Loans (Past Due Loans) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	$ 10,941		$ 10,423
Loans 60 to 89 Days Past Due	4,077		3,065
Loans Over 90 Days Past Due	8,596		12,785
Total Loans Past Due	23,614		26,273
Current Loans	2,233,083		2,120,886
Total loans	2,256,697	[1]	2,147,159	[1]
Loans Past Due and Nonaccrual	14,500		17,600
Commercial Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	3,978		1,621
Loans 60 to 89 Days Past Due	874		315
Loans Over 90 Days Past Due	2,495		4,995
Total Loans Past Due	7,347		6,931
Current Loans	685,874		617,882
Total loans	693,221		624,813
Commercial Construction and Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	0		0
Loans 60 to 89 Days Past Due	0		0
Loans Over 90 Days Past Due	0		0
Total Loans Past Due	0		0
Current Loans	25,132		10,955
Total loans	25,132		10,955
Commercial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	2,719		3,760
Loans 60 to 89 Days Past Due	1,169		982
Loans Over 90 Days Past Due	1,366		633
Total Loans Past Due	5,254		5,375
Current Loans	495,720		483,485
Total loans	500,974		488,860
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	2,368		3,969
Loans 60 to 89 Days Past Due	821		1,505
Loans Over 90 Days Past Due	3,924		6,283
Total Loans Past Due	7,113		11,757
Current Loans	685,546		666,825
Total loans	692,659		678,582
Homeowner Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	0		0
Loans 60 to 89 Days Past Due	0		0
Loans Over 90 Days Past Due	0		0
Total Loans Past Due	0		0
Current Loans	22,753		21,832
Total loans	22,753		21,832
Home Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	1,546		645
Loans 60 to 89 Days Past Due	914		210
Loans Over 90 Days Past Due	528		525
Total Loans Past Due	2,988		1,380
Current Loans	224,561		222,050
Total loans	227,549		223,430
Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	296		362
Loans 60 to 89 Days Past Due	241		46
Loans Over 90 Days Past Due	250		202
Total Loans Past Due	787		610
Current Loans	38,665		42,511
Total loans	39,452		43,121
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	34		66
Loans 60 to 89 Days Past Due	58		7
Loans Over 90 Days Past Due	33		147
Total Loans Past Due	125		220
Current Loans	54,832		55,346
Total loans	$ 54,957		$ 55,566

[1] Includes net unamortized loan origination costs of $39 thousand and $31 thousand, respectively, and net unamortized premiums on purchased loans of $76 thousand and $67 thousand, respectively, at September 30, 2012 and December 31, 2011.