Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financial assets
Cash and Due from Banks	$ 484,384	$ 436,952
Interest-bearing deposits in other financial institutions	425,089	156,693
Federal funds sold and securities purchased under agreements to resell	14,350	27,810
Debt Securities, Available-for-sale	3,600,892	2,742,025
Investment securities held to maturity	3,860,235	3,960,451
Investment securities held to maturity, fair value	3,380,624	3,401,018
Equity Securities with Readily Determined Fair Value	7,000	6,000
Equity Securities without Readily Determinable Fair Value, Amount	35,000	19,000
Equity securities	41,651	25,216
FHLB and Federal Reserve Bank stocks	229,171	295,496
Commercial Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	90,303	0
Loans and Leases Receivable, Net Amount	28,865,124	28,486,849
Life Insurance, Corporate or Bank Owned, Amount	682,649	676,530
Servicing Asset at Fair Value, Amount	84,390	77,351	$ 57,158
Financial liabilities
Short-term funding	326,780	605,937
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	1,940,194	4,319,861
Other long-term funding	1,741,463
Commitment on standby letters of credit	212,000	271,000
Fair Value, Inputs, Level 1
Financial assets
Cash and Due from Banks	484,384	436,952
Interest-bearing deposits in other financial institutions	425,089	156,693
Federal funds sold and securities purchased under agreements to resell	14,350	27,810
Debt Securities, Available-for-sale	35,902	109,378
Investment securities held to maturity	999	999
Investment securities held to maturity, fair value	963	936
Equity securities with readily determinable fair value, Carrying Amount	6,883	5,991
Equity Securities with Readily Determined Fair Value	6,883	5,991
Fair Value, Inputs, Level 2
Financial assets
Debt Securities, Available-for-sale	3,564,990	2,632,647
Investment securities held to maturity	3,859,161	3,959,399
Investment securities held to maturity, fair value	3,379,586	3,400,028
FHLB and Federal Reserve Bank stocks	229,171	295,496
Loans Held-for-sale, Fair Value Disclosure	33,011	20,383
Commercial Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	90,303	0
Commercial loans held for sale	90,303	0
Life Insurance, Corporate or Bank Owned, Amount	682,649	676,530
Financial liabilities
Brokered CDs and other time deposits	7,315,973	1,930,158
Brokered CDs and other time deposits, fair value	7,315,973	1,930,158
Short-term funding	326,780	605,937
Short-term funding, fair value	326,757	605,205
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	1,940,194	4,319,861
Advances, Fair Value Disclosure	1,944,600	4,322,264
Other long-term funding	541,269	248,071
Long-term funding, fair value	534,983	242,151
Standby letters of credit	2,157	2,881
Standby letters of credit, fair value	2,157	2,881
Fair Value, Inputs, Level 2 | Other Assets [Member]
Financial assets
Derivative Assets	123,284	67,603
Derivatives (trading and other assets), fair value	123,284	67,603
Fair Value, Inputs, Level 2 | Liability
Financial liabilities
Derivative Liability	202,285	254,033
Derivatives (trading and other liabilities), fair value	202,285	254,033
Fair Value, Inputs, Level 3
Financial assets
Equity Securities without Readily Determinable Fair Value, Amount	24,769	19,225
Equity securities	24,769	19,225
Loans and Leases Receivable, Net Amount	28,865,124	28,486,849
Loans Receivable, Fair Value Disclosure	27,371,086	27,481,426
Servicing Asset	84,390	77,351
Servicing Asset at Fair Value, Amount	84,390	77,351
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	26,130,076	27,705,996
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts, fair value	26,130,076	27,705,996
Fair Value, Inputs, Level 3 | Mortgage banking(a)
Financial assets
Derivative Assets	439	86
Financial liabilities
Derivative Liability	673	46
Derivatives (trading and other liabilities), fair value	673	46
Fair Value, Inputs, NAV
Financial assets
Equity securities with readily determinable fair value, Carrying Amount	10,000	0
Equity Securities with Readily Determined Fair Value	$ 10,000	$ 0