Goodwill and Intangible Assets - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Unit	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)
Goodwill [Line Items]
Number of reporting unit | Unit	1
Core Deposit [Member]
Goodwill [Line Items]
Intangible asset				$ 4,834
Amortization expense	$ 662	$ 835	$ 1,008
Net carrying value	899	1,561
Core Deposit [Member] | Lake National Bank of Mentor, Ohio [Member]
Goodwill [Line Items]
Intangible asset		1,583
Amortization expense	567	290
Net carrying value	$ 726	$ 1,293