Schedule of Detail Segment Information (Detail) (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
Net interest income	$ 18,533		$ 15,951		$ 53,865		$ 47,839
Less: loan loss provision	959		1,000		2,763		3,003
Net interest income after loan loss provision	17,574		14,951		51,102		44,836
Other income:
Fees for wealth management services	8,635		7,993		26,078		21,433
Service charges on deposit accounts	627		634		1,807		1,823
Loan servicing and other fees	481		432		1,380		1,303
Net gain on sale of loans	578		1,837		3,588		4,311
Net gain on sale of available for sale securities			416		2		1,132
Net (loss) on sale of other real estate owned	(1)		(45)		(194)		(86)
BOLI income	72		108		270		331
Other operating income	995		873		3,189		2,969
Total non-interest income	11,387		12,248		36,120		33,216
Other expenses:
Salaries & wages	9,012		8,703		26,908		24,283
Employee benefits	1,896		1,903		6,433		6,086
Occupancy & equipment	1,646		1,488		5,124		4,258
Amortization of intangible assets	658		669		1,978		1,738
Professional fee	636		609		1,875		1,837
Other operating expenses	5,475		5,517		17,764		15,610
Total non-interest expenses	19,323		18,889		60,082		53,812
Segment profit	9,638		8,310		27,140		24,240
Pre-tax segment profit after eliminations	9,638		8,310		27,140		24,240
% of segment pre-tax profit after eliminations	100.00%		100.00%		100.00%		100.00%
Segment assets	2,058,973		1,815,000		2,058,973		1,815,000		2,035,885
Banking
Net interest income	18,532		15,950		53,863		47,836
Less: loan loss provision	959		1,000		2,763		3,003
Net interest income after loan loss provision	17,573		14,950		51,100		44,833
Other income:
Service charges on deposit accounts	627		634		1,807		1,823
Loan servicing and other fees	481		432		1,380		1,303
Net gain on sale of loans	578		1,837		3,588		4,311
Net gain on sale of available for sale securities			416		2		1,132
Net (loss) on sale of other real estate owned	(1)		(45)		(194)		(86)
BOLI income	72		107		270		330
Other operating income	947		833		3,051		2,903
Total non-interest income	2,704		4,214		9,904		11,716
Other expenses:
Salaries & wages	5,986		5,799		17,898		16,294
Employee benefits	1,196		1,243		4,235		4,239
Occupancy & equipment	1,267		1,124		3,994		3,001
Amortization of intangible assets	78		71		237		218
Professional fee	609		537		1,732		1,672
Other operating expenses	4,812		4,594		15,082		13,602
Total non-interest expenses	13,948		13,368		43,178		39,026
Segment profit	6,329		5,796		17,826		17,523
Intersegment (revenues) expenses	(19)	[1]	(128)	[1]	(323)	[1]	(368)	[1]
Pre-tax segment profit after eliminations	6,310		5,668		17,503		17,155
% of segment pre-tax profit after eliminations	65.50%		68.20%		64.50%		70.80%
Segment assets	2,017,000		1,769,000		2,017,000		1,769,000
Wealth Management
Net interest income	1		1		2		3
Net interest income after loan loss provision	1		1		2		3
Other income:
Fees for wealth management services	8,635		7,993		26,078		21,433
Other operating income	48		41		138		67
Total non-interest income	8,683		8,034		26,216		21,500
Other expenses:
Salaries & wages	3,026		2,904		9,010		7,989
Employee benefits	700		660		2,198		1,847
Occupancy & equipment	379		364		1,130		1,257
Amortization of intangible assets	580		598		1,741		1,520
Professional fee	27		72		143		165
Other operating expenses	663		923		2,682		2,008
Total non-interest expenses	5,375		5,521		16,904		14,786
Segment profit	3,309		2,514		9,314		6,717
Intersegment (revenues) expenses	19	[1]	128	[1]	323	[1]	368	[1]
Pre-tax segment profit after eliminations	3,328		2,642		9,637		7,085
% of segment pre-tax profit after eliminations	34.50%		31.80%		35.50%		29.20%
Segment assets	$ 42,000		$ 46,000		$ 42,000		$ 46,000

[1] Inter-segment revenues consist of rental payments, interest on deposits and management fees.