Assets Held for Sale and Discontinued Operations - Operating Results of Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax (benefit) provision									$ (1,300)
Net (loss) income	$ (184)	$ 1,154	$ (6,647)	$ (2,620)	$ (7,843)	$ (8)	$ 1,774	$ 4,751	(8,297)	$ (1,326)	$ 5,892
Net loss attributable to non-controlling interest - discontinued operations											1,045
Tempress and SoLayTec | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues, net of returns and allowances									25,139	76,395	81,443
Cost of sales									23,669	58,156	60,617
Gross profit									1,470	18,239	20,826
Selling, general and administrative									8,857	11,792	10,408
Research, development and engineering									3,039	4,944	3,634
Restructuring charges									567	897	0
Impairment charges									0	4,759	0
Operating (loss) income									(10,993)	(4,153)	6,784
Gain on sale of subsidiary									1,614	0	0
Interest expense and other, net									(121)	(249)	(557)
(Loss) income from discontinued operations before income taxes									(9,500)	(4,402)	6,227
Income tax (benefit) provision									(1,203)	(3,076)	335
Net (loss) income									(8,297)	(1,326)	5,892
Net loss attributable to non-controlling interest - discontinued operations									0	0	1,045
Net (loss) income attributable to discontinued operations									$ (8,297)	$ (1,326)	$ 6,937