Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 91,785	$ 90,696	$ 84,955
Noninterest income	62,080	65,214	52,764
Total income	153,865	155,910	137,719
Provision for loan losses	2,400	2,700	4,700
Depreciation and amortization expense	3,963	3,941	4,125
Other noninterest expenses	94,822	98,397	86,248
Total noninterest expense	98,785	102,338	90,373
Income before income taxes	52,680	50,872	42,646
Income tax expense (benefit)	16,527	15,798	12,922
Net income	36,153	35,074	29,724
Total assets at period end	3,188,867	3,071,884	3,064,098
Expenditures for long-lived assets	1,491	5,110	3,644
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	79,633	79,505	75,967
Noninterest income	30,769	31,727	21,806
Total income	110,402	111,232	97,773
Provision for loan losses	2,400	2,700	4,700
Depreciation and amortization expense	2,473	2,384	2,512
Other noninterest expenses	61,976	62,963	55,543
Total noninterest expense	64,449	65,347	58,055
Income before income taxes	43,553	43,185	35,018
Income tax expense (benefit)	14,598	14,670	11,781
Net income	28,955	28,515	23,237
Total assets at period end	2,517,059	2,436,280	2,257,326
Expenditures for long-lived assets	1,286	4,082	2,982
Wealth Management Service [Member]
Segment Reporting Information [Line Items]
Net interest income	7	17	(1)
Noninterest income	31,825	29,640	28,306
Total income	31,832	29,657	28,305
Provision for loan losses	0	0	0
Depreciation and amortization expense	1,277	1,272	1,330
Other noninterest expenses	20,494	19,584	19,041
Total noninterest expense	21,771	20,856	20,371
Income before income taxes	10,061	8,801	7,934
Income tax expense (benefit)	3,724	3,296	2,957
Net income	6,337	5,505	4,977
Total assets at period end	50,297	51,730	51,104
Expenditures for long-lived assets	112	877	493
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net interest income	12,145	11,174	8,989
Noninterest income	(514)	3,847	2,652
Total income	11,631	15,021	11,641
Provision for loan losses	0	0	0
Depreciation and amortization expense	213	285	283
Other noninterest expenses	12,352	15,850	11,664
Total noninterest expense	12,565	16,135	11,947
Income before income taxes	(934)	(1,114)	(306)
Income tax expense (benefit)	(1,795)	(2,168)	(1,816)
Net income	861	1,054	1,510
Total assets at period end	621,511	583,874	755,668
Expenditures for long-lived assets	$ 93	$ 151	$ 169