Loans (Past Due Loans) (Details) (USD $)	Jun. 30, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Receivable, Past Due, Nonaccrual	$ 17,200,000		$ 21,000,000
Loans 30 to 59 Days Past Due	6,144,000		6,607,000
Loans 60 to 89 Days Past Due	2,956,000		3,040,000
Loans Over 90 Days Past Due	17,004,000		18,449,000
Total Loans Past Due	26,104,000		28,096,000
Current Loans	2,358,876,000		2,265,907,000
Total loans	2,384,980,000	[1]	2,294,003,000	[1]
Commercial Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	0		373,000
Loans 60 to 89 Days Past Due	536,000		408,000
Loans Over 90 Days Past Due	8,895,000		10,300,000
Total Loans Past Due	9,431,000		11,081,000
Current Loans	749,006,000		699,732,000
Total loans	758,437,000		710,813,000
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	39,449,000		27,842,000
Total loans	39,449,000		27,842,000
Commercial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	505,000		260,000
Loans 60 to 89 Days Past Due	34,000		296,000
Loans Over 90 Days Past Due	3,428,000		3,647,000
Total Loans Past Due	3,967,000		4,203,000
Current Loans	508,261,000		509,561,000
Total loans	512,228,000		513,764,000
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	4,051,000		4,840,000
Loans 60 to 89 Days Past Due	1,697,000		1,951,000
Loans Over 90 Days Past Due	4,266,000		3,658,000
Total Loans Past Due	10,014,000		10,449,000
Current Loans	718,144,000		682,349,000
Total loans	728,158,000		692,798,000
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	20,713,000		24,883,000
Total loans	20,713,000		24,883,000
Home Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	1,155,000		753,000
Loans 60 to 89 Days Past Due	205,000		207,000
Loans Over 90 Days Past Due	27,000		528,000
Total Loans Past Due	1,387,000		1,488,000
Current Loans	226,980,000		225,373,000
Total loans	228,367,000		226,861,000
Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	402,000		252,000
Loans 60 to 89 Days Past Due	451,000		114,000
Loans Over 90 Days Past Due	375,000		250,000
Total Loans Past Due	1,228,000		616,000
Current Loans	40,084,000		38,713,000
Total loans	41,312,000		39,329,000
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30 to 59 Days Past Due	31,000		129,000
Loans 60 to 89 Days Past Due	33,000		64,000
Loans Over 90 Days Past Due	13,000		66,000
Total Loans Past Due	77,000		259,000
Current Loans	56,239,000		57,454,000
Total loans	$ 56,316,000		$ 57,713,000

[1] Includes net unamortized loan origination costs of $439 thousand and $39 thousand, respectively, and net unamortized premiums on purchased loans of $97 thousand and $83 thousand, respectively, at June 30, 2013 and December 31, 2012.