Fair value disclosure only table (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	$ 611,490	$ 497,688
Loans and Leases Receivable, Net Amount	6,841,901	6,294,910
Securities held to maturity, fair value	603,640	494,194
Federal Home Loan Bank Stock	15,683	11,597
Bank Owned Life Insurance	160,456	151,528
Liabilities, Fair Value Disclosure [Abstract]
Advances from Federal Home Loan Banks	147,806	53,264
Junior subordinated debentures	76,173	73,073
Subordinated Debt	34,728	34,682
Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Financial Liabilities Book Value	6,716,017	6,084,952
Accrued Liabilities, Fair Value Disclosure	6,716,017	6,084,952
Bank Time Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Financial Liabilities Book Value	711,103	644,301
Accrued Liabilities, Fair Value Disclosure	703,728	639,060
Federal Home Loan Bank Advances [Member]
Liabilities, Fair Value Disclosure [Abstract]
Advances from Federal Home Loan Banks	147,806	53,264
Federal Home Loan Bank Borrowings, Fair Value Disclosure	147,603	52,111
Customer Repurchase Agreements [Member]
Liabilities, Fair Value Disclosure [Abstract]
Customer Repurchase Agreements and other short-term borrowings		162,679
Accrued Liabilities, Fair Value Disclosure		162,679
Junior Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Junior subordinated debentures	76,173	73,073
Accrued Liabilities, Fair Value Disclosure	73,827	74,680
Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Subordinated Debt	34,728	34,682
Accrued Liabilities, Fair Value Disclosure	32,509	32,707
Significant Other Observable Inputs (Level 2) [Member] \| Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	6,716,017	6,084,952
Significant Other Observable Inputs (Level 2) [Member] \| Bank Time Deposits [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	703,728	639,060
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	147,603
Accrued Liabilities, Fair Value Disclosure		52,111
Significant Other Observable Inputs (Level 2) [Member] \| Junior Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	73,827	74,680
Significant Unobservable Inputs (Level 3) [Member] \| Customer Repurchase Agreements [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure		162,679
Significant Unobservable Inputs (Level 3) [Member] \| Subordinated Debt [Member]
Liabilities, Fair Value Disclosure [Abstract]
Accrued Liabilities, Fair Value Disclosure	32,509	32,707
US Treasury Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	1,004	1,006
Securities held to maturity, fair value	1,015	1,035
US Treasury Securities [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	1,015	1,035
Agency mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	252,484	204,768
Securities held to maturity, fair value	250,928	205,823
Agency mortgage-backed securities \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	250,928	205,823
Agency collateralized mortgage obligations
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	332,775	262,998
Securities held to maturity, fair value	326,724	258,408
Agency collateralized mortgage obligations \| Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Securities held to maturity, fair value	326,724	258,408
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	1,529
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	1,529
Small Business Administration Pooled Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Debt Securities, Held-to-maturity	23,727	27,416
Securities held to maturity, fair value	23,483	27,399
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	23,483	27,399
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	6,812,792	6,261,343
Loans, net of allowance for loan losses	6,635,209	6,116,051
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	6,635,209	6,116,051
Investment in Federal Home Loan Bank Stock [Member]
Assets, Fair Value Disclosure [Abstract]
Federal Home Loan Bank Stock	15,683	11,597
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	15,683	11,597
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	15,683	11,597
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	160,456	151,528
Cash Surrender Value, Fair Value Disclosure	160,456	151,528
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	160,456	151,528
Cash Surrender Value [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Surrender Value, Fair Value Disclosure	$ 0	$ 0

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Financial liabilities book value.

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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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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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