Long-Term Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Apr. 30, 2021
Debt Instrument [Line Items]
Less: Unamortized Debt Issuance Costs	$ (1,567)	$ (1,686)
Principal amount	183,386	183,520
Less: amounts due in one year	(1,438)	(1,635)
Long-Term Debt	181,948	181,885
MEDCO Revenue Bonds in Series Due September 2025 at 5.75%
Debt Instrument [Line Items]
Long-term debt, gross	$ 102,865	$ 102,865
Stated interest rate percentage	5.75%	5.75%
PEDFA Solid Waste Disposal Revenue Bonds
Debt Instrument [Line Items]
Long-term debt, gross	$ 75,000	$ 75,000
Stated interest rate percentage	9.00%	9.00%	9.00%
Advance Royalty Commitments
Debt Instrument [Line Items]
Long-term debt, gross	$ 5,922	$ 5,922
Weighted average interest rate	8.80%	8.80%
Other Debt Arrangements
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,166	$ 1,419
Loans Payable \| Revolving Credit Facility
Debt Instrument [Line Items]
Finance lease, liability, current	$ 7,111	$ 9,471

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Present value of lessee's discounted obligation for lease payments from finance lease, classified as current.

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Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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