Commitments and contingencies (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended			1 Months Ended		1 Months Ended		12 Months Ended
	Jan. 01, 2010 Cynthia Richter, et al. v. Dolgencorp, Inc ("Richter") employee	May 04, 2012 Cynthia Richter, et al. v. Dolgencorp, Inc ("Richter") plaintiffs	May 04, 2012 Janet Calvert v. Dolgencorp, Inc ("Calvert")	Apr. 04, 2008 Janet Calvert v. Dolgencorp, Inc ("Calvert") plaintiffs	May 27, 2011 Winn-Dixie Stores, Inc., et al. v. Dolgencorp, LLC stores	May 04, 2012 Winn-Dixie Stores, Inc., et al. v. Dolgencorp, LLC	Apr. 29, 2011 Interest rate swap settlement	May 28, 2010 Interest rate swap settlement	Jan. 30, 2009 Interest rate swap settlement
Legal proceedings
Minimum number of current or former Dollar General store managers to whom notice was mailed	28,000
Approximate number of persons who opted into the lawsuit		3,950		2,100
Approximate number of opt-in plaintiffs dismissed		800
Settlement consideration			$ 15.5
Plaintiffs' legal fees			3.25
Aggregate anticipated settlement			18.75
Reimbursement from Employment Practices Liability Insurance (EPLI)			15.9
Insurance coverage under Employment Practices Liability Insurance (EPLI)			20
Settlement consideration paid			2.8
Approximate number of stores co-located with one of the plaintiffs' stores					55
Expected amount sought by plaintiffs						47
Interest rate swap settlement payment							9.85		7.60
Demand for additional settlement amount of interest rate swap								$ 19