Available-For-Sale Securities - Investment Securities with Unrealized Losses by Investment Category (Details) item in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Investment holdings
Fair Value, Less than 12 Months	$ 1,024	$ 1,718
Unrealized Losses, Less than 12 Months	(7)	(4)
Fair Value, 12 Months or More	23,337	32,749
Unrealized Losses, 12 Months or More	(490)	(927)
Fair Value, Total	24,361	34,467
Unrealized Losses, Total	$ (497)	(931)
Other than temporary impairment losses on investments
Number of adverse conditions identified, related to repayment of securities that are not rated | item	0
Impairment charge on available for sale securities	$ 0
Loss of principal anticipated	0
Loss of interest anticipated	0
U. S. government agencies and government sponsored entities
Investment holdings
Fair Value, 12 Months or More	3,591	6,243
Unrealized Losses, 12 Months or More	(34)	(118)
Fair Value, Total	3,591	6,243
Unrealized Losses, Total	(34)	(118)
Agency mortgage-backed securities: residential
Investment holdings
Fair Value, Less than 12 Months		1,029
Unrealized Losses, Less than 12 Months		(2)
Fair Value, 12 Months or More	12,543	15,431
Unrealized Losses, 12 Months or More	(127)	(353)
Fair Value, Total	12,543	16,460
Unrealized Losses, Total	(127)	(355)
State and municipal
Investment holdings
Fair Value, Less than 12 Months	1,024	689
Unrealized Losses, Less than 12 Months	(7)	(2)
Fair Value, 12 Months or More	5,563	9,445
Unrealized Losses, 12 Months or More	(75)	(193)
Fair Value, Total	6,587	10,134
Unrealized Losses, Total	(82)	(195)
Trust preferred security
Investment holdings
Fair Value, 12 Months or More	1,640	1,630
Unrealized Losses, 12 Months or More	(254)	(263)
Fair Value, Total	1,640	1,630
Unrealized Losses, Total	$ (254)	$ (263)