Loans, Allowance for Loan Losses, and Credit Quality (Details Textuals) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Loans Allowance for Loan Losses and Credit Quality Disclosure (Textuals) [Abstract]
Interest income recognized on accruing restructured loans	$ 4,200,000	$ 4,000,000
Restructured Loans Still Accruing	44,000,000	36,000,000
Restructured Loans Subsequently Accruing	77,000,000	77,000,000
Performing Restructured Loans	120,719,000	113,164,000
Nonaccrual Restructured Loans	79,946,000	87,493,000
Accruing loans past due 90 days or more	$ 2,497,000	$ 4,925,000