Investment Securities - Narrative (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) security	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Investments, Debt and Equity Securities [Abstract]
Securities in an unrealized loss position (number of positions) | security	66
Proceeds from sale of securities available-for-sale	$ 32,352,000	$ 410,000
Available-for-sale securities, gross gains on sales	375,000	0
Available-for-sale securities, gross losses on sales	(2,000)	$ 0
Securities pledged as collateral for public funding	$ 110,900,000		$ 162,500,000