Loans and reserve for credit losses (Schedule of Accounts, Notes, Loans and Financing Receivable) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Commercial real estate:
Owner occupied	$ 204,998	$ 196,821
Non-owner occupied	347,014	328,480
Total commercial real estate loans	552,012	525,301
Construction	52,503	45,650
Residential real estate	101,557	85,494
Commercial and industrial	254,170	162,213
Consumer	35,990	39,506
Total loans	996,232	858,164
Less:
Deferred loan fees, net	(1,757)	(1,846)
Reserve for loan losses	(20,857)	(27,261)
Loans, net, Amount	$ 973,618	$ 829,057
Owner occupied, Percent	20.60%	22.90%
Non-owner occupied, Percent	34.80%	38.30%
Total commercial real estate loans, Percent	55.40%	61.20%
Construction, Percent	5.30%	5.30%
Residential real estate, Percent	10.20%	10.00%
Commercial and industrial, Percent	25.50%	18.90%
Consumer, Percent	3.60%	4.60%
Total loans, Percent	100.00%	100.00%