Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Additional Information (Detail)

v2.4.1.9
Fair Value Measurements - Additional Information (Detail) (Fair Value, Inputs, Level 2 [Member], USD $)
In Thousands, unless otherwise specified
Jan. 31, 2015
Fair Value, Inputs, Level 2 [Member]
 
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Deferred compensation plan liability $ 5,574ulta_FinancialLiabilitiesRelatedToNonQualifiedDeferredCompensationPlan
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member