Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 103,982	$ 99,505	$ 91,785
Provision for loan losses	1,050	1,850	2,400
Net interest income after provision for loan losses	102,932	97,655	89,385
Noninterest income (expense)	58,340	59,015	62,080
Depreciation and amortization expense	4,285	3,777	3,963
Other noninterest expenses	92,644	93,070	94,822
Total noninterest expense	96,929	96,847	98,785
Income before income taxes	64,343	59,823	52,680
Income tax expense (benefit)	20,878	18,999	16,527
Net income	43,465	40,824	36,153
Total assets at period end	3,771,604	3,586,874	3,188,867
Expenditures for long-lived assets	5,479	5,226	1,491
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	84,757	80,500	79,633
Provision for loan losses	1,050	1,850	2,400
Net interest income after provision for loan losses	83,707	78,650	77,233
Noninterest income (expense)	20,618	17,575	30,769
Depreciation and amortization expense	2,584	2,447	2,473
Other noninterest expenses	55,203	52,639	61,976
Total noninterest expense	57,787	55,086	64,449
Income before income taxes	46,538	41,139	43,553
Income tax expense (benefit)	15,330	13,497	14,598
Net income	31,208	27,642	28,955
Total assets at period end	3,152,231	2,986,453	2,517,059
Expenditures for long-lived assets	4,714	3,474	1,286
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	(47)	(24)	7
Provision for loan losses	0	0	0
Net interest income after provision for loan losses	(47)	(24)	7
Noninterest income (expense)	35,416	33,378	31,825
Depreciation and amortization expense	1,488	1,127	1,277
Other noninterest expenses	25,632	22,386	20,494
Total noninterest expense	27,120	23,513	21,771
Income before income taxes	8,249	9,841	10,061
Income tax expense (benefit)	3,475	3,724	3,724
Net income	4,774	6,117	6,337
Total assets at period end	63,801	52,720	50,297
Expenditures for long-lived assets	411	1,578	112
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	19,272	19,029	12,145
Provision for loan losses	0	0	0
Net interest income after provision for loan losses	19,272	19,029	12,145
Noninterest income (expense)	2,306	8,062	(514)
Depreciation and amortization expense	213	203	213
Other noninterest expenses	11,809	18,045	12,352
Total noninterest expense	12,022	18,248	12,565
Income before income taxes	9,556	8,843	(934)
Income tax expense (benefit)	2,073	1,778	(1,795)
Net income	7,483	7,065	861
Total assets at period end	555,572	547,701	621,511
Expenditures for long-lived assets	$ 354	$ 174	$ 93