Mortgage Loans Held For Investment And Related Assets (Schedule Of Credit Quality Indicators And Portfolio Balance) (Details) (USD $) In Thousands	Jul. 31, 2011	Apr. 30, 2011
Portfolio balance	$ 553,991	$ 572,974
Purchased From SCC [Member]
Portfolio balance	346,695
Purchased From SCC [Member] | Occupancy Status, Owner Occupied [Member]
Portfolio balance	244,259
Purchased From SCC [Member] | Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	102,436
Purchased From SCC [Member] | Documentation Level, Full Documentation [Member]
Portfolio balance	105,547
Purchased From SCC [Member] | Documentation Level, Limited Documentation [Member]
Portfolio balance	10,447
Purchased From SCC [Member] | Documentation Level, Stated Income [Member]
Portfolio balance	198,898
Purchased From SCC [Member] | Documentation Level, No Documentation [Member]
Portfolio balance	31,803
Purchased From SCC [Member] | Internal Risk Rating, High [Member]
Portfolio balance	143,931
Purchased From SCC [Member] | Internal Risk Rating, Medium [Member]
Portfolio balance	202,764
All Other [Member]
Portfolio balance	207,296
All Other [Member] | Occupancy Status, Owner Occupied [Member]
Portfolio balance	132,132
All Other [Member] | Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	75,164
All Other [Member] | Documentation Level, Full Documentation [Member]
Portfolio balance	150,972
All Other [Member] | Documentation Level, Limited Documentation [Member]
Portfolio balance	22,411
All Other [Member] | Documentation Level, Stated Income [Member]
Portfolio balance	21,168
All Other [Member] | Documentation Level, No Documentation [Member]
Portfolio balance	12,745
All Other [Member] | Internal Risk Rating, High [Member]
Portfolio balance	357
All Other [Member] | Internal Risk Rating, Low [Member]
Portfolio balance	206,939
Occupancy Status, Owner Occupied [Member]
Portfolio balance	376,391
Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	177,600
Documentation Level, Full Documentation [Member]
Portfolio balance	256,519
Documentation Level, Limited Documentation [Member]
Portfolio balance	32,858
Documentation Level, Stated Income [Member]
Portfolio balance	220,066
Documentation Level, No Documentation [Member]
Portfolio balance	44,548
Internal Risk Rating, High [Member]
Portfolio balance	144,288
Internal Risk Rating, Medium [Member]
Portfolio balance	202,764
Internal Risk Rating, Low [Member]
Portfolio balance	$ 206,939