Commitments and Contingencies - Financial Instruments Representing Off-Balance-Sheet Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fixed Rate Commitments to Extend Credit [Member]
Other Commitments [Line Items]
Financial instruments off-balance sheet credit risks	$ 80,674	$ 96,648
Variable Rate Commitments To Extend Credit [Member]
Other Commitments [Line Items]
Financial instruments off-balance sheet credit risks	411,366	685,339
Standby Letters of Credit [Member]
Other Commitments [Line Items]
Financial instruments off-balance sheet credit risks	$ 8,619	$ 8,966