Loans (Past Due Loans) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	$ 6,114		$ 6,607
Loans 60 to 89 Days Past Due	2,446		3,040
Loans Over 90 Days Past Due	17,624		18,449
Total Loans Past Due	26,184		28,096
Current Loans	2,298,861		2,265,907
Total loans	2,325,045	[1]	2,294,003	[1]
Loans Past Due and Nonaccrual	19,000		21,000
Commercial Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	0		373
Loans 60 to 89 Days Past Due	193		408
Loans Over 90 Days Past Due	9,852		10,300
Total Loans Past Due	10,045		11,081
Current Loans	719,923		699,732
Total loans	729,968		710,813
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	34,179		27,842
Total loans	34,179		27,842
Commercial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	689		260
Loans 60 to 89 Days Past Due	341		296
Loans Over 90 Days Past Due	2,961		3,647
Total Loans Past Due	3,991		4,203
Current Loans	509,009		509,561
Total loans	513,000		513,764
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	3,891		4,840
Loans 60 to 89 Days Past Due	1,451		1,951
Loans Over 90 Days Past Due	4,327		3,658
Total Loans Past Due	9,669		10,449
Current Loans	692,749		682,349
Total loans	702,418		692,798
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	21,943		24,883
Total loans	21,943		24,883
Home Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	872		753
Loans 60 to 89 Days Past Due	115		207
Loans Over 90 Days Past Due	190		528
Total Loans Past Due	1,177		1,488
Current Loans	225,463		225,373
Total loans	226,640		226,861
Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	538		252
Loans 60 to 89 Days Past Due	346		114
Loans Over 90 Days Past Due	243		250
Total Loans Past Due	1,127		616
Current Loans	39,007		38,713
Total loans	40,134		39,329
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	124		129
Loans 60 to 89 Days Past Due	0		64
Loans Over 90 Days Past Due	51		66
Total Loans Past Due	175		259
Current Loans	56,588		57,454
Total loans	$ 56,763		$ 57,713

[1] Includes net unamortized loan origination costs of $56 thousand and $39 thousand, respectively, and net unamortized premiums on purchased loans of $42 thousand and $83 thousand, respectively, at March 31, 2013 and December 31, 2012.