Loans Receivable and Allowance for Loan Losses (Summary of Loans, Allowances and Impairment Balances, by Class and Impairment Method) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Allowance for loan losses:
Individually evaluated for impairment	$ 5,277	$ 5,643
Collectively evaluated for impairment	21,465	19,355
Total allowance for loan losses	26,742	24,998
Loans receivable:
Loans evaluated individually	47,488	46,322
Loans evaluated collectively	2,050,216	1,952,212
Total loans receivable	2,097,704	1,998,534
Commercial and industrial [Member]
Allowance for loan losses:
Individually evaluated for impairment	2,836	4,401
Collectively evaluated for impairment	8,880	7,313
Total allowance for loan losses	11,716	11,714
Loans receivable:
Loans evaluated individually	15,451	16,982
Loans evaluated collectively	591,633	508,145
Total loans receivable	607,084	525,127
Commercial tax-exempt [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	46	55
Total allowance for loan losses	46	55
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	58,999	71,151
Total loans receivable	58,999	71,151
Owner occupied real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	2,441	1,242
Collectively evaluated for impairment	572	689
Total allowance for loan losses	3,013	1,931
Loans receivable:
Loans evaluated individually	9,330	7,464
Loans evaluated collectively	306,225	324,606
Total loans receivable	315,555	332,070
Commercial construction and land development [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	4,470	4,242
Total allowance for loan losses	4,470	4,242
Loans receivable:
Loans evaluated individually	3,613	3,810
Loans evaluated collectively	136,522	134,254
Total loans receivable	140,135	138,064
Commercial real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	5,241	4,707
Total allowance for loan losses	5,241	4,707
Loans receivable:
Loans evaluated individually	10,806	9,976
Loans evaluated collectively	628,329	584,300
Total loans receivable	639,135	594,276
Residential [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	818	796
Total allowance for loan losses	818	796
Loans receivable:
Loans evaluated individually	6,438	5,657
Loans evaluated collectively	112,645	105,294
Total loans receivable	119,083	110,951
Consumer [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	852	931
Total allowance for loan losses	852	931
Loans receivable:
Loans evaluated individually	1,850	2,433
Loans evaluated collectively	215,863	224,462
Total loans receivable	217,713	226,895
Unallocated [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	586	622
Total allowance for loan losses	586	622
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	0	0
Total loans receivable	$ 0	$ 0