Derivative Financial Instruments (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Gain on derivative	$ 1.2
Deferred tax asset on gain on derivative	$ 0.3
Cash flow hedge ineffectiveness	Interest rate swap agreements are entered into with counterparties that meet established credit standards and the Corporation believes that the credit risk inherent in these contracts is not significant at December 31, 2019.
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 30.0
Number of interest rate swap contracts \| contract	4
Interest rate swap fair value (asset)	$ (0.1)	$ 1.0
Swap Contract 3 Year 5 Million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5.0
Derivative, maturity date	Jun. 17, 2019
Derivative, term of contract	3 years
Swap Contract 5 Year $5 Million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5.0
Derivative, maturity date	Mar. 17, 2021
Derivative, term of contract	5 years
Swap Contract- 7 year $5 Million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5.0
Derivative, maturity date	Mar. 17, 2023
Derivative, term of contract	7 years
Swap Contract 10 Year $15 Million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 15.0
Derivative, maturity date	Mar. 17, 2026
Derivative, term of contract	10 years

Information on the swap contracts and the number of swaps

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