Commitments and Contingencies	3 Months Ended
Jul. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	4. COMMITMENTS AND CONTINGENCIES Legal Proceedings In the ordinary course of our business and as a result of the extensive governmental regulation of the solid waste industry, we are subject to various judicial and administrative proceedings involving state and local agencies. In these proceedings, an agency may seek to impose fines or to revoke or deny renewal of an operating permit held by us. From time to time, we may also be subject to actions brought by special interest or other groups, adjacent landowners or residents in connection with the permitting and licensing of landfills and transfer stations, or alleging environmental damage or violations of the permits and licenses pursuant to which we operate. In addition, we have been named defendants in various claims and suits pending for alleged damages to persons and property, alleged violations of certain laws and alleged liabilities arising out of matters occurring during the ordinary operation of the waste management business. In accordance with FASB Accounting Standards Codification (“ASC”) 450-20, we accrue for legal proceedings when losses become probable and reasonably estimable. As of the end of each applicable reporting period, we review each of our legal proceedings to determine whether it is probable, reasonably possible or remote that a liability has been incurred and, if it is at least reasonably possible, whether a range of loss can be reasonably estimated under the provisions of FASB ASC 450-20. In instances where we determine that a loss is probable and we can reasonably estimate a range of loss we may incur with respect to such a matter, we record an accrual for the amount within the range that constitutes our best estimate of the possible loss. If we are able to reasonably estimate a range, but no amount within the range appears to be a better estimate than any other, we record an accrual in the amount that is the low end of such range. When a loss is reasonably possible, but not probable, we will not record an accrual, but we will disclose our estimate of the possible range of loss where such estimate can be made in accordance with ASC 450-20. New York Attorney General Matter In July 2014, we entered into an Assurance of Discontinuance (“AOD”) with the office of the New York Attorney General (“NYAG”) in connection with our commercial practices in certain specified counties in New York. The AOD requires, among other things, that we modify our service contracts for two (2) to ten (10) yard containers with our commercial customers in the specified counties by shortening the initial term of such contracts to two (2) years and providing for only one (1) extension term of one (1) year. We also agreed (i) to limit the liquidated damages to be paid by a customer if a customer prematurely terminates its contract with us to three (3) months in year one of the contract and one (1) month in year two or any extension year of the contract, (ii) to provide the NYAG with post-acquisition notice within thirty (30) days of an acquisition of a provider of solid waste services with a value of $350 or more, and (iii) to pay the State of New York the sum of $100. We recorded a charge of $100, included in general and administration costs, in the three months ended July 31, 2014. The counties in New York covered by the AOD are Allegany, Cattaraugus, Chautauqua, Chemung, Clinton, Franklin, Schuyler, St. Lawrence, Steuben, and Tompkins. Greenwood Street Landfill, Worcester, Massachusetts On July 2, 2014, we received a draft Administrative Consent Order with Penalty and Notice of Noncompliance (“Draft Order”) from the Massachusetts Department of Environmental Protection (“MADEP”) alleging that a subsidiary, NEWS of Worcester, LLC, had completed substantive closure of a portion of the Greenwood Street Landfill in Worcester, Massachusetts in 2010, at an elevation exceeding the applicable permit condition. The Draft Order seeks a civil administrative cash penalty of $67 and an additional administrative penalty in the form of a Supplemental Environmental Project in the amount of $201. We are working with the MADEP to address these allegations to arrive at an appropriate resolution thereof. It is probable that we will incur a loss with respect to this matter and we have recorded a charge of $200, included in general and administration costs, in the three months ended July 31, 2014. Environmental Remediation Liability We are subject to liability for environmental damage, including personal injury and property damage, that our solid waste, recycling and power generation facilities may cause to neighboring property owners, particularly as a result of the contamination of drinking water sources or soil, possibly including damage resulting from conditions existing before we acquired the facilities. We may also be subject to liability for similar claims arising from off-site environmental contamination caused by pollutants or hazardous substances if we or our predecessors arrange or arranged to transport, treat or dispose of those materials. The following matters represent our potential or outstanding material claims. Potsdam Environmental Remediation Liability On December 20, 2000, the State of New York Department of Environmental Conservation (“DEC”) issued an Order on Consent (“Order”) which named Waste-Stream, Inc. (“WSI”), our subsidiary, General Motors Corporation (“GM”) and Niagara Mohawk Power Corporation (“NiMo”) as Respondents. The Order required that the Respondents undertake certain work on a 25-acre scrap yard and solid waste transfer station owned by WSI, including the preparation of a Remedial Investigation and Feasibility Study (“Study”). A draft of the Study was submitted to the DEC in January 2009 (followed by a final report in May 2009). The Study estimated that the undiscounted costs associated with implementing the preferred remedies would be approximately $10,219. On February 28, 2011, the DEC issued a Proposed Remedial Action Plan for the site and accepted public comments on the proposed remedy through March 29, 2011. We submitted comments to the DEC on this matter. In April 2011, the DEC issued the final Record of Decision (“ROD”) for the site. The ROD was subsequently rescinded by the DEC for failure to respond to all submitted comments. The preliminary ROD, however, estimated that the present cost associated with implementing the preferred remedies would be approximately $12,130. The DEC issued