Debt (Details) € in Thousands, ¥ in Millions				1 Months Ended				3 Months Ended		96 Months Ended
	Apr. 28, 2017 USD ($)	Sep. 01, 2016 USD ($) Rate	Sep. 01, 2016 JPY (¥) Rate	Jul. 31, 2017 EUR (€)	Jul. 31, 2017 USD ($)	Jan. 31, 2017 EUR (€)	Jan. 31, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Feb. 01, 2025 EUR (€)	Feb. 01, 2025 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 Rate	Jul. 01, 2017 EUR (€)	Jul. 01, 2017 USD ($)	May 02, 2016 USD ($)	May 05, 2010
Debt, Long-term and Short-term, Combined Amount [Abstract]
Total debt								$ 320,223,000				$ 324,623,000
Revolving line of credit								0
Current maturities								(20,412,000)				(20,540,000)
Total long-term debt								299,811,000				304,083,000
Interest expense
Contractual interest expense								6,845,000	$ 10,425,000
Capitalized interest								(64,000)	(8,000)
Amortization of debt issuance costs								116,000	167,000
Amortization of debt (premium) discount								98,000	266,000
Imputed interest on acquisition-related obligations								15,000	27,000
Interest expense on capital lease								26,000	83,000
Total interest expense								7,036,000	$ 10,960,000
Long-term Debt, Unclassified [Abstract]
Second part of loan				€ 277	$ 325,000
Term Loan Credit Agreement [Member]
Debt
Debt Issuance Costs, Net								13,100,000				13,300,000
Debt, Long-term and Short-term, Combined Amount [Abstract]
Total debt								314,614,000				318,782,000
Long-term Debt, Unclassified [Abstract]
Interest payable								100,000				200,000
10.5% Senior Notes, net [Member]
Line of Credit Facility [Abstract]
Rate																	10.50%
Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Current borrowing capacity																$ 75,000,000
Remaining borrowing capacity								73,200,000
Other Debt Obligations [Member]
Debt, Long-term and Short-term, Combined Amount [Abstract]
Total debt								5,609,000				5,841,000
Long-term Debt, Unclassified [Abstract]
Proceeds from Issuance of Debt						€ 2,200	$ 2,500,000
Debt Instrument, Unamortized Discount								$ 500,000				$ 500,000		€ 600	$ 700,000
Term Loan Credit Agreement [Member] | Line of Credit [Member]
Debt
Line of Credit Facility, Periodic Payment	$ 4,300,000
Line of Credit, Debt Issue Discount Percent	3.00%
Line of Credit Facility, Maximum Borrowing Capacity	$ 345,000,000
Line of Credit Facility, Maximum Borrowing Capacity, Incremental Increase	$ 50,000,000
Debt Instrument, Redemption Price, Percentage	97.00%
Line of Credit, Covenant Compliance, Pledged Percent of Outstanding Voting Stock	65.00%
Line of Credit Facility, Periodic Payment, Percent	1.25%
Line of Credit Facility [Abstract]
Rate	0.97%
Term Loan Credit Agreement [Member] | Line of Credit [Member] | Base Rate [Member]
Line of Credit Facility [Abstract]
Basis spread on variable rate	5.00%
Term Loan Credit Agreement [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Abstract]
Basis spread on variable rate	6.00%
Minimum [Member] | Term Loan Credit Agreement [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Abstract]
Basis spread on variable rate	1.00%
Scenario, Forecast [Member] | Other Debt Obligations [Member]
Long-term Debt, Unclassified [Abstract]
Long-term Debt, Maturities, Repayment Terms										P8Y	P8Y
TOKIN [Member] | Other Debt Obligations [Member]
Debt
Line of Credit, Debt Issue Discount Percent | Rate		0.04%	0.04%
Line of Credit Facility [Abstract]
Rate | Rate													0.53%
Long-term Debt, Unclassified [Abstract]
Proceeds from Issuance of Debt		$ 3,200,000	¥ 350
Initial Repayment [Member] [Member] | Scenario, Forecast [Member] | Other Debt Obligations [Member]
Long-term Debt, Unclassified [Abstract]
Repayments of Other Debt										€ 185	$ 211,000
Remaining Repayment [Member] | Scenario, Forecast [Member] | Other Debt Obligations [Member]
Long-term Debt, Unclassified [Abstract]
Repayments of Other Debt										€ 210	$ 248,000