Goodwill and Intangible Assets Related to Acquisitions (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
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			$ 32,897
Additions / Adjustments			(54)
Amortization
Ending Balance	32,843		32,843
Amortization	(658)	(669)	(1,978)	(1,738)
Beginning Balance			21,998
Additions / Adjustments
Amortization			(1,978)
Ending Balance	20,020		20,020
Beginning Balance			54,895
Additions / Adjustments			(54)
Amortization			(1,978)
Ending Balance	52,863		52,863
Trade name
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			1,210
Additions / Adjustments
Amortization
Ending Balance	1,210		1,210
Amortization Period			Indefinite
Core deposit intangible
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			1,654
Additions / Adjustments
Amortization			(237)
Ending Balance	1,417		1,417
Amortization Period			10 years
Customer relationships
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			14,890
Additions / Adjustments
Amortization			(971)
Ending Balance	13,919		13,919
Non competition agreements
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			4,244
Additions / Adjustments
Amortization			(770)
Ending Balance	3,474		3,474
Minimum | Customer relationships
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Amortization Period			10 years
Minimum | Non competition agreements
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Amortization Period			5 years
Maximum | Customer relationships
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Amortization Period			20 years
Maximum | Non competition agreements
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Amortization Period			5 years 6 months
Wealth Segment
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			20,466
Additions / Adjustments			(54)
Amortization
Ending Balance	20,412		20,412
Amortization Period			Indefinite
Banking Segment
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Beginning Balance			12,431
Amortization
Ending Balance	$ 12,431		$ 12,431
Amortization Period			Indefinite