Investment in NEC TOKIN (Details) (USD $)	6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended	0 Months Ended			6 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 NEC TOKIN	Sep. 30, 2013 NEC TOKIN	Sep. 30, 2014 NEC TOKIN	Sep. 30, 2013 NEC TOKIN	Feb. 01, 2013 NEC TOKIN Stockholders' Agreement director_position	Sep. 30, 2014 NEC TOKIN Put Option	Sep. 30, 2014 NEC TOKIN Put Option	Feb. 01, 2013 NEC TOKIN KEC Stock Purchase Agreement	Mar. 12, 2012 NEC TOKIN KEC Stock Purchase Agreement	Feb. 01, 2013 NEC TOKIN KEC Stockholders' Agreement director_position	Sep. 30, 2014 NEC TOKIN KEC Option Agreement number_of_times	Sep. 30, 2014 NEC TOKIN KEC Put Option number_of_times	Sep. 30, 2014 Recurring	Sep. 30, 2014 Recurring Fair Value	Mar. 31, 2014 Recurring Fair Value	Sep. 30, 2014 Recurring Level 3 Fair Value	Mar. 31, 2014 Recurring Level 3 Fair Value	Sep. 30, 2014 Senior Notes	Mar. 31, 2014 Senior Notes
Schedule of Equity Method Investments [Line Items]
Common stock acquired (as a percent)											51.00%
Economic ownership to be acquired (as a percent)			34.00%	34.00%	34.00%	34.00%					34.00%		49.00%
Purchase price paid										$ 50,000,000
Number of director positions							7					4
Purchase price for expected additional shares that may be acquired													50,000,000
Ownership interest maintained after acquisition of additional shares (as a percent)													51.00%
LTM EBITDA multiple													6	6
Interest rate of senior notes (as a percent)																				10.50%	10.50%
Gain recognized included in Other expense, net	10,700,000	(382,000)						6,600,000	10,700,000						10,700,000
NEC TOKIN options, net																14,300,000	3,600,000	14,300,000	3,600,000
Summarized financial information
Current assets			232,991,000	245,709,000	232,991,000	245,709,000
Non-current assets			292,440,000	302,161,000	292,440,000	302,161,000
Current liabilities			123,962,000	120,929,000	123,962,000	120,929,000
Non-current liabilities			325,877,000	360,908,000	325,877,000	360,908,000
Sales			129,677,000	135,074,000	252,085,000	258,266,000
Gross profit			26,387,000	25,569,000	53,065,000	43,869,000
Net income (loss)			$ 2,454,000	$ (3,213,000)	$ (700,000)	$ (11,942,000)