Commitments and Contingencies - Financial instruments with off-Balance Sheet credit risk (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Commitments to extend credit | Credit card lines
Commitments and contingencies
Unused commitments to extend credit	$ 5,720,469	$ 5,853,990
Commitments to extend credit | Commercial and construction lines of credit
Commitments and contingencies
Unused commitments to extend credit	4,374,553	4,425,825
Commitments to extend credit | Other consumer unused credit commitments
Commitments and contingencies
Unused commitments to extend credit	250,571	250,271
Commercial letters of credit
Commitments and contingencies
Unused commitments to extend credit	3,083	3,351
Standby letters of credit
Commitments and contingencies
Unused commitments to extend credit	53,089	27,868
Commitments to originate or fund mortgage loans
Commitments and contingencies
Unused commitments to extend credit	$ 25,104	$ 45,170