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, 2013	Jan. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	$ 163,582	$ 259,423
Interest income on impaired loans	3,172	4,688
Interest income on impaired loans recognized on a cash basis on non-accrual status	3,095	4,506
Purchased From SCC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	137,703	224,002
Interest income on impaired loans	2,940	4,340
Interest income on impaired loans recognized on a cash basis on non-accrual status	2,881	4,182
All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average impaired loans	25,879	35,421
Interest income on impaired loans	232	348
Interest income on impaired loans recognized on a cash basis on non-accrual status	$ 214	$ 324