Assets and Liabilities Measured at Fair Value (Fair Value Assets And Liabilities Measured At Fair Value On A Recurring And Non-Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jul. 31, 2011	Jul. 31, 2010
Total gain (loss) on financial instruments	$ 430	$ (3,888)	[1]
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities [Member]
Gain (loss) on investments	1,936	(20)	[1]
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities [Member] | Total [Member]
Investments	192,491	21,893	[1]
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investments	192,491	21,893	[1]
Fair Value, Measurements, Recurring [Member] | Municipal Bonds [Member]
Gain (loss) on investments	449	566	[1]
Fair Value, Measurements, Recurring [Member] | Municipal Bonds [Member] | Total [Member]
Investments	7,758	8,981	[1]
Fair Value, Measurements, Recurring [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Investments	7,758	8,981	[1]
Fair Value, Measurements, Recurring [Member] | Trust Preferred Security [Member]
Gain (loss) on investments		(1,618)	[1]
Fair Value, Measurements, Recurring [Member] | Trust Preferred Security [Member] | Total [Member]
Investments		32	[1]
Fair Value, Measurements, Recurring [Member] | Trust Preferred Security [Member] | Fair Value, Inputs, Level 2 [Member]
Investments		32	[1]
Fair Value, Measurements, Non-recurring [Member]
Gain or Loss On Real Estate Owned	(482)	(589)	[1]
Gain (loss) on impaired mortgage loans held for investment	(1,473)	(2,227)	[1]
Fair Value, Measurements, Non-recurring [Member] | Total [Member]
REO	3,446	3,321	[1]
Impaired mortgage loans held for investment	61,997	69,467	[1]
Fair Value, Measurements, Non-recurring [Member] | Fair Value, Inputs, Level 3 [Member]
REO	3,446	3,321	[1]
Impaired mortgage loans held for investment	61,997	69,467	[1]
Total [Member]
Total financial assets at fair value	265,692	103,694	[1]
As a percentage of total assets	6.20%	2.30%	[1]
Fair Value, Inputs, Level 2 [Member]
Total financial assets at fair value	200,249	30,906	[1]
As a percentage of total assets	4.70%	0.70%	[1]
Fair Value, Inputs, Level 3 [Member]
Total financial assets at fair value	$ 65,443	$ 72,788	[1]
As a percentage of total assets	1.50%	1.60%	[1]

[1] Amounts have been restated to conform to the current period presentation.