Investment in NEC TOKIN - Equity Method Investment Income (Loss) Reconciliation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 19, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	$ 75,417	$ 238	$ (133)	$ 75,879	$ 271
NEC TOKIN Corporation [Member]
Schedule of Equity Method Investments [Line Items]
Net income (loss)	247,786				$ 5,444
KEC’s economic interest %		34.00%	34.00%	34.00%	34.00%
Equity Method Investment, Equity Income (Loss) Before Adjustments					$ 1,851
Amortization and depreciation					(1,686)
Equity Method investment, Inventory Profit Elimination					106
Income (Loss) from Equity Method Investments					$ 271
TOKIN [Member]
Schedule of Equity Method Investments [Line Items]
Net income (loss)			$ 1,082
KEC’s economic interest %			34.00%		34.00%
Equity Method Investment, Equity Income (Loss) Before Adjustments	84,247		$ 368
Amortization and depreciation	(113)		(562)
Equity Method Investment, Removal of EMD Memo Accounts	(8,981)		0		$ 0
Equity Method investment, Inventory Profit Elimination	24		61
Income (Loss) from Equity Method Investments	75,177	$ 123,400	(133)
Acquired Equity Method Investment [Member]
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	$ 240		$ 0		$ 0