Securities - Schedule of Net Gains and Losses on Equity Investments Recognized in Earnings and Portion of Unrealized Gains and Losses for Period that Relates to Equity Investments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Net gains recognized on equity securities during the period	$ 35	$ 75
Less: Net gains (losses) realized on the sale of equity securities during the period	0	0
Unrealized gains recognized in equity securities held at reporting date	$ 35	$ 75