Acquisitions - Additional Information (Detail) CAD in Millions				6 Months Ended
	Jun. 15, 2017 USD ($)	Feb. 02, 2017 USD ($) CAD / $	Feb. 02, 2017 CAD	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)	Feb. 02, 2017 CAD CAD / $
Business Acquisition [Line Items]
Goodwill				$ 230,214,000		$ 224,391,000
Flowchem Holdings LLC
Business Acquisition [Line Items]
Acquisition date				Jun. 15, 2017
Cash consideration	$ 495,000,000
Cash acquired	$ 11,400,000
Line of credit facility, maximum borrowing capacity				$ 550,000,000
Line of credit facility, term				7 years
Acquisition-related costs incurred				$ 500,000
Fair value of accounts receivable acquired				11,280,000
Goodwill				204,717,000	$ 204,717,000	$ 199,346,000
Acquisition, measurement period adjustment				3,132,000
Flowchem Holdings LLC | Measurement Period Adjustment
Business Acquisition [Line Items]
Goodwill					$ 5,371,000
Flowchem Holdings LLC | Performance Materials
Business Acquisition [Line Items]
Goodwill				204,700,000
Goodwill expected to be tax deductible				$ 155,900,000
Sealweld Corporation
Business Acquisition [Line Items]
Acquisition date				Feb. 01, 2017
Cash consideration		$ 17,200,000	CAD 22.3
Acquisition-related costs incurred				$ 56,000
Fair value of accounts receivable acquired				2,937,000
Goodwill		$ 2,700,000		2,771,000
Exchange rate | CAD / $		0.77					0.77
Estimated working capital		$ 4,200,000					CAD 5.5
Acquisition, measurement period adjustment				1,272,000
Sealweld Corporation | Measurement Period Adjustment
Business Acquisition [Line Items]
Goodwill				2,800,000
Acquisition, measurement period adjustment				100,000
Sealweld Corporation | Revolving Loan Facility
Business Acquisition [Line Items]
Line of credit facility, outstanding		$ 17,000,000
Sealweld Corporation | Performance Materials
Business Acquisition [Line Items]
Goodwill expected to be tax deductible				$ 100,000