Restructuring - Narrative (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2016 USD ($) workers	Mar. 31, 2015 USD ($) workers	Mar. 31, 2014 USD ($) workers
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 4,178	$ 13,017	$ 14,122
Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2,375	2,672	3,555
Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,803	10,345	10,567
Restructuring Plan Number of Employees Covered | workers	24
Solid Capacitors
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,916	3,297	8,108
Film and Electrolytic
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,714	8,221	5,657
Innovation Center [Member] | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Workforce reductions and administrative overhead			1,900
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring charges	548	1,499	357
Corporate | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1,100
Mexico | Solid Capacitors | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	400
Mexico | Solid Capacitors | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	900	1,900	$ 1,200
Europe and Asia [Member] | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 500
Europe and Asia [Member] | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	600
Victoria Mexico [Member] | Solid Capacitors | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	500
Europe and North America [Member] | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	500
Europe [Member] | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	300
Italy | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | workers		50	31
Italy | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 3,200	$ 900
Restructuring Reserve, Accrual Adjustment	(1,000)
China | Film and Electrolytic | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	400
Europe North America and Asia [Domain] | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	500
Mexico and Macedonia [Member] | Film and Electrolytic | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		300
Weymouth United Kingdom [Member] | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 500
Landsberg Germany [Member] | Film and Electrolytic | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,100	400
Landsberg Germany [Member] | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		4,100
Corporate Headquarters [Member] | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,100
Portugal | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | workers			126
Portugal | Solid Capacitors | Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1,400
Portugal | Solid Capacitors | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 4,500
Maximum | Italy | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | workers	50
Cassia Integrazione Guadagni Straordinaria [Member] | Film and Electrolytic | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 400
Cassia Integrazione Guadagni Straordinaria [Member] | Maximum | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring Plan Number of Employees Covered | workers			170
Cassia Integrazione Guadagni Straordinaria [Member] | Maximum | Italy | Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring Plan Term			12 months