Federal, State and Local Income Taxes - Provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Current tax expense:
Federal	$ 949	$ 727	$ 2,003	$ 2,054
State and local	66	156	140	258
Current tax expense	1,015	883	2,143	2,312
Deferred tax expense:
Federal	(9)	97	521	533
State and local	20	23	111	140
Deferred tax expense	11	120	632	673
Income tax provision:	$ 1,026	$ 1,003	$ 2,775	$ 2,985

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.