Accumulated Other Comprehensive Income (Loss) - Schedule of Before Tax Income (Loss) Related Income Tax effect and Accumulated Balances (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (7,327)	$ (7,176)	$ (4,930)
Foreign currency translation adjustment	(321)	84	(466)
Change in fair value of cash flow hedges	133	34	(157)
Change in unrecognized actuarial loss on pension obligations	2,116	(419)	(2,753)
Income tax effect	(874)	150	1,130
Ending Balance	(6,273)	(7,327)	(7,176)
Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(215)	(236)	(138)
Foreign currency translation adjustment
Change in fair value of cash flow hedges	133	34	(157)
Change in unrecognized actuarial loss on pension obligations
Income tax effect	(50)	(13)	59
Ending Balance	(132)	(215)	(236)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(344)	(428)	38
Foreign currency translation adjustment	(321)	84	(466)
Change in fair value of cash flow hedges
Change in unrecognized actuarial loss on pension obligations
Income tax effect
Ending Balance	(665)	(344)	(428)
Minimum Pension Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(6,768)	(6,512)	(4,830)
Foreign currency translation adjustment
Change in fair value of cash flow hedges
Change in unrecognized actuarial loss on pension obligations	2,116	(419)	(2,753)
Income tax effect	(824)	163	1,071
Ending Balance	$ (5,476)	$ (6,768)	$ (6,512)