Fair Value Measurement and Fair Value of Financial Instruments - Schedule of the Carrying and Fair Value Estimates Per the Fair Value Hierarchy of Financial Instruments Measured on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Financial assets:
Cash and cash equivalents	$ 5,088,923	$ 4,188,139
Interest-bearing deposits with banks	12,426	16,189
Resale agreements	425,000	425,000
HTM debt securities	2,845,364	2,870,058
Restricted equity securities, at cost	159,013	153,484
Loans held-for-investment, net	58,121,884	56,068,399
Financial liabilities:
FHLB advances	3,000,000	3,000,000
Repurchase agreements	956,894	0
Carrying Amount
Financial assets:
Cash and cash equivalents	5,088,923	4,188,139
Interest-bearing deposits with banks	12,426	16,189
Resale agreements	425,000	425,000
HTM debt securities	2,845,364	2,870,058
Restricted equity securities, at cost	159,013	153,484
Loans held-for-sale	17,425	20,976
Loans held-for-investment, net	58,121,884	56,068,399
Mortgage servicing rights	3,736	4,119
Accrued interest receivable	329,681	315,669
Financial liabilities:
Demand, checking, savings and money market deposits	44,553,844	41,797,887
Time deposits	25,538,849	25,284,814
FHLB advances	3,000,000	3,000,000
Repurchase agreements	956,894
Long-term debt	32,482	32,320
Accrued interest payable	48,042	60,513
Estimated Fair Value
Financial assets:
Cash and cash equivalents	5,088,923	4,188,139
Interest-bearing deposits with banks	12,426	16,189
Resale agreements	349,960	351,065
HTM debt securities	2,443,494	2,479,746
Restricted equity securities, at cost	159,013	153,484
Loans held-for-sale	17,425	20,976
Loans held-for-investment, net	56,556,874	54,665,865
Mortgage servicing rights	6,736	7,114
Accrued interest receivable	329,681	315,669
Financial liabilities:
Demand, checking, savings and money market deposits	44,553,844	41,797,887
Time deposits	25,494,748	25,285,076
FHLB advances	3,001,692	3,001,878
Repurchase agreements	956,895
Long-term debt	30,822	32,070
Accrued interest payable	45,889	60,513
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	5,088,923	4,188,139
Interest-bearing deposits with banks	0	0
Resale agreements	0	0
HTM debt securities	528,435	524,887
Restricted equity securities, at cost	0	0
Loans held-for-sale	0	0
Loans held-for-investment, net	0	0
Mortgage servicing rights	0	0
Accrued interest receivable	0	0
Financial liabilities:
Demand, checking, savings and money market deposits	0	0
Time deposits	0	0
FHLB advances	0	0
Repurchase agreements	0
Long-term debt	0	0
Accrued interest payable	0	0
Estimated Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Interest-bearing deposits with banks	12,426	16,189
Resale agreements	349,960	351,065
HTM debt securities	1,915,059	1,954,859
Restricted equity securities, at cost	159,013	153,484
Loans held-for-sale	17,425	20,976
Loans held-for-investment, net	0	0
Mortgage servicing rights	0	0
Accrued interest receivable	329,681	315,669
Financial liabilities:
Demand, checking, savings and money market deposits	44,553,844	41,797,887
Time deposits	25,494,748	25,285,076
FHLB advances	3,001,692	3,001,878
Repurchase agreements	956,895
Long-term debt	30,822	32,070
Accrued interest payable	45,889	60,513
Estimated Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Interest-bearing deposits with banks	0	0
Resale agreements	0	0
HTM debt securities	0	0
Restricted equity securities, at cost	0	0
Loans held-for-sale	0	0
Loans held-for-investment, net	56,556,874	54,665,865
Mortgage servicing rights	6,736	7,114
Accrued interest receivable	0	0
Financial liabilities:
Demand, checking, savings and money market deposits	0	0
Time deposits	0	0
FHLB advances	0	0
Repurchase agreements	0
Long-term debt	0	0
Accrued interest payable	$ 0	$ 0