Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		May 31, 2018	May 31, 2017	May 31, 2016
Income Statement [Abstract]
Net sales		$ 3,581,620	$ 3,014,108	$ 2,819,714
Cost of goods sold		3,018,763	2,478,203	2,367,121
Gross margin		562,857	535,905	452,593
Selling, general and administrative expense		367,460	316,373	297,402
Impairment of goodwill and long-lived assets		61,208		25,962
Restructuring and other expense (income), net		(7,421)	6,411	7,177
Operating income		141,610	213,121	122,052
Other income (expense):
Miscellaneous income, net		2,996	3,764	11,267
Interest expense		(38,675)	(29,796)	(31,670)
Equity in net income of unconsolidated affiliates		103,139	110,038	114,966
Earnings before income taxes		209,070	297,127	216,615
Income tax expense		8,220	79,190	58,987
Net earnings		200,850	217,937	157,628
Net earnings attributable to noncontrolling interests	[1]	6,056	13,422	13,913
Net earnings attributable to controlling interest		$ 194,794	$ 204,515	$ 143,715
Basic
Average common shares outstanding		60,923	62,443	62,469
Earnings per share attributable to controlling interest		$ 3.20	$ 3.28	$ 2.30
Diluted
Average common shares outstanding		63,042	64,874	64,755
Earnings per share attributable to controlling interest		$ 3.09	$ 3.15	$ 2.22

[1] Net earnings attributable to noncontrolling interests are not taxable to Worthington.