Basis of Financial Statement Presentation (Details)	3 Months Ended							3 Months Ended
	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2014 EUR (€)	Mar. 31, 2014 USD ($)	Aug. 28, 2012 USD ($)	Jun. 30, 2014 Carrying Value USD ($)	Mar. 31, 2014 Carrying Value USD ($)	Jun. 30, 2014 Recurring USD ($)	Jun. 30, 2014 Recurring Fair Value USD ($)	Mar. 31, 2014 Recurring Fair Value USD ($)	Jun. 30, 2014 Recurring Level 1 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 1 Fair Value USD ($)	Jun. 30, 2014 Recurring Level 2 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 2 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 3 Fair Value USD ($)	Jun. 30, 2014 Interest-bearing Deposits [Member] USD ($)	Jun. 30, 2014 Interest-bearing Deposits [Member] EUR (€)
Restricted Cash
Prepayment received from an OEM					$ 24,000,000
Amount of prepayment utilized for purchase of manufacturing equipment	13,000,000
Prepayment received from an OEM classified as restricted cash	11,000,000
Guarantee issued by the European bank in conjunction with the establishment of a VAT registration in The Netherlands	2,000,000		1,500,000
Fair Value Measurement
Money markets						725,000	714,000		725,000	714,000	725,000	714,000
Total debt						403,837,000	398,589,000		416,847,000	409,284,000	375,413,000	371,863,000	41,434,000	37,421,000
NEC TOKIN options, net							3,600,000		7,700,000	3,600,000					3,600,000
NEC TOKIN option valuation activity using significant unobservable inputs (Level 3)
Balance at the beginning of the period								3,600,000
Change in value of NEC TOKIN options	4,100,000	0						4,100,000
Balance at the end of the period								7,700,000
Restricted cash	13,210,000			13,512,000												2,300,000	1,700,000
Components of inventories
Raw materials and supplies	90,524,000			90,968,000
Work in process	57,768,000			61,310,000
Finished goods	62,594,000			62,522,000
Inventory, gross	210,886,000			214,800,000
Inventory reserves	(21,481,000)			(26,826,000)
Inventories, net	189,405,000			187,974,000
Reserve for inventory held by a third party	$ 3,900,000
Warrant
Number of shares subject to a warrant held by K Equity, LLC	8,416,815			8,400,000
Revenue Recognition
Period of product warranty	1 year
Warranty costs as a percentage of net sales, maximum	0.99%	1.50%