Income Taxes - Summary of Net Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2017
Deferred Tax Assets, Gross [Abstract]
Allowance for loan losses	$ 8,592	$ 7,187
Premises and equipment	1,670	1,390
Other real estate owned	207	207
Accrued stock compensation	2,547	1,569
Federal tax loss carryforward	4,699	4,755
State tax loss carryforward	2,912	5,578
Alternative minimum tax credit carryforward	0	2,209
Net unrealized securities losses	4,658	1,429
Deferred compensation	2,287	2,125
Accrued interest and fee income	7,674	2,411
Other	1,627	2,248
Gross deferred tax assets	36,873	31,108
Less: Valuation allowance	0	0
Deferred tax assets net of valuation allowance	36,873	31,108
Deferred Tax Liabilities, Gross [Abstract]
Core deposit base intangible	(5,706)	(3,964)
Other	(2,213)	(1,727)
Gross deferred tax liabilities	(7,919)	(5,691)
Net deferred tax assets	$ 28,954	$ 25,417	$ 34,000