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STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS (Employee Stock Purchase Plan) (Details) (2005 Employee Stock Purchase Plan, USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
2005 Employee Stock Purchase Plan
    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Weighted average per share fair values of the purchase rights (in dollars per share) $ 9.94clh_WeightedAveragePerShareFairValuesOfPurchaseRights
/ us-gaap_PlanNameAxis
= clh_EmployeeStockPurchasePlan2005Member		 $ 9.61clh_WeightedAveragePerShareFairValuesOfPurchaseRights
/ us-gaap_PlanNameAxis
= clh_EmployeeStockPurchasePlan2005Member