Federal, State and Local Income Taxes - Provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Current tax expense/(benefit):
Federal	$ 448	$ 50
State and local	73	(121)
Current tax expense (benefit)	521	(71)
Deferred tax expense (benefit):
Federal	467	1,006
State and local	87	210
Deferred tax expense (benefit)	554	1,216
Income tax provision:	$ 1,075	$ 1,145