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Fair Value Measurements (Narrative) (Details) € in Millions, gal in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) Swap $ / gal € / shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) Swap $ / gal € / shares gal	Sep. 30, 2023 USD ($)	Sep. 30, 2024 EUR (€) Swap $ / gal € / shares	Dec. 31, 2023 USD ($)
Fair Value, Inputs, Level 1 [Member]
Derivatives Fair Value [Line Items]
Fair value of debt	$ 302,100		$ 302,100
Fuel Hedge Contracts [Member]
Derivatives Fair Value [Line Items]
Derivative underlying hedge percent			80.00%
Derivative, nonmonetary notional amount, volume | gal			9.1
Reclassification of derivative gain (losses) to earnings net of tax	(644,000)	$ 297,000	$ (882,000)	$ (1,507,000)
Fair value hedge liabilities	$ 3,500		$ 3,500			$ 2,900
Fuel Hedge Contracts [Member] | Minimum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | $ / gal	2.35		2.35		2.35
Fuel Hedge Contracts [Member] | Maximum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | $ / gal	2.9		2.9		2.9
Foreign Currency Exchange Hedge Contracts [Member]
Derivatives Fair Value [Line Items]
Fair value hedge assets	$ 21,000		$ 21,000			$ 358,000
Reclassification of derivative gain (losses) to earnings net of tax		$ 198,000	$ (42,000)	$ 519,000
Derivative notional amount | €					€ 2.9
Foreign Currency Exchange Hedge Contracts [Member] | Minimum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | € / shares	1.11		1.11		1.11
Foreign Currency Exchange Hedge Contracts [Member] | Maximum [Member]
Derivatives Fair Value [Line Items]
Fixed price range | € / shares	1.13		1.13		1.13
Interest Rate Swaps [Member]
Derivatives Fair Value [Line Items]
Reclassification of derivative gain (losses) to earnings net of tax	$ 112,000		$ 112,000
Derivative notional amount	75,000,000		75,000,000
Fair value hedge liabilities	$ 536,000		$ 536,000
Derivative, maturity date			Aug. 24, 2026
Number of interest rate swaps | Swap	2		2		2

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