Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Statement of Cash Flows [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 230,463	$ 207,918	$ 286,846
Restricted Cash	8,064	0	0
Operating activities:
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	41,381	206,587	254,127
Adjustments to reconcile net income to net cash provided by (used in) operating activities, net of effect of acquisitions:
Depreciation and amortization	62,819	52,628	50,661
Stock-based compensation expense	(76)	3,304	(76,192)
Business combination bargain purchase, gain recognized	0	0	(130,880)
Non-cash debt and financing costs	4,173	1,872	2,467
Loss on early extinguishment of debt	0	15,946	486
Net (gain) loss on sales and disposals of assets	800	(1,000)	(1,200)
Stock-based compensation expense	12,084	12,866	7,657
Pension and other post-retirement benefits	6,816	4,938	4,717
Change in deferred income taxes	24,329	(49,757)	564
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down	19,710	1,660	(992)
Rent receivable	0	0	2,645
Other, net	70	(285)	(680)
Changes in assets and liabilities, net of the effect of acquisitions:
Accounts receivable	5,727	(8,910)	30,217
Inventories	(3,394)	(42,806)	(13,827)
Prepaid expenses and other assets	3,962	(4,381)	4,330
Accounts payable	(41,442)	7,650	(16,053)
Accrued income taxes	(236)	1,046	1,317
Other operating liabilities	22,933	(70,627)	197
Net cash provided by (used in) operating activities	158,856	131,731	120,761
Investing activities:
Capital expenditures	(146,331)	(146,056)	(65,004)
Contributions to equity method investments	(5,000)	(4,000)	(3,000)
Proceeds from Equity Method Investment, Distribution	433	776	2,745
Acquisitions, net of cash received	1,294	0	(163,985)
Proceeds from sale of discontinued operations			3,400
Proceeds from sale of assets	0	2,268	3,638
Payments for (Proceeds from) Hedge, Investing Activities	8,879	0	0
Net cash provided by (used in) investing activities	(143,313)	(147,012)	102,364
Financing activities:
Payments of revolving line of credit	0	0	(33,881)
Proceeds from issuance of debt	0	284,924	334,978
Payment of long-term debt	(26,862)	(344,461)	(365,938)
Proceeds from Issuance of Unsecured Debt	43,095	13,412	0
Proceeds from Hedge, Financing Activities	6,476	0	0
Payment for Debt Extinguishment or Debt Prepayment Cost	0	(3,234)	0
Debt issuance costs	0	(2,021)	(5,002)
Cash flow hedge settlement	(6,972)	0	0
Finance Lease, Principal Payments	(1,447)	0	0
Proceeds from exercise of stock options	327	485	5,207
Proceeds from exercise of stock warrants	0	0	8,838
Payments of Ordinary Dividends, Common Stock	(5,803)	(5,762)	0
Net cash provided by (used in) financing activities	8,814	(56,657)	(55,798)
Net increase (decrease) in cash, cash equivalents, and restricted cash	24,357	(71,938)	167,327
Effect of foreign currency fluctuations on cash	(1,812)	(6,990)	9,745
Cash, cash equivalents, and restricted cash at end of fiscal year	222,399	207,918	286,846
Supplemental Cash Flow Statement Information:
Interest paid, net of capitalized interest	6,675	18,701	44,905
Income taxes paid	9,668	10,863	7,120
Increase Decrease in Capital Expenditures Incurred But Not Yet Paid	$ 6,160	$ 18,029	$ 7,980