Federal, State and Local Income Taxes - Provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jul. 31, 2013	Jul. 31, 2012
Current tax expense:
Federal	$ 216	$ 448
State and local	28	73
Current tax expense	244	521
Deferred tax expense:
Federal	506	467
State and local	81	87
Deferred tax expense	587	554
Income tax provision:	$ 831	$ 1,075

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.