Condensed Consolidating Financial Statements (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 51,576	$ 57,929	$ 57,700	$ 95,978
Accounts receivable, net	95,581	98,947
Intercompany receivable	0	0
Inventories, net	188,833	187,974
Prepaid expenses and other	40,229	36,871
Deferred income taxes	6,569	6,695
Current assets of discontinued operations	0	12,160
Total current assets	382,788	400,576
Property and equipment, net	275,498	292,648
Goodwill	35,584	35,584
Intangible assets, net	35,377	37,184
Investment in NEC TOKIN	48,449	46,419
Investments in subsidiaries	0	0
Restricted cash	12,955	13,512
Deferred income taxes	6,423	6,778
Other assets	20,153	10,130
Non-current assets of discontinued operations	0	836
Long-term intercompany receivable	0	0
Total assets	817,227	843,667
Current liabilities:
Current portion of long-term debt	25,826	7,297
Accounts payable	72,629	74,818
Intercompany payable	0	0
Accrued expenses	66,400	76,468
Income taxes payable and deferred income taxes	345	980
Current liabilities of discontinued operations	0	7,269
Total current liabilities	165,200	166,832
Long-term debt, less current portion	376,256	391,292
Other non-current obligations	52,246	55,864
Deferred income taxes	8,687	5,203
Non-current liabilities of discontinued operations	0	2,592
Long-term intercompany payable	0	0
Total stockholders’ equity	214,838	221,884
Total liabilities and stockholders’ equity	817,227	843,667
Reportable legal entities | Parent
Current assets:
Cash and cash equivalents	641	616	1,656	17,202
Accounts receivable, net	0	0
Intercompany receivable	320,305	318,582
Inventories, net	0	0
Prepaid expenses and other	3,145	3,146
Deferred income taxes	0	0
Current assets of discontinued operations		0
Total current assets	324,091	322,344
Property and equipment, net	316	329
Goodwill	0	0
Intangible assets, net	0	0
Investment in NEC TOKIN	0	0
Investments in subsidiaries	421,754	402,090
Restricted cash	0	0
Deferred income taxes	0	0
Other assets	4,750	5,415
Non-current assets of discontinued operations		0
Long-term intercompany receivable	74,603	81,746
Total assets	825,514	811,924
Current liabilities:
Current portion of long-term debt	18,486	5,988
Accounts payable	93	84
Intercompany payable	208,989	176,624
Accrued expenses	25,301	34,236
Income taxes payable and deferred income taxes	0	0
Current liabilities of discontinued operations		0
Total current liabilities	252,869	216,932
Long-term debt, less current portion	357,807	372,251
Other non-current obligations	0	857
Deferred income taxes	0	0
Non-current liabilities of discontinued operations		0
Long-term intercompany payable	0	0
Total stockholders’ equity	214,838	221,884
Total liabilities and stockholders’ equity	825,514	811,924
Reportable legal entities | Guarantor Subsidiaries
Condensed Consolidating Balance Sheet
Percentage of ownership interest	100.00%
Current assets:
Cash and cash equivalents	29,984	22,200	23,816	52,056
Accounts receivable, net	41,010	49,462
Intercompany receivable	348,367	329,211
Inventories, net	127,232	119,340
Prepaid expenses and other	16,610	15,286
Deferred income taxes	1,957	1,022
Current assets of discontinued operations		0
Total current assets	565,160	536,521
Property and equipment, net	101,498	104,874
Goodwill	35,584	35,584
Intangible assets, net	27,688	28,380
Investment in NEC TOKIN	48,449	46,419
Investments in subsidiaries	424,312	424,386
Restricted cash	12,955	13,512
Deferred income taxes	969	1,010
Other assets	14,486	3,895
Non-current assets of discontinued operations		0
Long-term intercompany receivable	58,634	60,663
Total assets	1,289,735	1,255,244
Current liabilities:
Current portion of long-term debt	6,800	0
Accounts payable	35,621	36,579
Intercompany payable	590,222	570,535
Accrued expenses	12,692	13,698
Income taxes payable and deferred income taxes	2,923	2,909
Current liabilities of discontinued operations		0
Total current liabilities	648,258	623,721
Long-term debt, less current portion	6,449	6,449
Other non-current obligations	3,626	3,311
Deferred income taxes	4,191	3,258
Non-current liabilities of discontinued operations		0
Long-term intercompany payable	74,603	81,747
Total stockholders’ equity	552,608	536,758
Total liabilities and stockholders’ equity	1,289,735	1,255,244
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheet
Percentage of capital stock	51.00%
Current assets:
Cash and cash equivalents	20,951	35,113	32,228	26,720
Accounts receivable, net	54,571	49,485
Intercompany receivable	217,971	203,018
Inventories, net	61,601	68,634
Prepaid expenses and other	23,415	21,380
Deferred income taxes	4,612	5,673
Current assets of discontinued operations		12,160
Total current assets	383,121	395,463
Property and equipment, net	173,684	187,445
Goodwill	0	0
Intangible assets, net	7,689	8,804
Investment in NEC TOKIN	0	0
Investments in subsidiaries	30,285	30,285
Restricted cash	0	0
Deferred income taxes	5,454	5,768
Other assets	917	820
Non-current assets of discontinued operations		836
Long-term intercompany receivable	2,800	2,801
Total assets	603,950	632,222
Current liabilities:
Current portion of long-term debt	540	1,309
Accounts payable	36,915	38,155
Intercompany payable	87,432	103,652
Accrued expenses	28,407	28,534
Income taxes payable and deferred income taxes	363	1,012
Current liabilities of discontinued operations		7,269
Total current liabilities	153,657	179,931
Long-term debt, less current portion	12,000	12,592
Other non-current obligations	48,620	51,696
Deferred income taxes	4,496	1,945
Non-current liabilities of discontinued operations		2,592
Long-term intercompany payable	61,434	63,463
Total stockholders’ equity	323,743	320,003
Total liabilities and stockholders’ equity	603,950	632,222
Reclassifications and Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable	(886,643)	(850,811)
Inventories, net	0	0
Prepaid expenses and other	(2,941)	(2,941)
Deferred income taxes	0	0
Current assets of discontinued operations		0
Total current assets	(889,584)	(853,752)
Property and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in NEC TOKIN	0	0
Investments in subsidiaries	(876,351)	(856,761)
Restricted cash	0	0
Deferred income taxes	0	0
Other assets	0	0
Non-current assets of discontinued operations		0
Long-term intercompany receivable	(136,037)	(145,210)
Total assets	(1,901,972)	(1,855,723)
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	0	0
Intercompany payable	(886,643)	(850,811)
Accrued expenses	0	0
Income taxes payable and deferred income taxes	(2,941)	(2,941)
Current liabilities of discontinued operations		0
Total current liabilities	(889,584)	(853,752)
Long-term debt, less current portion	0	0
Other non-current obligations	0	0
Deferred income taxes	0	0
Non-current liabilities of discontinued operations		0
Long-term intercompany payable	(136,037)	(145,210)
Total stockholders’ equity	(876,351)	(856,761)
Total liabilities and stockholders’ equity	$ (1,901,972)	$ (1,855,723)
10.5% Senior Notes, net of premium of $2,807 and $3,144 as of September 30, 2014 and March 31, 2014, respectively
Condensed Consolidating Balance Sheet
Interest rate of senior notes (as a percent)	10.50%	10.50%