Stock-Based Awards - Narratives (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 28, 2018	Jul. 28, 2018	Jan. 27, 2018
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 3.3	$ 3.3
Total compensation cost not yet recognized, period for recognition	2 years 6 months
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 11.0	$ 11.0
Total compensation cost not yet recognized, period for recognition	2 years 7 months 6 days
Granted (in shares)		51,380
Shares outstanding	174,154	174,154	133,896
Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 27.2	$ 27.2
Total compensation cost not yet recognized, period for recognition	2 years 2 months 12 days
Compensation expense	$ 12.2	$ 12.2
RSUs outstanding (in shares)		158,841
Granted (in shares)		218,628
Shares outstanding	581,521	581,521	390,327
Target Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding	420,786	420,786
Supplemental Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		59,787
Shares outstanding	160,735	160,735

Potential Compensation Expense for Performance Based Shares If Performance Goals Are Met

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- Definition

Share-based compensation by share-based payment award, equity awards other than options, target amount of performance shares

+ References

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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- Definition

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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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