Stockholders' Equity and Earnings per Share, Amounts Reclassified Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Available-for-sale securities [Abstract]
Realized gains on sales of securities	$ 40	$ 87	$ 120	$ 87
Tax effect	8	30	25	30
Total	$ 32	$ 57	$ 95	$ 57

Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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