Basis of presentation and accounting policies (Detail 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 30, 2015	Jan. 31, 2014	Feb. 01, 2013
Revenue and gain recognition
Liability for outstanding gift cards	$ 2.5	$ 4.3
Breakage income related to the gift card program	2.4
Advertising costs
Advertising costs	77.3us-gaap_AdvertisingExpense	70.5us-gaap_AdvertisingExpense	61.7us-gaap_AdvertisingExpense
Expenses related to vendor funding for cooperative advertising offset	$ 35.0us-gaap_CooperativeAdvertisingAmount	$ 31.9us-gaap_CooperativeAdvertisingAmount	$ 23.6us-gaap_CooperativeAdvertisingAmount

Carrying value as of the balance sheet date of the liability for outstanding gift cards. Retail customers purchase gift cards or gift certificates that can be redeemed at a later date for merchandise or services; those unredeemed represent a liability of the entity because the revenue is being deferred.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 35

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

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- Definition

Total amount received by an entity from a vendor under a cooperative advertising arrangement that has been offset against advertising expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cooperative Advertising

-URI http://asc.fasb.org/extlink&oid=6509061

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 50

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6408645&loc=d3e63872-111659

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- Definition

The amount of breakage recognized related to unredeemed gift cards. Breakage occurs when a customer pays in advance of vendor performance and does not demand full performance for various reasons.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.B.Q1)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Breakage

-URI http://asc.fasb.org/extlink&oid=6506468

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