Fair Value Measurements (Details 2) - USD ($) $ in Thousands		Sep. 30, 2025	Dec. 31, 2024
ASSETS
Held to Maturity, Fair Value, Total		$ 1,260,752	$ 1,291,801
Federal Home Loan Bank Stock		21,835	31,573
Bank Owned Life Insurance		376,163	303,965
LIABILITIES
Federal Home Loan Bank and other borrowings (f)		416,240	638,514
Subordinated Debt		296,275	0
Reported Value Measurement
ASSETS
Loans Receivable, Fair Value Disclosure	[1]	18,219,929	14,294,628
Estimate of Fair Value Measurement
ASSETS
Loans Receivable, Fair Value Disclosure	[1]	17,551,952	13,213,596
Deposits [Member]
LIABILITIES
Time certificates of deposits (f)	[2]	16,875,881	12,558,632
Accrued Liabilities, Fair Value Disclosure	[2]	16,875,881	12,558,632
Time certificates of deposits (f)
LIABILITIES
Time certificates of deposits (f)	[3]	3,419,988	2,747,346
Accrued Liabilities, Fair Value Disclosure	[3]	3,414,295	2,739,606
Federal Home Loan Bank and other borrowings (f)
LIABILITIES
Federal Home Loan Bank and other borrowings (f)	[3]	416,240	638,514
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[3]	404,268	638,489
Junior subordinated debentures (g)
LIABILITIES
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	[4]	62,862	62,860
Accrued Liabilities, Fair Value Disclosure	[4]	62,416	61,661
Subordinated debentures (f)
LIABILITIES
Subordinated Debt	[3]	296,275
Accrued Liabilities, Fair Value Disclosure	[3]	313,553
Significant Other Observable Inputs (Level 2) | Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	16,875,881	12,558,632
Significant Other Observable Inputs (Level 2) | Time certificates of deposits (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	3,414,295	2,739,606
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank and other borrowings (f)
LIABILITIES
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[3]	404,268	638,489
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures (g)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[4]	62,416	61,661
Significant Unobservable Inputs (Level 3) | Estimate of Fair Value Measurement
ASSETS
Loans Receivable, Fair Value Disclosure	[1]	17,551,952	13,213,596
Significant Unobservable Inputs (Level 3) | Subordinated debentures (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	313,553
U.S. treasury securities
ASSETS
Debt Securities, Held-to-maturity	[5]	100,851	100,791
Held to Maturity, Fair Value, Total	[5]	96,324	93,022
U.S. treasury securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[5]	96,324	93,022
Agency mortgage-backed securities
ASSETS
Debt Securities, Held-to-maturity	[5]	759,083	788,470
Held to Maturity, Fair Value, Total	[5]	719,230	726,362
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[5]	719,230	726,362
Agency collateralized mortgage obligations
ASSETS
Debt Securities, Held-to-maturity	[5]	382,615	422,827
Held to Maturity, Fair Value, Total	[5]	334,666	357,684
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[5]	334,666	357,684
Small Business Administration Pooled Securities [Member]
ASSETS
Debt Securities, Held-to-maturity	[5]	115,068	122,868
Held to Maturity, Fair Value, Total	[5]	110,532	114,733
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[5]	110,532	114,733
Investment in Federal Home Loan Bank Stock [Member]
ASSETS
Federal Home Loan Bank Stock	[6]	21,835	31,573
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	21,835	31,573
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	21,835	31,573
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	0
Cash Surrender Value [Member]
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	376,163	303,965
Bank Owned Life Insurance	[7]	376,163	303,965
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	$ 376,163	$ 303,965

[1] Fair value of loans is measured using the exit price valuation method, determined primarily by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows, while incorporating liquidity and credit assumptions. Additionally, this amount excludes individually assessed collateral dependent loans, which are deemed to be marked to fair value on a non-recurring basis.

[2] Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date.

[3] Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.

[4] Fair value was determined based upon market prices of securities with similar terms and maturities.

[5] The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis.

[6] Federal Home Loan Bank stock has no quoted market value and is carried at cost; therefore, the carrying amount approximates fair value.

[7] Cash surrender value of life insurance policies is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore, carrying amount approximates fair value.