Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Net income (loss)	$ 252,096	$ (4,925)
Operating Activities:
Depreciation and amortization	36,694	27,971
Equity (income) loss from equity-method investments	(75,879)	(271)
Acquisition gains	137,183	0
Non-cash debt and financing costs	1,820	561
(Gain) loss on early extinguishment of debt	486	0
Stock-based compensation expense	4,837	3,471
Provision for Doubtful Accounts	162	64
Change in value of TOKIN option	0	3,500
(Gain) loss on write down and disposal of long-lived assets	(922)	6,500
Pension and other post-retirement benefits	3,897	2,096
Change in deferred income taxes	(3,792)	819
Change in operating assets	26,296	21,459
Change in operating liabilities	(26,316)	(18,918)
Other	499	(183)
Net cash provided by (used in) operating activities	82,695	42,144
Investing activities:
Capital expenditures	(30,925)	(15,011)
Acquisitions, net of cash received	167,129	0
Proceeds from Sale of Productive Assets	1,227	0
Net cash provided by (used in) investing activities	140,162	(15,011)
Financing activities:
Payments of revolving line of credit	(33,881)	0
Proceeds from Issuance of Secured Debt	334,978	0
Payments of Debt Issuance Costs	(5,002)	0
Payments on long-term obligations	(361,625)	(2,428)
Proceeds from exercise of stock options	5,122	69
Purchase of treasury stock	0	(1,052)
Proceeds from Equity Method Investment, Dividends or Distributions	2,731
Proceeds from Warrant Exercises	8,838	0
Net cash provided by (used in) financing activities	(51,570)	(3,411)
Net increase (decrease) in cash and cash equivalents	171,287	23,722
Effect of foreign currency fluctuations on cash	3,105	(1,370)
Cash and cash equivalents at beginning of fiscal period	109,774	65,004
Cash and cash equivalents at end of fiscal period	$ 284,166	$ 87,356