Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Worthington Samuel Coil Processing Llc	Common Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Loss, Net of Tax	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Total	Total Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests	Noncontrolling Interests Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests Worthington Samuel Coil Processing Llc
Balance at May. 31, 2018	$ 1,036,375				$ 295,592	$ (14,580)	$ 637,757		$ 918,769		$ 117,606
Balance (ASC 606) at May. 31, 2018		$ 1,744						$ 1,174		$ 1,174		$ 570
Balance (in shares) at May. 31, 2018				58,876,921
Net earnings	163,273						153,455		153,455		9,818
Other comprehensive income (loss)	(29,004)					(28,884)			(28,884)		(120)
Common shares issued, net of withholding tax	(6,371)				(6,371)				(6,371)
Common shares issued, net of withholding tax (in shares)				690,604
Theoretical common shares in NQ plans	680				680				680
Stock-based compensation	13,927				13,927				13,927
Repurchases and retirement of common shares	$ (168,113)				(20,651)		(147,462)		(168,113)
Repurchases and retirement of common shares (in shares)	4,100,000			(4,100,000)
Dividends to noncontrolling interests	$ (10,726)										(10,726)
Cash dividends declared ($0.80 per share in 2017, $0.84 per share in 2018 and $0.92 per share in 2019)	(53,391)						(53,391)		(53,391)
Balance at May. 31, 2019	948,394				283,177	(43,464)	591,533		831,246		117,148
Balance (in shares) at May. 31, 2019				55,467,525
Net earnings	84,444						78,796		78,796		5,648
Other comprehensive income (loss)	8,247					8,247			8,247
Common shares issued, net of withholding tax	(6,513)				(6,513)				(6,513)
Common shares issued, net of withholding tax (in shares)				448,960
Theoretical common shares in NQ plans	547				547				547
Stock-based compensation	13,191				13,191				13,191
Consolidation of Worthington Samuel Coil Processing LLC			$ 24,269										$ 24,269
Repurchases and retirement of common shares	$ (50,972)				(6,626)		(44,346)		(50,972)
Repurchases and retirement of common shares (in shares)	1,300,000			(1,300,000)
Dividends to noncontrolling interests	$ (1,453)										(1,453)
Cash dividends declared ($0.80 per share in 2017, $0.84 per share in 2018 and $0.92 per share in 2019)	(53,721)						(53,721)		(53,721)
Balance at May. 31, 2020	966,433				283,776	(35,217)	572,262		820,821		145,612
Balance (in shares) at May. 31, 2020				54,616,485
Net earnings	741,450						723,795		723,795		17,655
Other comprehensive income (loss)	80,604					80,604			80,604
Common shares issued, net of withholding tax	6,581				6,581				6,581
Common shares issued, net of withholding tax (in shares)				732,326
Theoretical common shares in NQ plans	556				556				556
Stock-based compensation	13,005				13,005				13,005
Partner contribution to Worthington Samuel Coil Processing, LLC			$ 925										$ 925
Repurchases and retirement of common shares	$ (192,054)				(21,128)		(170,926)		(192,054)
Repurchases and retirement of common shares (in shares)	4,018,464			(4,018,464)
Dividends to noncontrolling interests	$ (10,690)										(10,690)
Cash dividends declared ($0.80 per share in 2017, $0.84 per share in 2018 and $0.92 per share in 2019)	(55,115)						(55,115)		(55,115)
Balance at May. 31, 2021	$ 1,551,695				$ 282,790	$ 45,387	$ 1,070,016		$ 1,398,193		$ 153,502
Balance (in shares) at May. 31, 2021				51,330,347