Earnings Per Share - Schedule of Numerator and Denominator Used in Computation of Earnings Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014 Class A Common Stock [Member]	Apr. 30, 2014 Class A Common Stock [Member]	Oct. 31, 2013 Class A Common Stock [Member]	Oct. 31, 2014 Class B Common Stock [Member]	Apr. 30, 2014 Class B Common Stock [Member]	Oct. 31, 2013 Class B Common Stock [Member]
Numerator:
Income (loss) from continuing operations before discontinued operations attributable to common stockholders	$ 259	$ (294)	$ (31)	$ (437)
Number of shares outstanding, end of period:
Common stock shares outstanding					39,545,000	39,086,000	39,011	988,000	988,000	988,000
Unvested restricted stock	(159,000)	(130,000)	(159,000)	(130,000)
Effect of weighted average shares outstanding during period	(48,000)	(48,000)	(149,000)	(127,000)
Weighted average number of common shares used in basic EPS	40,326,000	39,821,000	40,225,000	39,742,000
Impact of potentially dilutive securities:
Dilutive effect of options and restricted / performance stock units	216,000
Weighted average number of common shares used in diluted EPS	40,542,000	39,821,000	40,225,000	39,742,000
Number of antidilutive potentially issuable shares not included in the diluted earnings per share calculations	1,230,000	2,332,000	2,191,000	2,332,000