Fair Value Accounting - Carrying And Estimated Fair Values Of Financial Instruments Carried On Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financial assets
Total investment securities available for sale	$ 9,678,103	$ 10,918,329
Mutual funds and mutual funds held in rabbi trusts	42,659	43,657
Loans, net	43,272,929	38,884,361
Derivative assets	89,815	191,708
Financial liabilities
Non-interest-bearing deposits	15,639,899	16,392,653
Time deposits	6,295,025
Total deposits	48,871,559	49,427,276
Federal funds purchased and securities sold under repurchase agreements	146,588	264,133
Short-term FHLB advances	603,384	200
Long-term debt	4,109,597	1,204,229
Fair Value, Measurements, Recurring
Financial assets
Trading securities	8,295	8,391
Total investment securities available for sale	9,678,103	10,918,329
Other investments	11,172	12,185
Mutual funds and mutual funds held in rabbi trusts	42,659	43,657
SBA loans servicing asset	2,354	3,233
Derivative assets	89,815	191,708
Financial liabilities
Securities sold short	3,370	200
Mutual fund held in rabbi trusts	27,944	27,205
Derivative liabilities	342,680	98,602
Level 1 | Fair Value, Measurements, Recurring
Financial assets
Total cash, cash equivalents, and restricted cash	1,977,780	3,009,853
Trading securities	0	0
Total investment securities available for sale	471,813	117,838
Loans held for sale	0	0
Other investments	0	0
Mutual funds and mutual funds held in rabbi trusts	42,659	43,657
Loans, net	0	0
SBA loans servicing asset	0	0
FRB and FHLB stock	0	0
Derivative assets	0	0
Financial liabilities
Non-interest-bearing deposits	0	0
Non-time interest-bearing deposits	0	0
Time deposits	0	0
Total deposits	0	0
Federal funds purchased and securities sold under repurchase agreements	146,588	264,133
Securities sold short	3,370	0
Short-term FHLB advances	0
Long-term debt	0	0
Mutual fund held in rabbi trusts	27,944	27,205
Derivative liabilities	0	0
Level 2 | Fair Value, Measurements, Recurring
Financial assets
Total cash, cash equivalents, and restricted cash	0	0
Trading securities	8,295	8,391
Total investment securities available for sale	9,206,290	10,800,491
Loans held for sale	51,136	108,198
Other investments	0	0
Mutual funds and mutual funds held in rabbi trusts	0	0
Loans, net	0	0
SBA loans servicing asset	0	0
FRB and FHLB stock	308,321	159,941
Derivative assets	89,815	191,708
Financial liabilities
Non-interest-bearing deposits	15,639,899	16,392,653
Non-time interest-bearing deposits	26,936,635	28,917,148
Time deposits	6,260,315	4,125,673
Total deposits	48,836,849	49,435,474
Federal funds purchased and securities sold under repurchase agreements	0	0
Securities sold short	0	200
Short-term FHLB advances	600,014
Long-term debt	4,120,113	1,243,147
Mutual fund held in rabbi trusts	0	0
Derivative liabilities	339,227	95,067
Level 3 | Fair Value, Measurements, Recurring
Financial assets
Total cash, cash equivalents, and restricted cash	0	0
Trading securities	0	0
Total investment securities available for sale	0	0
Loans held for sale	339,949	641,782
Other investments	11,172	12,185
Mutual funds and mutual funds held in rabbi trusts	0	0
Loans, net	42,192,295	39,118,275
SBA loans servicing asset	2,354	3,233
FRB and FHLB stock	0	0
Derivative assets	0	0
Financial liabilities
Non-interest-bearing deposits	0	0
Non-time interest-bearing deposits	0	0
Time deposits	0	0
Total deposits	0	0
Federal funds purchased and securities sold under repurchase agreements	0	0
Securities sold short	0	0
Short-term FHLB advances	0
Long-term debt	0	0
Mutual fund held in rabbi trusts	0	0
Derivative liabilities	3,453	3,535
Carrying Value | Fair Value, Measurements, Recurring
Financial assets
Total cash, cash equivalents, and restricted cash	1,977,780	3,009,853
Trading securities	8,295	8,391
Total investment securities available for sale	9,678,103	10,918,329
Loans held for sale	391,502	750,642
Other investments	11,172	12,185
Mutual funds and mutual funds held in rabbi trusts	42,659	43,657
Loans, net	43,272,929	38,884,361
SBA loans servicing asset	2,354	3,233
FRB and FHLB stock	308,321	159,941
Derivative assets	89,815	191,708
Financial liabilities
Non-interest-bearing deposits	15,639,899	16,392,653
Non-time interest-bearing deposits	26,936,635	28,917,148
Time deposits	6,295,025	4,117,475
Total deposits	48,871,559	49,427,276
Federal funds purchased and securities sold under repurchase agreements	146,588	264,133
Securities sold short	3,370	200
Short-term FHLB advances	600,014
Long-term debt	4,109,597	1,204,229
Mutual fund held in rabbi trusts	27,944	27,205
Derivative liabilities	342,680	98,602
Fair Value | Fair Value, Measurements, Recurring
Financial assets
Total cash, cash equivalents, and restricted cash	1,977,780	3,009,853
Trading securities	8,295	8,391
Total investment securities available for sale	9,678,103	10,918,329
Loans held for sale	391,085	749,980
Other investments	11,172	12,185
Mutual funds and mutual funds held in rabbi trusts	42,659	43,657
Loans, net	42,192,295	39,118,275
SBA loans servicing asset	2,354	3,233
FRB and FHLB stock	308,321	159,941
Derivative assets	89,815	191,708
Financial liabilities
Non-interest-bearing deposits	15,639,899	16,392,653
Non-time interest-bearing deposits	26,936,635	28,917,148
Time deposits	6,260,315	4,125,673
Total deposits	48,836,849	49,435,474
Federal funds purchased and securities sold under repurchase agreements	146,588	264,133
Securities sold short	3,370	200
Short-term FHLB advances	600,014
Long-term debt	4,120,113	1,243,147
Mutual fund held in rabbi trusts	27,944	27,205
Derivative liabilities	$ 342,680	$ 98,602