Credit Available Subject to Percentage of Accounts Receivable

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

Credit Available Subject to Percentage of Cash Deposited

+ References

No definition available.

+ Details

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Namespace Prefix:	clh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Periodic Payment, Percentage of Face Amount

+ References

No definition available.

+ Details

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Namespace Prefix:	clh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Spread on Variable Rate, Period for Measurement of Average Liquidity

+ References

No definition available.

+ Details

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Namespace Prefix:	clh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchasedFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of debt issuance costs that were incurred during a noncash or partial noncash transaction.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
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+ Details

Name:	us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash paid for interest. Includes, but is not limited to, payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Period Type:

- Details

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Balance Type:
Period Type:

- Details

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- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=clh_RepurchasedNotesMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
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- Details

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Period Type:

- Details

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Period Type:

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FINANCING ARRANGEMENTS (Narrative) (Details) - USD ($)		6 Months Ended	12 Months Ended
FINANCING ARRANGEMENTS (Narrative) (Details) - USD ($)	Aug. 01, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Mar. 14, 2016	Dec. 07, 2012	Jul. 30, 2012
Financing arrangements
Debt Instrument, Periodic Payment, Percentage of Face Amount			0.25%
Revolving credit facility, available borrowing capacity			$ 217,800,000	$ 195,200,000
Letters of credit outstanding, amount			134,100,000	132,600,000
Premiums to repay debt early			$ 6,028,000	0	$ 0
Parent and Domestic Subsidiaries
Financing arrangements
Credit available subject to percentage of accounts receivable			85.00%
Credit available subject to percentage of cash deposited			100.00%
Canadian Subsidiaries
Financing arrangements
Credit available subject to percentage of accounts receivable			85.00%
Credit available subject to percentage of cash deposited			100.00%
Term Loan Agreement \| Eurodollar
Financing arrangements
Basis spread on variable rate		2.00%
Term Loan Agreement \| Base rate loans
Financing arrangements
Basis spread on variable rate		1.00%
Term Loan Agreement \| Minimum \| Base rate loans
Financing arrangements
Basis spread on variable rate		0.00%
Secured Debt \| Term Loan Agreement
Financing arrangements
Face amount		$ 400,000,000.0
Fair value of notes			$ 400,500,000
Effective interest rate						3.57%
Premiums to repay debt early	$ 6,000,000
Expenses incurred from financing	6,500,000
Secured Debt \| Repurchased Notes
Financing arrangements
Repurchased amount		296,200,000
Amount used to repurchase notes		312,600,000
Accrued interest paid		6,400,000
Unsecured Debt \| Senior unsecured notes, at 5.25%, due August 1, 2020 (2020 Notes)
Financing arrangements
Face amount		$ 503,800,000
Repurchased amount	$ 103,800,000
Redemption price percentage	101.313%
Senior Notes \| Senior unsecured notes, at 5.25%, due August 1, 2020 (2020 Notes)
Financing arrangements
Face amount									$ 800,000,000
Interest rate			5.25%						5.25%
Fair value of notes			$ 404,600,000	820,000,000
Repurchased amount			$ 400,000,000
Senior Notes \| Senior unsecured notes, at 5.125%, due June 1, 2021 (2021 Notes)
Financing arrangements
Face amount							$ 250,000,000.0	$ 600,000,000.0
Interest rate			5.125%					5.125%
Fair value of notes			$ 855,700,000	$ 861,900,000
Repurchased amount					$ 5,000,000
Revolving credit facility
Financing arrangements
Revolving credit facility, maximum borrowing capacity			$ 400,000,000.0
Period for measurement of average liquidity			30 days
Revolving credit facility \| Minimum
Financing arrangements
Commitment fee			0.25%
Revolving credit facility \| Minimum \| LIBOR loans
Financing arrangements
Basis spread on variable rate			1.25%
Revolving credit facility \| Minimum \| Base rate loans
Financing arrangements
Basis spread on variable rate			0.25%
Revolving credit facility \| Maximum
Financing arrangements
Commitment fee			0.30%
Revolving credit facility \| Maximum \| LIBOR loans
Financing arrangements
Basis spread on variable rate			1.50%
Revolving credit facility \| Maximum \| Base rate loans
Financing arrangements
Basis spread on variable rate			0.50%
Revolving credit facility \| Parent and Domestic Subsidiaries
Financing arrangements
Revolving credit facility, maximum borrowing capacity			$ 300,000,000
Revolving credit facility \| Canadian Subsidiaries
Financing arrangements
Revolving credit facility, maximum borrowing capacity			100,000,000
Letters of credit \| Parent and Domestic Subsidiaries
Financing arrangements
Revolving credit facility, maximum borrowing capacity			250,000,000
Letters of credit \| Canadian Subsidiaries
Financing arrangements
Revolving credit facility, maximum borrowing capacity			$ 75,000,000