Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Operating activities:
Net earnings (loss)	$ (68,512)	$ 56,922	$ 550,226	$ 54,467
Adjustments to reconcile net earnings (loss) to net cash provided by operating activities:
Depreciation and amortization	21,560	22,596	43,771	46,773
Impairment of long-lived assets	3,815	0	13,739	40,601
Provision for (benefit from) deferred income taxes	(31,776)	6,843	39,255	3,345
Bad debt (income) expense	(159)	143	(65)	311
Equity in net income of unconsolidated affiliates, net of distributions	4,608	(19,879)	(2,149)	(14,797)
Net (gain) loss on sale of assets	7,271	(17)	7,673	601
Stock-based compensation	4,854	3,280	9,710	7,275
(Gains) loss on investment in Nikola	143,780	0	(652,362)	0
Charitable contribution of Nikola shares			20,653
Loss on extinguishment of debt	0	0	0	4,034
Changes in assets and liabilities:
Receivables	3,580	(5,456)	(78,614)	9,525
Inventories	4,623	43,601	90,245	87,883
Accounts payable	48,176	(20,743)	95,330	(57,977)
Accrued compensation and employee benefits	13,960	9,619	37,812	(13,596)
Income taxes payable	(44,623)	(118)	39,041	(1,132)
Other operating items, net	(3,729)	7,369	10,551	1,216
Net cash provided by operating activities	107,428	104,160	224,816	168,529
Investing activities:
Investment in property, plant and equipment	(16,073)	(28,381)	(48,944)	(50,555)
Proceeds from sale of Nikola shares			487,859
Acquisitions, net of cash acquired	(75)	(29,283)	(75)	(29,283)
Proceeds from sale of assets	21,580	23	21,580	9,199
Net cash provided (used) by investing activities	5,432	(57,641)	460,420	(70,639)
Financing activities:
Proceeds from long-term debt, net of issuance costs		(134)		101,464
Principal payments on long-term obligations and debt redemption costs	(96)	(490)	(193)	(154,467)
Proceeds from issuance of common shares, net of tax withholdings	2,294	(3,811)	1,144	(7,024)
Payments to noncontrolling interests		(1,453)	(560)	(1,453)
Repurchase of common shares	(38,563)		(92,883)	(29,599)
Dividends paid	(13,433)	(13,954)	(26,812)	(26,914)
Net cash used by financing activities	(49,798)	(19,842)	(119,304)	(117,993)
Increase (decrease) in cash and cash equivalents	63,062	26,677	565,932	(20,103)
Cash and cash equivalents at beginning of period	650,068	45,583	147,198	92,363
Cash and cash equivalents at end of period	$ 713,130	$ 72,260	$ 713,130	$ 72,260