Contingent Liabilities and Commitments - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended			21 Months Ended
	May. 31, 2014	May. 31, 2015	May. 31, 2013	May. 31, 2012	May. 31, 2015
Commitment And Contingencies [Line Items]
Exposure related to legal matter		$ 2,000,000			$ 2,000,000
Loss related to litigation settlement		2,000,000
Insurance proceeds for replacement value of damaged property and equipment		1,248			13,414,000
Book value of assets		243,000
Gain on damaged property and equipment		1,005,000
Coleman Cylinders | Minimum
Commitment And Contingencies [Line Items]
Annual royalty payments in exchange for rights		2,000,000			2,000,000
Pressure Cylinders Voluntary Product Recall
Commitment And Contingencies [Line Items]
Inventory recall expenses			$ 2,571,000	$ 9,671,000
Gain on legal dispute settlement	$ 3,951,000
Business interruption
Commitment And Contingencies [Line Items]
Insurance proceeds for replacement value of damaged property and equipment					5,521,000
Other expenses
Commitment And Contingencies [Line Items]
Insurance proceeds for replacement value of damaged property and equipment					$ 1,001,000
Manufacturing Expense | Business interruption
Commitment And Contingencies [Line Items]
Insurance proceeds for replacement value of damaged property and equipment		2,653,000
Manufacturing Expense | Other expenses
Commitment And Contingencies [Line Items]
Insurance proceeds for replacement value of damaged property and equipment		$ 256,000