Condensed Consolidating Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2010	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities		$ (22,827)	$ 80,730	$ 113,968
Investing activities:
Capital expenditures		(46,174)	(49,314)	(34,989)
Investment in NEC TOKIN		(50,917)
Change in restricted cash		(15,284)
Acquisitions, net of cash received			(42,613)
Proceeds from sales of assets	3,400	398	74	5,425
Net cash used in investing activities		(111,977)	(91,853)	(29,564)
Financing activities:
Proceeds from issuance of debt		39,825	116,050	227,525
Deferred acquisition payments		(16,900)
Payment of long-term debt		(1,909)	(40,581)	(230,413)
Net (payments) borrowings under other credit facilities			(3,154)	(2,479)
Debt issuance costs		(275)	(2,313)	(7,853)
Debt extinguishment costs				(207)
Proceeds from exercise of stock options		111	290	89
Net cash provided by (used in) financing activities		20,852	70,292	(13,338)
Net (decrease) increase in cash and cash equivalents		(113,952)	59,169	71,066
Effect of foreign currency fluctuations on cash		(591)	(699)	1,786
Cash and cash equivalents at beginning of fiscal year		210,521	152,051	79,199
Cash and cash equivalents at end of fiscal year		95,978	210,521	152,051
Parent
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities		(14,492)	(71,930)	(13,967)
Financing activities:
Proceeds from issuance of debt		39,825	116,050	226,976
Deferred acquisition payments		(15,900)
Payment of long-term debt			(40,581)	(210,604)
Debt issuance costs		(275)	(2,313)	(7,472)
Debt extinguishment costs				(207)
Proceeds from exercise of stock options		111	290	89
Net cash provided by (used in) financing activities		23,761	73,446	8,782
Net (decrease) increase in cash and cash equivalents		9,269	1,516	(5,185)
Cash and cash equivalents at beginning of fiscal year		7,933	6,417	11,602
Cash and cash equivalents at end of fiscal year		17,202	7,933	6,417
Guarantor Subsidiaries
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities		(43,099)	124,591	90,445
Investing activities:
Capital expenditures		(15,841)	(23,099)	(15,842)
Investment in NEC TOKIN		(50,917)
Change in restricted cash		(15,284)
Acquisitions, net of cash received			(42,613)
Proceeds from sales of assets				5,425
Net cash used in investing activities		(82,042)	(65,712)	(10,417)
Financing activities:
Deferred acquisition payments		(1,000)
Payment of long-term debt		(8)		(15,000)
Debt issuance costs				(381)
Net cash provided by (used in) financing activities		(1,008)		(15,381)
Net (decrease) increase in cash and cash equivalents		(126,149)	58,879	64,647
Effect of foreign currency fluctuations on cash				(28)
Cash and cash equivalents at beginning of fiscal year		178,205	119,326	54,707
Cash and cash equivalents at end of fiscal year		52,056	178,205	119,326
Non-Guarantor Subsidiaries
Sources (uses) of cash and cash equivalents
Net cash provided by (used in) operating activities		34,764	28,069	37,490
Investing activities:
Capital expenditures		(30,333)	(26,215)	(19,147)
Proceeds from sales of assets		398	74
Net cash used in investing activities		(29,935)	(26,141)	(19,147)
Financing activities:
Proceeds from issuance of debt				549
Payment of long-term debt		(1,901)		(4,809)
Net (payments) borrowings under other credit facilities			(3,154)	(2,479)
Net cash provided by (used in) financing activities		(1,901)	(3,154)	(6,739)
Net (decrease) increase in cash and cash equivalents		2,928	(1,226)	11,604
Effect of foreign currency fluctuations on cash		(591)	(699)	1,814
Cash and cash equivalents at beginning of fiscal year		24,383	26,308	12,890
Cash and cash equivalents at end of fiscal year		$ 26,720	$ 24,383	$ 26,308