Fair Value Measurements (Details 1) - USD ($) $ in Thousands		Jun. 30, 2026	Dec. 31, 2025
ASSETS
Trading		$ 4,835	$ 4,720
Equity		21,602	21,581
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value		1,117,644	1,190,733
Federal Home Loan Bank Stock		13,631	21,835
Bank Owned Life Insurance		381,230	378,576
Federal Home Loan Bank and other borrowings (f)		216,719	416,549
Deposits [Member]
LIABILITIES
Financial Liabilities Book Value	[1]	17,142,663	16,858,570
Accrued Liabilities, Fair Value Disclosure	[1]	17,142,663	16,858,570
Bank Time Deposits [Member]
LIABILITIES
Financial Liabilities Book Value	[2]	3,249,455	3,268,220
Accrued Liabilities, Fair Value Disclosure	[2]	3,241,759	3,262,605
Federal Home Loan Bank Advances [Member]
LIABILITIES
Federal Home Loan Bank and other borrowings (f)	[2]	216,719	416,549
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	217,510	417,352
Junior Subordinated Debt [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	62,689	62,492
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	[3]	62,864	62,862
Reported Value Measurement
LIABILITIES
Loans Receivable, Fair Value Disclosure	[4]	18,127,775	18,234,032
Estimate of Fair Value Measurement
LIABILITIES
Loans Receivable, Fair Value Disclosure	[4]	17,770,945	17,842,036
Agency mortgage-backed securities
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value		615,058	659,415
Small Business Administration Pooled Securities [Member]
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value		102,010	108,396
US Treasury Securities [Member]
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value		97,503	97,124
Recurring fair value measurements
ASSETS
Trading		4,835	4,720
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS		2,115,668	2,058,622
Recurring fair value measurements | Equity Securities [Member]
ASSETS
Equity		21,602	21,581
Recurring fair value measurements | U.S. government agency securities
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		218,788	218,672
Recurring fair value measurements | Agency mortgage-backed securities
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		961,809	772,963
Recurring fair value measurements | Agency collateralized mortgage obligations
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		251,529	269,576
Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		228,801	233,078
Recurring fair value measurements | Pooled trust preferred securities issued by banks and insurers
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		966	1,042
Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		34,904	37,832
Recurring fair value measurements | Loans held for sale
ASSETS
Loans Held-for-sale, Fair Value Disclosure		21,982	35,909
Recurring fair value measurements | Derivative Financial Instruments, Assets [Member]
ASSETS
Derivative Asset, Fair Value, Gross Asset		56,600	60,130
Recurring fair value measurements | Derivative instruments
LIABILITIES
Financial and Nonfinancial Liabilities, Fair Value Disclosure		65,323	67,965
Recurring fair value measurements | US Treasury Securities [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		379,175	471,084
Non-recurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS		70,859	81,968
Non-recurring fair value measurements | Collateral Dependent Loans [Member]
ASSETS
Assets, Fair Value Disclosure	[5]	70,653	79,868
Non-recurring fair value measurements | Other Real Estate Owned and Other Foreclosed Assets
ASSETS
Assets, Fair Value Disclosure	[5]	206	2,100
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements
ASSETS
Trading		4,835	4,720
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS		26,437	26,301
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Equity Securities [Member]
ASSETS
Equity		21,602	21,581
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements | Collateral Dependent Loans [Member]
ASSETS
Assets, Fair Value Disclosure		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements | Other Real Estate Owned and Other Foreclosed Assets
ASSETS
Assets, Fair Value Disclosure		0	0
Significant Other Observable Inputs (Level 2) | Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[1]	17,142,663	16,858,570
Significant Other Observable Inputs (Level 2) | Bank Time Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	3,241,759	3,262,605
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank Advances [Member]
LIABILITIES
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	217,510	417,352
Significant Other Observable Inputs (Level 2) | Junior Subordinated Debt [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	62,689	62,492
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS		2,089,231	2,032,321
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. government agency securities
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		218,788	218,672
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Agency mortgage-backed securities
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		961,809	772,963
