property, plant and equipment			$ 118	$ 1,160