Securities Fair Value Option Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	$ 167,860	$ 284,296	$ 331,887
Fair Value Option Securities, Unrealized Gain or Loss	(5,364)	4,770	15,186
U.S. agency residential mortgage-backed securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	163,567	257,040	305,445
Fair Value Option Securities, Unrealized Gain or Loss	(5,365)	3,314	13,827
Corporate debt securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	0	26,486	26,442
Fair Value Option Securities, Unrealized Gain or Loss	0	1,409	1,359
Other debt securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	4,293	770	0
Fair Value Option Securities, Unrealized Gain or Loss	$ 1	$ 47	$ 0