Deposits (Additional Information) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Banking and Thrift [Abstract]
Demand Deposit Overdrafts Reclassified As Loan	$ 2,200,000	$ 1,300,000
Percentage of time deposits over total deposits	6.70%
Interest expense on time deposits of $100,000 or more	$ 1,500,000	$ 1,700,000	$ 2,400,000