the final ROD in June 2011 with proposed remedies consistent with its earlier ROD. An Order on Consent and Administrative Settlement naming WSI and NiMo as Respondents was executed by the Respondents and DEC with an effective date of October 25, 2013. It is unlikely that any significant costs relating to onsite remediation will be incurred until fiscal year 2016. WSI is jointly and severally liable for the total cost to remediate, and we initially expected to be responsible for approximately 30% of such costs pursuant to a cost-sharing agreement with NiMo and GM. Based on these estimates, we recorded an environmental remediation charge of $2,823 in the third quarter of fiscal year 2009. In the fourth quarter of fiscal year 2009, we recognized an additional charge of $1,532, representing an additional 15% of the estimated costs, in recognition of the deteriorating financial condition and eventual bankruptcy filing of GM. In the fourth quarter of fiscal year 2010, we recognized an additional charge of $335 based on changes in the expected timing of cash outflows. Based on the estimated costs in the ROD, and changes in the estimated timing of cash flows, we recorded an environmental remediation charge of $549 in the fourth quarter of fiscal year 2011. Such charges could be significantly higher if costs exceed estimates. We inflate these estimated costs in current dollars until the expected time of payment and discount the total cost to present value using a risk free interest rate of 2.0%. As of July 31, 2014 and April 30, 2014, we have recorded liabilities of $5,354 and $5,320, including the recognition of $34 of accretion expense in the three months ended July 31, 2014 and 2013, respectively. In September 2011, the DEC settled its environmental claim against the estate of the former GM (known as “Motors Liquidation Trust”) for future remediation costs relating to the WSI site for face value of $3,000. In addition, in November 2011 we settled our own claim against the Motors Liquidation Trust for face value of $100. These claims will be paid by GM in warrants to obtain stock of the reorganized GM. We began receiving the warrants in May 2013 and at this time there is no way to accurately estimate when the remainder of these claims will be paid. We have not assumed that any future proceeds from the sale of securities received in payment of these claims will reduce our exposure. Southbridge Landfill Environmental Remediation Liability On or about August 24, 2013, we experienced the movement of stockpiled earth at our Southbridge landfill in Southbridge, Massachusetts. The stockpiled materials consisted of soil removed and relocated to create space for the construction of additional landfill airspace at our Southbridge landfill. The earth had been relocated and stored during the fall, winter and spring construction season of fiscal year 2013. The movement caused some of the stockpiled earth to enter wetlands on property owned by us. On or about August 29, 2013 we notified the MADEP, and the Towns of Southbridge and Charlton, Massachusetts, of the occurrence of the movement. On or about September 6, 2013, MADEP issued a “Unilateral Administrative Order” (“UAO”) requiring us to provide MADEP with a plan to remove any materials deposited in the wetlands as a result of the movement (“Plan”). On or about October 3, 2013, we submitted the Plan to MADEP, and on or about October 15, 2013, MADEP approved the Plan and verbally issued permission for us implement the Plan. We have implemented the Plan under the supervision of MADEP. In January 2014, we received correspondence from the Massachusetts’ Office of the Attorney General (“MAAG”), advising us that the MAAG intended to schedule a meeting with us to discuss this incident, and to possibly file suit against us for violation of the Massachusetts Wetlands Protection, Clean Air and Solid Waste Acts. We met with the MAAG in March 2014 and again in July 2014 to discuss our ongoing remediation effort, and the parties are continuing to hold discussions regarding the resolution of this matter. On or about April 25, 2014, we notified MADEP and other interested parties that areas of sloughing had occurred in a plateau created as part of new cell construction at our Southbridge landfill. Some of the same contractors and technical advisors that were involved in the initial movement of stockpiled earth are also involved in the new cell construction that includes this area of sloughing. We repaired the areas of sloughing on April 25, 2014 and no damage occurred in the abutting wetlands. On May 9, 2014, MADEP issued a UAO directing us to ensure that the areas of sloughing at the plateau were repaired and to take steps to ensure that there would be no incursion into the wetlands, and requiring that we undertake corrective actions to ensure the stability of the plateau. Prior to MADEP’s issuance of the latest UAO, we were in the process of awarding a contract to a soil remediation company to undertake and ensure stability at the plateau. This contract has been awarded, and we and the contractor expect the work to be finished in September 2014. We filed a written notice of claim for an adjudicatory hearing with respect to the efficacy of MADEP’s issuance of the latest UAO, but the parties have agreed to a Stipulation that includes the withdrawal by us of our notice of claim for an adjudicatory hearing. We anticipate that the execution of the Plan and related matters will involve remediation costs of approximately $2,322 and that such costs could be higher if actual costs exceed estimates. We have provided our insurer with notice of the Plan, and the costs expended by us to date to comply with the Plan. We have also provided notice to certain of our contractors and technical advisors that the movement has occurred, that significant remediation costs will be incurred in executing the Plan and related matters, and that we expect our contractors and technical advisors to assist in the execution of the Plan and related matters, to share in the remediation costs thereof as responsible parties, and to provide notice to their own insurers. We believe that a loss in the range of $475 to $2,322, including the resolution of our discussions with the MAAG, after taking into account amounts we expect to be reimbursed by our insurer and third-parties, is probable and have therefore recorded a charge of $75 in the three months ended July 31, 2014. We had previously recorded a charge of $400 in fiscal year 2014 as an environmental remediation charge.

