Contingent Liabilities and Commitments with Off-Balance Sheet Risk - Summary of Financial Instruments with Off-Balance-Sheet Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Contract or Notional Amount
Commitments to extend credit	$ 1,548,482	$ 1,018,020
Unfunded limited partner equity commitment	21,390	6,011
Secured
Contract or Notional Amount
Standby letters of credit and financial guarantees written	11,167	13,073
Unsecured
Contract or Notional Amount
Standby letters of credit and financial guarantees written	$ 1,197	$ 663