Income Taxes (Details 2) (USD $)	12 Months Ended
Apr. 30, 2013	Apr. 30, 2012
Unrecognized tax benefits
Unrecognized tax benefits which would impact the Company's effective tax rate if recognized	$ 5,083,000	$ 4,507,000
Activity related to gross unrecognized tax benefits
Beginning balance	4,507,000	4,655,000
Increases related to prior year tax positions	539,000
Decreases related to prior year tax positions	(19,000)	(533,000)
Increases related to current year tax positions	1,141,000	973,000
Decreases related to lapsing of statute of limitations	(1,085,000)	(588,000)
Ending balance	5,083,000	4,507,000
Accrued interest and penalties related to unrecognized tax positions	238,000	125,000
Statute of limitation expiration
Unrecognized tax benefits
Estimated decrease in unrecognized tax benefits in the next twelve months	$ 1,316,000

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The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.

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The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

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The gross amount of decreases in unrecognized tax benefits resulting from tax positions taken in prior period tax returns, excluding amounts pertaining to examined tax returns.

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This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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