XML 80 R45.htm IDEA: XBRL DOCUMENT
v3.20.1

LEASES - Narrative (Details) | 3 Months Ended
--- | ---
Mar. 31, 2020 Agreement
Leases [Abstract] |
Number of landfill operation and management agreements | 3

X
- Definition Number of Landfill Operation and Management Agreements Entered Into + References No definition available. + Details
Name: | cwst_NumberofLandfillOperationandManagementAgreementsEnteredInto
Namespace Prefix: | cwst_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration