XML 45 R33.htm IDEA: XBRL DOCUMENT
v3.8.0.1

BUSINESS COMBINATIONS - Additional Information (Details) - transfer_station | 9 Months Ended
--- | ---
Sep. 30, 2017 | Sep. 30, 2016
Eastern | Solid Waste Collection |  |
Business Acquisition [Line Items] |  |
Number of transfer stations acquired | 1 |
Western | Solid Waste Collection |  |
Business Acquisition [Line Items] |  |
Number of transfer stations acquired | 2 |
Western | Transfer Stations Acquisition |  |
Business Acquisition [Line Items] |  |
Number of transfer stations acquired |  | 3

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

X
- Definition The number of businesses acquired by the entity during the period. + References No definition available. + Details
Name: | us-gaap_NumberOfBusinessesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cwst_EasternRegionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cwst_SolidWasteCollectionBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cwst_WesternRegionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cwst_TransferStationsAcquisitionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |