Fair Value - Quantitative Information about Level 3 Fair Value Measurements (Details) - Non-recurring basis $ in Thousands	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($) item
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans - held-for-investment, Fair Value	$ 862	$ 702
Significant Unobservable Inputs (Level 3)
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans - held-for-investment, Fair Value	862	702
Commercial | Commercial
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans - held-for-investment, Fair Value	862	702
Commercial | Commercial | Significant Unobservable Inputs (Level 3)
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans - held-for-investment, Fair Value	$ 862	$ 702
Commercial | Commercial | Significant Unobservable Inputs (Level 3) | Minimum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales - Impaired loan held for investment (as a percent) | item	0.01	0.00
Commercial | Commercial | Significant Unobservable Inputs (Level 3) | Maximum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales - Impaired loan held for investment (as a percent) | item		1.00