XML 122 R107.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Segment Reporting - Summary of Financial Information by Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified | 2 Months Ended | 3 Months Ended | 8 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Dec. 31, 2014 | Oct. 31, 2014 | Jul. 31, 2014 | Apr. 30, 2014 | Jan. 31, 2014 | Oct. 31, 2013 | Jul. 31, 2013 | Apr. 30, 2013 | Jan. 31, 2013 | Oct. 31, 2012 | Jul. 31, 2012 | Apr. 30, 2012 | Jan. 31, 2012 | Oct. 31, 2011 | Jul. 31, 2011 | Dec. 31, 2014 | Dec. 31, 2013 | Apr. 30, 2014 | Apr. 30, 2013 | Apr. 30, 2012
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues | $ 85,646 us-gaap_Revenues | $ 141,341 us-gaap_Revenues | $ 141,387 us-gaap_Revenues | $ 118,927 us-gaap_Revenues | $ 117,852 us-gaap_Revenues | $ 132,296 us-gaap_Revenues | $ 128,558 us-gaap_Revenues | $ 108,694 us-gaap_Revenues | $ 112,167 us-gaap_Revenues | $ 116,836 us-gaap_Revenues | $ 117,638 us-gaap_Revenues | $ 106,375 us-gaap_Revenues | $ 111,520 us-gaap_Revenues | $ 125,989 us-gaap_Revenues | $ 124,066 us-gaap_Revenues | $ 368,374 us-gaap_Revenues | $ 340,069 us-gaap_Revenues | $ 497,633 us-gaap_Revenues | $ 455,335 us-gaap_Revenues | $ 467,950 us-gaap_Revenues
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 41,485 us-gaap_DepreciationDepletionAndAmortization | 40,618 us-gaap_DepreciationDepletionAndAmortization | 60,339 us-gaap_DepreciationDepletionAndAmortization | 56,576 us-gaap_DepreciationDepletionAndAmortization | 58,415 us-gaap_DepreciationDepletionAndAmortization
Operating income (loss) | 2,708 us-gaap_OperatingIncomeLoss | 10,064 us-gaap_OperatingIncomeLoss | 9,338 us-gaap_OperatingIncomeLoss | (5,973)us-gaap_OperatingIncomeLoss | (1,298)us-gaap_OperatingIncomeLoss | 9,450 us-gaap_OperatingIncomeLoss | 9,737 us-gaap_OperatingIncomeLoss | 2,110 us-gaap_OperatingIncomeLoss | 78 us-gaap_OperatingIncomeLoss | 4,426 us-gaap_OperatingIncomeLoss | 5,807 us-gaap_OperatingIncomeLoss | (37,679)us-gaap_OperatingIncomeLoss | 4,448 us-gaap_OperatingIncomeLoss | 11,730 us-gaap_OperatingIncomeLoss | 10,468 us-gaap_OperatingIncomeLoss | 22,110 us-gaap_OperatingIncomeLoss | 21,891 us-gaap_OperatingIncomeLoss | 11,916 us-gaap_OperatingIncomeLoss | 12,421 us-gaap_OperatingIncomeLoss | (11,033)us-gaap_OperatingIncomeLoss
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25,639 us-gaap_InterestExpense | 25,357 us-gaap_InterestExpense | 38,175 us-gaap_InterestExpense | 41,570 us-gaap_InterestExpense | 45,008 us-gaap_InterestExpense
Capital expenditures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55,061 us-gaap_PaymentsToAcquireProductiveAssets |  | 45,959 us-gaap_PaymentsToAcquireProductiveAssets | 55,027 us-gaap_PaymentsToAcquireProductiveAssets | 58,364 us-gaap_PaymentsToAcquireProductiveAssets
Goodwill | 119,170 us-gaap_Goodwill |  |  | 119,139 us-gaap_Goodwill |  |  |  | 115,928 us-gaap_Goodwill |  |  |  | 101,706 us-gaap_Goodwill |  |  |  | 119,170 us-gaap_Goodwill |  | 119,139 us-gaap_Goodwill | 115,928 us-gaap_Goodwill | 101,706 us-gaap_Goodwill
Total Assets | 669,795 us-gaap_Assets |  |  | 649,897 us-gaap_Assets |  |  |  | 663,119 us-gaap_Assets |  |  |  | 633,743 us-gaap_Assets |  |  |  | 669,795 us-gaap_Assets |  | 649,897 us-gaap_Assets | 663,119 us-gaap_Assets | 633,743 us-gaap_Assets
Recycling [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 33,741 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | 43,825 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 42,273 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 52,195 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,876 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | 4,262 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 4,303 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 4,130 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (238)us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | (2,435)us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | (697)us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 5,088 us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,553 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 6,795 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Capital expenditures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,016 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | 1,111 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 935 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 5,494 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Goodwill | 12,315 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  | 12,315 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 12,190 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 12,190 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 12,315 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | 12,315 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 12,190 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 12,190 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Total Assets | 52,016 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  | 49,652 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 50,921 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 55,434 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  |  |  | 52,016 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember |  | 49,652 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 50,921 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember | 55,434 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember
Other [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 69,333 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 89,567 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 77,426 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 75,598 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,639 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 2,423 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 2,309 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 2,938 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 74 us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 2,158 us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | (1,649)us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | (2,196)us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25,713 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 38,023 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 10,133 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 6,454 us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Capital expenditures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,807 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 4,507 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 3,325 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 5,669 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Goodwill | 1,729 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  | 1,729 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  |  |  |  |  |  |  |  |  |  | 1,729 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 1,729 us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |
Total Assets | 73,731 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  | 68,706 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  |  | 65,033 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  |  | 77,990 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  |  |  | 73,731 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember |  | 68,706 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 65,033 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember | 77,990 us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember
Intersubsegment Eliminations [Member] | Recycling [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (175)us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember |  | (139)us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 116 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 57 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = cwst_RecyclingMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember
