Investment in NEC TOKIN (Details) - NEC TOKIN Corporation [Member] - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2016
Summarized financial information
Net income (loss)	$ 2,350	$ 5,255
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Current assets	247,713		$ 240,427
Non-current assets	263,824		260,614
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Current liabilities	178,451		179,360
Non-current liabilities	364,926		$ 335,500
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Sales	120,510	114,734
Gross profit	$ 26,546	$ 24,668