Off-Balance Sheet Credit Risk (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Fair value of securities accepted as collateral permitted to sell or repledge	$ 1,300,000,000	$ 1,200,000,000
Fair value of collateral securities sold or repledged	246,200,000	263,800,000
Outstanding commitments to originate loans	104,000,000	66,800,000
Letters of credit outstanding	5,300,000	5,100,000
Unused lines of Credit [Member]
Unused lines of credit to commercial and consumer borrowers	$ 321,500,000	$ 282,000,000