Federal, State and Local Income Taxes - Provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Current tax expense:
Federal	$ 1,083	$ 838	$ 1,952	$ 1,054
State and local	62	46	152	74
Current tax expense	1,145	884	2,104	1,128
Deferred tax expense:
Federal	(106)	24		530
State and local	40	10	64	91
Deferred tax expense	(66)	34	64	621
Income tax provision:	$ 1,079	$ 918	$ 2,168	$ 1,749

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.