Investment in NEC TOKIN (Details 2) - NECTOKIN - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Summarized financial information
Current assets continuing operations	$ 204,654	$ 199,527
Assets held for sale (current) (1)	118,983	43,146
Noncurrent assets continuing operations	285,952	188,925
Assets held for sale (noncurrent) (1)	0	72,360
Current liabilities continuing operations	375,433	146,207
Liabilities held for sale (current) (1)	50,008	36,078
Noncurrent liabilities continuing operations	65,657	313,768
Liabilities held for sale (noncurrent) (1)	0	21,720
Net sales	328,822	301,898	$ 321,540
Gross profit	74,465	67,409	66,722
Net income (loss) from continuing operations	106,103	(54,575)	(43,085)
Net income (loss) from discontinued operations (1)	22,399	11,580	18,994
Net income (loss)	$ 128,502	$ (42,995)	$ (24,091)