Acquisitions - Schedule of Consideration Transferred and the Fair Value Assigned to the Assets Acquired And Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Feb. 29, 2020	May 31, 2019
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Goodwill		$ 321,128	$ 334,607
Worthington Samuel Coil Processing LLC
Consideration Transferred:
Assets contributed (37% of Heidtman net assets)	$ 11,122
Capital contribution	315
Fair value of previously held equity interest in Samuel	10,948
Total consideration	22,385
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Cash	694
Accounts receivable	1,778
Inventories	108
Prepaid expenses	1,535
Total acquired identifiable intangible assets	10,100
Property, plant and equipment	19,459
Total identifiable assets	33,674
Accounts payable	(766)
Accrued liabilities	(1,148)
Net identifiable assets	31,760
Goodwill	3,772
Net assets	35,532
Noncontrolling interest	(13,147)
Total consideration	$ 22,385