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Derivative Instruments (Narrative) (Details)	1 Months Ended		3 Months Ended			6 Months Ended		12 Months Ended
	Feb. 28, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Derivative
Debt Instrument, Interest Rate, Effective Percentage		5.10%	4.20%			4.20%		5.10%
Amount of derivaitve cash flow hedge to be repcognized in the next 12 months						$ 2,400,000	$ 5,700,000
Repayments of Secured Debt						200,000,000	100,028,000
Amortization of Debt Issuance Costs			$ 1,337,000		$ 1,031,000	5,368,000	2,062,000
Separated Host Financial Instrument, Fair Value Option
Derivative
Derivative liability fair value			8,500,000			8,500,000
Not Designated as Hedging Instrument
Derivative
Derivative liability fair value		$ 1,063,000	272,000			272,000		$ 1,063,000
Other long-term obligations | Separated Host Financial Instrument, Fair Value Option
Derivative
Derivative liability fair value			5,700,000			5,700,000
Other accrued liabilities | Separated Host Financial Instrument, Fair Value Option
Derivative
Derivative liability fair value			2,800,000			2,800,000
2018 Credit Agreement | Term Loan Facility
Derivative
Repayments of Secured Debt		$ 500,000,000	50,000,000.0			200,000,000
Amortization of Debt Issuance Costs	$ 900,000		$ 300,000			$ 1,200,000
Foreign currency derivatives
Derivative
Derivative, notional amount		71,000,000.0	80,500,000			80,500,000		71,000,000.0
Commodity derivative contracts
Derivative
Derivative, notional amount		61,300,000	38,400,000			38,400,000		61,300,000
Unrealized (loss) gain in other comprehensive income						$ 12,800,000		$ 2,200,000
Derivative Instruments Not Designated as Hedging Instruments, Loss						900,000
Commodity derivative contracts | Not Designated as Hedging Instrument | Interest expense
Derivative
Derivative, Gain (Loss) on Derivative, Net						(242,000)	(114,000)
Commodity derivative contracts | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative liability fair value		$ 13,769,000	$ 844,000			844,000		13,769,000
Commodity derivative contracts | Other long-term obligations | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative liability fair value		1,898,000	0			0		1,898,000
Commodity derivative contracts | Other accrued liabilities | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative liability fair value		888,000	0			0		888,000
Interest rate swap contract
Derivative
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent				$ 11,000,000.0		1,900,000
Derivative, Notional Amount					500,000,000		500,000,000
Interest rate swap contract | Designated as Hedging Instrument | Interest expense
Derivative
Derivative, Gain (Loss) on Derivative, Net			289,000		1,521,000	1,285,000	1,315,000
Interest rate swap contract | Not Designated as Hedging Instrument | Interest expense
Derivative
Derivative, Gain (Loss) on Derivative, Net						866,000	0
Interest rate swap contract | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount		250,000,000						250,000,000
Interest rate swap contract | Other long-term obligations | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative liability fair value		6,903,000	0			0		6,903,000
Interest rate swap contract | Other accrued liabilities | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative liability fair value		$ 4,080,000	844,000			844,000		$ 4,080,000
Interest rate swap contract 2
Derivative
Derivative, Notional Amount					$ 500,000,000		$ 500,000,000
Interest Rate Swap Four
Derivative
Derivative, Notional Amount			$ 250,000,000			$ 250,000,000
Scenario, Plan
Derivative
Debt Instrument, Interest Rate, Effective Percentage		4.85%	3.95%			3.95%		4.85%

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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