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Employee Retirement Benefits - Defined contribution plan (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Jan. 31, 2015
contribution_plan
Jan. 31, 2014
Jan. 31, 2013
Schedule of Defined Contribution Plans Disclosure [Line Items]      
Number of defined contribution plans 2ravn_DefinedContributionPlanNumberofPlans    
Current payroll matching percentage by the Company 4.00%ravn_DefinedContributionCurrentPayrollMatchingPercentage    
Participant contribution rate for company stock, maximum 20.00%ravn_Participantcontributionrateforcompanystockmaximum    
Total contribution expense $ 2,416us-gaap_DefinedContributionPlanCostRecognized $ 2,412us-gaap_DefinedContributionPlanCostRecognized $ 2,021us-gaap_DefinedContributionPlanCostRecognized
Vista Research [Member]      
Schedule of Defined Contribution Plans Disclosure [Line Items]      
Current payroll matching percentage by the Company 3.00%ravn_DefinedContributionCurrentPayrollMatchingPercentage
/ us-gaap_BusinessAcquisitionAxis
= ravn_VistaResearchMember