Commitments, Guarantees, and Contingent Liabilities (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Other Commitments [Line Items]
Letters of credit		$ 122,592	$ 103,684
Commitments to extend credit
Other Commitments [Line Items]
Commercial, industrial, and agricultural		2,011,047	1,852,040
Commercial real estate		325,291	296,053
Home equity		596,402	576,956
Other commitments	[1]	246,644	251,093
Total commitments to extend credit		$ 3,179,384	$ 2,976,142

[1] Other commitments includes installment and overdraft protection program commitments.