Mortgage Loans Held for Investment and Related Assets (Schedule of Credit Quality Indicators and Portfolio Balance) (Details) (USD $) In Thousands	Apr. 30, 2011	Apr. 30, 2010
Portfolio balance	$ 572,974	$ 683,684
Purchased from SCC [Member]
Portfolio balance	357,814
Purchased from SCC [Member] | Occupancy Status, Owner Occupied [Member]
Portfolio balance	249,048
Purchased from SCC [Member] | Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	108,766
Purchased from SCC [Member] | Documentation Level, Full Documentation [Member]
Portfolio balance	108,509
Purchased from SCC [Member] | Documentation Level, Limited Documentation [Member]
Portfolio balance	11,146
Purchased from SCC [Member] | Documentation Level, Stated Income [Member]
Portfolio balance	205,485
Purchased from SCC [Member] | Documentation Level, No Documentation [Member]
Portfolio balance	32,674
Purchased from SCC [Member] | Internal Risk Rating, High [Member]
Portfolio balance	151,522
Purchased from SCC [Member] | Internal Risk Rating, Medium [Member]
Portfolio balance	206,292
All Other [Member]
Portfolio balance	215,160
All Other [Member] | Occupancy Status, Owner Occupied [Member]
Portfolio balance	136,380
All Other [Member] | Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	78,780
All Other [Member] | Documentation Level, Full Documentation [Member]
Portfolio balance	157,270
All Other [Member] | Documentation Level, Limited Documentation [Member]
Portfolio balance	23,355
All Other [Member] | Documentation Level, Stated Income [Member]
Portfolio balance	21,705
All Other [Member] | Documentation Level, No Documentation [Member]
Portfolio balance	12,830
All Other [Member] | Internal Risk Rating, High [Member]
Portfolio balance	357
All Other [Member] | Internal Risk Rating, Low [Member]
Portfolio balance	214,803
Occupancy Status, Owner Occupied [Member]
Portfolio balance	385,428
Occupancy Status, Non-Owner Occupied [Member]
Portfolio balance	187,546
Documentation Level, Full Documentation [Member]
Portfolio balance	265,779
Documentation Level, Limited Documentation [Member]
Portfolio balance	34,501
Documentation Level, Stated Income [Member]
Portfolio balance	227,190
Documentation Level, No Documentation [Member]
Portfolio balance	45,504
Internal Risk Rating, High [Member]
Portfolio balance	151,879
Internal Risk Rating, Medium [Member]
Portfolio balance	206,292
Internal Risk Rating, Low [Member]
Portfolio balance	$ 214,803