Commitments, Guarantees, and Contingent Liabilities (Details) - Contractual or Notional Amounts of Financial Instruments - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Commitments to extend credit:
Letters of credit	$ 115,130	$ 103,684
Commitments to extend credit
Commitments to extend credit:
Commercial, industrial, and agricultural	2,318,346	1,852,040
Commercial real estate	378,282	296,053
Home equity	611,640	576,956
Other commitments	264,869	251,093
Total commitments to extend credit	$ 3,573,137	$ 2,976,142