Benefit plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Feb. 03, 2017	Jan. 29, 2016	Jan. 30, 2015
Benefit plans
Matching contribution expense related to the Company's 401(k) plan	$ 16.0	$ 15.0	$ 13.7
Compensation expense for the Dollar General Corporation CDP/SERP Plan	$ 0.7	$ 1.1	$ 0.8