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INCOME TAXES (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Income Tax Contingency [Line Items]      
The Company's effective tax rate (as a percent) 39.50%clh_EffectiveIncomeTaxRate 38.30%clh_EffectiveIncomeTaxRate  
Unrecognized tax benefits $ 2.3us-gaap_UnrecognizedTaxBenefits   $ 2.5us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits, interest     0.4us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued
Foreign and State      
Income Tax Contingency [Line Items]      
Amount of decrease in unrecognized tax benefits that, if realized, will impact the effective tax rate $ 0.6us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
/ us-gaap_IncomeTaxAuthorityAxis
= clh_ForeignAndStateMember