Debt - Narrative (Details)					1 Months Ended	12 Months Ended
	Aug. 08, 2018 USD ($)	Feb. 08, 2018	Aug. 04, 2017 USD ($)	Nov. 09, 2016 USD ($)	Aug. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2015 USD ($)	Aug. 03, 2017 USD ($)	Jan. 01, 2016 USD ($)
Line of Credit Facility [Line Items]
Gain (loss) on extinguishment of debt						$ (496,000)	$ 0
Line of credit facility, agreement terms, required debt repayment using proceeds form asset sale						$ 5,505,000	14,332,000
Foreign subsidiary borrowings | Euro Interbank Offered Rate (Euribor) | Minimum
Line of Credit Facility [Line Items]
Euribor variable interest rates						1.00%
Foreign subsidiary borrowings | Euro Interbank Offered Rate (Euribor) | Maximum
Line of Credit Facility [Line Items]
Euribor variable interest rates						4.00%
2018 Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, covenant terms, fixed charge coverage ratio	1.1
Line of credit facility, availability of revolving commitment, fixed charge coverage ratio threshold	12.50%
Line of credit facility, stock pledged, non-U.S. subsidiaries, percentage	66.67%
2018 Credit Agreement | Revolving credit agreement | Line of Credit
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 30,000
Credit facility accordion feature, increase amount	$ 10,000
Line of credit facility, amount available						$ 8,437,000
Weighted average interest rate						3.85%
Commitment fee	0.25%
Write off of debt issuance cost					$ 490,000
Debt issuance costs, gross					$ 212,000
Accumulated amortization of debt issuance costs, revolver						$ 12
2018 Credit Agreement | Revolving credit agreement | Line of Credit | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on LIBOR	1.75%
2016 Amended and Restated Credit and Security Agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity				$ 39,871,000
Non-U.S. subsidiaries stock percentage pledged				65.00%
Debt issuance costs, amount							768,000
2016 Amended and Restated Credit and Security Agreement | Line of Credit
Line of Credit Facility [Line Items]
Debt issuance cost related to revolving credit facility							707,000
Accumulated amortization of debt issuance costs, revolver							$ 282,000
2016 Amended and Restated Credit and Security Agreement | London Interbank Offered Rate (LIBOR) | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on LIBOR		3.75%
2016 Amended and Restated Credit and Security Agreement | Secured Debt
Line of Credit Facility [Line Items]
Weighted average interest rate							5.50%
Issued amount of debt				$ 4,871,000
Installment payment				81,000
Fixed interest rate after effect of interest rate swap		5.80%
Debt issuance costs, gross							$ 61,000
Accumulated amortization of debt issuance costs, term loan							$ 14,000
2016 Amended and Restated Credit and Security Agreement | Secured Debt | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on LIBOR							4.25%
2016 Amended and Restated Credit and Security Agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity				$ 35,000,000
Weighted average interest rate							4.80%
2016 Amended and Restated Credit and Security Agreement | Revolving credit agreement | Minimum
Line of Credit Facility [Line Items]
Commitment fee		0.15%
2016 Amended and Restated Credit and Security Agreement | Revolving credit agreement | Maximum
Line of Credit Facility [Line Items]
Commitment fee		0.375%
Second Amendment Agreement | Line of Credit
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity			$ 30,000						$ 35,000
Second Amendment Agreement | Secured Debt
Line of Credit Facility [Line Items]
Line of credit facility, agreement terms, required debt repayment using proceeds form asset sale			$ 700
2015 Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Issued amount of debt								$ 20,000,000
Installment payment								$ 714,000
Debt agreement term								5 years
2015 Credit Agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity								$ 25,000,000		$ 20,000,000
Non-U.S. subsidiaries stock percentage pledged								65.00%
Debt agreement term								5 years