Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	$ 200	$ 200	$ 200
Valuation Allowances and Reserves, Charged to (Reduced from) Expenses	110	141	115
Valuation Allowances and Reserves, Deductions from Reserves	110	141	115
Valuation Allowances and Reserves, Ending Balance	200	200	200
Warranty reserve
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	1,000	950	1,000
Valuation Allowances and Reserves, Charged to (Reduced from) Expenses	415	375	442
Valuation Allowances and Reserves, Deductions from Reserves	415	325	492
Valuation Allowances and Reserves, Ending Balance	1,000	1,000	950
Product, general, workers’ compensation and automobile liability reserves
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	2,050	2,130	2,425
Valuation Allowances and Reserves, Charged to (Reduced from) Expenses	777	975	204
Valuation Allowances and Reserves, Deductions from Reserves	1,177	1,055	499
Valuation Allowances and Reserves, Ending Balance	1,650	2,050	2,130
Deferred tax valuation allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	21,906	26,399	24,210
Valuation Allowances and Reserves, Charged to (Reduced from) Expenses	0	0	2,189
Valuation Allowances and Reserves, Deductions from Reserves	21,391	4,493	0
Valuation Allowances and Reserves, Ending Balance	$ 515	$ 21,906	$ 26,399