Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer.

+ References+ Details

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

+ References+ Details

Commitments and Contingencies - Additional Information (Detail) (USD $)	6 Months Ended
	Oct. 31, 2013 Claim Case	Apr. 30, 2013	Apr. 30, 2012
Schedule Of Commitments And Contingencies [Line Items]
Number of derivative lawsuits	2
Allegations of lawsuit	The lawsuits are based principally on a theory of breach of fiduciary duties.
Number of Product liability cases	10
Number of Other product liability claims	8
Environmental reserve in non-current liabilities	$ 577,000		$ 577,000
Restricted cash		3,345,000
Letter of Credit
Schedule Of Commitments And Contingencies [Line Items]
Outstanding Letters of Credit	1,100,000
Restricted cash	0
Minimum
Schedule Of Commitments And Contingencies [Line Items]
Compensatory damages sought	75,000
Maximum
Schedule Of Commitments And Contingencies [Line Items]
Compensatory damages sought	$ 1,400,000