4. COMMITMENTS AND CONTINGENCIES

Legal Proceedings

In the ordinary course of our business and as a result of the extensive governmental regulation of the solid waste industry, we are subject to various judicial and administrative proceedings involving state and local agencies. In these proceedings, an agency may seek to impose fines or to revoke or deny renewal of an operating permit held by us. From time to time, we may also be subject to actions brought by special interest or other groups, adjacent landowners or residents in connection with the permitting and licensing of landfills and transfer stations, or alleging environmental damage or violations of the permits and licenses pursuant to which we operate. In addition, we have been named defendants in various claims and suits pending for alleged damages to persons and property, alleged violations of certain laws and alleged liabilities arising out of matters occurring during the ordinary operation of the waste management business.

In accordance with FASB Accounting Standards Codification (“ASC”) 450-20, we accrue for legal proceedings when losses become probable and reasonably estimable. As of the end of each applicable reporting period, we review each of our legal proceedings to determine whether it is probable, reasonably possible or remote that a liability has been incurred and, if it is at least reasonably possible, whether a range of loss can be reasonably estimated under the provisions of FASB ASC 450-20. In instances where we determine that a loss is probable and we can reasonably estimate a range of loss we may incur with respect to such a matter, we record an accrual for the amount within the range that constitutes our best estimate of the possible loss. If we are able to reasonably estimate a range, but no amount within the range appears to be a better estimate than any other, we record an accrual in the amount that is the low end of such range. When a loss is reasonably possible, but not probable, we will not record an accrual, but we will disclose our estimate of the possible range of loss where such estimate can be made in accordance with ASC 450-20.

