Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 22,736	$ 21,549	$ 67,532	$ 62,940
Noninterest income	16,921	12,956	47,327	37,938
Total income	39,657	34,505	114,859	100,878
Provision for loan losses	600	1,000	2,100	3,700
Depreciation and amortization	968	1,015	2,925	3,030
Other noninterest expenses related to segments	25,322	21,580	71,992	62,569
Total noninterest expense	26,290	22,595	74,917	65,599
Income before income taxes	12,767	10,910	37,842	31,579
Income tax expense	3,867	3,328	11,791	9,632
Net income	8,900	7,582	26,051	21,947
Total assets	3,048,868	2,969,613	3,048,868	2,969,613	3,064,098
Expenditures for long-lived assets	1,060	998	4,513	2,237
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	19,946	19,170	59,126	56,383
Noninterest income	8,683	5,879	22,970	14,910
Total income	28,629	25,049	82,096	71,293
Provision for loan losses	600	1,000	2,100	3,700
Depreciation and amortization	588	616	1,792	1,815
Other noninterest expenses related to segments	16,538	14,298	47,162	40,569
Total noninterest expense	17,126	14,914	48,954	42,384
Income before income taxes	10,903	9,135	31,042	25,209
Income tax expense	3,751	3,072	10,665	8,424
Net income	7,152	6,063	20,377	16,785
Total assets	2,384,219	2,209,333	2,384,219	2,209,333
Expenditures for long-lived assets	935	926	3,609	1,742
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income	0	(1)	1	(10)
Noninterest income	7,193	6,791	21,850	21,381
Total income	7,193	6,790	21,851	21,371
Provision for loan losses	0	0	0	0
Depreciation and amortization	325	326	958	1,004
Other noninterest expenses related to segments	4,850	4,667	14,649	14,254
Total noninterest expense	5,175	4,993	15,607	15,258
Income before income taxes	2,018	1,797	6,244	6,113
Income tax expense	755	670	2,332	2,278
Net income	1,263	1,127	3,912	3,835
Total assets	51,525	50,149	51,525	50,149
Expenditures for long-lived assets	72	43	785	391
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	2,790	2,380	8,405	6,567
Noninterest income	1,045	286	2,507	1,647
Total income	3,835	2,666	10,912	8,214
Provision for loan losses	0	0	0	0
Depreciation and amortization	55	73	175	211
Other noninterest expenses related to segments	3,934	2,615	10,181	7,746
Total noninterest expense	3,989	2,688	10,356	7,957
Income before income taxes	(154)	(22)	556	257
Income tax expense	(639)	(414)	(1,206)	(1,070)
Net income	485	392	1,762	1,327
Total assets	613,124	710,131	613,124	710,131
Expenditures for long-lived assets	$ 53	$ 29	$ 119	$ 104