Restructuring Charges (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) workers	Dec. 31, 2014 USD ($)
Restructuring Charges
Document Period End Date			Dec. 31, 2015
Restructuring charges	$ 1,714	$ 6,063	$ 3,561	$ 9,580
Reconciliation of restructuring liability
Costs charged to expense	1,714	6,063	3,561	9,580
Solid Capacitors
Restructuring Charges
Restructuring charges	754	496	1,556	1,895
Reconciliation of restructuring liability
Costs charged to expense	754	496	1,556	1,895
Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	987	4,496	1,524	6,485
Reconciliation of restructuring liability
Costs charged to expense	987	4,496	1,524	6,485
Manufacturing Relocation [Member]
Restructuring Charges
Restructuring charges	919	174	1,656	2,397
Reconciliation of restructuring liability
Beginning of period	0	0	0	0
Costs charged to expense	919	174	1,656	2,397
Costs paid or settled	(919)	(174)	(1,656)	(2,397)
Change in foreign exchange	0	0	0	0
End of period	0	0	0	0
Manufacturing Relocation [Member] | Mexican operations | Solid Capacitors
Restructuring Charges
Restructuring charges		500		600
Reconciliation of restructuring liability
Costs charged to expense		500		600
Manufacturing Relocation [Member] | China and Macedonia [Member] | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	919		1,656
Reconciliation of restructuring liability
Costs charged to expense	919		1,656
Manufacturing Relocation [Member] | PORTUGAL | Solid Capacitors
Restructuring Charges
Restructuring charges		174		1,300
Reconciliation of restructuring liability
Costs charged to expense		174		1,300
Manufacturing Relocation [Member] | Europe and Asia [Member] | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	900			1,100
Reconciliation of restructuring liability
Costs charged to expense	900			1,100
Employee Severance [Member]
Restructuring Charges
Restructuring charges	795	5,889	1,905	7,183
Reconciliation of restructuring liability
Beginning of period	2,279	3,026	7,239	6,217
Costs charged to expense	795	5,889	1,905	7,183
Costs paid or settled	1,209	(1,982)	(7,492)	(6,169)
Change in foreign exchange	(43)	(207)	170	(505)
End of period	1,822	6,726	$ 1,822	6,726
Restructuring Plan Number of Employees Covered | workers			24
Employee Severance [Member] | Maximum
Reconciliation of restructuring liability
Restructuring Plan Number of Employees Covered | workers			50
Employee Severance [Member] | CHINA | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges			$ 600
Reconciliation of restructuring liability
Costs charged to expense			600
Employee Severance [Member] | Europe
Restructuring Charges
Restructuring charges		5,889	400
Reconciliation of restructuring liability
Costs charged to expense		5,889	400
Employee Severance [Member] | Landsberg Germany [Member]
Restructuring Charges
Restructuring charges		4,000		5,200
Reconciliation of restructuring liability
Costs charged to expense		4,000		5,200
Employee Severance [Member] | Mexican operations | Solid Capacitors
Restructuring Charges
Restructuring charges	100		900
Reconciliation of restructuring liability
Costs charged to expense	100		900
Employee Severance [Member] | Europe and North America [Member]
Restructuring Charges
Restructuring charges	100	1,400	600	1,400
Reconciliation of restructuring liability
Costs charged to expense	100	$ 1,400	600	1,400
Employee Severance [Member] | ITALY | Film and Electrolytic [Member]
Restructuring Charges
Restructuring Reserve, Accrual Adjustment			(1,200)
Restructuring Charges [Member] | Mexican operations | Solid Capacitors
Restructuring Charges
Restructuring charges	500		500
Reconciliation of restructuring liability
Costs charged to expense	$ 500		$ 500
Other Restructuring [Member] | Italy and Evora Portugal [Member]
Restructuring Charges
Restructuring charges				2,397
Reconciliation of restructuring liability
Costs charged to expense				$ 2,397