New York Attorney General Matter

In July 2014, we entered into an Assurance of Discontinuance (“AOD”) with the office of the New York Attorney General (“NYAG”) in connection with our commercial practices in certain specified counties in New York. The AOD requires, among other things, that we modify our service contracts for two (2) to ten (10) yard containers with our commercial customers in the specified counties by shortening the initial term of such contracts to two (2) years and providing for only one (1) extension term of one (1) year. We also agreed (i) to limit the liquidated damages to be paid by a customer if a customer prematurely terminates its contract with us to three (3) months in year one of the contract and one (1) month in year two or any extension year of the contract, (ii) to provide the NYAG with post-acquisition notice within thirty (30) days of an acquisition of a provider of solid waste services with a value of $350 or more, and (iii) to pay the State of New York the sum of $100. We recorded a charge of $100, included in general and administration costs, in the three months ended July 31, 2014. The counties in New York covered by the AOD are Allegany, Cattaraugus, Chautauqua, Chemung, Clinton, Franklin, Schuyler, St. Lawrence, Steuben, and Tompkins.

Greenwood Street Landfill, Worcester, Massachusetts

On July 2, 2014, we received a draft Administrative Consent Order with Penalty and Notice of Noncompliance (“Draft Order”) from the Massachusetts Department of Environmental Protection (“MADEP”) alleging that a subsidiary, NEWS of Worcester, LLC, had completed substantive closure of a portion of the Greenwood Street Landfill in Worcester, Massachusetts in 2010, at an elevation exceeding the applicable permit condition. The Draft Order seeks a civil administrative cash penalty of $67 and an additional administrative penalty in the form of a Supplemental Environmental Project in the amount of $201. We are working with the MADEP to address these allegations to arrive at an appropriate resolution thereof. It is probable that we will incur a loss with respect to this matter and we have recorded a charge of $200, included in general and administration costs, in the three months ended July 31, 2014.

Environmental Remediation Liability

We are subject to liability for environmental damage, including personal injury and property damage, that our solid waste, recycling and power generation facilities may cause to neighboring property owners, particularly as a result of the contamination of drinking water sources or soil, possibly including damage resulting from conditions existing before we acquired the facilities. We may also be subject to liability for similar claims arising from off-site environmental contamination caused by pollutants or hazardous substances if we or our predecessors arrange or arranged to transport, treat or dispose of those materials. The following matters represent our potential or outstanding material claims.

Potsdam Environmental Remediation Liability

On December 20, 2000, the State of New York Department of Environmental Conservation (“DEC”) issued an Order on Consent (“Order”) which named Waste-Stream, Inc. (“WSI”), our subsidiary, General Motors Corporation (“GM”) and Niagara Mohawk Power Corporation (“NiMo”) as Respondents. The Order required that the Respondents undertake certain work on a 25-acre scrap yard and solid waste transfer station owned by WSI, including the preparation of a Remedial Investigation and Feasibility Study (“Study”). A draft of the Study was submitted to the DEC in January 2009 (followed by a final report in May 2009). The Study estimated that the undiscounted costs associated with implementing the preferred remedies would be approximately $10,219. On February 28, 2011, the DEC issued a Proposed Remedial Action Plan for the site and accepted public comments on the proposed remedy through March 29, 2011. We submitted comments to the DEC on this matter. In April 2011, the DEC issued the final Record of Decision (“ROD”) for the site. The ROD was subsequently rescinded by the DEC for failure to respond to all submitted comments. The preliminary ROD, however, estimated that the present cost associated with implementing the preferred remedies would be approximately $12,130. The DEC issued the final ROD in June 2011 with proposed remedies consistent with its earlier ROD. An Order on Consent and Administrative Settlement naming WSI and NiMo as Respondents was executed by the Respondents and DEC with an effective date of October 25, 2013. It is unlikely that any significant costs relating to onsite remediation will be incurred until fiscal year 2016.

WSI is jointly and severally liable for the total cost to remediate, and we initially expected to be responsible for approximately 30% of such costs pursuant to a cost-sharing agreement with NiMo and GM. Based on these estimates, we recorded an environmental remediation charge of $2,823 in the third quarter of fiscal year 2009. In the fourth quarter of fiscal year 2009, we recognized an additional charge of $1,532, representing an additional 15% of the estimated costs, in recognition of the deteriorating financial condition and eventual bankruptcy filing of GM. In the fourth quarter of fiscal year 2010, we recognized an additional charge of $335 based on changes in the expected timing of cash outflows. Based on the estimated costs in the ROD, and changes in the estimated timing of cash flows, we recorded an environmental remediation charge of $549 in the fourth quarter of fiscal year 2011. Such charges could be significantly higher if costs exceed estimates. We inflate these estimated costs in current dollars until the expected time of payment and discount the total cost to present value using a risk free interest rate of 2.0%. As of July 31, 2014 and April 30, 2014, we have recorded liabilities of $5,354 and $5,320, including the recognition of $34 of accretion expense in the three months ended July 31, 2014 and 2013, respectively.

