Fair Value - Financial Assets and Liabilities Measured on a Non-Recurring Basis (Details) - Non-recurring basis - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	$ 361	$ 783
Foreclosed Assets Fair Value Disclosure		229
Significant Unobservable Inputs (Level 3)
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	361	783
Foreclosed Assets Fair Value Disclosure		229
Commercial
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	242	165
Commercial | Significant Unobservable Inputs (Level 3)
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	242	165
Land and construction
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Foreclosed Assets Fair Value Disclosure		229
Land and construction | Significant Unobservable Inputs (Level 3)
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Foreclosed Assets Fair Value Disclosure		229
Land and construction | Real estate
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	119	199
Land and construction | Real estate | Significant Unobservable Inputs (Level 3)
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:	$ 119	199
CRE | Real estate
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:		419
CRE | Real estate | Significant Unobservable Inputs (Level 3)
Financial Assets and Liabilities Measured on a Non-Recurring Basis
Impaired loans - held-for-investment:		$ 419