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, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net interest income	$ 23,388	$ 22,736	$ 68,264	$ 67,532
Noninterest income	17,400	16,921	46,960	47,327
Total income	40,788	39,657	115,224	114,859
Provision for loan losses	700	600	2,000	2,100
Depreciation and amortization	982	968	3,005	2,925
Other Noninterest Expenses Related to Segments	24,566	25,322	71,732	71,992
Total noninterest expense	25,548	26,290	74,737	74,917
Income before income taxes	14,540	12,767	38,487	37,842
Income tax expense	4,580	3,867	12,123	11,791
Net income	9,960	8,900	26,364	26,051
Total assets	3,131,958	3,048,868	3,131,958	3,048,868	3,071,884
Expenditures for long-lived assets	341	1,060	1,178	4,513
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	20,364	19,946	59,606	59,126
Noninterest income	8,302	8,683	24,239	22,970
Total income	28,666	28,629	83,845	82,096
Provision for loan losses	700	600	2,000	2,100
Depreciation and amortization	614	588	1,876	1,792
Other Noninterest Expenses Related to Segments	15,840	16,538	47,244	47,162
Total noninterest expense	16,454	17,126	49,120	48,954
Income before income taxes	11,512	10,903	32,725	31,042
Income tax expense	3,875	3,751	11,421	10,665
Net income	7,637	7,152	21,304	20,377
Total assets	2,460,150	2,384,219	2,460,150	2,384,219
Expenditures for long-lived assets	277	935	1,014	3,609
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income	(4)	0	5	1
Noninterest income	7,629	7,193	23,015	21,850
Total income	7,625	7,193	23,020	21,851
Provision for loan losses	0	0	0	0
Depreciation and amortization	316	325	968	958
Other Noninterest Expenses Related to Segments	4,944	4,850	15,078	14,649
Total noninterest expense	5,260	5,175	16,046	15,607
Income before income taxes	2,365	2,018	6,974	6,244
Income tax expense	876	755	2,635	2,332
Net income	1,489	1,263	4,339	3,912
Total assets	50,297	51,525	50,297	51,525
Expenditures for long-lived assets	39	72	93	785
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net interest income	3,028	2,790	8,653	8,405
Noninterest income	1,469	1,045	(294)	2,507
Total income	4,497	3,835	8,359	10,912
Provision for loan losses	0	0	0	0
Depreciation and amortization	52	55	161	175
Other Noninterest Expenses Related to Segments	3,782	3,934	9,410	10,181
Total noninterest expense	3,834	3,989	9,571	10,356
Income before income taxes	663	(154)	(1,212)	556
Income tax expense	(171)	(639)	(1,933)	(1,206)
Net income	834	485	721	1,762
Total assets	621,511	613,124	621,511	613,124
Expenditures for long-lived assets	$ 25	$ 53	$ 71	$ 119