Loans and Allowance for Loan Losses - ALL Roll Forward (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 5,105,000	$ 4,354,000	$ 4,354,000
Loans charged off	(234,000)		(306,000)
Recoveries of loans charged off	182,000		269,000
Provision (reallocation) charged to operating expense	340,482	616,543	788,000
Ending balance	5,393,000		5,105,000
Commercial Real Estate [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,369,000	1,906,000	1,906,000
Loans charged off	0		0
Recoveries of loans charged off	8,000		45,000
Provision (reallocation) charged to operating expense	166,000		418,000
Ending balance	2,543,000		2,369,000
Consumer Real Estate [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,382,000	1,015,000	1,015,000
Loans charged off	(110,000)		(102,000)
Recoveries of loans charged off	58,000		76,000
Provision (reallocation) charged to operating expense	85,000		393,000
Ending balance	1,415,000		1,382,000
Construction and Land Development [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	717,000	627,000	627,000
Loans charged off	0		(14,000)
Recoveries of loans charged off	10,000		22,000
Provision (reallocation) charged to operating expense	(162,000)		82,000
Ending balance	565,000		717,000
Commercial and Industrial [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	520,000	777,000	777,000
Loans charged off	(18,000)		(35,000)
Recoveries of loans charged off	55,000		58,000
Provision (reallocation) charged to operating expense	188,000		(280,000)
Ending balance	745,000		520,000
Consumer and Other [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	117,000	$ 29,000	29,000
Loans charged off	(106,000)		(155,000)
Recoveries of loans charged off	51,000		68,000
Provision (reallocation) charged to operating expense	63,000		175,000
Ending balance	$ 125,000		$ 117,000