Schedule of Acquisition of Identifiable Intangible Assets (Detail) - AMTROL $ in Thousands	6 Months Ended
	Nov. 30, 2017 USD ($)
Business Acquisition [Line Items]
Total acquired identifiable intangible assets	$ 166,000
Trade Names
Business Acquisition [Line Items]
Acquired indefinite lived intangible assets	62,200
Customer relationships
Business Acquisition [Line Items]
Acquired finite lived intangible assets	90,800
Technology
Business Acquisition [Line Items]
Acquired finite lived intangible assets	$ 13,000
Minimum | Customer relationships
Business Acquisition [Line Items]
Useful Life (Years)	14 years
Minimum | Technology
Business Acquisition [Line Items]
Useful Life (Years)	15 years
Maximum | Customer relationships
Business Acquisition [Line Items]
Useful Life (Years)	17 years
Maximum | Technology
Business Acquisition [Line Items]
Useful Life (Years)	16 years