Federal, State and Local Income Taxes - Provision for income taxes differs from the amount of income tax determined by applying the applicable U.S. statutory income tax rate (Details 2)	3 Months Ended
	Jul. 31, 2013	Jul. 31, 2012
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
U.S. statutory federal rate	35.00%	35.00%
Increase (decrease) in tax rate from:
State and local income taxes, net of federal income tax benefit	2.24%	2.93%
Effect of dividends received deductions	(0.37%)	(0.22%)
Other, net	(0.36%)	0.00%
Effective income tax rate	36.51%	37.71%