Consolidated Statements of Equity - USD ($) $ in Thousands	Total	DHybrid Systems LLC	Worthington Aritas	WEI	Common Shares	Additional Paid-in Capital	Additional Paid-in Capital DHybrid Systems LLC	Additional Paid-in Capital Worthington Aritas	Accumulated Other Comprehensive Loss, Net of Tax	Retained Earnings	Total	Total DHybrid Systems LLC	Total Worthington Aritas	Noncontrolling Interests	Noncontrolling Interests DHybrid Systems LLC	Noncontrolling Interests Worthington Aritas	Noncontrolling Interests WEI
Balance at May. 31, 2015	$ 840,049					$ 289,078			$ (50,704)	$ 510,738	$ 749,112			$ 90,937
Balance (in shares) at May. 31, 2015					64,141,478
Net earnings	157,628									143,715	143,715			13,913
Other comprehensive income (loss)	24,866								22,139		22,139			2,727
Acquisition	28,004													28,004
Common shares issued, net of withholding tax	8,707					8,707					8,707
Common shares issued, net of withholding tax (in shares)					892,190
Theoretical common shares in NQ plans	960					960					960
Stock-based compensation	16,534					16,534					16,534
Purchases and retirement of common shares	$ (99,847)					(16,295)				(83,552)	(99,847)
Purchases and retirement of common shares (in shares)	(3,500,000)				(3,500,000)
Dividends to noncontrolling interests	$ (9,106)													(9,106)
Cash dividends declared ($0.76 per share in 2016, $0.80 per share in 2017 and $0.84 per share in 2018)	(47,949)									(47,949)	(47,949)
Balance at May. 31, 2016	919,846					298,984			(28,565)	522,952	793,371			126,475
Balance (in shares) at May. 31, 2016					61,533,668
Net earnings	217,937									204,515	204,515			13,422
Other comprehensive income (loss)	762								790		790			(28)
Common shares issued, net of withholding tax	(9,075)					(9,075)					(9,075)
Common shares issued, net of withholding tax (in shares)					1,268,788
Theoretical common shares in NQ plans	1,259					1,259					1,259
Stock-based compensation	13,158					13,158					13,158
Purchase of noncontrolling interest		$ (2,888)					$ (935)					$ (935)			$ (1,953)
Dividends to noncontrolling interests	(15,622)													(15,622)
Cash dividends declared ($0.76 per share in 2016, $0.80 per share in 2017 and $0.84 per share in 2018)	(51,448)									(51,448)	(51,448)
Balance at May. 31, 2017	1,073,929					303,391			(27,775)	676,019	951,635			122,294
Balance (in shares) at May. 31, 2017					62,802,456
Net earnings	200,850									194,794	194,794			6,056
Other comprehensive income (loss)	15,269								14,896		14,896			373
Common shares issued, net of withholding tax	(2,120)					(2,120)					(2,120)
Common shares issued, net of withholding tax (in shares)					449,465
Theoretical common shares in NQ plans	1,218					1,218					1,218
Stock-based compensation	13,460					13,460					13,460
Purchase of noncontrolling interest			$ (1,913)					$ 924					$ 924			$ (2,837)
Sale of controlling interest				$ (365)													$ (365)
Reclassification of stranded tax effects	(1,701)								(1,701)	1,701
Purchases and retirement of common shares	$ (204,267)					(21,281)				(182,986)	(204,267)
Purchases and retirement of common shares (in shares)	(4,375,000)				(4,375,000)
Dividends to noncontrolling interests	$ (7,915)													(7,915)
Cash dividends declared ($0.76 per share in 2016, $0.80 per share in 2017 and $0.84 per share in 2018)	(51,771)									(51,771)	(51,771)
Balance at May. 31, 2018	$ 1,036,375					$ 295,592			$ (14,580)	$ 637,757	$ 918,769			$ 117,606
Balance (in shares) at May. 31, 2018					58,876,921