Mortgage Loans Held For Investment And Related Assets (Information Related To Activities Of Non-Performing Assets) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Oct. 31, 2012	Oct. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	$ 167,864	$ 262,405
Interest income on impaired loans	2,150	3,314
Interest income on impaired loans recognized on a cash basis on non-accrual status	2,101	3,197
Purchased From SCC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	141,521	226,880
Interest income on impaired loans	1,992	3,076
Interest income on impaired loans recognized on a cash basis on non-accrual status	1,956	2,973
All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	26,343	35,525
Interest income on impaired loans	158	238
Interest income on impaired loans recognized on a cash basis on non-accrual status	$ 145	$ 224