Business Combination - Additional Information (Detail)			9 Months Ended
	Sep. 08, 2016 USD ($) BankingCenter $ / shares	Jan. 29, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill and other intangible assets			$ 1,538,000
Total assets			$ 2,160,234,000	$ 1,987,989,000
Premier Bank & Trust [Member]
Business Acquisition [Line Items]
Total assets	$ 320,000,000
Full-service banking centers | BankingCenter	4
James & Sons Insurance Company [Member]
Business Acquisition [Line Items]
Business acquisition date			Jan. 29, 2016
Business acquisition, company stock		$ 1,500,000
Business acquisition, cash		360,000
Business acquisition, related costs			$ 9,000
Business acquisition, total assets purchase		2,300,000
Goodwill and other intangible assets		$ 1,600,000
Ohio Legacy Corp [Member]
Business Acquisition [Line Items]
Business acquisition, date of acquisition agreement			Sep. 08, 2016
Business acquisition, per share price | $ / shares	$ 18.00
Business acquisition, aggregate consideration	$ 40,300,000