Benefit plans (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 30, 2015	Jan. 31, 2014	Feb. 01, 2013
Benefit plans
Matching contribution expense related to the Company's 401(k) plan	$ 13.7	$ 13.0	$ 11.9
Compensation expense for the Dollar General Corporation CDP/SERP Plan	$ 0.8	$ 1.2	$ 1.4

The amount of the cost recognized during the period for defined contribution plans.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration