Fair Values of Financial Instruments, Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Transfers between Levels [Abstract]
Transfers from Level 1 to Level 2	$ 0	$ 0
Transfers from Level 2 to Level 1	4,000	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
AFS securities [Abstract]
AFS Securities	998,496	1,255,925
Equity securities	23,053	0
Trading securities	0	11,467
Liabilities [Abstract]
Loans and Leases Receivable, Collateral Dependent Impaired Loans	200	1,000
Reserves on collateral dependent impaired loans	$ 25	57
Minimum [Member]
Liabilities [Abstract]
Liquidation expense ratio on impaired collateral	10.00%
Maximum [Member]
Liabilities [Abstract]
Liquidation expense ratio on impaired collateral	35.00%
Recurring Basis [Member]
AFS securities [Abstract]
AFS Securities	$ 998,496	1,255,925
Equity securities	23,053
Trading securities		11,467
Derivatives	20,000	3,720
Total	1,041,549	1,271,112
Liabilities [Abstract]
Derivatives	17,572	210
Total	17,572	210
Recurring Basis [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0	5,845
Equity securities	19,053
Trading securities		11,467
Derivatives	0	0
Total	19,053	17,312
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	998,496	1,250,080
Equity securities	4,000
Trading securities		0
Derivatives	20,000	3,720
Total	1,022,496	1,253,800
Liabilities [Abstract]
Derivatives	17,572	210
Total	17,572	210
Recurring Basis [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Equity securities	0
Trading securities		0
Derivatives	0	0
Total	0	0
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] \| Federal Agency [Member]
AFS securities [Abstract]
AFS Securities	84,299	108,899
Recurring Basis [Member] \| Federal Agency [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| Federal Agency [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	84,299	108,899
Recurring Basis [Member] \| Federal Agency [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| State & Municipal [Member]
AFS securities [Abstract]
AFS Securities	29,915	41,956
Recurring Basis [Member] \| State & Municipal [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| State & Municipal [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	29,915	41,956
Recurring Basis [Member] \| State & Municipal [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| Mortgage-Backed [Member]
AFS securities [Abstract]
AFS Securities	512,295	554,927
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	512,295	554,927
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member]
AFS securities [Abstract]
AFS Securities	371,987	535,994
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0	0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	371,987	535,994
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	$ 0	0
Recurring Basis [Member] \| Other Securities [Member]
AFS securities [Abstract]
AFS Securities		14,149
Recurring Basis [Member] \| Other Securities [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities		5,845
Recurring Basis [Member] \| Other Securities [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities		8,304
Recurring Basis [Member] \| Other Securities [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities		$ 0

Collateral dependent impaired loans with specific reserves included in the allowance for loan losses.

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The percentage of liquidation expenses estimated with liquidating impaired collateral.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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Fair value of financial and nonfinancial obligations.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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