Accumulated Other Comprehensive Income (Loss) - Schedule of Before Tax Income (Loss) Related Income Tax effect and Accumulated Balances (Detail) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2019	Apr. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ (5,900)	$ (6,319)
Effect of changes in tax rates	67	999
Foreign currency translation adjustment	(464)	(430)
Change in fair value of cash flow hedges	4	57
Change in unrecognized actuarial loss on pension obligations	(99)	(586)
Income tax effect	(15)	379
Ending Balance	(6,407)	(5,900)
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3)	(40)
Effect of changes in tax rates		3
Change in fair value of cash flow hedges	4	57
Income tax effect	(1)	(23)
Ending Balance	0	(3)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1,427)	(997)
Foreign currency translation adjustment	(464)	(430)
Ending Balance	(1,891)	(1,427)
Minimum Pension Liability Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(4,470)	(5,282)
Effect of changes in tax rates	67	996
Change in unrecognized actuarial loss on pension obligations	(99)	(586)
Income tax effect	(14)	402
Ending Balance	$ (4,516)	$ (4,470)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates.

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Amount before tax, after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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