Loans and Leases - Narrative for Impaired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Interest income recognized on a cash basis for nonaccrual loans	$ 37	$ 23	$ 6
Interest income recognized on accrual method for accruing impaired loans	1,500	1,800	$ 1,200
Reserve for uncollected interest	0	1
Off-balance Sheet Risks, Amount, Liability	$ 381	$ 338