Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2019	Jun. 30, 2018
Statement of Cash Flows [Abstract]
Restricted Cash		$ 2,575	$ 0
Net income (loss)	[1],[2]	40,340	35,220
Operating Activities:
Depreciation and amortization	[3]	14,259	13,097
Equity (income) loss from equity method investments		250	69
Non-cash debt and financing costs		894	229
Stock-based compensation expense		2,725	4,060
Rent receivable		0	3,077
(Gain) loss on write down and disposal of long-lived assets		960	511
Pension and other post-retirement benefits		1,341	1,274
Change in deferred income taxes	[3]	14,895	951
Change in operating assets	[3]	(15,626)	(24,520)
Change in operating liabilities	[3]	(26,268)	(49,330)
Other		(57)	(488)
Net cash provided by (used in) operating activities	[3]	33,713	(15,850)
Investing activities:
Capital expenditures		(37,112)	(16,021)
Payments to Acquire Interest in Joint Venture		(2,000)	0
Net cash used in investing activities		(38,679)	(15,249)
Financing activities:
Proceeds from Issuance of Secured Debt		12,541	0
Proceeds from Hedge, Financing Activities		6,476	0
Finance Lease, Principal Payments		(367)	0
Payments of long-term debt		0	(4,313)
Proceeds from exercise of stock options		30	275
Payments of Ordinary Dividends, Common Stock		(2,900)	0
Proceeds from Equity Method Investment, Distribution		433	772
Net cash provided by (used in) financing activities		15,780	(4,038)
Net increase (decrease) in cash, cash equivalents and restricted cash		10,814	(35,137)
Effect of foreign currency fluctuations on cash, cash equivalents and restricted cash	[3]	1,150	(7,061)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		219,882	244,648
Cash, cash equivalents, and restricted cash, at end of fiscal period		$ 217,307	$ 244,648

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