Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Restructuring Charges
Restructuring charges	$ 688	$ 1,824
Reconciliation of restructuring liability
Costs charged to expense	688	1,824
Solid Capacitors
Restructuring Charges
Restructuring charges	136	232
Reconciliation of restructuring liability
Costs charged to expense	136	232
Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	549	1,286
Reconciliation of restructuring liability
Costs charged to expense	549	1,286
Manufacturing Relocation [Member]
Restructuring Charges
Restructuring charges	41	280
Reconciliation of restructuring liability
Beginning of period	0	0
Costs charged to expense	41	280
Costs paid or settled	(41)	(280)
Change in foreign exchange	0	0
End of period	0	0
Manufacturing Relocation [Member] | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	41	280
Reconciliation of restructuring liability
Costs charged to expense	41	280
Employee Severance [Member]
Restructuring Charges
Restructuring charges	647	1,544
Reconciliation of restructuring liability
Beginning of period	976	7,239
Costs charged to expense	647	1,544
Costs paid or settled	(523)	(2,439)
Change in foreign exchange	(21)	212
End of period	1,079	6,556
Employee Severance [Member] | SWEDEN | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	300
Reconciliation of restructuring liability
Costs charged to expense	300
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] | Landsberg Germany [Member] | Film and Electrolytic [Member]
Restructuring Charges
Restructuring charges	200	500
Reconciliation of restructuring liability
Costs charged to expense	200	500
Employee Severance [Member] | Mexican operations | Solid Capacitors
Restructuring Charges
Restructuring charges		200
Reconciliation of restructuring liability
Costs charged to expense		200
Employee Severance [Member] | Europe and North America [Member] | Corporate, Non-Segment [Member]
Restructuring Charges
Restructuring charges		200
Reconciliation of restructuring liability
Costs charged to expense		$ 200
Employee Severance [Member] | Victoria Mexico [Member] | Solid Capacitors
Restructuring Charges
Restructuring charges	100
Reconciliation of restructuring liability
Costs charged to expense	$ 100