Fair Value (Assets Remeasured At Fair Value On Non-Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014
Non-Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss, Impaired mortgage loans held for investment	$ (1,756)	$ (4,022)
Non-Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for investment	0	0
As a percentage of total assets	0.00%	0.00%
Non-Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for investment	0	0
As a percentage of total assets	0.00%	0.00%
Non-Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for investment	57,314	71,053
As a percentage of total assets	1.30%	2.00%
Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired mortgage loans held for investment	$ 57,314	$ 71,053
As a percentage of total assets	1.30%	2.00%