Summary of significant accounting policies - Loyalty Program (Details)	12 Months Ended
Feb. 02, 2019
Summary of significant accounting policies
Minimum term that loyalty program points are valid	1 year

The expiration term of points earned through loyalty programs.

No definition available.

Name:	ulta_ExpirationTermOfLoyaltyProgramPoints
Namespace Prefix:	ulta_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration