Debt - Narrative (Details)				1 Months Ended
	Dec. 17, 2018 USD ($)	Nov. 05, 2018	Aug. 08, 2018 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)
Line of Credit Facility [Line Items]
Short-term debt arrangement				$ 20,982,000	$ 21,253,000
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]
Fixed charge coverage ratio			1.1
Percent availability under revolving commitment			12.50%
Percentage of stock pledged on credit agreement		66.67%
2018 Credit Agreement | Line of Credit | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity			$ 30,000
Accordion feature, increase limit			$ 10,000
Remaining borrowing capacity				$ 9,393,000	$ 8,437,000
Weighted average interest rate, revolving credit facility				4.05%	3.85%
Commitment fee percentage			0.25%
Debt issuance costs incurred			$ 212,000
Revolving line of credit, accumulated amortization of debt issuance costs				$ 23,000	$ 12,000
2018 Credit Agreement | Line of Credit | Revolving credit agreement | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on LIBOR			1.75%
First Amendment To Credit Agreement And Security Agreement | Line of Credit
Line of Credit Facility [Line Items]
Coverage ratio threshold for three or more business days in consecutive thirty day period		12.50%
Export Credit Facility | Line of Credit | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 5,000,000
Accordion feature, increase limit	$ 35,000,000
Weighted average interest rate, revolving credit facility				3.59%
Export Credit Facility | Line of Credit | Revolving credit agreement | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on LIBOR	1.25%
First and Second Amendment | Line of Credit | Revolving credit agreement
Line of Credit Facility [Line Items]
Debt issuance costs incurred				$ 75,000
Short Term Debt Arrangement For Working Capital Purposes
Line of Credit Facility [Line Items]
Debt instrument, term				6 months
Short-term debt arrangement				$ 1,137,000
As Of August 31, 2018 Or September 30, 2018 | First Amendment To Credit Agreement And Security Agreement | Line of Credit
Line of Credit Facility [Line Items]
Fixed charge coverage ratio		1.1
On Or After October 31, 2018 | First Amendment To Credit Agreement And Security Agreement | Line of Credit
Line of Credit Facility [Line Items]
Fixed charge coverage ratio		1.1