XML 135 R88.htm IDEA: XBRL DOCUMENT v2.4.0.8

Stockholders' (Deficit) Equity - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Parenthetical) (Detail) (Performance Stock Units [Member]) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2014
Performance Stock Units [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Performance stock units, percentage of attainment level	100.00%
Common stock additional issue	255

X

- Definition

Additional shares of Class A Common Stock that could be issued if maximum attainment levels are met.

+ References

No definition available.

+ Details

Name:	cwst_AdditionalSharesIssuedMaximumAttainmentLevel
Namespace Prefix:	cwst_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	cwst_ScheduleOfRestrictedStockRestrictedStockUnitAndPerformanceStockUnitActivityLineItems
Namespace Prefix:	cwst_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of vesting of share-based compensation awards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration