Securities - Securities in Unrealized Loss Position (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) security	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) security	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) security
Securities
Number of securities held with unrealized losses | security	1		1		10
Estimated Fair Value
Less than 12 months	$ 623		$ 623		$ 4,628
12 months or more					7,448
Total	623		623		12,076
Gross Unrealized Losses
Less than 12 months	(2)		(2)		(35)
12 months or more					(223)
Total	(2)		(2)		(258)
Securities pledged to secure public deposits	$ 0		$ 0		$ 0
Securities pledged to secure public deposits	us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember
Securities of any one issuer, other than U.S. Government, greater than 10% of stockholders' equity			0.00%		0.00%
Sales of securities	$ 0	$ 0	$ 0	$ 0
Federal agency mortgage-backed securities
Estimated Fair Value
Less than 12 months	623		623		$ 2,649
12 months or more					4,213
Total	623		623		6,862
Gross Unrealized Losses
Less than 12 months	(2)		(2)		(25)
12 months or more					(130)
Total	$ (2)		$ (2)		(155)
Federal agency debt
Estimated Fair Value
Less than 12 months					1,979
12 months or more					3,235
Total					5,214
Gross Unrealized Losses
Less than 12 months					(10)
12 months or more					(93)
Total					$ (103)