Securities - Narrative (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) Security	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales of securities	$ 79,300,000	$ 11,600,000	$ 58,900,000
Proceeds from maturity, calls, principal repayments and sales of securities available for sale	76,200,000	89,900,000	73,400,000
Gross gains realized on sale of securities	1,500,000	172,000	770,000
Gross loss realized on sale of securities	28,000	37,000	584,000
Net impairment losses	0	0	0
Tax expense related to realized gains	528,000	48,000	$ 63,000
Carrying value of securities pledged for fiduciary powers	$ 115,700,000	$ 113,100,000
Number of securities temporarily impaired | Security	256
Number of securities temporarily impaired in investment grade | Security	251
Number of securities temporarily impaired in speculative grade | Security	5