Leases (Schedule of Future Minimum Payments for Capital Leases And Noncancelable Operating Leases) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Leases [Abstract]
Capital leases, Future minimum payments due, 2014	$ 1,352
Capital leases, Future minimum payments due, 2015	989
Capital leases, Future minimum payments due, 2016	814
Capital leases, Future minimum payments due, 2017	772
Capital leases, Future minimum payments due, 2018	773
Capital leases, Future minimum payments due, Thereafter	12,675
Total minimum capital lease payments	17,375
Less amount representing interest	7,484
Present value of net minimum lease payments	9,891
Operating leases, Future minimum payments due, 2014	910
Operating leases, Future minimum payments due, 2015	514
Operating leases, Future minimum payments due, 2016	231
Operating leases, Future minimum payments due, 2017	131
Operating leases, Future minimum payments due, 2018	131
Operating leases, Future minimum payments due, Thereafter	350
Total minimum operating lease payments	2,267
Rent expense under operating leases	$ 1,773	$ 1,269	$ 674