Federal, State and Local Income Taxes - Provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Current tax expense (benefit):
Federal	$ 2,707	$ 2,679	$ 139
State and local	239	130	(54)
Current tax expense (benefit)	2,946	2,809	85
Deferred tax expense (benefit):
Federal	572	728	3,785
State and local	(108)	350	503
Deferred tax expense (benefit)	464	1,078	4,288
Income tax provision	$ 3,410	$ 3,887	$ 4,373

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.