Acquisitions - Schedule of Consideration Transferred and the Preliminary Fair Value Assigned to Assets Acquired And Liabilities Assumed (Detail) - USD ($) $ in Thousands	Jun. 02, 2017	May 31, 2020	May 31, 2019	May 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 321,434	$ 334,607	$ 345,183
AMTROL
Business Acquisition [Line Items]
Cash	$ 6,893
Accounts receivable	40,212
Inventories	37,249
Prepaid expenses	981
Other assets	2,550
Intangible assets	166,000			$ 166,000
Property, plant and equipment	52,870
Total identifiable assets	306,755
Accounts payable	25,945
Accrued liabilities	21,016
Long-term debt including current maturities	2,287
Other accrued items	5,494
Deferred income taxes, net	63,529
Net identifiable assets	188,484
Goodwill	103,437
Purchase price	291,921
AMTROL | Preliminary Valuation
Business Acquisition [Line Items]
Cash	6,893
Accounts receivable	40,212
Inventories	37,249
Prepaid expenses	981
Other assets	2,550
Intangible assets	166,000
Property, plant and equipment	52,870
Total identifiable assets	306,755
Accounts payable	25,945
Accrued liabilities	21,016
Long-term debt including current maturities	2,287
Other accrued items	3,993
Deferred income taxes, net	64,495
Net identifiable assets	189,019
Goodwill	102,902
Purchase price	291,921
AMTROL | Measurement Period Adjustments
Business Acquisition [Line Items]
Other accrued items	1,501
Deferred income taxes, net	(966)
Net identifiable assets	(535)
Goodwill	$ 535