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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net interest income	$ 22,409	$ 22,411	$ 44,876	$ 44,796
Noninterest income	16,394	16,174	29,560	30,406
Total income	38,803	38,585	74,436	75,202
Provision for loan losses	700	600	1,300	1,500
Depreciation and amortization	1,003	987	2,023	1,957
Other noninterest expenses related to segments	24,002	24,241	47,166	46,670
Total noninterest expense	25,005	25,228	49,189	48,627
Income before income taxes	13,098	12,757	23,947	25,075
Income tax expense	4,115	4,044	7,543	7,924
Net income	8,983	8,713	16,404	17,151
Total assets	3,061,307	3,041,050	3,061,307	3,041,050	3,071,884
Expenditures for long-lived assets	410	1,801	837	3,453
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	19,731	19,552	39,242	39,180
Noninterest income	7,991	7,580	15,937	14,287
Total income	27,722	27,132	55,179	53,467
Provision for loan losses	700	600	1,300	1,500
Depreciation and amortization	624	602	1,262	1,204
Other noninterest expenses related to segments	16,268	15,858	31,404	30,624
Total noninterest expense	16,892	16,460	32,666	31,828
Income before income taxes	10,130	10,072	21,213	20,139
Income tax expense	3,402	3,463	7,898	6,914
Net income	6,728	6,609	13,315	13,225
Total assets	2,509,407	2,331,097	2,509,407	2,331,097
Expenditures for long-lived assets	367	1,782	737	2,674
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income	2	(2)	9	1
Noninterest income	7,912	7,472	15,386	14,657
Total income	7,914	7,470	15,395	14,658
Provision for loan losses	0	0	0	0
Depreciation and amortization	325	331	652	633
Other noninterest expenses related to segments	5,022	4,827	10,134	9,799
Total noninterest expense	5,347	5,158	10,786	10,432
Income before income taxes	2,567	2,312	4,609	4,226
Income tax expense	949	858	1,815	1,577
Net income	1,618	1,454	2,794	2,649
Total assets	52,129	49,869	52,129	49,869
Expenditures for long-lived assets	28	7	54	713
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income	2,676	2,861	5,625	5,615
Noninterest income	491	1,122	(1,763)	1,462
Total income	3,167	3,983	3,862	7,077
Provision for loan losses	0	0	0	0
Depreciation and amortization	54	54	109	120
Other noninterest expenses related to segments	2,712	3,556	5,628	6,247
Total noninterest expense	2,766	3,610	5,737	6,367
Income before income taxes	401	373	(1,875)	710
Income tax expense	(236)	(277)	(2,170)	(567)
Net income	637	650	295	1,277
Total assets	499,771	660,084	499,771	660,084
Expenditures for long-lived assets	$ 15	$ 12	$ 46	$ 66