Fair Value - Assets Measured at Fair Value on Non-Recurring Basis (Parenthetical) (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Aug. 31, 2018	May 31, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets			$ 8,289,000	$ 2,381,000	$ 8,289,000
Oil And Gas Equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets		$ 10,497,000
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset measured at fair value on non-recurring basis		30,000,000		$ 0
Fair Value, Measurements, Nonrecurring | Oil And Gas Equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset measured at fair value on non-recurring basis		21,000,000
Worthington Aritas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets	$ 2,381,000	42,422,000
Worthington Aritas | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset measured at fair value on non-recurring basis	$ 7,000,000	$ 9,000,000