Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net sales	$ 215,821	$ 207,339	$ 208,449	$ 202,057	$ 199,539	$ 197,697	$ 211,165	$ 215,500	$ 833,666	$ 823,903	$ 924,052
Operating costs and expenses:
Cost of sales									712,925	697,076	731,312
Selling, general and administrative expenses									95,856	107,620	106,534
Research and development									24,466	26,876	27,765
Restructuring charges									14,122	18,719	14,254
Write down of long-lived assets									4,476	7,582	15,786
Goodwill impairment									0	1,092	0
Net loss on sales and disposals of assets									32	18	318
Total operating costs and expenses									851,877	858,983	895,969
Operating (loss) income	(5,207)	3,623	1,585	(18,212)	(14,448)	(3,437)	(12,872)	(4,323)	(18,211)	(35,080)	28,083
Other (income) expense:
Interest income									(195)	(139)	(175)
Interest expense									40,962	41,331	28,567
Other (income) expense, net									(2,681)	(2,295)	965
Loss from continuing operations before income taxes and equity loss from NEC TOKIN									(56,297)	(73,977)	(1,274)
Income tax expense									1,482	3,281	1,076
Loss from continuing operations before equity loss from NEC TOKIN									(57,779)	(77,258)	(2,350)
Equity loss from NEC TOKIN									(7,090)	(1,254)	0
Loss from continuing operations	(14,550)	(4,744)	(11,945)	(33,630)	(23,704)	(13,169)	(23,642)	(17,997)	(64,869)	(78,512)	(2,350)
Income (loss) from discontinued operations	103	(1,076)	(1,151)	(1,510)	(1,547)	(1,088)	(1,278)	243	(3,634)	(3,670)	9,042
Net income (loss)	$ (14,447)	$ (5,820)	$ (13,096)	$ (35,140)	$ (25,251)	$ (14,257)	$ (24,920)	$ (17,754)	$ (68,503)	$ (82,182)	$ 6,692
Net income (loss) per basic share:
Loss from continuing operations (in dollars per share)	$ (0.32)	$ (0.11)	$ (0.26)	$ (0.75)	$ (0.53)	$ (0.29)	$ (0.53)	$ (0.40)	$ (1.44)	$ (1.75)	$ (0.05)
Income (loss) from discontinued operations (in dollars per share)	$ 0.00	$ (0.02)	$ (0.03)	$ (0.03)	$ (0.03)	$ (0.03)	$ (0.03)	$ 0.00	$ (0.08)	$ (0.08)	$ 0.21
Net income (loss) (in dollars per share)	$ (0.32)	$ (0.13)	$ (0.29)	$ (0.78)	$ (0.56)	$ (0.32)	$ (0.56)	$ (0.40)	$ (1.52)	$ (1.83)	$ 0.16
Net income (loss) per diluted share:
Loss from continuing operations (in dollars per share)	$ (0.32)	$ (0.11)	$ (0.26)	$ (0.75)	$ (0.53)	$ (0.29)	$ (0.53)	$ (0.40)	$ (1.44)	$ (1.75)	$ (0.04)
Income (loss) from discontinued operations (in dollars per share)	$ 0.00	$ (0.02)	$ (0.03)	$ (0.03)	$ (0.03)	$ (0.03)	$ (0.03)	$ 0.00	$ (0.08)	$ (0.08)	$ 0.17
Net income (loss) (in dollars per share)	$ (0.32)	$ (0.13)	$ (0.29)	$ (0.78)	$ (0.56)	$ (0.32)	$ (0.56)	$ (0.40)	$ (1.52)	$ (1.83)	$ 0.13
Weighted-average shares outstanding:
Basic (in shares)									45,102	44,897	43,285
Diluted (in shares)									45,102	44,897	52,320