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Summary of significant accounting policies - Additional Information (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
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Nov. 02, 2013
|
Oct. 27, 2012
|
Nov. 02, 2013
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Oct. 27, 2012
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Stock compensation expenses | $ 11,936 | $ 9,721 | ||
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Stock Options [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Number of shares granted | 286 | 213 | ||
| Weighted average fair value of stock option | $ 36.77 | $ 45.84 | ||
| Stock compensation expenses | 2,167 | 2,937 | 7,804 | 8,799 |
| Unrecognized compensation expense related to unvested stock awards | 20,513 | 20,513 | ||
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Restricted Stock [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Number of shares granted | 139 | 58 | ||
| Stock compensation expenses | 2,230 | 438 | 4,132 | 922 |
| Unrecognized compensation expense related to unvested stock awards | $ 10,758 | $ 10,758 | ||