Benefit plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Jan. 29, 2016	Jan. 30, 2015	Jan. 31, 2014
Benefit plans
Matching contribution expense related to the Company's 401(k) plan	$ 15.0	$ 13.7	$ 13.0
Compensation expense for the Dollar General Corporation CDP/SERP Plan	$ 1.1	$ 0.8	$ 1.2