Long-Term Borrowings (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		3 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Callable national market repurchase agreements	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 FHLB putable non-amortizing, fixed rate advances Minimum [Member]	Dec. 31, 2012 FHLB putable non-amortizing, fixed rate advances Maximum [Member]	Mar. 31, 2012 FHLB convertible rate advances	Dec. 31, 2012 FHLB convertible rate advances Minimum [Member]	Dec. 31, 2012 FHLB convertible rate advances Maximum [Member]	Dec. 31, 2012 FHLB amortizing, fixed rate advances Minimum [Member]	Dec. 31, 2012 FHLB amortizing, fixed rate advances Maximum [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt	$ 24
Maturity Period of Long-Term Borrowing	5 years
Total Risk-Based Capital Ratio Minimum Under Debt Covenant	12.50%
Nonperforming Assets to Tangible Capital plus Allowance for Loan Losses Maximum Under Debt Covenant	20.00%
Allowance for Loan Losses to Nonperforming Loans Minimum Under Debt Covenant	80.00%
Repurchase agreements, maturities period				5 years	10 years
Repurchase agreements, call option features at buyer discretion, initial call period				3 months	5 years
Prepayment of wholesale borrowings			25.0					10.0
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate								3.05%
Early termination fees			$ 2.2					$ 0.9
Callable national market repurchase agreements, Weighted-Average Rate	3.63%	3.43%	3.10%
FHLB advances, maturities period						10 years	20 years				10 years	20 years
FHLB advances,fixed rate intial period									3 months	5 years