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STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS (Details) (USD $)
In Millions, except Share data, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
performance_criteria
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of performance criteria, achieved 1clh_NumberOfPerformanceCriteriaAchieved      
Number of performance criteria 3clh_NumberofPerformanceCriteria      
Percentage of original award 0.20clh_StockBasedCompensationRecognizedPercentageofOriginalAward      
Allocated share-based compensation expense $ 8.8us-gaap_AllocatedShareBasedCompensationExpense $ 9.0us-gaap_AllocatedShareBasedCompensationExpense $ 7.5us-gaap_AllocatedShareBasedCompensationExpense  
Total income tax benefit from compensation cost 1.9us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense 3.2us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense 2.9us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense  
2000 Equity Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Options outstanding, number (in shares) 36,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_PlanNameAxis
= clh_A2000EquityIncentivePlanMember		      
2010 Equity Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Options outstanding, number (in shares)       6,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_PlanNameAxis
= clh_A2010EquityIncentivePlanMember
Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-bases payment award, award vesting period 5 years      
Minimum | Restricted stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-bases payment award, award vesting period 3 years      
Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-bases payment award, award vesting period 10 years      
Maximum | Restricted stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-bases payment award, award vesting period 5 years      
Performance stock awards        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense $ 0.7us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= clh_PerformanceStockAwardsMember