Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 business_group	Sep. 30, 2013	Mar. 31, 2014
Segment Reporting [Abstract]
Number of business groups			2
Segment and geographic information
Net sales	$ 215,293	$ 208,449	$ 428,174	$ 410,506
Operating loss (loss)	12,770	1,585	12,164	(16,627)
Depreciation and amortization expense	10,177	11,951	20,974	25,590
Restructuring charges included in Operating income (loss)
Restructuring charges	1,687	1,364	3,517	5,974
Assets
Total assets	817,227		817,227		843,667
North and South America (“Americas”)
Segment and geographic information
Net sales	72,167	65,398	138,150	124,751
Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Net sales	69,930	68,166	147,135	141,157
Asia and Pacific Rim (“APAC”)
Segment and geographic information
Net sales	73,196	74,885	142,889	144,598
Unallocated/Corporate
Segment and geographic information
Operating loss (loss)	(24,699)	(21,590)	(48,963)	(46,292)
Depreciation and amortization expense	1,513	1,466	3,015	3,380
Restructuring charges included in Operating income (loss)
Restructuring charges	18	203	129	357
Assets
Total assets	87,822		87,822		76,429
Solid Capacitors
Segment and geographic information
Number of manufacturing sites			9
Net sales	163,019	157,714	322,809	307,115
Operating loss (loss)	38,386	25,386	68,120	38,178
Depreciation and amortization expense	5,463	7,302	10,941	14,612
Restructuring charges included in Operating income (loss)
Restructuring charges	169	99	1,399	3,145
Assets
Total assets	475,009		475,009		479,377
Film and Electrolytic
Segment and geographic information
Number of manufacturing sites			12
Net sales	52,274	50,735	105,365	103,391
Operating loss (loss)	(917)	(2,211)	(6,993)	(8,513)
Depreciation and amortization expense	3,201	3,183	7,018	7,598
Restructuring charges included in Operating income (loss)
Restructuring charges	1,500	1,062	1,989	2,472
Assets
Total assets	$ 254,396		$ 254,396		$ 287,861