XML 106 R93.htm IDEA: XBRL DOCUMENT
v3.24.0.1

EMPLOYEE BENEFIT PLANS (Detail) - USD ($) shares in Thousands |  | 12 Months Ended
--- | --- | ---
Jun. 01, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2019
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Employer contributions vesting period |  | 2 years |  |  |
Employer contributions |  | $ 4,371,000 | $ 3,558,000 | $ 2,811,000 |
Contingent liability term |  |  |  |  | 17 years
Multiemployer pension plan withdrawal obligation, undiscounted |  |  |  |  | $ 4,224,000
Estimated accumulated benefit obligation as complete withdrawal |  |  |  |  | $ 18,511,000
Multiemployer pension plan withdrawal obligation |  | 1,496,000 |  |  |
Pension Plan |  |  |  |  |
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Contributions by employer |  | $ 479,000 | $ 442,000 | $ 398,000 |
Hourly employees | First matching contribution |  |  |  |  |
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Employer matching contribution, percent of match |  | 100.00% |  |  |
Employer matching contribution, percent of employees' annual income |  | 1.00% |  |  |
Hourly employees | Next matching contribution |  |  |  |  |
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Employer matching contribution, percent of match |  | 50.00% |  |  |
Employer matching contribution, percent of employees' annual income |  | 3.00% |  |  |
Salary employees |  |  |  |  |
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Employer matching contribution, percent of match |  | 50.00% |  |  |
Employer matching contribution, percent of employees' annual income |  | 2.00% |  |  |
Maximum annual contributions per employee |  | $ 1,500 |  |  |
Class A Common Stock |  |  |  |  |
Employee Stock Purchase Plan [Line Items] |  |  |  |  |
Discount rate |  | 15.00% |  |  |
Common stock, additional authorized shares | 400 |  |  |  |
Stock issued under stock purchase plan (in shares) |  | 24 | 22 | 20 |
Stock available for distribution under stock purchase plan (in shares) |  | 407 |  |  |

X
- Definition Multiemployer Plans, Complete Withdrawal, Estimated Accumulated Benefit Obligation + References No definition available. + Details
Name: | cwst_MultiemployerPlansCompleteWithdrawalEstimatedAccumulatedBenefitObligation
Namespace Prefix: | cwst_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Multiemployer Plans, Withdrawal Obligation, Contingent Liability Term + References No definition available. + Details
Name: | cwst_MultiemployerPlansWithdrawalObligationContingentLiabilityTerm
Namespace Prefix: | cwst_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Multiemployer Plans, Withdrawal Obligation, Undiscounted + References No definition available. + Details
Name: | cwst_MultiemployerPlansWithdrawalObligationUndiscounted
Namespace Prefix: | cwst_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Minimum period the individual is required to perform services to be fully vested under the deferred compensation arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 55 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482943/710-10-55-7 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contribution received by defined benefit plan from employer which increases plan assets. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480794/715-70-50-1 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum amount the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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_EmployeeStockOwnershipPlanESOPDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. + References No definition available. + Details
Name: | us-gaap_MultiemployerPlansWithdrawalObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Discount rate from fair value on purchase date that participants pay for shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of additional shares authorized for issuance under share-based payment arrangement. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares issued during the period as a result of an employee stock purchase plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481112/505-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GranteeStatusAxis=cwst_HourlyEmployeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cwst_DefinedContributionPlanMatchingContributionHierarchyAxis=cwst_DefinedContributionPlanFirstMatchingContributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cwst_DefinedContributionPlanMatchingContributionHierarchyAxis=cwst_DefinedContributionPlanSecondMatchingContributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GranteeStatusAxis=cwst_SalaryEmployeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |