Loans and reserve for credit losses (Financing Receivable Credit Quality Indicators) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Commercial real estate:
Owner occupied	$ 195,111	$ 204,998
Non-owner occupied	348,597	347,014
Total commercial real estate loans	543,708	552,012
Construction	55,436	52,503
Residential real estate	100,550	101,557
Commercial and industrial	273,444	254,170
Consumer	34,216	35,990
Total loans, Amount	1,007,354	996,232
Acceptable
Commercial real estate:
Owner occupied	145,041	147,865
Non-owner occupied	289,886	278,854
Total commercial real estate loans	434,927	426,719
Construction	50,188	46,274
Residential real estate	97,910	98,633
Commercial and industrial	257,166	242,053
Consumer	34,165	35,984
Total loans, Amount	874,356	849,663
Pass-Watch
Commercial real estate:
Owner occupied	17,945	19,798
Non-owner occupied	35,332	33,827
Total commercial real estate loans	53,277	53,625
Construction	2,322	2,772
Residential real estate	1,536	1,570
Commercial and industrial	8,572	3,518
Consumer	0	0
Total loans, Amount	65,707	61,485
Special Mention
Commercial real estate:
Owner occupied	10,777	14,730
Non-owner occupied	13,814	24,188
Total commercial real estate loans	24,591	38,918
Construction	1,798	2,131
Residential real estate	167	147
Commercial and industrial	1,571	2,694
Consumer	0	0
Total loans, Amount	28,127	43,890
Substandard
Commercial real estate:
Owner occupied	21,348	22,605
Non-owner occupied	9,565	10,145
Total commercial real estate loans	30,913	32,750
Construction	1,128	1,326
Residential real estate	937	1,207
Commercial and industrial	6,135	5,905
Consumer	51	6
Total loans, Amount	$ 39,164	$ 41,194

Amount before allowance of consumer loans, including, but not limited to, mortgage, home equity, vehicles, credit card, installment, and lease financing. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance of consumer real estate loans. Includes, but not limited to, construction financing, residential mortgage loans, and home equity lines of credit. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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- Definition

Amount before allowance of commercial loans to acquire real property. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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- Definition

Amount before allowance of loans issued to commercial and industrial institutions. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes real estate loans and loans covered under loss sharing agreements.

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- Definition

Amount before allowance of commercial construction loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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- Definition

Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5066-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 51, 52, 53

-IssueDate 2006-05-01

-Chapter 8

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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