Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2015	May 01, 2014
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits that would impact the effective tax rate if recognized	$ 1,678
Accrued for the payment of interest and penalties	289
Reductions for lapse of statue of limitations / settlements	250
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	45,500
Stanadyne [Member]
Operating Loss Carryforwards [Line Items]
General business credits		$ 1,700

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible general business tax credit carryforwards.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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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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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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