Goodwill and Other Intangible Assets (Net Carrying Amount of Goodwill By Segment) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014
Goodwill [Line Items]
Beginning balance	$ 84,808,000	$ 84,171,000
Acquisition fair value adjustment	(637,000)
Ending balance	84,171,000	84,171,000
Community Banking
Goodwill [Line Items]
Beginning balance	70,628,000	69,991,000
Acquisition fair value adjustment	(637,000)
Ending balance	69,991,000	69,991,000
Insurance
Goodwill [Line Items]
Beginning balance	5,191,000	5,191,000
Acquisition fair value adjustment	0
Ending balance	5,191,000	5,191,000
Investment Management
Goodwill [Line Items]
Beginning balance	8,989,000	8,989,000
Acquisition fair value adjustment	0
Ending balance	$ 8,989,000	$ 8,989,000