Allowance for Loan Losses Financing Receivable and Allowance Element by Class (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 12,720	$ 12,500	$ 12,954	$ 13,000
Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	3,105	3,539	2,348
General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	4,315	4,304	4,532
Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	4,211	3,815	4,375
Unallocated Reserves [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,089	842	1,699
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	5,879	5,865	5,862	5,659
Commercial Real Estate Portfolio Segment [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,473	1,523	944
Commercial Real Estate Portfolio Segment [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	2,177	2,369	2,648
Commercial Real Estate Portfolio Segment [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	2,229	1,973	2,270
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,064	1,359	704	658
Commercial Construction [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	760	969	117
Commercial Construction [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	150	213	316
Commercial Construction [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	154	177	271
Commercial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	2,115	2,050	2,125	2,063
Commercial Other [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	535	652	480
Commercial Other [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	781	763	886
Commercial Other [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	799	635	759
Municipal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	18	18	19	19
Municipal [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		0	0
Municipal [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		0	0
Municipal [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	18	18	19
Residential Term [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,113	1,109	1,236	1,159
Residential Term [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	337	395	592
Residential Term [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	336	278	185
Residential Term [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	440	436	459
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	9	11	59	255
Residential Construction [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	0	0	49
Residential Construction [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	4	4	2
Residential Construction [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	5	7	8
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	859	654	682	595
Home Equity [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	0	0	156
Home Equity [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	522	315	176
Home Equity [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	337	339	350
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	574	592	568	584
Consumer Portfolio Segment [Member] \| Specific Reserves Evaluated Individually for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	0	0	10
Consumer Portfolio Segment [Member] \| General Reserves Based on Historical Loss Experience [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	345	362	319
Consumer Portfolio Segment [Member] \| Reserve for Qualitative Factors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	229	230	239
Unallocated Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,089	842	1,699	2,008
Unallocated Financing Receivables [Member] \| Unallocated Reserves [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 1,089	$ 842	$ 1,699

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 8, 9

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 3: 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(d))

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

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

-Publisher OTS

-Name Federal Regulation (FR)

-Number Title 12

-Section 563c.102

-Paragraph 8

-Subparagraph a(ii)

-Chapter V

-Subsection I

-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph d

-Article 9

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1

+ Details