Premises and Equipment - Schedule of Premises and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total cost	$ 11,138	$ 10,420
Accumulated depreciation	(6,055)	(5,787)
Net book value	5,083	4,633
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total cost	6,058	5,518
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total cost	2,893	2,791
Equipment and Others
Property Plant And Equipment [Line Items]
Total cost	$ 2,187	$ 2,111