Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended	12 Months Ended
	May 23, 2018 USD ($)	Jan. 01, 2017 USD ($)	May 31, 2018 USD ($) Entity Facility JointVenture	May 31, 2018 USD ($) Entity Facility Segment JointVenture Customer	May 31, 2017 USD ($)	May 31, 2016 USD ($)
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company	25.00%
Tax amount related to purchase of noncontrolling interest and its carrying value					$ 539,000
Derivative financial instruments, credit losses				$ 0
Number of manufacturing facilities operated | Facility			36	36
Number of reportable segments | Segment				3
Number of joint ventures | JointVenture			9	9
Returns and allowances increase (decrease)				$ (538,000)
Returns and Allowances			$ 6,199,000	6,199,000
Allowance for doubtful accounts increase (decrease)				(2,812,000)
Receivables, allowances			632,000	632,000	3,444,000
Depreciation Expenses				83,680,000	73,268,000	$ 68,886,000
Advertising Expenses				15,236,000	$ 14,822,000	$ 13,970,000
Reclassification of stranded tax effects			1,701,000	(1,701,000)
Lessee, operating lease, liability, future minimum lease payments			$ 43,400,000	$ 43,400,000
Building and Improvements | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life				10 years
Building and Improvements | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life				40 years
Machinery and Equipment | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life				3 years
Machinery and Equipment | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life				20 years
Largest Customer
Significant Accounting Policies [Line Items]
Number of customers | Customer				10
Sales Revenue, Net | Product Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage				37.00%	43.00%	42.00%
Sales Revenue, Net | Foreign Operations
Significant Accounting Policies [Line Items]
Concentration risk percentage				9.00%	7.00%	6.00%
Sales Revenue, Net | Customer Concentration Risk | Largest Customer
Significant Accounting Policies [Line Items]
Concentration risk percentage				8.00%
Sales Revenue, Net | Customer Concentration Risk | Ten Largest Customers
Significant Accounting Policies [Line Items]
Concentration risk percentage				30.00%
Net Earnings | Foreign Operations
Significant Accounting Policies [Line Items]
Concentration risk percentage				6.00%	4.00%	8.00%
Net Assets, Geographic Area | Foreign Operations
Significant Accounting Policies [Line Items]
Concentration risk percentage				14.00%	11.00%
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk [Member]
Significant Accounting Policies [Line Items]
Concentration risk percentage				9.00%
Joint Venture Transactions
Significant Accounting Policies [Line Items]
Number of joint ventures | Entity			3	3
Number of manufacturing facilities operated | Facility			49	49
Spartan | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company			52.00%	52.00%
TWB | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company			55.00%	55.00%
Worthington Specialty Processing | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company			51.00%	51.00%
DHybrid Systems LLC
Significant Accounting Policies [Line Items]
Purchase of noncontrolling interest and its carrying value					$ (2,888,000)
Tax amount related to purchase of noncontrolling interest and its carrying value		$ 539,000
DHybrid Systems LLC | Additional Paid-in Capital
Significant Accounting Policies [Line Items]
Purchase of noncontrolling interest and its carrying value					$ (935,000)
Worthington Aritas
Significant Accounting Policies [Line Items]
Purchase of noncontrolling interest and its carrying value				$ (1,913,000)
Worthington Aritas | Additional Paid-in Capital
Significant Accounting Policies [Line Items]
Purchase of noncontrolling interest and its carrying value	$ 924,000			$ 924,000