Securities Part 6 (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Marketable Securities [Abstract]
Securities Pledged as Collateral, Amortized Cost	$ 3,700,000,000	$ 4,400,000,000	$ 3,600,000,000
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities Fair Value	325,177,000	651,226,000	553,231,000
Fair Value Option Securities Unrealized Gain or Loss	8,994,000	19,251,000	5,731,000
U.S. agency residental mortgage backed securities - Other [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities Fair Value	299,467,000	626,109,000	553,231,000
Fair Value Option Securities Unrealized Gain or Loss	8,373,000	19,233,000	5,731,000
Corporate Debt Securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities Fair Value	25,710,000	25,117,000	0
Fair Value Option Securities Unrealized Gain or Loss	$ 621,000	$ 18,000	$ 0