Commitments and Contingencies (Schedule of Loss Commitments and Letters of Credit) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Carrying amount included in other assets	$ 525,072	$ 488,944
Amount of future funding commitments	300,722	283,212
Permanent and short-term construction loans and letter of credit commitments	208,699	177,998
Funded portion of permanent and short-term loans and letters of credit	195,748	234,166
Guarantee obligations
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	16,772,795	17,181,946
Letters of credit
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	203,911	220,622
Contractual amount net of risk participations	23,400	25,700
Commitments to fund commercial and industrial loans
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	10,143,330	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	3,100,361	3,629,531
Commitments under home equity lines of credit
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	2,163,660	2,156,641
Unused credit card lines
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	463,440	461,443
Other loan commitments
Loss Contingencies [Line Items]
Total letters of credit and unfunded lending commitments	698,093	742,976
Permanent and short-term construction loans and letter of credit commitments
Loss Contingencies [Line Items]
Contractual amount net of risk participations	10,000	4,700
Funded portion of permanent and short-term loans and letters of credit
Loss Contingencies [Line Items]
Contractual amount net of risk participations	$ 2,900	$ 6,900