Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Expected federal tax expense	$ 5,927	$ 9,126	$ 8,158
Tax impact from enacted change in tax rate	0	2,747	0
Nondeductible interest expense	69	85	94
Tax-exempt interest	(504)	(949)	(1,265)
State income taxes	337	296	296
Other, net	(183)	(479)	(276)
Total income tax expense	5,646	10,826	7,007
Downward adjustment of net deferred tax assets	$ 0	$ 2,747	$ 0