Investment Securities (Visa Class B restricted Shares) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net Investment Income [Line Items]
Gain on sale of securities	$ 2,160	$ 0
Visa Class B Restricted Securities [Member]
Net Investment Income [Line Items]
Conversion ratio of convertible securities	0.4206
Gain on sale of securities	$ 2,000
Sale of investment securities, shares	22,000
Equity securities remaining, shares	482,114
Visa Class A Unrestricted Securities [Member]
Net Investment Income [Line Items]
Sale of investment securities, shares	9,253
Equity securities remaining, shares	202,777