Fair Value Measurements - Estimated Fair Values and Related Carrying Amounts of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, net	$ 2,984,040	$ 1,517,378
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	679,410	1,650,653
Interest bearing balances due from banks - time	1,290	1,882
Held-to-maturity securities, net	3,787,076	1,529,221
Interest receivable	86,637	72,990
Loans and other loans held for sale, net	15,411,838	11,807,171
Federal funds purchased and securities sold under agreements to repurchase	168,513	185,403
Other borrowings	964,772	1,337,973
Subordinated notes and debentures	365,951	384,131
Interest payable	13,077	6,759
Carrying Amount | Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,218,283	5,325,318
Carrying Amount | Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	12,103,994	11,588,770
Carrying Amount | Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	3,826,415	2,452,460
Fair Value Measurements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	679,410	1,650,653
Interest bearing balances due from banks - time	1,290	1,882
Held-to-maturity securities, net	2,984,040	1,517,378
Interest receivable	86,637	72,990
Loans and other loans held for sale, net	14,967,078	11,922,735
Federal funds purchased and securities sold under agreements to repurchase	168,513	185,403
Other borrowings	961,666	1,393,711
Subordinated notes and debentures	362,823	394,464
Interest payable	13,077	6,759
Fair Value Measurements | Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,218,283	5,325,318
Fair Value Measurements | Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	12,103,994	11,588,770
Fair Value Measurements | Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	3,761,408	2,451,055
Fair Value Measurements | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	679,410	1,650,653
Interest bearing balances due from banks - time	0	0
Held-to-maturity securities, net	0	0
Interest receivable	0	0
Loans and other loans held for sale, net	0	0
Federal funds purchased and securities sold under agreements to repurchase	0	0
Other borrowings	0	0
Subordinated notes and debentures	0	0
Interest payable	0	0
Fair Value Measurements | Level 1 | Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 1 | Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 1 | Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing balances due from banks - time	1,290	1,882
Held-to-maturity securities, net	2,984,040	1,517,378
Interest receivable	86,637	72,990
Loans and other loans held for sale, net	0	0
Federal funds purchased and securities sold under agreements to repurchase	168,513	185,403
Other borrowings	961,666	1,393,711
Subordinated notes and debentures	362,823	394,464
Interest payable	13,077	6,759
Fair Value Measurements | Level 2 | Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,218,283	5,325,318
Fair Value Measurements | Level 2 | Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	12,103,994	11,588,770
Fair Value Measurements | Level 2 | Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing balances due from banks - time	0	0
Held-to-maturity securities, net	0	0
Interest receivable	0	0
Loans and other loans held for sale, net	14,967,078	11,922,735
Federal funds purchased and securities sold under agreements to repurchase	0	0
Other borrowings	0	0
Subordinated notes and debentures	0	0
Interest payable	0	0
Fair Value Measurements | Level 3 | Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 3 | Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements | Level 3 | Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	$ 3,761,408	$ 2,451,055