Commitments And Contingencies (Narrative) (Details) (USD $)	3 Months Ended										6 Months Ended		12 Months Ended
	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2009	Jul. 31, 2009	Oct. 31, 2011	Oct. 31, 2010	Apr. 30, 2009	Apr. 30, 2007	Apr. 30, 2006	Apr. 30, 2005
Standard guarantee accrual amount	$ 11,800,000		$ 14,700,000								$ 11,800,000
Contingent business acquisition obligations	8,700,000		11,000,000								8,700,000
Claims received for loans	483,000,000	31,000,000	55,000,000	33,000,000	21,000,000	109,000,000	45,000,000	11,000,000	83,000,000	6,000,000	1,309,000,000		432,000,000
Percentage of denied loan repurchase claims received											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%
Losses incurred on claim settlements											120,000,000
Loss severity rates on repurchases and indemnification											58.00%
Net balance of all mortgage loans held for sale by SCC	11,800,000										11,800,000
Claims subject to review by SCC, amount	537,000,000										537,000,000
Amount of claims under review representing requests for additions											46,000,000
Percentage of loans originated in 2006 and 2007	90.00%										90.00%
Amount of loans originated during 2005 through 2007	84,000,000,000										84,000,000,000
Percentage of loans issued to government sponsored entities, maximum	1.00%										1.00%
Value of loans which have defaulted in the first two years														2,900,000,000	6,300,000,000	4,000,000,000
Reserve for losses on repurchases		126,260,000			49,651,000	188,200,000						49,651,000
Payments under indemnity agreement	49,800,000											(134,000)
Loss severity rate, assumed	1.00%										1.00%
Increase in losses due to assumed 1% increase in validity rates and loss severities	28,000,000
Private-Label Securitization Transactions [Member]
Claims received for loans	385,000,000
Monoline Insurers [Member]
Claims received for loans	84,000,000
2005 [Member]
Claims received for loans			1,000,000		1,000,000	6,000,000			15,000,000		85,000,000		62,000,000
2006 [Member]
Claims received for loans	130,000,000	29,000,000	50,000,000	29,000,000	15,000,000	100,000,000	45,000,000	4,000,000	57,000,000	2,000,000	678,000,000		217,000,000
2007 [Member]
Claims received for loans	$ 353,000,000	$ 2,000,000	$ 4,000,000	$ 4,000,000	$ 5,000,000	$ 3,000,000		$ 7,000,000	$ 11,000,000	$ 4,000,000	$ 546,000,000		$ 153,000,000
Minimum [Member]
Number of days to respond to representation and warranty claims, in days											60
Maximum [Member]
Number of days to respond to representation and warranty claims, in days											120