Commitments And Contingencies (Narrative) (Details) (USD $)	3 Months Ended		39 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Apr. 30, 2011	Apr. 30, 2009
Standard guarantee accrual amount	$ 13,000,000		$ 13,000,000	$ 14,700,000
Contingent business acquisition obligations	1,400,000		1,400,000	3,800,000
Contingent consideration liability recorded	10,200,000		10,200,000	11,000,000
Maximum exposure to economic loss under the administrative services agreement	95,200,000		95,200,000
Percentage of loans originated in 2006 and 2007	89.00%		89.00%
Amount of loans originated during 2005 through 2007	84,000,000,000		84,000,000,000
Percentage of loans issued to government sponsored entities	1.00%		1.00%
Reserve for losses on repurchases	125,775,000	188,130,000	125,775,000	126,260,000	188,200,000
Payments under indemnity agreement dated April 2008		(70,000)
Increase in losses due to assumed 1% increase in validity rates and loss severities	16,000,000
Claims subject to review by SCC, amount	66,000,000		66,000,000
Percentage of claims denied by SCC	85.00%
Percentage of valid claims that resulted in loan repurchases	22.00%
Percentage of valid claims that resulted in indemnification or settlement payments	78.00%
Loss severity rate	57.00%		57.00%
Losses incurred on claim settlements			117,000,000
Net balance of all mortgage loans held for sale by SCC	11,900,000		11,900,000
Provisions for additional losses on repurchases	0
Minimum [Member]
Number of days to respond to representation and warranty claims	60
Maximum [Member]
Percentage of loans issued to government sponsored entities	1.00%		1.00%
Number of days to respond to representation and warranty claims	120
2005 [Member]
Value of loans which have defaulted in the first two years	4,000,000,000		4,000,000,000
2006 [Member]
Value of loans which have defaulted in the first two years	6,300,000,000		6,300,000,000
2007 [Member]
Value of loans which have defaulted in the first two years	2,900,000,000		2,900,000,000
Private-Label Securitization Transactions [Member]
Claims subject to review by SCC, amount	52,000,000		52,000,000
Monoline Insurers [Member]
Claims subject to review by SCC, amount	14,000,000		14,000,000
Indemnity Agreement With Single Counterparty [Member]
Reserve for losses on repurchases	49,800,000		49,800,000
Additional Information Requested By Counterparty [Member]
Claims subject to review by SCC, amount	$ 8,000,000		$ 8,000,000