Fair Value Measurement and Fair Value of Financial Instruments - Carrying and Fair Value Estimates per the Fair Value Hierarchy of Financial Instruments Measured on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial assets:
Cash and cash equivalents	$ 2,163,353	$ 3,912,935
Interest-bearing deposits with banks	630,543	736,492
Resale agreements	892,986	2,353,503
HTM debt securities	3,012,667	0
Restricted equity securities, at cost	78,254	77,434
Loans held-for-investment, net	46,859,738	41,152,202
Financial liabilities:
Federal funds purchased	200,000	0
FHLB advances	324,920	249,331
Repurchase agreements	611,785	300,000
Carrying Amount
Financial assets:
Cash and cash equivalents	2,163,353	3,912,935
Interest-bearing deposits with banks	630,543	736,492
Resale agreements	892,986	2,353,503
HTM debt securities	3,012,667
Restricted equity securities, at cost	78,254	77,434
Loans held-for-sale	14,500	635
Loans held-for-investment, net	46,859,738	41,152,202
Mortgage servicing rights	6,523	5,706
Accrued interest receivable	208,520	159,833
Financial liabilities:
Demand, checking, savings and money market deposits	43,498,799	45,388,550
Time deposits	10,358,563	7,961,982
Federal funds purchased	200,000
FHLB advances	324,920	249,331
Repurchase agreements	611,785	300,000
Long-term debt	147,875	147,658
Accrued interest payable	23,934	11,435
Estimated Fair Value
Financial assets:
Cash and cash equivalents	2,163,353	3,912,935
Interest-bearing deposits with banks	630,543	736,492
Resale agreements	790,239	2,335,901
HTM debt securities	2,459,135
Restricted equity securities, at cost	78,254	77,434
Loans held-for-sale	14,500	635
Loans held-for-investment, net	46,147,082	41,199,599
Mortgage servicing rights	10,532	9,104
Accrued interest receivable	208,520	159,833
Financial liabilities:
Demand, checking, savings and money market deposits	43,498,799	45,388,550
Time deposits	10,256,100	7,966,116
Federal funds purchased	200,000
FHLB advances	325,000	250,372
Repurchase agreements	617,513	310,525
Long-term debt	140,902	151,020
Accrued interest payable	23,934	11,435
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	2,163,353	3,912,935
Interest-bearing deposits with banks	0	0
Resale agreements	0	0
HTM debt securities	466,085
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
Federal funds purchased	0
FHLB advances	0	0
Repurchase agreements	0	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	630,543	736,492
Resale agreements	790,239	2,335,901
HTM debt securities	1,993,050
Restricted equity securities, at cost	78,254	77,434
Loans held-for-sale	14,500	635
Loans held-for-investment, net	0	0
Mortgage servicing rights	0	0
Accrued interest receivable	208,520	159,833
Financial liabilities:
Demand, checking, savings and money market deposits	43,498,799	45,388,550
Time deposits	10,256,100	7,966,116
Federal funds purchased	200,000
FHLB advances	325,000	250,372
Repurchase agreements	617,513	310,525
Long-term debt	140,902	151,020
Accrued interest payable	23,934	11,435
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
Restricted equity securities, at cost	0	0
Loans held-for-sale	0	0
Loans held-for-investment, net	46,147,082	41,199,599
Mortgage servicing rights	10,532	9,104
Accrued interest receivable	0	0
Financial liabilities:
Demand, checking, savings and money market deposits	0	0
Time deposits	0	0
Federal funds purchased	0
FHLB advances	0	0
Repurchase agreements	0	0
Long-term debt	0	0
Accrued interest payable	$ 0	$ 0