v3.5.0.2

ACQUISITON (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Oct. 31, 2015 | Oct. 29, 2016 | Oct. 31, 2015
Business Acquisition [Line Items] |  |  |
Expected Synergies |  | $ 300.0 |
Family Dollar |  |  |
Business Acquisition [Line Items] |  |  |
Business Combination, Acquisition Related Costs | $ 11.8 |  | $ 38.7

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- Definition The goodwill recognized is attributable to growth opportunities and expected synergies expected to be achieved by the third year following the Acquisition Date. + References No definition available. + Details
Name: | dltr_ExpectedSynergies
Namespace Prefix: | dltr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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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. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e1043-128460 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
Name: | us-gaap_BusinessAcquisitionAxis=dltr_FamilyDollarMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |