Loans and Leases - Non-Performing Assets (Detail) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Non-accrual Non-PCI loans and leases	$ 15,345,000	$ 15,805,000
Loans 90 days or more past due and still accruing	17,000	0
Total non-performing loans	15,362,000	15,805,000
OREO	1,660,000	1,946,000
Total non-performing assets	$ 17,022,000	$ 17,751,000