Fair Value - Assets Measured at Fair Value on Non-recurring Basis (Details) - Non-Recurring Basis - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Total	$ 80
Impaired loans carried at fair value of collateral | Significant Unobservable Inputs (Level 3)
Fair Value
Assets, fair value	742	$ 1,744
Real estate owned
Fair Value
Total	80
Real estate owned | Significant Unobservable Inputs (Level 3)
Fair Value
Assets, fair value	$ 878