Loans Receivable and Allowance for Loan Losses (Summary of Loans, Allowances and Impairment Balances, by Class and Impairment Method) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Allowance for loan losses:
Individually evaluated for impairment	$ 8,320	$ 3,630
Collectively evaluated for impairment	17,838	17,990
Total allowance for loan losses	26,158	21,620
Loans receivable:
Loans evaluated individually	64,442	63,504
Loans evaluated collectively	1,428,313	1,373,164
Total loans receivable	1,492,755	1,436,668
Period used to analyze future loan losses	2 years
Commercial and industrial [Member]
Allowance for loan losses:
Individually evaluated for impairment	3,187	1,000
Collectively evaluated for impairment	7,388	7,400
Total allowance for loan losses	10,575	8,400
Loans receivable:
Loans evaluated individually	18,996	15,504
Loans evaluated collectively	337,747	306,484
Total loans receivable	356,743	321,988
Commercial tax-exempt [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	74	79
Total allowance for loan losses	74	79
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	84,616	81,532
Total loans receivable	84,616	81,532
Owner occupied real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	1,456	30
Collectively evaluated for impairment	661	699
Total allowance for loan losses	2,117	729
Loans receivable:
Loans evaluated individually	5,188	7,492
Loans evaluated collectively	269,316	271,880
Total loans receivable	274,504	279,372
Commercial construction and land development [Member]
Allowance for loan losses:
Individually evaluated for impairment	3,677	2,600
Collectively evaluated for impairment	5,240	5,240
Total allowance for loan losses	8,917	7,840
Loans receivable:
Loans evaluated individually	23,508	23,216
Loans evaluated collectively	84,511	79,937
Total loans receivable	108,019	103,153
Commercial real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,139	3,241
Total allowance for loan losses	3,139	3,241
Loans receivable:
Loans evaluated individually	10,312	12,117
Loans evaluated collectively	366,936	352,288
Total loans receivable	377,248	364,405
Residential [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	438	435
Total allowance for loan losses	438	435
Loans receivable:
Loans evaluated individually	4,137	3,346
Loans evaluated collectively	80,243	80,594
Total loans receivable	84,380	83,940
Consumer [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	797	831
Total allowance for loan losses	797	831
Loans receivable:
Loans evaluated individually	2,301	1,829
Loans evaluated collectively	204,944	200,449
Total loans receivable	207,245	202,278
Unallocated [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	101	65
Total allowance for loan losses	101	65
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	0	0
Total loans receivable	$ 0	$ 0