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Final Capping, Closure and Post-Closure Costs | 12 Months Ended
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Apr. 30, 2014
Asset Retirement Obligation Disclosure [Abstract] |
Final Capping, Closure and Post-Closure Costs |
8. | FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS
Accrued final capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for final capping closure and post-closure of our landfills. We estimate our future final capping, closure and post-closure costs in order to determine the final capping, closure and post-closure expense per ton of waste placed into each landfill as further described in Note 3 to these consolidated financial statements. The anticipated timeframe for paying these costs varies based on the remaining useful life of each landfill, as well as the duration of the post-closure monitoring period. The changes to accrued final capping, closure and post-closure liabilities for fiscal years 2014 and 2013 are as follows:
|  | Fiscal Year Ended April 30, |
|  | 2014 |  |  | 2013 |
Beginning balance |  | $ | 43,170 |  |  | $ | 39,629 |
Obligations incurred |  |  | 3,621 |  |  |  | 3,188 |
Revisions in estimates (1) |  |  | (3,728 | ) |  |  | (694 | )
Accretion expense |  |  | 3,967 |  |  |  | 3,538 |
Payments |  |  | (2,376 | ) |  |  | (2,491 | )
Ending balance |  | $ | 44,654 |  |  | $ | 43,170 |
(1) | The revisions in estimates for final capping, closure and post-closure for fiscal years 2014 and 2013 consist of changes in cost estimates and the timing of final capping and closure events, as well as changes to expansion airspace and tonnage placement assumptions.

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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7569-110849 + Details
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