Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory rate times pre-tax income									$ 5,703	$ 5,030	$ 8,025
(Subtract) add the tax effect of:
Income from tax-exempt securities and loans									(4,881)	(3,833)	(2,512)
State income tax, net of federal tax effect									1,285	1,164	693
Bank-owned life insurance									(198)	(200)	(318)
Net deferred tax asset revaluation									0	0	1,846
Tax credits									(181)	(180)	0
Other differences									189	71	(32)
Total	$ 602	$ 449	$ 340	$ 526	$ (334)	$ 743	$ 781	$ 862	$ 1,917	$ 2,052	$ 7,702