Restructuring and Other Expense - Additional Information (Detail) - USD ($)		9 Months Ended
	Jan. 28, 2016	Feb. 29, 2016
Restructuring Cost and Reserve [Line Items]
Gain on asset disposal		$ 6,647,000
Joint Venture Transactions | Worthington Nitin Cylinders
Restructuring Cost and Reserve [Line Items]
Gain from sale of interest	$ 1,928,000
Closure of Precision Specialty Metals, Inc
Restructuring Cost and Reserve [Line Items]
Severance costs		1,122,000
Facility exit costs		5,184,000
Pending Closure, Pennsylvania Steel Packaging Facility
Restructuring Cost and Reserve [Line Items]
Severance costs		556,000
Facility Closing, Baltimore Steel Processing Facility
Restructuring Cost and Reserve [Line Items]
Facility exit costs		134,000
Gain on asset disposal		2,978,000
Severance expense credit		240,000
Legacy Metal Framing
Restructuring Cost and Reserve [Line Items]
Gain on asset disposal		1,484,000
Other Non-significant Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Severance costs		260,000
Facility costs		370,000
Engineered Cabs | Facility Closing | Florence, South Carolina
Restructuring Cost and Reserve [Line Items]
Severance costs		2,171,000
Facility exit costs		888,000
Pressure Cylinders
Restructuring Cost and Reserve [Line Items]
Severance costs		$ 1,496,000