Commitments and contingencies - Schedule of Financial Instruments with Off-Balance Sheet Credit Risk (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Commitments to extend credit: \| Credit card lines
Commitments and contingencies
Commitments to extend credit:	$ 7,001,118	$ 6,415,208
Commitments to extend credit: \| Commercial lines of credit
Commitments and contingencies
Commitments to extend credit:	4,359,079	4,257,505
Commitments to extend credit: \| Construction lines of credit
Commitments and contingencies
Commitments to extend credit:	1,068,649	1,197,319
Commitments to extend credit: \| Other consumer unused credit commitments
Commitments and contingencies
Commitments to extend credit:	290,569	277,635
Commercial letters of credit
Commitments and contingencies
Commitments to extend credit:	8,957	21,248
Standby letters of credit
Commitments and contingencies
Commitments to extend credit:	134,686	111,554
Commitments to originate or fund mortgage loans
Commitments and contingencies
Commitments to extend credit:	$ 21,709	$ 20,099