The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
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The current portion of money or property received from customers which is either to be returned upon satisfactory contract completion or applied to customer receivables in accordance with the terms of the contract or the understandings.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Average contractual rate at which a foreign currency can be purchased or sold.

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Aggregate net fair value of all derivative instruments designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-SubTopic 10
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The percentage of expected requirements covered by the aggregate notional amount of derivative contracts expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract as a percentage of expected need.

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The net gain (loss) recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

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-Name Accounting Standards Codification
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The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

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Derivatives, Hedging Programs and Other Financial Instruments, Narrative (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Debt Instrument, Term		12 months
Derivative Instruments in Hedges, at Fair Value, Net	$ 7,600,000	$ 7,600,000				$ 4,000,000
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months		100,000
Aggregate fair value of derivative instruments that contain credit-risk-related contingency features that were in a net liability position	400,000	400,000				100,000
Margin Deposit Assets	0	0				$ 0
Customer Deposits, Current	0	0
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	$ 0	$ 0
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument \| Purchase
Derivative [Line Items]
Derivative, Average Forward Exchange Rate	1.12	1.12
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument \| Purchase
Derivative [Line Items]
Derivative, Average Forward Exchange Rate	1.08	1.08
Scenario, Forecast [Member] \| Natural Gas Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage			71.00%	71.00%	73.00%
Scenario, Forecast [Member] \| Electricity Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage			54.00%	54.00%	54.00%