Investment Securities - Narrative (Details)	Jun. 30, 2017 USD ($) security	Dec. 31, 2016 USD ($)
Investments, Debt and Equity Securities [Abstract]
Carrying value of securities pledged as collateral	$ 519,265,000	$ 572,896,000
Book value of securities sold under agreements to repurchase	127,020,000	145,936,000
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Available-for-sale unrealized losses	4,181,000	9,674,000
Held-to-maturity unrealized losses	2,174,000	3,802,000
State and municipal
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Available-for-sale unrealized losses	$ 2,005,000	5,564,000
Available-for-sale, number of securities in unrealized loss positions | security	56
Held-to-maturity unrealized losses	$ 747,000	1,796,000
Held-to-maturity, number of securities in unrealized loss positions | security	33
U.S. Government-sponsored agency securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Available-for-sale unrealized losses	$ 0
Available-for-sale, number of securities in unrealized loss positions | security	0
Held-to-maturity unrealized losses	$ 382,000	479,000
Held-to-maturity, number of securities in unrealized loss positions | security	4
U.S. Government-sponsored mortgage-backed securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Available-for-sale unrealized losses	$ 2,176,000	3,071,000
Available-for-sale, number of securities in unrealized loss positions | security	37
Held-to-maturity unrealized losses	$ 1,045,000	$ 1,527,000
Held-to-maturity, number of securities in unrealized loss positions | security	23