Restructuring (Details 2) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 14,122,000	$ 18,719,000	$ 14,254,000
Lease termination costs related to the closure of a sales office		600,000
Solid Capacitors
Restructuring Cost and Reserve [Line Items]
Restructuring charges	8,108,000	7,335,000	1,161,000
Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10,567,000	16,370,000	12,334,000
Workforce reductions and administrative overhead	1,100,000	4,900,000
Personnel reduction costs | Mexican operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,500,000
Personnel reduction costs | Weymouth, United Kingdom
Restructuring Cost and Reserve [Line Items]
Restructuring charges	500,000	2,900,000
Personnel reduction costs | Portugal
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4,500,000	1,100,000
Number of employees eliminated	126
Personnel reduction costs | Italy
Restructuring Cost and Reserve [Line Items]
Restructuring charges	900,000		6,100,000
Workforce reductions and administrative overhead			4,500,000
Number of employees eliminated	31
Personnel reduction costs | Landsberg, Germany
Restructuring Cost and Reserve [Line Items]
Restructuring charges		2,800,000
Personnel reduction costs | Corporate headquarters
Restructuring Cost and Reserve [Line Items]
Restructuring charges		2,700,000
Personnel reduction costs | Solid Capacitors | Mexican operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,200,000		1,700,000
Personnel reduction costs | Innovation center
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,900,000
Workforce reductions and administrative overhead		500,000
Personnel reduction costs | Cassia Integrazione Guadagni Straordinaria [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	400,000
Personnel reduction costs | Cassia Integrazione Guadagni Straordinaria [Member] | Maximum
Restructuring Cost and Reserve [Line Items]
Number of employees covered under Cassia Integrazione Guadagni Straordinaria plan	170
Term of Cassia Integrazione Guadagni Straordinaria plan	12 months
Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,555,000	2,349,000	1,920,000
Manufacturing and sales office relocation costs | Italy and Evora Portugal and Skopje Macedonia [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,600,000
Manufacturing and sales office relocation costs | Bulgaria, China, Macedonia and Mexico
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,800,000
Manufacturing and sales office relocation costs | China and Mexico
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 1,900,000