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Social Cost Reimbursements, COVID-19

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Basis of Financial Statement Presentation - Narrative (Details) $ in Thousands	1 Months Ended		3 Months Ended			6 Months Ended		9 Months Ended
	Apr. 30, 2020	Dec. 31, 2019 USD ($) arrangement	Jun. 30, 2020 USD ($)	Mar. 31, 2020	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Debt Instrument [Line Items]
Social cost reimbursements related to COVID-19						$ 1,700
Limit on monthly payments for production of medical supplies, COVID-19						13,500
Net cash provided by operating activities						40,415	$ 36,219
Cash on hand		$ 51,331	$ 92,546			92,546
Number of arrangements to sell accounts receivable \| arrangement		2
Trade accounts receivable sold subject to risk of loss		$ 500
Proportion of trade receivables in cash at time of sale (as a percent)		90.00%
Proportion of trade receivables in cash when customer pays (as a percent)		10.00%
Trade receivables sold during period			10,300			43,000
Cash received for trade receivables sold			40,000			40,000
Fees related to trade receivables sold			100
Comprehensive (loss) income			$ (1,396)		$ 13,319	(66,997)	16,622
Revision of Prior Period, Adjustment
Debt Instrument [Line Items]
Comprehensive (loss) income					$ 19,000		$ 19,000	$ 19,000
Thermal Acoustical Solutions
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)	(90.00%)		(62.10%)	(11.20%)
Technical Nonwovens
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)				(12.50%)
Technical Nonwovens \| Industrial Filtration
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)			(25.00%)
Technical Nonwovens \| Advanced Materials
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)			(9.30%)
Performance Materials \| Filtration
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)	20.00%		19.80%	1.00%
Performance Materials \| Sealing and Advanced Solutions
Debt Instrument [Line Items]
Increase (decrease) in revenue (as a percent)			(28.60%)
Revolving Credit Facility \| Amended Credit Facility
Debt Instrument [Line Items]
Draw on credit facility						$ 20,000