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Agency collateralized mortgage obligations
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		251,529	269,576
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		228,801	233,078
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Pooled trust preferred securities issued by banks and insurers
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		966	1,042
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		34,904	37,832
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Loans held for sale
ASSETS
Loans Held-for-sale, Fair Value Disclosure		21,982	35,909
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Derivative Financial Instruments, Assets [Member]
ASSETS
Derivative Asset, Fair Value, Gross Asset		56,600	60,130
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Derivative instruments
LIABILITIES
Financial and Nonfinancial Liabilities, Fair Value Disclosure		65,323	67,965
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | US Treasury Securities [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		379,175	471,084
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS		0	0
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements | Collateral Dependent Loans [Member]
ASSETS
Assets, Fair Value Disclosure		0
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements | Other Real Estate Owned and Other Foreclosed Assets
ASSETS
Assets, Fair Value Disclosure		0	0
Significant Unobservable Inputs (Level 3) | Estimate of Fair Value Measurement
LIABILITIES
Loans Receivable, Fair Value Disclosure	[4]	17,770,945	17,842,036
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS		0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale (amortized cost $2,146,923 and $2,051,822)		0
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS		70,859	81,968
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements | Collateral Dependent Loans [Member]
ASSETS
Assets, Fair Value Disclosure	[5]	70,653	79,868
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements | Other Real Estate Owned and Other Foreclosed Assets
ASSETS
Assets, Fair Value Disclosure	[5]	206	2,100
US Treasury Securities [Member]
LIABILITIES
Debt Securities, Held-to-maturity	[6]	100,911	100,872
Debt Securities, Held-to-maturity, Fair Value	[6]	97,503	97,124
US Treasury Securities [Member] | Significant Other Observable Inputs (Level 2)
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value	[6]	97,503	97,124
Agency mortgage-backed securities
LIABILITIES
Debt Securities, Held-to-maturity	[6]	653,630	694,903
Debt Securities, Held-to-maturity, Fair Value	[6]	615,058	659,415
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2)
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value	[6]	615,058	659,415
Agency collateralized mortgage obligations
LIABILITIES
Debt Securities, Held-to-maturity	[6]	348,671	370,698
Debt Securities, Held-to-maturity, Fair Value	[6]	303,073	325,798
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value	[6]	303,073	325,798
Small Business Administration Pooled Securities [Member]
LIABILITIES
Debt Securities, Held-to-maturity	[6]	107,098	112,554
Debt Securities, Held-to-maturity, Fair Value	[6]	102,010	108,396
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2)
LIABILITIES
Debt Securities, Held-to-maturity, Fair Value	[6]	102,010	108,396
Investment in Federal Home Loan Bank Stock [Member]
LIABILITIES
Federal Home Loan Bank Stock	[7]	13,631	21,835
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[7]	13,631	21,835
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2)
LIABILITIES
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[7]	13,631	21,835
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3)
LIABILITIES
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[7]	0
Cash Surrender Value [Member]
LIABILITIES
Bank Owned Life Insurance	[8]	381,230	378,576
Cash Surrender Value, Fair Value Disclosure	[8]	381,230	378,576
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2)
LIABILITIES
Cash Surrender Value, Fair Value Disclosure	[8]	$ 381,230	$ 378,576

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

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

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

[4] 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.

[5] The carrying value of individually assessed collateral dependent loans is based on the lower of amortized cost or fair value of the underlying collateral less costs to sell. The fair value of the underlying collateral is generally determined through independent appraisals, which generally include various Level 3 inputs which are not identifiable. Appraisals may be adjusted by management for qualitative factors such as economic factors and estimated liquidation expenses. The range of these possible adjustments may vary.

[6] 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.

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

[8] 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.