Investment Securities, Non-agency Securities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Investment Securities (Additional Textual) [Abstract]
Discount rate (in hundredths)		11.00%
Voluntary Prepayments (in hundredths)		16.20%
Conditional Default Rates (in hundredths)		16.20%
Duration period of 16.2% Conditional Default Rates		24 months
Conditional Default Rates after 24 months (in hundredths)		9.30%
Duration period of 9.3% Conditional Default Rates		12 months
Conditional Default Rates For 17 yrs after thirty six months (in hundredths)		0.00%
Duration period of zero Conditional Default Rates		17 years
Loss Severity (in hundredths)		55.50%
Terminal loss severities (in hundredths)		23.00%
Linear fashion loss severities (in hundredths)		2.50%
Percent of shares redeemed in Visa, Inc. public offering (in hundredths)	39.00%
Rating [Abstract]
Total Fair Value	$ 402,353	$ 299,204
Total Amortized Cost	385,781	279,209
Total OTTI Related To Credit Loss	0	1,052	0
CMOs [Member] | Non-Agency [Member]
Rating [Abstract]
Year of Vintage 2006		7,994
Total Fair Value		7,994
Total Amortized Cost		9,147
Total OTTI Related To Credit Loss		1,052
CCC and Below [Member] | Non-Agency [Member]
Rating [Abstract]
Year of Vintage 2006		7,994
Total Fair Value		7,994
Total Amortized Cost		9,147
Total OTTI Related To Credit Loss		$ 1,052