Mortgage Loans Held For Investment And Related Assets (Information Related To Activities Of Non-Performing Assets) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2012	Jan. 31, 2011
Mortgage Loans Held For Investment And Related Assets [Line Items]
Average impaired loans	$ 259,423	$ 308,282
Interest income on impaired loans	4,688	4,975
Interest income on impaired loans recognized on a cash basis on non-accrual status	4,506	4,711
Purchased From SCC [Member]
Mortgage Loans Held For Investment And Related Assets [Line Items]
Average impaired loans	224,002
Interest income on impaired loans	4,340
Interest income on impaired loans recognized on a cash basis on non-accrual status	4,182
All Other [Member]
Mortgage Loans Held For Investment And Related Assets [Line Items]
Average impaired loans	35,421
Interest income on impaired loans	348
Interest income on impaired loans recognized on a cash basis on non-accrual status	$ 324