Guarantees, Commitments and Contingencies - Additional Information (Detail)				6 Months Ended
	Jul. 31, 2017 USD ($) Plantiff	Nov. 23, 2015 USD ($)	Oct. 11, 2011 USD ($)	Jan. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Liabilities related to agreements				$ 0
Revolving credit agreement period		5 years
Pending Litigation
Commitments and Contingencies Disclosure [Line Items]
Excess of unspecified damages	$ 1,000,000
Loss Contingency, Number of Plaintiffs | Plantiff	24
Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Credit facility maximum borrow capacity		$ 100,000,000
Credit facility, expiry date		Nov. 23, 2020
Leverage ratio				0.90%
Interest expense				$ 0
Credit facility transaction costs incurred				$ 500,000
Credit facility, maturity period				5 years
Line of credit amount outstanding	$ 0			$ 0
Revolving Credit Facility | Other Revolving Credit Facilities
Commitments and Contingencies Disclosure [Line Items]
Credit facility available borrowing capacity	1,200,000			1,200,000
Revolving Credit Facility Termination | Facility Exit Costs
Commitments and Contingencies Disclosure [Line Items]
Revolving credit agreement period			5 years
Credit facility maximum borrow capacity			$ 100,000,000
Prior credit facility, start date			Oct. 11, 2011
Product Extended Warranty Contracts
Commitments and Contingencies Disclosure [Line Items]
Deferred revenue	$ 400,000			$ 500,000
Minimum
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term				12 months
Minimum | Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Credit facility commitment fee percentage		0.20%
Interest coverage ratio				300.00%
Minimum | Revolving Credit Facility | LIBOR Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate		1.25%
Minimum | Revolving Credit Facility | Base Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate		0.00%
Maximum
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term				60 months
Maximum | Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Aggregate available credit amount under specified circumstances		$ 200,000,000
Credit facility commitment fee percentage		0.35%
Leverage ratio of total debt to earnings before interest, taxes, depreciation, and amortization or EBITDA				275.00%
Maximum | Revolving Credit Facility | LIBOR Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate		1.75%
Maximum | Revolving Credit Facility | Base Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate		1.00%