Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 22,411	$ 21,064	$ 44,796	$ 41,391
Noninterest income	16,174	13,285	30,406	24,982
Total income	38,585	34,349	75,202	66,373
Provision for loan losses	600	1,200	1,500	2,700
Depreciation and amortization	987	1,010	1,957	2,015
Other noninterest expenses related to segments	24,241	21,254	46,670	40,989
Total noninterest expense	25,228	22,264	48,627	43,004
Income before income taxes	12,757	10,885	25,075	20,669
Income tax expense	4,044	3,320	7,924	6,304
Net income	8,713	7,565	17,151	14,365
Total assets	3,041,050	2,936,306	3,041,050	2,936,306	3,064,098
Expenditures for long-lived assets	1,801	526	3,453	1,239
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	19,364	18,809	38,992	37,213
Noninterest income	7,580	4,850	14,287	9,031
Total income	26,944	23,659	53,279	46,244
Provision for loan losses	600	1,200	1,500	2,700
Depreciation and amortization	602	599	1,204	1,199
Other noninterest expenses related to segments	15,858	13,581	30,624	26,271
Total noninterest expense	16,460	14,180	31,828	27,470
Income before income taxes	9,884	8,279	19,951	16,074
Income tax expense	3,397	2,764	6,848	5,352
Net income	6,487	5,515	13,103	10,722
Total assets	2,331,097	2,151,315	2,331,097	2,151,315
Expenditures for long-lived assets	1,782	394	2,674	816
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income	(2)	(3)	1	(9)
Noninterest income	7,472	7,510	14,657	14,590
Total income	7,470	7,507	14,658	14,581
Provision for loan losses	0	0	0	0
Depreciation and amortization	331	341	633	678
Other noninterest expenses related to segments	4,827	4,917	9,799	9,587
Total noninterest expense	5,158	5,258	10,432	10,265
Income before income taxes	2,312	2,249	4,226	4,316
Income tax expense	858	838	1,577	1,608
Net income	1,454	1,411	2,649	2,708
Total assets	49,869	51,520	49,869	51,520
Expenditures for long-lived assets	7	90	713	348
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	3,049	2,258	5,803	4,187
Noninterest income	1,122	925	1,462	1,361
Total income	4,171	3,183	7,265	5,548
Provision for loan losses	0	0	0	0
Depreciation and amortization	54	70	120	138
Other noninterest expenses related to segments	3,556	2,756	6,247	5,131
Total noninterest expense	3,610	2,826	6,367	5,269
Income before income taxes	561	357	898	279
Income tax expense	(211)	(282)	(501)	(656)
Net income	772	639	1,399	935
Total assets	660,084	733,471	660,084	733,471
Expenditures for long-lived assets	$ 12	$ 42	$ 66	$ 75