Benefit plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Feb. 02, 2018	Feb. 03, 2017	Jan. 29, 2016
Benefit plans
Matching contribution expense related to the Company's 401(k) plan	$ 17.5	$ 16.0	$ 15.0
Compensation expense for the Dollar General Corporation CDP/SERP Plan	$ 0.7	$ 0.7	$ 1.1