Disclosures About Fair Value of Assets and Liabilities - Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements Other Than Goodwill (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
State and municipal securities | Discounted cash flow
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 3,935	$ 3,943
State and municipal securities | Discounted cash flow | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Maturity/Call date	1 month	1 month
US Muni BQ curve	A-	A-
Discount rate	1.00%	0.69%
State and municipal securities | Discounted cash flow | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Maturity/Call date	20 years	20 years
US Muni BQ curve	BBB-	BBB-
Discount rate	5.00%	5.00%
Corporate obligations and U.S. Government-sponsored mortgage backed securities | Discounted cash flow
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 35
Corporate obligations and equity securities | Discounted cash flow
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value		$ 35
Risk free rate	3 month LIBOR	3 month LIBOR
Discount to reflect current market conditions	2.00%	2.00%
Impaired loans (collateral dependent) | Collateral based measurements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 5,168	$ 9,576
Impaired loans (collateral dependent) | Collateral based measurements | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	0.00%	0.00%
Impaired loans (collateral dependent) | Collateral based measurements | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	10.00%	10.00%
Impaired loans (collateral dependent) | Collateral based measurements | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	2.00%	1.00%
Other real estate owned | Appraisals
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 916	$ 859
Other real estate owned | Appraisals | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions	0.00%	0.00%
Other real estate owned | Appraisals | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions	24.00%	10.00%
Other real estate owned | Appraisals | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions	4.00%	2.00%