Stock-based Compensation - 2008 Share Incentive Plan - Stock Options Activity (Details) (Share Incentive Plan (2008 Plan), USD $)	9 Months Ended	12 Months Ended
	Jan. 31, 2014	Apr. 30, 2013
Share Incentive Plan (2008 Plan)
Number of options:
Outstanding, beginning of year	531,479	559,305
Granted	0	0
Forfeited	0	(27,826)
Outstanding, end of period	531,479	531,479
Exercisable, end of period	531,479	502,261
Weighted average exercise price:
Outstanding, beginning of year	$ 40.00	$ 40.00
Granted	$ 0.00	$ 0.00
Forfeited	$ 0.00	$ 40.00
Outstanding, end of period	$ 40.00	$ 40.00
Weighted remaining contractual life	4 years 7 months 6 days	5 years 4 months 24 days