Credit Quality and Nonperforming Assets - Troubled Debt Restructurings, by Type of Loan Modification (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	$ 233	$ 124	$ 804	$ 1,304
Real Estate Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	97	344	964
Real Estate Sector [Member] | Other construction/land [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Real Estate Sector [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Real Estate Sector [Member] | Equity Lines [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	97	344	964
Real Estate Sector [Member] | Multi-Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Real Estate Sector [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Real Estate Sector [Member] | Farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Agricultural Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	7	0	7
Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	233	10	401	323
Consumer Loans Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	10	59	10
Troubled Debt Restructurings Rate Modifications [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	94	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | Other construction/land [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | Equity Lines [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | Multi-Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Real Estate Sector [Member] | Farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Agricultural Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate Modifications [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	94	0
Troubled Debt Restructurings Rate Modifications [Member] | Consumer Loans Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	233	114	608	540
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	97	344	460
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | Other construction/land [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | Equity Lines [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	97	344	460
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | Multi-Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member] | Real Estate Sector [Member] | Farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Term Modifications [Member] | Agricultural Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	7	0	7
Troubled Debt Restructurings Term Modifications [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	233	10	255	73
Troubled Debt Restructurings Term Modifications [Member] | Consumer Loans Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	9	0
Troubled Debt Restructurings Interest Only Modification [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	10	0	539
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	504
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | Other construction/land [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | Equity Lines [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	504
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | Multi-Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Real Estate Sector [Member] | Farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Agricultural Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Interest Only Modification [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	25
Troubled Debt Restructurings Interest Only Modification [Member] | Consumer Loans Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	10	0	10
Troubled Debt Restructurings Rate And Term Modifications [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	102	225
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | Other construction/land [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | Equity Lines [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | Multi-Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Real Estate Sector [Member] | Farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Agricultural Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	0	0
Troubled Debt Restructurings Rate And Term Modifications [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	0	0	52	225
Troubled Debt Restructurings Rate And Term Modifications [Member] | Consumer Loans Sector [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Post Modification Recorded Investment During Period	$ 0	$ 0	$ 50	$ 0