Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Dec. 31, 2012 segment	Dec. 31, 2011	Mar. 31, 2012
Segment and Geographic Information
Number of business groups				3
Segment and geographic information
Net sales	$ 200,297		$ 218,795	$ 639,920	$ 774,165
Operating income (loss)	(5,290)		(17,962)	(23,355)	47,793
Depreciation and amortization expenses	10,502		10,373	33,679	33,384
Restructuring charges
Total restructuring	3,886		10,748	13,672	13,378
Operating expenses (benefits)
Goodwill impairment				1,092
Write down of long-lived assets	3,084	4,200	15,786	7,318	15,786
Net curtailment and settlement (gain) loss on benefit plans	587			(1,088)
Assets
Total assets	926,340			926,340		975,552
North and South America ("Americas")
Segment and geographic information
Net sales	62,185		64,256	184,913	218,678
Europe, Middle East, Africa ("EMEA")
Segment and geographic information
Net sales	66,056		84,676	216,114	294,285
Asia and Pacific Rim ("APAC")
Segment and geographic information
Net sales	72,056		69,863	238,893	261,202
Tantalum
Segment and geographic information
Number of manufacturing sites				7
Net sales	98,496		92,091	317,003	326,824
Operating income (loss)	10,117		(4,842)	34,050	46,418
Depreciation and amortization expenses	5,251		5,351	17,269	18,264
Restructuring charges
Total restructuring	652		6	2,759	905
Operating expenses (benefits)
Write down of long-lived assets	3,084		15,786	7,318	15,786
Assets
Total assets	455,530			455,530		511,193
Ceramic
Segment and geographic information
Number of manufacturing sites				2
Net sales	51,276		47,510	155,937	163,001
Operating income (loss)	14,639		13,927	39,275	46,199
Depreciation and amortization expenses	1,576		1,586	5,505	5,391
Restructuring charges
Total restructuring	1,378		1	2,630	89
Assets
Total assets	237,141			237,141		201,971
Film and Electrolytic
Segment and geographic information
Number of manufacturing sites				14
Net sales	50,525		79,194	166,980	284,340
Operating income (loss)	(7,431)		(5,926)	(25,853)	27,329
Depreciation and amortization expenses	3,675		3,436	10,905	9,729
Restructuring charges
Total restructuring	1,856		10,741	8,283	12,384
Operating expenses (benefits)
Goodwill impairment				1,092
Write down of long-lived assets				4,200
Net curtailment and settlement (gain) loss on benefit plans				(1,500)
Assets
Total assets	233,669			233,669		262,388
Reportable segment
Segment and geographic information
Operating income (loss)	17,325		3,159	47,472	119,946
Unallocated
Segment and geographic information
Operating income (loss)	$ 22,615		$ 21,121	$ 70,827	$ 72,153