Loans (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Unpaid Principal Balance
Total with no related allowance recorded	$ 11,875		$ 15,035
Total with an allowance recorded	6,589		7,303
Total	18,464		22,338
Recorded Investment
Total with no related allowance recorded	11,875		14,083
Total with an allowance recorded	6,506		5,561
Total	18,381	16,591	19,644
Total with an allowance recorded, Allowance for Loan Losses Allocated	3,026		2,740
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	19,013	17,252
Interest income during impairment		15
Cash-basis interest earned		15
Commercial
Unpaid Principal Balance
Total with no related allowance recorded	3,939		7,829
Total with an allowance recorded	4,272		3,678
Recorded Investment
Total with no related allowance recorded	3,939		6,978
Total with an allowance recorded	4,189		3,182
Total with an allowance recorded, Allowance for Loan Losses Allocated	2,031		1,963
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	9,145	11,450
Real estate | Commercial and residential
Unpaid Principal Balance
Total with no related allowance recorded	3,622		2,755
Total with an allowance recorded	1,882		3,183
Recorded Investment
Total with no related allowance recorded	3,622		2,741
Total with an allowance recorded	1,882		1,937
Total with an allowance recorded, Allowance for Loan Losses Allocated	683		465
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	5,090	2,773
Interest income during impairment		1
Cash-basis interest earned		1
Real estate | Home equity
Unpaid Principal Balance
Total with no related allowance recorded	2,137		2,141
Total with an allowance recorded	294		295
Recorded Investment
Total with no related allowance recorded	2,137		2,141
Total with an allowance recorded	294		295
Total with an allowance recorded, Allowance for Loan Losses Allocated	294		295
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	2,434	16
Real estate | Land and construction
Unpaid Principal Balance
Total with no related allowance recorded	2,177		2,310
Recorded Investment
Total with no related allowance recorded	2,177		2,223
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	2,200	3,002
Interest income during impairment		14
Cash-basis interest earned		14
Consumer
Unpaid Principal Balance
Total with an allowance recorded	141		147
Recorded Investment
Total with an allowance recorded	141		147
Total with an allowance recorded, Allowance for Loan Losses Allocated	18		17
Average impaired loans with interest recognized and cash-basis interest earned on impaired loans
Average of impaired loans during the period	$ 144	$ 11