Short-Term Borrowings and Long-Term Debt (Subordinated Debt) (Details) (CommunityOne [Member], USD $)	0 Months Ended	3 Months Ended	12 Months Ended
	Oct. 21, 2011	Mar. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Subordinated debt	$ 0
Nonvoting, nonconvertible, nonredeemable cumulative preferred stock [Member]
Debt Instrument [Line Items]
Preferred stock repurchased, liquidation preference	12,500,000
Portion of repurchase price, percentage of aggregate liquidation preference	25.00%
Portion of repurchase price, percentage of unpaid and accrued dividends	100.00%
Nonvoting, nonconvertible, nonredeemable cumulative preferred stock [Member] | Retained earnings [Member]
Debt Instrument [Line Items]
Increase in equity resulting from preferred stock repurchased	9,400,000
Subordinated debt [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt settled	2,500,000
Portion of cash settlement price, percentage of aggregate principal amount	35.00%
Portion of cash settlement price, percentage of unpaid and accrued interest	100.00%
Gains on extinguishment of debt	1,600,000
Debt amount converted		5,000,000	7,500,000
Subordinated debt [Member] | Nonvoting, nonconvertible, nonredeemable cumulative preferred stock [Member]
Debt Instrument [Line Items]
Amount of preferred stock debt was converted into			$ 7,500,000