Loans - Summarizes Changes in Total Contractually Required Principal and Interest Cash Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Contractually Required Principal And Interest Cash Payments Changes [Line Items]
Beginning balance	$ 3,807	$ 2,610	$ 1,192
Additions	763	2,052	702
Deletions	(11)	(15)	(357)
Accretion	(1,647)	(1,734)	(601)
Reclassifications from non-accretable difference	787	894	1,674
Ending Balance	$ 3,699	$ 3,807	$ 2,610