Fair Values of Assets and Liabilities - Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financial Assets:
Interest-bearing deposits with banks	$ 2,084,323	$ 1,988,719
Available-for-sale securities	3,502,915	3,243,017
Held-to-maturity securities	3,215,468	2,949,821
Equity securities with readily determinable fair value	139,268	110,365
FHLB and FRB stock, at cost	205,003	224,759
Brokerage customer receivables	10,592	16,387
Mortgage loans held-for-sale, at fair value	292,722	299,935
Accrued interest receivable and other assets	1,551,899	1,391,342
Financial Liabilities:
Federal Home Loan Bank advances	2,326,071	2,316,071
Other borrowings	645,813	596,614
Subordinated notes	437,866	437,392
Junior subordinated debentures	253,566	253,566
Carrying Value
Financial Assets:
Cash and cash equivalents	423,464	490,966
Interest-bearing deposits with banks	2,084,323	1,988,719
Available-for-sale securities	3,502,915	3,243,017
Held-to-maturity securities	3,856,916	3,640,567
Trading account securities	4,707	1,127
Equity securities with readily determinable fair value	139,268	110,365
FHLB and FRB stock, at cost	205,003	224,759
Brokerage customer receivables	10,592	16,387
Mortgage loans held-for-sale, at fair value	292,722	299,935
Nonqualified deferred compensation assets	15,238	13,899
Derivative assets	275,726	296,848
Accrued interest receivable and other assets	477,832	379,719
Total financial assets	53,420,537	49,902,793
Financial Liabilities:
Non-maturity deposits	38,772,098	38,167,409
Deposits with stated maturities	6,625,072	4,735,135
Federal Home Loan Bank advances	2,326,071	2,316,071
Other borrowings	645,813	596,614
Subordinated notes	437,866	437,392
Junior subordinated debentures	253,566	253,566
Derivative liabilities	267,255	338,078
Accrued interest payable	51,116	22,176
Total financial liabilities	49,378,857	46,866,441
Carrying Value | Loans held-for-investment, at fair value
Financial Assets:
Loans held-for-investment	155,261	179,932
Carrying Value | Loans held-for-investment, at amortized cost
Financial Assets:
Loans held-for-investment	41,976,570	39,016,553
Fair Value
Financial Assets:
Cash and cash equivalents	423,464	490,966
Interest-bearing deposits with banks	2,084,323	1,988,719
Available-for-sale securities	3,502,915	3,243,017
Held-to-maturity securities	3,215,468	2,949,821
Trading account securities	4,707	1,127
Equity securities with readily determinable fair value	139,268	110,365
FHLB and FRB stock, at cost	205,003	224,759
Brokerage customer receivables	10,592	16,387
Mortgage loans held-for-sale, at fair value	292,722	299,935
Nonqualified deferred compensation assets	15,238	13,899
Derivative assets	275,726	296,848
Accrued interest receivable and other assets	477,832	379,719
Total financial assets	51,892,529	48,214,172
Financial Liabilities:
Non-maturity deposits	38,772,098	38,167,409
Deposits with stated maturities	6,603,746	4,085,058
Federal Home Loan Bank advances	2,367,107	2,219,983
Other borrowings	643,755	569,342
Subordinated notes	413,501	409,395
Junior subordinated debentures	253,579	253,405
Derivative liabilities	267,255	338,078
Accrued interest payable	51,116	22,176
Total financial liabilities	49,372,157	46,064,846
Fair Value | Loans held-for-investment, at fair value
Financial Assets:
Loans held-for-investment	155,261	179,932
Fair Value | Loans held-for-investment, at amortized cost
Financial Assets:
Loans held-for-investment	$ 41,090,010	$ 38,018,678