Accrued Capping, Closure and Post Closure

3 Months Ended

Jul. 31, 2014

Asset Retirement Obligation Disclosure [Abstract]

Accrued Capping, Closure and Post Closure

3. ACCRUED CAPPING, CLOSURE AND POST CLOSURE

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. 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 the three months ended July 31, 2014 and 2013 are as follows:

	Three Months Ended July 31,
	2014			2013
Beginning balance	$	44,654		$	43,170
Obligations incurred		884			877
Accretion expense		798			1,011
Payments		(2,821	)		(309	)
Ending balance	$	43,515		$	44,749