Securities Securities Part 5 (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	$ 331,887	$ 651,226	$ 672,191
Fair Value Option Securities, Unrealized Gain or Loss	15,186	19,251	18,875
U.S. Agency Residential Mortgage-backed Securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	305,445	626,109	672,191
Fair Value Option Securities, Unrealized Gain or Loss	13,827	19,233	18,875
Corporate Debt Securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	26,442	25,117	0
Fair Value Option Securities, Unrealized Gain or Loss	$ 1,359	$ 18	$ 0