Loans - Summary of Activities in Allowance for Credit Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2012
Allowance for Loan & Lease Losses
Balance at beginning of year			$ 5,194	$ 5,224	$ 5,224
Provision for loan loss	282	303	1,154	582	858
Loans charged off	(95)	(647)	(630)	(1,008)	(1,262)
Recoveries	66	77	198	233	374
Allowance for Loan & Lease Losses	5,916		5,916		5,194
Allowance for Unfunded Loan Commitments & Letters of Credit	196		196		163
Total Allowance for Credit Losses	$ 6,112	$ 5,199	$ 6,112	$ 5,199	$ 5,357	$ 5,849	$ 5,484	$ 5,386