Intersubsegment Eliminations [Member] | Other [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,763 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember |  | 2,019 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 3,933 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 4,466 us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis = us-gaap_AllOtherSegmentsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember
Eastern Region [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 108,423 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | 147,330 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 129,889 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 127,930 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 17,195 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | 24,961 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 23,518 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 25,179 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,434 us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | (1,105)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | (5,291)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | (43,640)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (315)us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | (272)us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 27,054 us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 31,637 us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Capital expenditures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 27,354 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | 19,870 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 20,383 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 19,734 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Goodwill | 17,429 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  | 17,429 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 16,858 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 58 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 17,429 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | 17,429 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 16,858 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 58 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Total Assets | 211,020 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  | 200,235 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 198,710 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 166,938 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  |  |  | 211,020 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember |  | 200,235 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 198,710 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember | 166,938 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember
Eastern Region [Member] | Intersubsegment Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 31,840 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember |  | 38,946 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 30,933 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 33,559 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_EasternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember
Western Region [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 156,877 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 216,911 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 205,747 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 212,227 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,775 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 28,693 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 26,446 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 26,168 us-gaap_DepreciationDepletionAndAmortization / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 18,840 us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 13,298 us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 20,058 us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 29,715 us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (6)us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 112 us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | (1,311)us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 80 us-gaap_InterestExpense / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Capital expenditures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 21,884 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 20,471 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 30,384 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 27,467 us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Goodwill | 87,697 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  | 87,666 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 86,880 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 89,458 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 87,697 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 87,666 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 86,880 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 89,458 us-gaap_Goodwill / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Total Assets | 333,028 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  | 331,304 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 348,455 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 333,381 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  |  |  | 333,028 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember |  | 331,304 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 348,455 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember | 333,381 us-gaap_Assets / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember
Western Region [Member] | Intersubsegment Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50,235 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember |  | 70,809 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 65,390 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | 67,776 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = cwst_WesternRegionMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember
Elimination [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depreciation and amortization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Expense, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (32,868)us-gaap_InterestExpense / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember | (39,863)us-gaap_InterestExpense / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember
Goodwill |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total Assets | 9,888 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember |  |  | 36,006 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember |  |  |  | 59,759 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember |  |  |  |  |  |  |  | 9,888 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember |  | 36,006 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember | 59,759 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember |
Elimination [Member] | Intersubsegment Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inter-company revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (83,663)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember |  | $ (111,635)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | $ (100,372)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember | $ (105,858)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = us-gaap_ConsolidationEliminationsMember / us-gaap_SubsegmentsConsolidationItemsAxis = us-gaap_IntersubsegmentEliminationsMember

X
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 + Details
Name: | us-gaap_Assets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 + Details
Name: | us-gaap_InterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues. + References No definition available. + Details
Name: | us-gaap_OperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_ConsolidationEliminationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_SubsegmentsConsolidationItemsAxis=us-gaap_IntersubsegmentEliminationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |