Loans and Allowance for Credit Losses Narrative (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan losses gross		$ 1,200,000	$ 176,000	$ 816,000	$ 302,000
Provision for credit losses		9,500,000	23,000,000	38,000,000	76,500,000
Percentage of unallocated allowance		9.00%	10.00%	9.00%	10.00%
Recorded Investment, Loans Sold	44,110,000	16,420,000		41,830,000
Charge-offs Upon Sale, Loan Sold	21,180,000	6,040,000		17,970,000
Minimum balance of loans evaluated individually for impairment				1,000,000
Impaired loans with principal balances approximately in percentage				79.00%	78.00%
Impaired loans balances, real estate as collateral		1,000,000		1,000,000
Loan to value ratio in the Corporation's policy		70.00%		70.00%
Recorded investment, with no related allowance		73,932,000		73,932,000		94,451,000
TDR additional commitments to lend		$ 12,000,000		$ 12,000,000		$ 7,400,000
Delinquent [Member] | Minimum [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Days past due				31
Delinquent [Member] | Maximum [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Days past due				89
Non-performing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Days past due				90