Fair Value Measurements (Details 2) - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
ASSETS
Held to Maturity, Fair Value, Total		$ 1,384,430	$ 1,524,710
Federal Home Loan Bank Stock		43,878	5,218
Bank Owned Life Insurance		295,670	293,323
LIABILITIES
Federal Home Loan Bank borrowings (f)		887,548	637
Subordinated Debt		49,957	49,885
Deposits [Member]
LIABILITIES
Time certificates of deposits (f)	[1]	13,046,763	14,683,266
Accrued Liabilities, Fair Value Disclosure	[1]	13,046,763	14,683,266
Time certificates of deposits (f)
LIABILITIES
Time certificates of deposits (f)	[2]	2,012,763	1,195,741
Accrued Liabilities, Fair Value Disclosure	[2]	1,990,899	1,164,892
Federal Home Loan Bank borrowings (f)
LIABILITIES
Federal Home Loan Bank borrowings (f)	[2]	887,548	637
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	886,799	563
Junior subordinated debentures (g)
LIABILITIES
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	[3]	62,857	62,855
Accrued Liabilities, Fair Value Disclosure	[3]	57,347	60,002
Subordinated debentures (f)
LIABILITIES
Subordinated Debt	[2]	49,957	49,885
Accrued Liabilities, Fair Value Disclosure	[2]	45,990	45,891
Significant Other Observable Inputs (Level 2) | Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[1]	13,046,763	14,683,266
Significant Other Observable Inputs (Level 2) | Time certificates of deposits (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	1,990,899	1,164,892
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings (f)
LIABILITIES
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	886,799	563
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures (g)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	57,347	60,002
Significant Unobservable Inputs (Level 3) | Subordinated debentures (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	45,990	45,891
U.S. Government agency securities
ASSETS
Debt Securities, Held-to-maturity		29,961	31,258	[4]
Held to Maturity, Fair Value, Total		28,342	29,036	[4]
U.S. Government agency securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total		28,342	29,036	[4]
U.S. treasury securities
ASSETS
Debt Securities, Held-to-maturity	[4]	100,693	100,634
Held to Maturity, Fair Value, Total	[4]	88,331	88,879
U.S. treasury securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	88,331	88,879
Agency mortgage-backed securities
ASSETS
Debt Securities, Held-to-maturity	[4]	839,945	898,927
Held to Maturity, Fair Value, Total	[4]	741,995	815,952
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	741,995	815,952
Agency collateralized mortgage obligations
ASSETS
Debt Securities, Held-to-maturity	[4]	490,011	535,971
Held to Maturity, Fair Value, Total	[4]	404,144	458,417
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	404,144	458,417
Single issuer trust preferred securities issued by banks
ASSETS
Debt Securities, Held-to-maturity	[4]	1,500	1,500
Held to Maturity, Fair Value, Total	[4]	1,335	1,508
Single issuer trust preferred securities issued by banks | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	1,335	1,508
Small Business Administration Pooled Securities [Member]
ASSETS
Debt Securities, Held-to-maturity	[4]	132,169	136,830
Held to Maturity, Fair Value, Total	[4]	120,283	130,918
Small Business Administration Pooled Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Held to Maturity, Fair Value, Total	[4]	0	0
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	120,283	130,918
Small Business Administration Pooled Securities [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Held to Maturity, Fair Value, Total	[4]	0	0
Loans, net of allowance for credit losses (b)
ASSETS
Loans, net of allowance for credit losses (b)	[5]	14,071,675	13,760,164
Loans Receivable, Fair Value Disclosure	[5]	13,102,058	13,260,873
Loans, net of allowance for credit losses (b) | Significant Unobservable Inputs (Level 3)
ASSETS
Loans Receivable, Fair Value Disclosure	[5]	13,102,058	13,260,873
Investment in Federal Home Loan Bank Stock [Member]
ASSETS
Federal Home Loan Bank Stock	[6]	43,878	5,218
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	43,878	5,218
Investment in Federal Home Loan Bank Stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	0	0
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]	43,878	5,218
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	0
Cash Surrender Value [Member]
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	295,670	293,323
Bank Owned Life Insurance	[7]	295,670	293,323
Cash Surrender Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	0	0
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	295,670	293,323
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	$ 0	$ 0

[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] 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.

[5] 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 nonrecurring basis.

[6] FHLB 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.