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Summary of Significant Accounting Policies (Cash and Cash Equivalents) (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Feb. 03, 2018 | Jan. 28, 2017
Significant Accounting Policies [Line Items] |  |
Cash Equivalents | $ 91.2 | $ 36.3
Cash and Cash Equivalents [Member] |  |
Significant Accounting Policies [Line Items] |  |
Cash Equivalents | $ 6.0 | $ 4.3
Minimum [Member] |  |
Significant Accounting Policies [Line Items] |  |
Debit and credit card transaction processing period (hours) | 24 hours |
Maximum [Member] |  |
Significant Accounting Policies [Line Items] |  |
Debit and credit card transaction processing period (hours) | 48 hours |

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- Definition Cash Equivalents + References No definition available. + Details
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Balance Type: | debit
Period Type: | instant

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- Definition Debit and Credit Card Transaction Processing Period + References No definition available. + Details
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Data Type: | xbrli:durationItemType
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Period Type: | duration

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- Definition Significant Accounting Policies [Line Items] + References No definition available. + Details
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Namespace Prefix: | five_
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Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |