Fair Value Measurements (Details 2) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
ASSETS
Debt Securities, Held-to-maturity		$ 1,282,441	$ 1,066,818
Held to Maturity, Fair Value, Total		1,210,938	1,064,133
Loans, net of allowance for credit losses (b)		13,435,509	13,440,364
Federal Home Loan Bank Stock		11,407	11,407
Bank Owned Life Insurance		291,192	289,304
LIABILITIES
Federal Home Loan Bank borrowings (f)		25,660	25,667
Long-term Debt	[1]		14,063
Long-term Debt, Fair Value	[1]		13,989
Subordinated Debt		49,814	49,791
Deposits [Member]
LIABILITIES
Time certificates of deposits (f)	[2]	15,364,782	15,385,894
Accrued Liabilities, Fair Value Disclosure	[2]	15,364,782	15,385,894
Time certificates of deposits (f)
LIABILITIES
Time certificates of deposits (f)	[1]	1,398,610	1,531,150
Accrued Liabilities, Fair Value Disclosure	[1]	1,384,450	1,529,857
Federal Home Loan Bank borrowings (f)
LIABILITIES
Federal Home Loan Bank borrowings (f)	[1]	25,660	25,667
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[1]	25,626	25,663
Junior subordinated debentures (g)
LIABILITIES
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	[3]	62,854	62,853
Accrued Liabilities, Fair Value Disclosure	[3]	63,654	67,019
Subordinated debentures (f)
LIABILITIES
Subordinated Debt	[1]	49,814	49,791
Accrued Liabilities, Fair Value Disclosure	[1]	43,754	45,532
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term Debt [Member]
LIABILITIES
Long-term Debt, Fair Value	[1]		0
Significant Other Observable Inputs (Level 2) | Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	15,364,782	15,385,894
Significant Other Observable Inputs (Level 2) | Time certificates of deposits (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[1]	1,384,450	1,529,857
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings (f)
LIABILITIES
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[1]	25,626	25,663
Significant Other Observable Inputs (Level 2) | Long-term Debt [Member]
LIABILITIES
Long-term Debt, Fair Value	[1]		13,989
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures (g)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	63,654	67,019
Significant Unobservable Inputs (Level 3) | Long-term Debt [Member]
LIABILITIES
Long-term Debt, Fair Value	[1]		0
Significant Unobservable Inputs (Level 3) | Subordinated debentures (f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[1]	43,754	45,532
U.S. Government agency securities
ASSETS
Debt Securities, Held-to-maturity		32,555	32,987	[4]
Held to Maturity, Fair Value, Total		30,981	32,546	[4]
U.S. Government agency securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total		30,981	32,546	[4]
U.S. treasury securities
ASSETS
Debt Securities, Held-to-maturity	[4]	100,576	102,560
Held to Maturity, Fair Value, Total	[4]	94,596	102,242
U.S. treasury securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	94,596	102,242
Agency mortgage-backed securities
ASSETS
Debt Securities, Held-to-maturity	[4]	550,333	493,012
Held to Maturity, Fair Value, Total	[4]	521,183	497,236
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	521,183	497,236
Agency collateralized mortgage obligations
ASSETS
Debt Securities, Held-to-maturity	[4]	576,964	415,736
Held to Maturity, Fair Value, Total	[4]	542,566	408,845
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	542,566	408,845
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]	1,508	1,508
Single issuer trust preferred securities issued by banks | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	1,508	1,508
Small Business Administration Pooled Securities [Member]
ASSETS
Debt Securities, Held-to-maturity	[4]	20,513	21,023
Held to Maturity, Fair Value, Total	[4]	20,104	21,756
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]	20,104	21,756
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]	13,410,278	13,439,190
Loans Receivable, Fair Value Disclosure	[5]	13,301,406	13,389,515
Loans, net of allowance for credit losses (b) | Significant Unobservable Inputs (Level 3)
ASSETS
Loans Receivable, Fair Value Disclosure	[5]	13,301,406	13,389,515
Investment in Federal Home Loan Bank Stock [Member]
ASSETS
Federal Home Loan Bank Stock	[6]	11,407	11,407
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	11,407	11,407
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]	11,407	11,407
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]	291,192	289,304
Bank Owned Life Insurance	[7]	291,192	289,304
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]	291,192	289,304
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	$ 0	$ 0

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

[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 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] 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.