Changes in Equity - Summary of Changes in Equity by Component and in Total (Detail) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
	Nov. 30, 2021	Nov. 30, 2021	Aug. 31, 2021	Nov. 30, 2020	Aug. 31, 2020	Nov. 30, 2021	Nov. 30, 2020
Balance		$ 1,606,632	$ 1,551,695	$ 1,529,900	$ 966,433	$ 1,551,695	$ 966,433
Net earnings (loss)		113,185	141,475	(68,512)	618,738	254,660	550,226
Other comprehensive income (loss)	$ (57,858)	(57,858)	(4,274)	14,163	11,242	(62,132)	25,406
Common shares issued, net of withholding tax		(2,694)	(4,091)	2,294	(1,150)
Common shares in non-qualified plans		257	89	292	90
Stock-based compensation		3,304	6,324	3,499	3,022
Purchases and retirement of common shares		(12,702)	(60,885)	(38,563)	(54,320)
Contribution to Samuel joint venture				925
Cash dividends declared		(14,154)	(14,504)	(13,527)	(13,595)
Dividends to noncontrolling interests		(2,879)	(9,197)		(560)
Balance	1,633,091	1,633,091	1,606,632	1,430,471	1,529,900	1,633,091	1,430,471
Additional Paid-in Capital
Balance		279,635	282,790	278,202	283,776	282,790	283,776
Net earnings (loss)		0	0	0	0
Other comprehensive income (loss)		0	0	0	0
Common shares issued, net of withholding tax		(2,694)	(4,091)	2,294	(1,150)
Common shares in non-qualified plans		257	89	292	90
Stock-based compensation		3,304	6,324	3,499	3,022
Purchases and retirement of common shares		(1,297)	(5,477)	(4,486)	(7,536)
Contribution to Samuel joint venture				0
Cash dividends declared		0	0	0	0
Dividends to noncontrolling interests		0	0		0
Balance	279,205	279,205	279,635	279,801	278,202	279,205	279,801
Accumulated Other Comprehensive Income (Loss), Net of Tax
Balance		41,113	45,387	(23,975)	(35,217)	45,387	(35,217)
Net earnings (loss)		0	0	0	0
Other comprehensive income (loss)		(57,858)	(4,274)	14,163	11,242
Common shares issued, net of withholding tax		0	0	0	0
Common shares in non-qualified plans		0	0	0	0
Stock-based compensation		0	0	0	0
Purchases and retirement of common shares		0	0	0	0
Contribution to Samuel joint venture				0
Cash dividends declared		0	0	0	0
Dividends to noncontrolling interests		0	0		0
Balance	(16,745)	(16,745)	41,113	(9,812)	(23,975)	(16,745)	(9,812)
Retained Earnings
Balance		1,132,595	1,070,016	1,128,558	572,262	1,070,016	572,262
Net earnings (loss)		110,301	132,491	(74,044)	616,675
Other comprehensive income (loss)		0	0	0	0
Common shares issued, net of withholding tax		0	0	0	0
Common shares in non-qualified plans		0	0	0	0
Stock-based compensation		0	0	0	0
Purchases and retirement of common shares		(11,405)	(55,408)	(34,077)	(46,784)
Contribution to Samuel joint venture				0
Cash dividends declared		(14,154)	(14,504)	(13,527)	(13,595)
Dividends to noncontrolling interests		0	0		0
Balance	1,217,337	1,217,337	1,132,595	1,006,910	1,128,558	1,217,337	1,006,910
Parent
Balance		1,453,343	1,398,193	1,382,785	820,821	1,398,193	820,821
Net earnings (loss)		110,301	132,491	(74,044)	616,675
Other comprehensive income (loss)		(57,858)	(4,274)	14,163	11,242
Common shares issued, net of withholding tax		(2,694)	(4,091)	2,294	(1,150)
Common shares in non-qualified plans		257	89	292	90
Stock-based compensation		3,304	6,324	3,499	3,022
Purchases and retirement of common shares		(12,702)	(60,885)	(38,563)	(54,320)
Contribution to Samuel joint venture				0
Cash dividends declared		(14,154)	(14,504)	(13,527)	(13,595)
Dividends to noncontrolling interests		0	0		0
Balance	1,479,797	1,479,797	1,453,343	1,276,899	1,382,785	1,479,797	1,276,899
Noncontrolling Interest
Balance		153,289	153,502	147,115	145,612	153,502	145,612
Net earnings (loss)		2,884	8,984	5,532	2,063
Other comprehensive income (loss)		0	0	0	0
Common shares issued, net of withholding tax		0	0	0	0
Common shares in non-qualified plans		0	0	0	0
Stock-based compensation		0	0	0	0
Purchases and retirement of common shares		0	0	0	0
Contribution to Samuel joint venture				925
Cash dividends declared		0	0	0	0
Dividends to noncontrolling interests		(2,879)	(9,197)		(560)
Balance	$ 153,294	$ 153,294	$ 153,289	$ 153,572	$ 147,115	$ 153,294	$ 153,572