Loans and the Allowance for Loan Losses (Allowance for Loan and Lease Losses) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Individually evaluated for impairment	$ 758		$ 1,085
Allowance for loan and lease losses: Collectively evaluated for impairment	9,482		8,517
Allowance for loan and lease losses: Total	10,240	10,221	9,602	9,536	9,836	8,867
Loans Receivable: Individually evaluated for impairment	18,255		21,816
Loans Receivable: Collectively evaluated for impairment	802,634		734,177
Loans receivable: Loans acquired with discounts related to credit quality	50,009
Total Loans Receivable	870,898		755,993
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Collectively evaluated for impairment	1,692		1,527
Allowance for loan and lease losses: Total	1,692	1,747	1,527	1,376	1,376	1,272
Loans Receivable: Individually evaluated for impairment	827		953
Loans Receivable: Collectively evaluated for impairment	166,838		145,758
Loans receivable: Loans acquired with discounts related to credit quality	3,828
Total Loans Receivable	171,493		146,711
Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Individually evaluated for impairment	512		567
Allowance for loan and lease losses: Collectively evaluated for impairment	5,764		5,405
Allowance for loan and lease losses: Total	6,276	6,173	5,972	5,882	6,155	5,715
Loans Receivable: Individually evaluated for impairment	14,312		12,769
Loans Receivable: Collectively evaluated for impairment	448,039		395,395
Loans receivable: Loans acquired with discounts related to credit quality	21,792
Total Loans Receivable	484,143		408,164
Construction [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Individually evaluated for impairment			200
Allowance for loan and lease losses: Collectively evaluated for impairment	492		507
Allowance for loan and lease losses: Total	492	449	707	705	1,130	551
Loans Receivable: Individually evaluated for impairment			3,044
Loans Receivable: Collectively evaluated for impairment	38,475		36,344
Loans receivable: Loans acquired with discounts related to credit quality	2,408
Total Loans Receivable	40,883		39,388
Residential mortgage [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Individually evaluated for impairment	246		318
Allowance for loan and lease losses: Collectively evaluated for impairment	918		945
Allowance for loan and lease losses: Total	1,164	1,300	1,263	1,238	1,005	1,038
Loans Receivable: Individually evaluated for impairment	3,116		5,050
Loans Receivable: Collectively evaluated for impairment	148,892		155,721
Loans receivable: Loans acquired with discounts related to credit quality	21,849
Total Loans Receivable	173,857		160,771
Installment [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Collectively evaluated for impairment	64		51
Allowance for loan and lease losses: Total	64	59	51	48	56	52
Loans Receivable: Collectively evaluated for impairment	390		959
Loans receivable: Loans acquired with discounts related to credit quality	132
Total Loans Receivable	522		959
Unallocated [Member]
Financing Receivable, Impaired [Line Items]
Allowance for loan and lease losses: Collectively evaluated for impairment	552		82
Allowance for loan and lease losses: Total	$ 552	$ 493	$ 82	$ 287	$ 114	$ 239