Condensed Consolidating Financial Statements Balance Sheet (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015
Current assets:
Cash and cash equivalents	$ 52,938	$ 65,004	$ 31,059	$ 56,362
Accounts receivable, net	89,085	93,168
Intercompany receivable	0	0
Inventories, net	167,916	168,879
Prepaid expenses and other	30,925	25,496
Deferred income taxes	0
Total current assets	340,864	352,547
Assets, Noncurrent [Abstract]
Property and equipment, net	231,688	241,839
Goodwill	40,294	40,294
Intangible assets, net	32,613	33,301
Investment in NEC TOKIN	15,172	20,334
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Deferred income taxes	7,605	8,397
Other assets	2,744	3,068
Long-term intercompany receivable	0	0
Total assets	670,980	699,780
Current liabilities:
Current portion of long-term debt	0	2,000
Accounts payable	66,825	70,981
Intercompany payable	0	0
Accrued expenses	41,898	50,320
Taxes Payable, Current	216	453
Total current liabilities	108,939	123,754
Liabilities, Noncurrent [Abstract]
Long-term debt, less current portion	385,968	385,833
Other non-current obligations	84,694	74,892
Deferred income taxes	2,984	2,820
Long-term intercompany payable	0	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	88,395	112,481
Total liabilities and stockholders’ equity	670,980	699,780
Parent
Current assets:
Cash and cash equivalents	640	640	640	640
Accounts receivable, net	0	0
Intercompany receivable	30,994	30,210
Inventories, net	0	0
Prepaid expenses and other	3,325	3,325
Deferred income taxes	0
Total current assets	34,959	34,175
Assets, Noncurrent [Abstract]
Property and equipment, net	244	255
Goodwill	0	0
Intangible assets, net	0	0
Investment in NEC TOKIN	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	369,627	382,108
Deferred income taxes	0	0
Other assets	0	0
Long-term intercompany receivable	65,822	67,500
Total assets	470,652	484,038
Current liabilities:
Current portion of long-term debt	0	2,000
Accounts payable	67	20
Intercompany payable	22,783	280
Accrued expenses	7,320	17,305
Taxes Payable, Current	0	0
Total current liabilities	30,170	19,605
Liabilities, Noncurrent [Abstract]
Long-term debt, less current portion	352,087	351,952
Other non-current obligations	0	0
Deferred income taxes	0	0
Long-term intercompany payable	0	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	88,395	112,481
Total liabilities and stockholders’ equity	470,652	484,038
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	22,573	36,209	12,756	33,094
Accounts receivable, net	33,716	41,025
Intercompany receivable	169,569	132,523
Inventories, net	110,132	113,289
Prepaid expenses and other	16,833	12,161
Deferred income taxes	0
Total current assets	352,823	335,207
Assets, Noncurrent [Abstract]
Property and equipment, net	90,226	93,936
Goodwill	40,294	40,294
Intangible assets, net	26,861	27,252
Investment in NEC TOKIN	15,172	20,334
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	427,702	429,723
Deferred income taxes	768	800
Other assets	2,144	2,452
Long-term intercompany receivable	40,397	41,428
Total assets	996,387	991,426
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	34,863	34,618
Intercompany payable	272,840	275,498
Accrued expenses	13,042	11,807
Taxes Payable, Current	2,988	2,983
Total current liabilities	323,733	324,906
Liabilities, Noncurrent [Abstract]
Long-term debt, less current portion	19,881	19,881
Other non-current obligations	37,296	25,797
Deferred income taxes	2,242	2,242
Long-term intercompany payable	65,822	67,500
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	547,413	551,100
Total liabilities and stockholders’ equity	996,387	991,426
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	29,725	28,155	17,663	22,628
Accounts receivable, net	55,369	52,143
Intercompany receivable	160,801	170,224
Inventories, net	57,784	55,590
Prepaid expenses and other	13,731	12,974
Deferred income taxes	0
Total current assets	317,410	319,086
Assets, Noncurrent [Abstract]
Property and equipment, net	141,218	147,648
Goodwill	0	0
Intangible assets, net	5,752	6,049
Investment in NEC TOKIN	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	93,359	93,359
Deferred income taxes	6,837	7,597
Other assets	600	616
Long-term intercompany receivable	1,089	1,088
Total assets	566,265	575,443
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	31,895	36,343
Intercompany payable	65,741	57,179
Accrued expenses	21,536	21,208
Taxes Payable, Current	192	434
Total current liabilities	119,364	115,164
Liabilities, Noncurrent [Abstract]
Long-term debt, less current portion	14,000	14,000
Other non-current obligations	47,398	49,095
Deferred income taxes	742	578
Long-term intercompany payable	41,486	42,516
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	343,275	354,090
Total liabilities and stockholders’ equity	$ 566,265	575,443
Reportable legal entities | Guarantor Subsidiaries
Condensed Consolidating Balance Sheet
Percentage of ownership interest	100.00%
Reclassifications and Eliminations
Current assets:
Cash and cash equivalents	$ 0	0	$ 0	$ 0
Accounts receivable, net	0	0
Intercompany receivable	(361,364)	(332,957)
Inventories, net	0	0
Prepaid expenses and other	(2,964)	(2,964)
Deferred income taxes	0
Total current assets	(364,328)	(335,921)
Assets, Noncurrent [Abstract]
Property and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in NEC TOKIN	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(890,688)	(905,190)
Deferred income taxes	0	0
Other assets	0	0
Long-term intercompany receivable	(107,308)	(110,016)
Total assets	(1,362,324)	(1,351,127)
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	0	0
Intercompany payable	(361,364)	(332,957)
Accrued expenses	0	0
Taxes Payable, Current	(2,964)	(2,964)
Total current liabilities	(364,328)	(335,921)
Liabilities, Noncurrent [Abstract]
Long-term debt, less current portion	0	0
Other non-current obligations	0	0
Deferred income taxes	0	0
Long-term intercompany payable	(107,308)	(110,016)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(890,688)	(905,190)
Total liabilities and stockholders’ equity	$ (1,362,324)	$ (1,351,127)
10.5% Senior Notes, net (1)
Condensed Consolidating Balance Sheet
Interest rate of senior notes (as a percent)	10.50%
10.5% Senior Notes, net (1) | Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheet
Percentage of capital stock	51.00%