Commitments, Guarantees, and Contingent Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Letters of credit	$ 114,797	$ 115,130
Commitments to extend credit
Other Commitments [Line Items]
Commercial, industrial, and agricultural	2,313,362	2,318,346
Commercial real estate	515,624	378,282
Home equity	608,440	611,640
Other commitments	273,734	264,869
Total commitments to extend credit	$ 3,711,160	$ 3,573,137