Investment Securities (Schedule Of Amortized Cost And Fair Value By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012	Jun. 30, 2012
Schedule of Investments [Line Items]
Within 1 year, Amortized Cost	$ 39,991
After 1 year; within 5 years, Amortized Cost	4,187
After 5 years; within 10 years, Amortized Cost	667
After 10 years, Amortized Cost	14,267
Subtotal, Amortized Cost	59,112
Within 1 year, Fair Value	39,997
After 1 year; within 5 years, Fair Value	4,354
After 5 years; within 10 years, Fair Value	667
After 10 years, Fair Value	14,278
Subtotal, Fair Value	59,296
Securities available for sale, Amortized Cost	3,213,047	[1]		3,160,646	[1]
Securities available for sale, Fair Value	3,229,071	[1]	3,061,808	3,264,866	[1]
Government Agency Issued Mbs And Cmo [Member]
Schedule of Investments [Line Items]
Securities available for sale, Amortized Cost	2,930,694
Securities available for sale, Fair Value	2,946,492
Equity Securities Other [Member]
Schedule of Investments [Line Items]
Securities available for sale, Amortized Cost	223,241
Securities available for sale, Fair Value	$ 223,283

[1] Includes $3.0 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.