Income Taxes - Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts
Income tax computed at federal statutory rates	$ 6,272	$ 6,084	$ 6,120
Tax effect of exclusion of interest income on obligations of states and political subdivisions (in Dollars)	(1,310)	(1,456)	(1,546)
Reduction of interest expense incurred to carry tax-exempt assets	36	38	42
Increase in bank-owned life insurance	(324)	(159)	(38)
State income taxes, net of federal tax benefit	403	563	532
Amortization of investments in qualified affordable housing projects, net of federal tax benefit	217	264	270
Tax credit on investments in qualified affordable housing projects	(364)	(400)	(180)
Share-based compensation	(476)
Other	5	(81)	(56)
Income tax expense (benefit)	$ 4,459	$ 4,853	$ 5,144
Percent of Pre-tax Income
Income tax computed at federal statutory rates (as a percent)	35.00%	35.00%	35.00%
Tax effect of exclusion of interest income on obligations of states and political subdivisions (as a percent)	(7.30%)	(8.40%)	(8.80%)
Reduction of interest expense incurred to carry tax-exempt assets (as a percent)	0.20%	0.20%	0.20%
Increase in bank-owned life insurance	(1.80%)	(0.90%)	(0.20%)
State income taxes, net of federal tax benefit	2.20%	3.30%	3.00%
Amortization of investments in qualified affordable housing projects	1.20%	1.50%	1.50%
Tax credit on investments in qualified affordable housing projects	(2.00%)	(2.30%)	(1.00%)
Share-based compensation	(2.70%)
Other		(0.50%)	(0.30%)
Income tax expense (as a percent)	24.80%	27.90%	29.40%