Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015		Dec. 31, 2015
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 27,379		$ 25,997		$ 81,890		$ 77,727
Provision for loan losses	1,800		200		2,750		300
Net interest income after provision for loan losses	25,579		25,797		79,140		77,427
Noninterest income	17,261		13,913		47,809		43,194
Depreciation and amortization expense	1,268		1,080		3,703		3,106
Other noninterest expenses related to segments	23,382		23,458		72,427		69,262
Total noninterest expense	24,650		24,538		76,130		72,368
Income before income taxes	18,190		15,172		50,819		48,253
Income tax expense	5,863		4,964		16,500		15,532
Net income	12,327		10,208		34,319		32,721
Total assets	4,204,034		3,674,836		4,204,034		3,674,836		$ 3,771,604
Expenditures for long-lived assets	762		1,118		2,608		3,220
Change in fair value of contingent consideration	(939)		16		(898)		16
Acquisition related expenses	0		504		0		937
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	22,860		21,278		67,414		63,115
Provision for loan losses	1,800		200		2,750		300
Net interest income after provision for loan losses	21,060		21,078		64,664		62,815
Noninterest income	7,101		4,498		17,331		15,164
Depreciation and amortization expense	709		626		2,093		1,936
Other noninterest expenses related to segments	14,759		13,805		43,788		41,259
Total noninterest expense	15,468		14,431		45,881		43,195
Income before income taxes	12,693		11,145		36,114		34,784
Income tax expense	4,392		3,747		12,336		10,878
Net income	8,301		7,398		23,778		23,906
Total assets	3,617,967		3,074,611		3,617,967		3,074,611
Expenditures for long-lived assets	424		1,006		1,779		2,774
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	(11)		(15)		(46)		(38)
Provision for loan losses	0		0		0		0
Net interest income after provision for loan losses	(11)		(15)		(46)		(38)
Noninterest income	9,623		8,902		28,278		26,249
Depreciation and amortization expense	501		404		1,440		1,009
Other noninterest expenses related to segments	5,584	[1]	6,820	[1]	19,084	[2]	19,200	[2]
Total noninterest expense	6,085		7,224		20,524		20,209
Income before income taxes	3,527		1,663		7,708		6,002
Income tax expense	1,261		688		2,788		2,682
Net income	2,266		975		4,920		3,320
Total assets	53,236		62,461		53,236		62,461
Expenditures for long-lived assets	280		51		468		252
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	4,530		4,734		14,522		14,650
Provision for loan losses	0		0		0		0
Net interest income after provision for loan losses	4,530		4,734		14,522		14,650
Noninterest income	537		513		2,200		1,781
Depreciation and amortization expense	58		50		170		161
Other noninterest expenses related to segments	3,039		2,833		9,555		8,803
Total noninterest expense	3,097		2,883		9,725		8,964
Income before income taxes	1,970		2,364		6,997		7,467
Income tax expense	210		529		1,376		1,972
Net income	1,760		1,835		5,621		5,495
Total assets	532,831		537,764		532,831		537,764
Expenditures for long-lived assets	$ 58		$ 61		$ 361		$ 194

[1] Other noninterest expenses for the Wealth Management Services segment includes a $939 thousand benefit resulting from the reduction of a contingent consideration liability in the three months ended September 30, 2016 and $504 thousand of acquisition related expenses in the three months ended September 30, 2015.

[2] Other noninterest expenses for the Wealth Management Services segment includes a $898 thousand benefit resulting from the reduction of a contingent consideration liability in the nine months ended September 30, 2016 and $937 thousand of acquisition related expenses in the nine months ended September 30, 2015.