Loans, Loans Classified by Credit Quality Indicator (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Loans by categories [Abstract]
Total loans	$ 1,856,992,000	$ 1,744,828,000	$ 1,715,648,000
Threshold amount of commercial and construction loans and leases subject to loan review	3,000,000
Percentage of loan portfolio review coverage (in hundredths)	68.00%	65.00%
Period of full review in loan committee for loans with relatively short term, minimum	1 year
Period of full review in loan committee for loans with relatively short term, maximum	3 years
Commercial [Member]
Loans by categories [Abstract]
Total loans	453,444,000	450,411,000	461,679,000
Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	614,410,000	609,487,000	577,237,000
Construction [Member]
Loans by categories [Abstract]
Total loans	263,726,000	246,611,000	242,806,000
Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	146,728,000	129,682,000	129,400,000
Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	97,589,000	96,110,000	96,139,000
Consumer loans and others [Member]
Loans by categories [Abstract]
Total loans	232,150,000	165,397,000
Consumer [Member]
Loans by categories [Abstract]
Total loans	276,427,000	209,041,000	205,243,000
Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	4,668,000	3,486,000	3,144,000
Pass [Member]
Loans by categories [Abstract]
Total loans	1,197,670,000	1,078,774,000
Pass [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	331,624,000	320,287,000
Pass [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	490,001,000	476,421,000
Pass [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	236,486,000	176,824,000
Pass [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	54,747,000	12,025,000
Pass [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	28,792,000	28,981,000
Pass [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	56,020,000	64,236,000
Pass [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Special Mention [Member]
Loans by categories [Abstract]
Total loans	26,801,000	22,664,000
Special Mention [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	2,939,000	1,049,000
Special Mention [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	23,862,000	21,615,000
Special Mention [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	0	0
Special Mention [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	0	0
Special Mention [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	0	0
Special Mention [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	0	0
Special Mention [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Substandard [Member]
Loans by categories [Abstract]
Total loans	34,071,000	25,910,000
Substandard [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	8,045,000	7,696,000
Substandard [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	12,740,000	6,867,000
Substandard [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	9,553,000	6,716,000
Substandard [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	61,000	649,000
Substandard [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	0	1,264,000
Substandard [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	3,672,000	2,718,000
Substandard [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member]
Loans by categories [Abstract]
Total loans	93,000	0
Doubtful [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	93,000	0
Doubtful [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	0	0
Doubtful [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	0	0
Loss [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Unrated subject to review [Member]
Loans by categories [Abstract]
Total loans	89,629,000	171,312,000
Unrated subject to review [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	28,253,000	60,938,000
Unrated subject to review [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	23,502,000	26,543,000
Unrated subject to review [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	10,711,000	49,700,000
Unrated subject to review [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	0	29,174,000
Unrated subject to review [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	1,590,000	2,084,000
Unrated subject to review [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	25,573,000	2,873,000
Unrated subject to review [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	0	0
Unrated not subject to review [Member]
Loans by categories [Abstract]
Total loans	508,728,000	446,168,000
Unrated not subject to review [Member] | Commercial [Member]
Loans by categories [Abstract]
Total loans	82,583,000	60,441,000
Unrated not subject to review [Member] | Commercial mortgage [Member]
Loans by categories [Abstract]
Total loans	64,305,000	78,041,000
Unrated not subject to review [Member] | Construction [Member]
Loans by categories [Abstract]
Total loans	6,976,000	13,371,000
Unrated not subject to review [Member] | Direct lease financing [Member]
Loans by categories [Abstract]
Total loans	91,920,000	87,834,000
Unrated not subject to review [Member] | Residential mortgage [Member]
Loans by categories [Abstract]
Total loans	67,114,000	63,781,000
Unrated not subject to review [Member] | Consumer [Member]
Loans by categories [Abstract]
Total loans	191,162,000	139,214,000
Unrated not subject to review [Member] | Unamortized loan costs [Member]
Loans by categories [Abstract]
Total loans	$ 4,668,000	$ 3,486,000