Commitments and Contingencies - Loss Commitments and Letters of Credit (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Carrying amount included in other assets	$ 508,575	$ 488,944
Amount of future funding commitments	303,388	283,212
Permanent and short-term construction loans and letter of credit commitments	207,249	177,998
Funded portion of permanent and short-term loans and letters of credit	242,676	234,166
Guarantee obligations
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	16,649,944	17,181,946
Letters of credit
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	232,955	220,622
Contractual amount net of risk participations	25,700	25,700
Commitments to fund commercial and industrial loans
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	9,504,608	9,970,733
Commitments to fund commercial real estate, construction, and land development loans
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	3,543,525	3,629,531
Commitments under home equity lines of credit
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	2,190,048	2,156,641
Unused credit card lines
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	467,520	461,443
Other loan commitments
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	711,288	742,976
Permanent and short-term construction loans and letter of credit commitments
Loss Contingencies [Line Items]
Contractual amount net of risk participations	4,000	4,700
Funded portion of permanent and short-term loans and letters of credit
Loss Contingencies [Line Items]
Contractual amount net of risk participations	$ 5,100	$ 6,900