Loans, Allowance for Loan Losses, and Credit Quality (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loans Allowance for Loan Losses and Credit Quality Disclosure (Textuals) [Abstract]
Interest income recognized on accruing restructured loans	$ 6,000,000	$ 6,000,000
Restructured Loans Subsequently Accruing	28,000,000
YTD restructured loans still on nonaccrual	32,000,000
Restructured loans during the period	59,599,000	120,806,000
Performing Restructured Loans	121,087,000	113,164,000
Nonaccrual Restructured Loans	80,590,000	87,493,000
Average Recorded Investment	399,793,000	522,649,000	702,000,000
Interest Income Recognized	11,726,000	13,414,000	16,000,000
Commitments to lend additional funds to borrowers with restructured loans	$ 8,000,000