Investment Securities (Schedule Of Investments Within The Available For Sale Portfolio That Had Unrealized Losses) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Schedule of Investments [Line Items]
Less than 12 months, Fair Value	$ 349,413	$ 101,397
Less than 12 months, Unrealized Losses	(1,391)	(734)
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
Total Fair Value	349,413	101,397
Total Unrealized Losses	(1,391)	(734)
Mortgage Backed Securities Issued By U S Government Sponsored Enterprises [Member]
Schedule of Investments [Line Items]
Less than 12 months, Fair Value	44,095	101,397
Less than 12 months, Unrealized Losses	(381)	(734)
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
Total Fair Value	44,095	101,397
Total Unrealized Losses	(381)	(734)
Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Less than 12 months, Fair Value	305,318
Less than 12 months, Unrealized Losses	(1,010)
12 months or longer, Fair Value	0
12 months or longer, Unrealized Losses	0
Total Fair Value	305,318
Total Unrealized Losses	$ (1,010)