Fair Value Disclosures - Significant Unobservable Inputs Used to Value Level 3 Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Impaired loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on non-recurring basis	$ 534	$ 239
Valuation Technique	Appraisal	Cash Flow
Significant Other Unobservable Input	Appraisal Discounts	Discounted Cash Flow / Appraisal Discounts
Weighted Average of Input (as a percent)	24.70%	2.40%
Foreclosed assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on non-recurring basis	$ 2,888	$ 2,386
Valuation Technique	Appraisal	Appraisal
Significant Other Unobservable Input	Appraisal Discounts	Appraisal Discounts
Weighted Average of Input (as a percent)	19.30%	12.20%