Fair Value - Quantitative Information about Level 3 Fair Value Measurements (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Non-recurring basis
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	$ 1,314	$ 783
Non-recurring basis | 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	$ 1,314	783
Commercial | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach
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		$ 165
Commercial | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | 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 (as a percent)	1.00%	1.00%
Foreclosed Assets | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Foreclosed assets - commercial | Market Approach | 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 (as a percent)		0.00%
Foreclosed Assets | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Foreclosed assets - commercial | Market Approach | 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 (as a percent)		2.00%
Foreclosed Assets | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Foreclosed assets - land and construction | Market Approach
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		$ 229
Commercial | Commercial | Significant Unobservable Inputs (Level 3) | Market Approach
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	$ 246
Commercial | Commercial | Non-recurring basis
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	246	165
Commercial | Commercial | Non-recurring basis | 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	$ 246	165
Commercial | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach
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		$ 419
Commercial | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | 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 (as a percent)		0.00%
Commercial | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | 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 (as a percent)		3.00%
Commercial | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | Weighted average
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 (as a percent)		3.00%
Commercial | Foreclosed Assets | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Foreclosed assets - commercial | Market Approach | Weighted average
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 (as a percent)		2.00%
Land and construction | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | 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 (as a percent)	1.00%
Land and construction | Real estate | Significant Unobservable Inputs (Level 3) | Market Approach
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	$ 1,068
Land and construction | Real estate | Non-recurring basis
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	1,068	$ 199
Land and construction | Real estate | Non-recurring basis | 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	$ 1,068	199
Land and construction | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach
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		$ 199
Land and construction | Real estate | Non-recurring basis | Significant Unobservable Inputs (Level 3) | Market Approach | 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 (as a percent)		1.00%
CRE | Real estate | Non-recurring basis
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		$ 419
CRE | Real estate | Non-recurring basis | 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		$ 419