Stock-based compensation Restricted stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
Jul. 31, 2018	Jan. 31, 2018
Disclosure of compensation, restricted shares [Abstract]
Outstanding	333	360
Share-based compensation nonvested weighted average grant date fair value	$ 9.05	$ 9.05
Aggregate Intrinsic Value, Outstanding	$ 3,022	$ 3,254
Granted	124
Weighted Average Grant Date Fair Value	$ 9.75
Issued	(88)
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	(63)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 7.19
Deferred compensation liabilities	$ 3,460	4,098
Stockholders' equity	51,211	51,812
Restatement Adjustment [Member]
Deferred compensation liabilities	(723)
Additional Paid-in Capital [Member]
Stockholders' equity	58,080	$ 56,304
Additional Paid-in Capital [Member] \| Restatement Adjustment [Member]
Stockholders' equity	$ 700

Disclosure of compensation, restricted shares [Abstract]

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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

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Weighted average grant-date fair value of non-vested options outstanding.

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Number of shares related to Restricted Stock Award forfeited during the period.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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