Income taxes Reconcilation to the ETR rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Income Tax Expense [Line Items]
Tax benefit at federal statutory rate	$ (3,459)	$ (4,683)
Federal rate change	2,243	0
State benefit, net of federal income tax effect	(440)	(103)
Excess income tax on share-based compensation	(183)	0
Permanent differences other	162	205
Differences in foreign tax rate	732	2,131
Foreign tax credit	0	(1,249)
Domestic deferred tax true ups	(364)	0
Repatriation	1,880	1,338
Nontaxable income from the Canadian joint venture	0	551
Nondeductible interest	0	242
All other, net expense	105	33
Total income tax benefit	(233)	(611)
United States
Income Tax Expense [Line Items]
Valuation allowance	(1,206)	838
State and Local Jurisdiction [Member]
Income Tax Expense [Line Items]
Valuation allowance	297	122
Foreign Tax Authority [Member]
Income Tax Expense [Line Items]
Valuation allowance	$ 0	$ (36)