Consolidated Statements Of Shareholders' Equity (USD $) In Thousands, except Share data	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Apr. 30, 2011	$ 92,408	$ 83,495	$ (21,938)	$ 153,965
Balance, Shares at Apr. 30, 2011	14,295,540
Net income (loss)		(20,786)		(20,786)
Other comprehensive loss, net of tax			(5,669)	(5,669)
Stock-based compensation	3,413			3,413
Adjustments to excess tax benefit from stock-based compensation	(859)			(859)
Cash dividends		(1,287)		(1,287)
Exercise of stock-based compensation awards, shares	19,410
Exercise of stock-based compensation awards	12			12
Employee benefit plan contributions, shares	80,323
Employee benefit plan contributions	1,231			1,231
Balance at Apr. 30, 2012	96,205	61,422	(27,607)	130,020
Balance, Shares at Apr. 30, 2012	14,395,273
Net income (loss)		9,758		9,758
Other comprehensive loss, net of tax			(4,543)	(4,543)
Stock-based compensation	3,509			3,509
Adjustments to excess tax benefit from stock-based compensation	(650)			(650)
Exercise of stock-based compensation awards, shares	328,490
Exercise of stock-based compensation awards	5,768			5,768
Employee benefit plan contributions, shares	98,817
Employee benefit plan contributions	2,333			2,333
Balance at Apr. 30, 2013	107,165	71,180	(32,150)	146,195
Balance, Shares at Apr. 30, 2013	14,822,580			14,822,580
Net income (loss)		20,461		20,461
Other comprehensive loss, net of tax			6,170	6,170
Stock-based compensation	3,295			3,295
Adjustments to excess tax benefit from stock-based compensation	600			600
Exercise of stock-based compensation awards, shares	643,558
Exercise of stock-based compensation awards	13,122			13,122
Stock repurchases, shares	(100,000)
Stock repurchases	(654)	(2,487)		(3,141)
Employee benefit plan contributions, shares	110,160
Employee benefit plan contributions	3,843			3,843
Balance at Apr. 30, 2014	$ 127,371	$ 89,154	$ (25,980)	$ 190,545
Balance, Shares at Apr. 30, 2014	15,476,298			15,476,298