Fair value disclosure only table (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	$ 740,806	$ 611,490
Loans and Leases Receivable, Net Amount	8,805,899	6,841,901
Securities held to maturity, fair value	753,263	603,640
Federal Home Loan Bank Stock	14,424	15,683
Bank Owned Life Insurance	197,372	160,456
Liabilities, Fair Value Disclosure [Abstract]
Advances from Federal Home Loan Banks	115,748	147,806
Junior subordinated debentures (less unamortized debt issuance costs of $40 and $118)	62,848	76,173
Subordinated Debt	49,601	34,728
Long-term Debt	74,906	0
Long-term Debt, Fair Value	72,219
Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Financial Liabilities Book Value	7,752,052	6,716,017
Accrued Liabilities, Fair Value Disclosure	7,752,052	6,716,017
Bank Time Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Financial Liabilities Book Value	1,395,315	711,103
Accrued Liabilities, Fair Value Disclosure	1,396,760	703,728
Federal Home Loan Bank Advances [Member]
Liabilities, Fair Value Disclosure [Abstract]
Advances from Federal Home Loan Banks	115,748	147,806
Federal Home Loan Bank Borrowings, Fair Value Disclosure	115,881	147,603
Junior Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Junior subordinated debentures (less unamortized debt issuance costs of $40 and $118)	62,848	76,173
Accrued Liabilities, Fair Value Disclosure	65,603	73,827
Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Subordinated Debt	49,601	34,728
Accrued Liabilities, Fair Value Disclosure	52,870	32,509
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Long-term Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Long-term Debt, Fair Value	0
Significant Other Observable Inputs (Level 2) [Member] \| Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	7,752,052	6,716,017
Significant Other Observable Inputs (Level 2) [Member] \| Bank Time Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	1,396,760	703,728
Significant Other Observable Inputs (Level 2) [Member] \| Federal Home Loan Bank Advances [Member]
Liabilities, Fair Value Disclosure [Abstract]
Federal Home Loan Bank Borrowings, Fair Value Disclosure	115,881
Accrued Liabilities, Fair Value Disclosure		147,603
Significant Other Observable Inputs (Level 2) [Member] \| Junior Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	65,603	73,827
Significant Other Observable Inputs (Level 2) [Member] \| Long-term Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Long-term Debt, Fair Value	72,219
Significant Unobservable Inputs (Level 3) [Member] \| Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	52,870	32,509
Significant Unobservable Inputs (Level 3) [Member] \| Long-term Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Long-term Debt, Fair Value	0
US Government Agencies Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	12,874
Securities held to maturity, fair value	12,997
US Government Agencies Debt Securities [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	12,997
US Treasury Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	4,032	1,004
Securities held to maturity, fair value	4,053	1,015
US Treasury Securities [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	4,053	1,015
Agency mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	397,414	252,484
Securities held to maturity, fair value	405,802	250,928
Agency mortgage-backed securities \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	405,802	250,928
Agency collateralized mortgage obligations
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	293,662	332,775
Securities held to maturity, fair value	297,314	326,724
Agency collateralized mortgage obligations \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	297,314	326,724
Single issuer trust preferred securities issued by banks and insurers
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	1,500	1,500
Securities held to maturity, fair value	1,490	1,490
Single issuer trust preferred securities issued by banks and insurers \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	1,490	1,490
Small Business Administration Pooled Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	31,324	23,727
Securities held to maturity, fair value	31,607	23,483
Small Business Administration Pooled Securities [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	0	0
Small Business Administration Pooled Securities [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	31,607	23,483
Small Business Administration Pooled Securities [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	0	0
Loans Net Of Allowance For Loan Loses [Member]
Assets, Fair Value Disclosure [Abstract]
Loans and Leases Receivable, Net Amount	8,780,384	6,812,792
Loans, net of allowance for loan losses	8,613,635	6,635,209
Loans Net Of Allowance For Loan Loses [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Loans, net of allowance for loan losses	8,613,635	6,635,209
Investment in Federal Home Loan Bank Stock [Member]
Assets, Fair Value Disclosure [Abstract]
Federal Home Loan Bank Stock	14,424	15,683
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	14,424	15,683
Investment in Federal Home Loan Bank Stock [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	0	0
Investment in Federal Home Loan Bank Stock [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	14,424	15,683
Investment in Federal Home Loan Bank Stock [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	0	0
Cash Surrender Value [Member]
Assets, Fair Value Disclosure [Abstract]
Bank Owned Life Insurance	197,372	160,456
Cash Surrender Value, Fair Value Disclosure	197,372	160,456
Cash Surrender Value [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Surrender Value, Fair Value Disclosure	0	0
Cash Surrender Value [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Surrender Value, Fair Value Disclosure	197,372	160,456
Cash Surrender Value [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Surrender Value, Fair Value Disclosure	$ 0	$ 0

Financial liabilities book value.

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Fair value portion of accrued expenses.

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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