Impairment of Long-Lived Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2018	May 31, 2018
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets	$ 2,381
Worthington Aritas
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets	2,381	$ 42,422
Fair Value, Measurements, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets	7,000	30,000
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets	7,000	30,000
Fair Value, Measurements, Nonrecurring | Worthington Aritas
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets	7,000	$ 9,000
Fair Value, Measurements, Nonrecurring | Worthington Aritas | Significant Other Observable Inputs (Level 2)
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets	$ 7,000