XML 64 R51.htm IDEA: XBRL DOCUMENT v2.4.1.9

Divestiture Transactions - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	0 Months Ended	12 Months Ended
	Mar. 31, 2015	Feb. 09, 2015	Apr. 30, 2013	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestiture	$ 4,935cwst_DivestitureTransactions
Other accrued liabilities	16,200us-gaap_OtherAccruedLiabilitiesCurrent			16,667us-gaap_OtherAccruedLiabilitiesCurrent
Proceeds from sale of assets	4,550us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets
Casella-Altela Regional Environmental Services, LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestiture		2,850cwst_DivestitureTransactions / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Membership interest	51.00%us-gaap_MinorityInterestOwnershipPercentageByParent / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Proceeds from sale of assets		3,500us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Casella-Altela Regional Environmental Services, LLC [Member] | Other Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestiture	928cwst_DivestitureTransactions / us-gaap_BalanceSheetLocationAxis = us-gaap_OtherAssetsMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Proceeds from sale of assets		1,050us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets / us-gaap_BalanceSheetLocationAxis = us-gaap_OtherAssetsMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Casella-Altela Regional Environmental Services, LLC [Member] | Altela, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Membership interest		49.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / dei_LegalEntityAxis = cwst_AltelaIncMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Maine Energy Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Undiscounted purchase consideration			6,650us-gaap_SignificantAcquisitionsAndDisposalsAcquisitionCostsOrSaleProceeds / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = cwst_MaineEnergyFacilityMember
Undiscounted purchase consideration paid in installments			21 years
Gain on divestiture	1,157cwst_DivestitureTransactions / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = cwst_MaineEnergyFacilityMember
Other accrued liabilities	$ 115us-gaap_OtherAccruedLiabilitiesCurrent / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = cwst_MaineEnergyFacilityMember

X

- Definition

(Gain) loss associated with the disposal of an asset group or an individually significant group of assets that do not constitute a disposal group.

+ References

No definition available.

+ Details

Name:	cwst_DivestitureTransactions
Namespace Prefix:	cwst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Period over which consideration for sale of disposal group assets to be received.

+ References

No definition available.

+ Details

Name:	cwst_PeriodOverWhichConsiderationForSaleOfDisposalGroupAssetsToBeReceived
Namespace Prefix:	cwst_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

X

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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

X

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Current Liabilities

-URI http://asc.fasb.org/extlink&oid=6509677



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6911-107765



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e7018-107765

+ Details

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

X

- Definition

Aggregate cash proceeds received from a combination of transactions in which noncurrent assets are sold, which may include the sale of a business, an investment in an affiliate (including an equity method investee), property, plant and equipment and intangible assets. Excludes sales of trading, available-for-sale, and held-to-maturity securities.

+ References

No definition available.

+ Details

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

X

- Definition

The value of all consideration given or received by the Entity in the significant acquisition or disposal.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=cwst_CasellaAltelaRegionalEnvironmentalServicesLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis=cwst_MaineEnergyFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: