Fair Value - Assets and Liabilities Subject to Fair Value Adjustments (Impairment) on Non-Recurring Basis Carried on Balance Sheet by Caption and by Level within Hierarchy (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO	$ 56	$ 426
Impaired collateral-dependent loans	2,765	1,126
OREO, Net Provision (Credit)	(196)	(299)
Impaired collateral-dependent loans, Net Provision (Credit)	(84)	(52)
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO	56	426
Impaired collateral-dependent loans	2,765	1,126
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO	0	0
Impaired collateral-dependent loans	0	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO	0	0
Impaired collateral-dependent loans	$ 0	$ 0