Federal, State and Local Income Taxes - Tax effect of temporary differences in deferred tax asset and deferred tax liability (Details 1) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Deferred Tax Assets and Liabilities [Line Items]
Deferred tax asset, short term	$ 364	$ 227
Deferred gain on deconsolidation of EAM	50,510
Deferred non-cash post-employment compensation	1,770
Deferred tax liability, long term	22,520	21,326
Federal tax benefit (liability)
Deferred Tax Assets and Liabilities [Line Items]
Unrealized gains on securities available-for-sale	(134)	(136)
Operating lease exit obligation	70	13
Deferred professional fees	36	49
Deferred charges	327	265
Deferred tax asset, short term	299	191
Deferred gain on deconsolidation of EAM	17,679	17,679
Deferred non-cash post-employment compensation	(619)	(619)
Depreciation and amortization	2,416	1,642
Other	646	262
Deferred tax liability, long term	20,122	18,964
State and local tax liability (benefit)
Deferred Tax Assets and Liabilities [Line Items]
Other - deferred charges	65	36
Deferred tax asset, short term	65	36
Deferred gain on deconsolidation of EAM	2,181	2,243
Deferred non-cash post-employment compensation	(76)	(79)
Depreciation and amortization	298	208
Deferred professional fees	(5)	(10)
Deferred tax liability, long term	$ 2,398	$ 2,362