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, 2013	Dec. 31, 2012
Allowance for loan losses:
Individually evaluated for impairment	$ 10,335	$ 7,120
Collectively evaluated for impairment	17,703	18,162
Total allowance for loan losses	28,038	25,282
Loans receivable:
Loans evaluated individually	63,668	56,641
Loans evaluated collectively	1,570,198	1,472,156
Total loans receivable	1,633,866	1,528,797
Period used to analyze future loan losses	2 years
Commercial and industrial [Member]
Allowance for loan losses:
Individually evaluated for impairment	2,695	2,399
Collectively evaluated for impairment	7,854	7,560
Total allowance for loan losses	10,549	9,959
Loans receivable:
Loans evaluated individually	15,406	13,082
Loans evaluated collectively	400,334	363,906
Total loans receivable	415,740	376,988
Commercial tax-exempt [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	74	83
Total allowance for loan losses	74	83
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	82,455	92,202
Total loans receivable	82,455	92,202
Owner occupied real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	1,415	1,451
Collectively evaluated for impairment	792	678
Total allowance for loan losses	2,207	2,129
Loans receivable:
Loans evaluated individually	5,260	3,380
Loans evaluated collectively	283,442	264,992
Total loans receivable	288,702	268,372
Commercial construction and land development [Member]
Allowance for loan losses:
Individually evaluated for impairment	3,470	2,470
Collectively evaluated for impairment	4,340	4,752
Total allowance for loan losses	7,810	7,222
Loans receivable:
Loans evaluated individually	15,526	15,549
Loans evaluated collectively	90,070	84,850
Total loans receivable	105,596	100,399
Commercial real estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	1,755	800
Collectively evaluated for impairment	3,304	3,183
Total allowance for loan losses	5,059	3,983
Loans receivable:
Loans evaluated individually	15,330	17,136
Loans evaluated collectively	418,298	377,268
Total loans receivable	433,628	394,404
Residential [Member]
Allowance for loan losses:
Individually evaluated for impairment	508	0
Collectively evaluated for impairment	355	324
Total allowance for loan losses	863	324
Loans receivable:
Loans evaluated individually	8,283	4,163
Loans evaluated collectively	82,307	79,736
Total loans receivable	90,590	83,899
Consumer [Member]
Allowance for loan losses:
Individually evaluated for impairment	492	0
Collectively evaluated for impairment	766	793
Total allowance for loan losses	1,258	793
Loans receivable:
Loans evaluated individually	3,863	3,331
Loans evaluated collectively	213,292	209,202
Total loans receivable	217,155	212,533
Unallocated [Member]
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	218	789
Total allowance for loan losses	218	789
Loans receivable:
Loans evaluated individually	0	0
Loans evaluated collectively	0	0
Total loans receivable	$ 0	$ 0