XML 146 R101.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Divestiture Transactions and Discontinued Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 12 Months Ended
--- | --- | ---
Jul. 31, 2013 | Jul. 31, 2012 | Apr. 30, 2014 | Apr. 30, 2012
Divestitures [Line Items] |  |  |  |
Undiscounted purchase consideration paid in installments | 5 years | 21 years |  |
Loss on disposal of discontinued operations, net of tax | $ (378) |  | $ (378) | $ 725
BioFuels Assets [Member] |  |  |  |
Divestitures [Line Items] |  |  |  |
Undiscounted purchase consideration | 2,000 |  |  |
Maine Energy Facility [Member] |  |  |  |
Divestitures [Line Items] |  |  |  |
Undiscounted purchase consideration |  | $ 6,650 |  |

X
- Details
Name: | cwst_DivestituresLineItems
Namespace Prefix: | cwst_
Data Type: | xbrli:stringItemType
Balance Type: | na
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
- Definition Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 + Details
Name: | us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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