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SIGNIFICANT ACCOUNTING POLICIES (Cash, Cash Equivalents and Uncashed Checks) (Details) | Dec. 31, 2020 USD ($)
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Accounting Policies [Abstract] |
Bank disbursement account balance | $ 0

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- Definition Cash and Cash Equivalents, Bank Disbursement Account, Minimum Balance Allowed + References No definition available. + Details
Name: | clh_CashAndCashEquivalentsBankDisbursementAccountMinimumBalanceAllowed
Namespace Prefix: | clh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration