Summary of Significant Accounting Policies - Recent Accounting Pronouncements - Leases (Details) $ in Thousands	Dec. 31, 2019	Dec. 31, 2019 store	Dec. 31, 2019 Office	Dec. 31, 2019 item	Dec. 31, 2019 USD ($)	Jan. 01, 2019 USD ($)
Assets and Liabilities, Lessee [Abstract]
Number of branch locations		21		21
Number of administration offices | Office			1
Number of ATM locations		3		3
Right-of-use assets					$ 8,308	$ 10,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position	us-gaap:OtherAssets					us-gaap:OtherAssets
Operating lease liabilities					$ 8,915	$ 10,000
Operating Lease, Liability, Statement of Financial Position	us-gaap:OtherLiabilities					us-gaap:OtherLiabilities