Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 item	Sep. 30, 2012	Mar. 31, 2013
Segment and Geographic Information
Number of business groups			2
Segment and geographic information
Net sales	$ 212,740	$ 215,991	$ 415,463	$ 439,623
Operating income (loss)	309	(14,020)	(19,649)	(18,065)
Depreciation and amortization expenses	12,049	11,521	25,780	23,177
Restructuring charges included in Operating income (loss)
Restructuring charges	1,365	8,522	5,975	9,786
Goodwill impairment		1,092		1,092
Write down of long-lived assets		4,234		4,234
Settlement gain on benefit plans				(1,675)
Assets
Total assets	880,211		880,211		911,591
North and South America ("Americas")
Segment and geographic information
Net sales	67,798	62,243	127,368	122,728
Europe, Middle East, Africa ("EMEA")
Segment and geographic information
Net sales	69,470	70,673	142,511	150,058
Asia and Pacific Rim ("APAC")
Segment and geographic information
Net sales	75,472	83,075	145,584	166,837
Solid Capacitors
Segment and geographic information
Number of manufacturing sites			10
Net sales	157,714	162,424	307,115	323,168
Operating income (loss)	25,386	23,098	38,194	48,768
Depreciation and amortization expenses	7,301	7,336	14,611	14,527
Restructuring charges included in Operating income (loss)
Restructuring charges	99	3,217	3,144	3,210
Assets
Total assets	502,624		502,624		517,024
Film and Electrolytic
Segment and geographic information
Number of manufacturing sites			15
Net sales	55,026	53,567	108,348	116,455
Operating income (loss)	(3,487)	(12,743)	(11,530)	(18,764)
Depreciation and amortization expenses	3,282	3,097	7,789	6,546
Restructuring charges included in Operating income (loss)
Restructuring charges	1,063	5,305	2,473	6,576
Goodwill impairment		1,100		1,100
Write down of long-lived assets		4,200		4,200
Settlement gain on benefit plans		(1,700)		(1,700)
Assets
Total assets	302,105		302,105		308,751
Unallocated
Segment and geographic information
Operating income (loss)	(21,590)	(24,375)	(46,313)	(48,069)
Depreciation and amortization expenses	1,466	1,088	3,380	2,104
Restructuring charges included in Operating income (loss)
Restructuring charges	203		358
Assets
Total assets	$ 75,482		$ 75,482		$ 85,816