Commitments and Contingent Liabilities - Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	$ 174,501	$ 106,835
Variable Rate	1,579,465	1,319,992
Total	1,753,966	1,426,827
Commitments to Extend Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	173,848	106,183
Variable Rate	1,520,986	1,261,872
Total	1,694,834	1,368,055
Letters of Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	653	652
Variable Rate	58,479	58,120
Total	$ 59,132	$ 58,772