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Derivative Financial Instruments (Narrative) (Details) $ in Millions | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2016 USD ($) contract | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Derivative [Line Items] |  |  |
Decrease in fair value of derivatives |  | $ 0.9 |
Cash flow hedge ineffectiveness |  | $ 0.2 |
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, 2021. |
Interest Rate Swap Agreements [Member] |  |  |
Derivative [Line Items] |  |  |
Interest rate swap notional amount | $ 30.0 | $ 20.0 |
Number of interest rate swap contracts | contract | 4 |  |
Interest rate swap fair value |  | $ (0.5) | $ (1.3)

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- Definition Fair value, before 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 elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226052-175313 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624163-113959 + Details
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