In September 2011, the DEC settled its environmental claim against the estate of the former GM (known as “Motors Liquidation Trust”) for future remediation costs relating to the WSI site for face value of $3,000. In addition, in November 2011 we settled our own claim against the Motors Liquidation Trust for face value of $100. These claims will be paid by GM in warrants to obtain stock of the reorganized GM. We began receiving the warrants in May 2013 and at this time there is no way to accurately estimate when the remainder of these claims will be paid. We have not assumed that any future proceeds from the sale of securities received in payment of these claims will reduce our exposure.

Southbridge Landfill Environmental Remediation Liability

On or about August 24, 2013, we experienced the movement of stockpiled earth at our Southbridge landfill in Southbridge, Massachusetts. The stockpiled materials consisted of soil removed and relocated to create space for the construction of additional landfill airspace at our Southbridge landfill. The earth had been relocated and stored during the fall, winter and spring construction season of fiscal year 2013.

The movement caused some of the stockpiled earth to enter wetlands on property owned by us. On or about August 29, 2013 we notified the MADEP, and the Towns of Southbridge and Charlton, Massachusetts, of the occurrence of the movement. On or about September 6, 2013, MADEP issued a “Unilateral Administrative Order” (“UAO”) requiring us to provide MADEP with a plan to remove any materials deposited in the wetlands as a result of the movement (“Plan”). On or about October 3, 2013, we submitted the Plan to MADEP, and on or about October 15, 2013, MADEP approved the Plan and verbally issued permission for us implement the Plan. We have implemented the Plan under the supervision of MADEP.

In January 2014, we received correspondence from the Massachusetts’ Office of the Attorney General (“MAAG”), advising us that the MAAG intended to schedule a meeting with us to discuss this incident, and to possibly file suit against us for violation of the Massachusetts Wetlands Protection, Clean Air and Solid Waste Acts. We met with the MAAG in March 2014 and again in July 2014 to discuss our ongoing remediation effort, and the parties are continuing to hold discussions regarding the resolution of this matter.

On or about April 25, 2014, we notified MADEP and other interested parties that areas of sloughing had occurred in a plateau created as part of new cell construction at our Southbridge landfill. Some of the same contractors and technical advisors that were involved in the initial movement of stockpiled earth are also involved in the new cell construction that includes this area of sloughing. We repaired the areas of sloughing on April 25, 2014 and no damage occurred in the abutting wetlands. On May 9, 2014, MADEP issued a UAO directing us to ensure that the areas of sloughing at the plateau were repaired and to take steps to ensure that there would be no incursion into the wetlands, and requiring that we undertake corrective actions to ensure the stability of the plateau. Prior to MADEP’s issuance of the latest UAO, we were in the process of awarding a contract to a soil remediation company to undertake and ensure stability at the plateau. This contract has been awarded, and we and the contractor expect the work to be finished in September 2014. We filed a written notice of claim for an adjudicatory hearing with respect to the efficacy of MADEP’s issuance of the latest UAO, but the parties have agreed to a Stipulation that includes the withdrawal by us of our notice of claim for an adjudicatory hearing.

We anticipate that the execution of the Plan and related matters will involve remediation costs of approximately $2,322 and that such costs could be higher if actual costs exceed estimates. We have provided our insurer with notice of the Plan, and the costs expended by us to date to comply with the Plan. We have also provided notice to certain of our contractors and technical advisors that the movement has occurred, that significant remediation costs will be incurred in executing the Plan and related matters, and that we expect our contractors and technical advisors to assist in the execution of the Plan and related matters, to share in the remediation costs thereof as responsible parties, and to provide notice to their own insurers. We believe that a loss in the range of $475 to $2,322, including the resolution of our discussions with the MAAG, after taking into account amounts we expect to be reimbursed by our insurer and third-parties, is probable and have therefore recorded a charge of $75 in the three months ended July 31, 2014. We had previously recorded a charge of $400 in fiscal year 2014 as an environmental remediation charge.